ECE 3400 Intelligent Physical Systems
Transcript of ECE 3400 Intelligent Physical Systems
1
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Actuators
ECE 3400 Intelligent Physical Systems
bull What is itbull How does it workbull How do your characterize thembull Gearsbull Sizing thembull Driving them
ActuatorsA device that converts energy into mechanical motion
bull Electricbull Mechanicalbull Hydraulicbull Pneumatic
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybrid
A device that converts energy into mechanical motion
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermal
A device that converts energy into mechanical motion
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermalbull hellipanything goes
A device that converts energy into mechanical motion
ActuatorsBrushed DC motors
Brushed DC motor
PHYS 2213 ElectromagnetismECE 3030 Electromagnetic fields and waves
Brushed DC motor
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
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ActuatorsA device that converts energy into mechanical motion
bull Electricbull Mechanicalbull Hydraulicbull Pneumatic
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybrid
A device that converts energy into mechanical motion
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermal
A device that converts energy into mechanical motion
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermalbull hellipanything goes
A device that converts energy into mechanical motion
ActuatorsBrushed DC motors
Brushed DC motor
PHYS 2213 ElectromagnetismECE 3030 Electromagnetic fields and waves
Brushed DC motor
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
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- Slide Number 2
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- Slide Number 32
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- Slide Number 35
-
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybrid
A device that converts energy into mechanical motion
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermal
A device that converts energy into mechanical motion
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermalbull hellipanything goes
A device that converts energy into mechanical motion
ActuatorsBrushed DC motors
Brushed DC motor
PHYS 2213 ElectromagnetismECE 3030 Electromagnetic fields and waves
Brushed DC motor
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
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- Slide Number 28
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- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermal
A device that converts energy into mechanical motion
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermalbull hellipanything goes
A device that converts energy into mechanical motion
ActuatorsBrushed DC motors
Brushed DC motor
PHYS 2213 ElectromagnetismECE 3030 Electromagnetic fields and waves
Brushed DC motor
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
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- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Actuators
bull Electricbull Mechanicalbull Hydraulicbull Pneumaticbull Bio-hybridbull Magneticbull Light-drivenbull Thermalbull hellipanything goes
A device that converts energy into mechanical motion
ActuatorsBrushed DC motors
Brushed DC motor
PHYS 2213 ElectromagnetismECE 3030 Electromagnetic fields and waves
Brushed DC motor
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
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- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
ActuatorsBrushed DC motors
Brushed DC motor
PHYS 2213 ElectromagnetismECE 3030 Electromagnetic fields and waves
Brushed DC motor
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motor
PHYS 2213 ElectromagnetismECE 3030 Electromagnetic fields and waves
Brushed DC motor
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motor
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motorbull Amperersquos Right Hand Rule
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motor
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motor
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motor
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
bull What is torque
Brushed DC motor characterization
Torque [Nm]
Speed [rpm]
free-running current
Stall current
vmotor = 6V
vmotor = 45V
vmotor = 3V
τ = F ∙ a
Stall torque
free-running speed
Pmotor = τmotor vmotor[kW] = [Nm] [rpm]
a
m
F = m ∙ gbull What happens if you turn
down the voltage
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Brushed DC motorbull Advantages
bull Easy to controlbull Inexpensive
bull Disadvantagesbull Brushes suffer from wearbull Not very energy efficient
bull Standard motors are fast and weakbull What is done to decrease the speed
bull Gear trains
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Gear Trains
Helical gears Transmit power between parallel and non-parallel shafts (less noise)
Spur gears Transmit power between parallel shafts
Bevel gears Transmit rotary motion between intersecting shafts
Worm gears Used for very high gear ratios
Linear gears Rotary to linear motion
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Gear Trains
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
N1 = 30
N2 = 20
Gear Trains
Drive gear(motor)
Driven gear
What is the gear ratio
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Gear Trains
N1 = 30
N2 = 20
1199071199072 = 1199071199071 11987311987311198731198732
What is the gear ratio
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Gear Trains
1199071199073 = 1199071199071 11987311987311198731198733
3
21
What is the gear ratio
1199071199073 = 1199071199071 11987311987311198731198732
11987311987321198731198733
real gears have loss - rule of thumb gears loose ~10 per contact point
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
(It will take the robot ~70ms to reach top speed)
Sizing your DC motor Datasheetbull Speed 0-50RPMbull 38 oz-in torque 6 V
bull What is torque
τ = F ∙ a
a
m
F = m ∙ g
bull τstall = 38 oz-in = 234 kg-cmbull Wheel diameter = 2rdquo rarr rwheel = 254cmbull The ldquoforcerdquo that the motor can apply is
bull mforce = τstall rwheel = 234kgcm 254cm = 921 gbull (if you used the wheel as a winch it could lift a weight of 921g before stalling)
bull vno-load = 50RPMbull One round corresponds to the wheel circumference Cwheel = 254cm2π = 16cmbull Without a load vrobot-top_speed = Cwheel vno-load = 800cmmin = 13cmsbull What about the accelerationbull Constant max torque 234kg-cm and a robot weight of 05kg
bull F = mforce g bull What does that mean
rarr a = 0921kg0500kg 982ms2 = 18ms2= mrobot a
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Sizing your DC motorbull Except that is not truehellipbull What slows the robot down
bull NEVER size your motor for stall torquebull (Itrsquos okay to overcome static friction but donrsquot do it continuously)
bull Friction in the bearingsbull Friction between wheel and groundbull Aerodynamics (probably not)bull Turning off axisbull Imperfect wheel balancebull hellipthe motor has to overcome all of this
bull So how could you estimate how much power is neededbull Example How much weight at the end of a pulley does it take to move your robot
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Sizing your DC motor
Torque
Speed [rpm]
50RPM Pmotor = τmotor vmotor[kW] = [Nm] [rpm]vmotor = 5V
vmotor = 6V
234kg-cmtorque caused by robot weight friction etc
Robot speed
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Driving a DC motor
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Driving a DC motor
bull Analog voltagebull Why is this circuit
not enough
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
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- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
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Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
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- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
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- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Driving a DC motor
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
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- Slide Number 19
- Slide Number 20
- Slide Number 21
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- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Driving a DC motor
bull Electromotive Force (EMF)
ldquoMotorrdquo
bull Analog voltagebull H-Bridge
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
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- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
Driving a DC motor
bull Electromotive Force (EMF)
bull Analog voltagebull H-Bridge
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
- Slide Number 6
- Slide Number 7
- Slide Number 8
- Slide Number 9
- Slide Number 10
- Slide Number 11
- Slide Number 12
- Slide Number 13
- Slide Number 14
- Slide Number 15
- Slide Number 16
- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
-
- Slide Number 1
- Slide Number 2
- Slide Number 3
- Slide Number 4
- Slide Number 5
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- Slide Number 11
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- Slide Number 17
- Slide Number 19
- Slide Number 20
- Slide Number 21
- Slide Number 22
- Slide Number 23
- Slide Number 24
- Slide Number 25
- Slide Number 26
- Slide Number 27
- Slide Number 28
- Slide Number 29
- Slide Number 30
- Slide Number 31
- Slide Number 32
- Slide Number 33
- Slide Number 34
- Slide Number 35
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