Automatic Windshield Wiper systemE-552

Sensors and ActuatorsINSTRUCTOR: DR. Mohan Krishnan

Presented by:Divesh MittalSteven Lee

Contents

Objective / Introduction Physics of Optical Sensor Practical Setup LabviewTM code/ Flow chart Conclusion / Final Comments Question???

Objective

Selection and study of particular application of sensor.

Automated windshield wiper system. Prepare demo setup.

Automated Windshield Wiper System

What is automated windshield wiper system?

Who commercialized it?

Significance

Active Safety

Automation better than manual

Possible Transduction Mechanism

Conductive transduction mechanism

Piezoelectric transduction mechanism

Optical transduction mechanism

Where are we??

Objective Physics of Optical Sensor Practical Setup LabviewTM code/ Flow chart Conclusion / Final Comments Question???

Physics of Optical Sensor

Optical sensor works on concept of reflection and refraction.

At critical angle of incidence only reflection occurs.

Air

Glass

Air

Glass

(a) Reflection and Refraction (b) Total Internal Reflection

θr

θi θi

θi>θcritReflection

Refraction

Total Internal Reflection

Physics of Optical Sensor Contd..

Critical angle of incidence for some material combinations

Material Critical angle

Windshield Glass / Air 41.15 degree

Windshield Glass / Water 61.28 degree

Windshield Glass / Ice 59.52 degree

Windshield Glass / PVC 76.83 degree

PVC / Air 42.52 degree

Physics of Optical Sensor contd..

Angle of incidence is kept slightly more than critical angle for Windshield material/air combination.

Presence of rain changes critical angle value.

Where Are We??

Objective / Introduction Physics of Optical Sensor Practical Setup LabviewTM code/ Flow chart Conclusion / Final Comments Question???

Practical setup

Servo Motor Wiper PMMA plate PMMA 90∘Prism Phototransistor: QSD124 880nm wave length IR LED: QED223 AlGaAs 880nm Resistor: 1KΩ for Phototransistor; 910Ω for IR LED. PCI DAQ 9024E

Practical setup

1

2

3

Prisms

Air

IR LED IR Phototransistor

Measure area

Plastic

Practical Setup

Rain SensorMeasure Area

Practical Setup

IRPhototransistor

IR LED

Where Are We??

Objective / Introduction Physics of Optical Sensor Practical Setup LabviewTM code/ Flow chart Conclusion / Final Comments Question???

RainSensorStart

Read Rain Sensor

Data from DAQ card

DifferentialGet the peak data

Get the average voltage

Average voltage < 4.5 V ? Or

Peak data >10

Turn on wiper

No

Yes

Labview coding

Control Chart

IR LED

IR PhototransistorDAQ card

Servo Motor

Wiper

Wiper

Wiper System

Rain-

Labview

PC

Demo Video

Where Are We??

Objective / Introduction Physics of Optical Sensor Practical Setup LabviewTM code/ Flow chart Conclusion / Final Comments Question???

LabviewTM Results

No rain condition

Less water on windshield

More water on windshield

Final Comments/ Conclusion

Mechatronic systems are best option for active safety systems.

Rain sensor is effective control system to replace manual wipers.

Limitations

Motor speed constant

Smaller sensitive area

Questions