TigerBot IVRochester Institute of Technology
Group MembersMike Lew (ISE)Dan Wiatroski (ME)Tom Whitmore (ME)Geoff Herman (ME)Sean Lillis (CE)Brian Stevenson (EE)James O’Donoghue (CE)Mohammad Arefin (EE)Sasha Yevstifeev (EE)
ObjectivesBalance and walk with human gaitRecover to upright position after a fallAutonomous, untethered operation for up
to 30 minutesSupport 125% of total robot weightObstacle avoidanceVoice activatedAble to withstand a fallDesigned, built, and debugged – currently
20 weeksBudget: $2500 (Actual Budget: ~$3100)
TigerBot Family
TigerBot
TigerBot 2
TigerBot 3
Human ThemeShell theme
“Ironman”, enables easy definition of future shell enclosures
Designed using Pepakura software
Made from 0.016” aluminum to be as light as possible
Head Design
Front Chest
Back Plate
Component Layout
System Design23 Rotational Degrees of Freedom (4
per arm, 6 per leg, 1 in torso, 2 in head)
Full load bearing joint design at every axis of rotation, allowing completely free and unrestricted servo rotation◦ Servo motors take no structural loads
Low center of gravity ~2 inches below pelvis plate (avoids falling, assists recovery)
Higher torque servos (legs) and lower torque servos (upper body)
Structural ConceptLighter weight
◦18.5 lbsImproved joint
performanceFuture
expandability with rod design
Structural Design
Knee - Exploded View
Elbow – Close Up
Inverse Kinematics Concept
Integrated Controls32-bit Roboard Vortex86
CPU with 256MB DDR2 RAM and 16GB Class 10 SD Card running Ubuntu
ATmega2560 Arduino with 16 analog input ports
9-Axis IMU (Accelerometer, Magnetometer, and Gryoscope)
EasyVR Voice Recognition with 26 pre-programmed commands and up to 9 minutes of audio playback
Roboard RB-100 CPU
9-Axis IMU
EasyVR Voice Recognition
Software Design
Electronic Block Diagram
Electrical DesignPower Distribution Fuse and switches for
circuit protection Low battery indicator I2C communication bus
with up to 4 slaves
Current Monitoring Determine servo strain
to determine forces acting on robot
Measure currents drawn by each servo
Capable of sensing current for up to 25 servos
High side and low side current sensing
Custom PCB - Powerboard
Custom PCB – Current Sensing
Hall Effect
ResultsCurrent State
◦Operates autonomously◦Responds to multiple commands
Challenges◦Time constraint◦Manufacturing limitations
Results: Customer NeedsCustomer
Need #Importance Description Comments/Status
CN1 1 Mobile - can walk straight and turn CE's did not get to this code (time)
CN2 AutonomousCN2.1 1 Voice ActivatedCN2.2 1 Non-tetheredCN2.3 1 Obstacle avoidance capable Capability is there, not codedCN2.4 1 Self-balancing Capability is there, not codedCN2.5 1 Wireless Comunication
CN3 2 Can survive and get up from backward, forward, and sideways fall Un-tested
CN4 2 Fall resistance Un-tested
CN5 Target 20 Degrees of FreedomCN5.1 1 4 DOF for each leg and armCN5.2 1 2 DOF for head: up/down and right/leftCN5.3 1 2 DOF for torso: up/down and right/left
CN6 Humanoid DesignCN6.1 1 Human Torso DesignCN6.2 1 Human Leg and Ankle design Slightly Large AnklesCN6.3 1 Humanoid Shell / Armor to cover robotCN6.4 1 Humanoid Proportions Shell and Head offset proportions to legs
CN7 Manuals In ProgressCN7.1 1 Operation Manual In ProgressCN7.2 1 Software Manual for Software Libraries In Progress
CN8 1 Able to hold 1/4 total weight of robot
CN9 1 Center of balance below the waist
CN10 1 Uses a small factor computer with an OS
CN11 2 Stay with in budget of 2500 Total Spent: $3100
Future RecommendationsCE’s to work on coding on previous
TigerBot early in MSDII◦ Relieve end of quarter scramble after
mechanical build is completedTower layout for electrical boards
◦ As more and more boards/components are introduced, wiring becomes difficult
Individual current shutoff for each servo
More design focus on servo coupling
Questions?
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