1. Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics  TEMA  IEETA  http://www.mec.ua.pt/robotics Sensors for Humanoid Robot Daniel Baptista 1 Filipe M. T. Silva 1 Vítor M. F. Santos 2 1 Department of Electronics and Telecommunications 2 Department of Mechanical Engineering University of Aveiro, PORTUGAL

2. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Overview  Introduction  Sensors for humanoid  Feet Sensors Strain gauges >New Solutions »Load cell »The linear variable differential transformer (LVDT) »Capacitive sensors »The pressure linear potentiometer »Multi-Axis Force/Torque Sensor  Accelerometers  Gyroscope  Electronic Magnetic Compasses  CCD Camera

3. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Introduction  Complete humanoid model  22 degrees of freedom  Weight - 5 kg  Height - 60 cm  Max. width - 25 cm  Foot print - 20  8 (cm 2 )  Actuation  Servomotors with transmission belts  Sensors  A CCD Camera  Servos’ position (through its internal potentiometers)  Sensitive feet to applied forces  Accelerometers/Inclinometers  Gyroscopes

4. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Envisaged sensorial capabilities Accelerometers for accelerations and inclinations Gyroscopes for angular velocity Potentiometer for position feedback (HITEC Motor) GYROSTAR ENJ03JA from MURATA ADXL202E from ANALOG DEVICE Vision unit (on the head) Motor electric current Sensitive feet Strain gauges on a slightly compliant material

5. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors  The strain gauges sensors esteem the Humanoid’s body balance  There are 4 strain gauges sensors on each foot. They are used to…  measure ground reaction forces  calculate the location of the Center of Pressure (CoP)

6. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors  The first version of strain gauges amplifier  No temperature compensation  Unbalanced Wheatstone bridge

7. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors  The second version of strain gauges Amplifier  High consumption of current  Bad contact in connectors the white board

8. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors  The third version of strain gauges amplifier  The mechanical screw adjust in the feet introduces perturbations  The potentiometer in the bridge causes problems  But, we are not satisfied!  PCB Design

9. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors – New solution 1  Load Cell  The load cell used piezoresistors sensors in Wheatstone bridge  The force sensor operates on the principle that the resistance of silicon implanted in the piezoresistors will increase when the resistors flex under an applied force.

10. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors – New solution 2  The linear variable differential transformer (LVDT)  The transformer has three solenoidal coils placed end-to-end around a tube. The centre coil is the primary, and the two outer coils are secondaries.  A cylindrical ferromagnetic core, attached to the object whose position is to be measured, slides along the axis of the tube.  As the core moves, these mutual inductances change, causing the voltages induced in the secondaries to change.  The coils are connected in reverse series, so that the output voltage is the difference between the two secondary voltages.

11. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors – New solution 3  Capacitive sensors  Capacitive sensors measure the distance between two plates via their capacitive effect

12. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors – New solution 4  The pressure linear potentiometer  Implementation in Sony’s SDR-4X and suspected in QRIO  There are 4 force sensors in the foot sole. The sensors are specially designed diaphragm type sensor. The measurable range is 0~5 kg and the resolution is 10g.

13. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors – New solution 5  The Multi-Axis Force/Torque Sensor system measures all six components of force and torque  Strain gauge sensor is attached to each measurement beam and each beam measures only one component of translational force.

14. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Feet sensors – New solution 5  Honda’s ASIMO utilizes six-axis force sensors in each foot of the robot.  These sensors measure forces and moments in all three directions as seen at the ankle.

15. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Accelerometer/Inclinometer  The Accelerometer/Inclinometer used are ADXL202E (Analog Devices).  The ADXL202E will measure accelerations with a full- scale range of ±2 g.  The ADXL202E can measure both dynamic acceleration (e.g., vibration) and static acceleration (e.g., gravity).  When the accelerometer is oriented so both its X and Y axes are parallel to the earth’s surface it can be used as a two axis tilt sensor with a roll and a pitch axis.

16. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Accelerometer/Inclinometer  Circuit of conditioning signal for Accelerometer /Inclinometer

17. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Accelerometer/Inclinometer  Gravity acceleration measurement  Static acceleration (gravity)  Dynamic acceleration (gravity + dynamic moving)

18. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Gyroscope  Piezoelectric Vibrating Gyroscopes  The gyroscopes is an angular velocity sensor that uses the phenomenon of Coriolis force, which is generated when a rotational angular velocity is applied to the vibrator.

19. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Gyroscope  Piezoelectric Vibrating Gyroscopes (GYROSTARr) (muRata)

20. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Electronic Magnetic Compasses  Electronic Compasses  Two-axis magnetic compasses measure the horizontal vector components of the earth's magnetic field using two sensor elements in the horizontal plane but orthogonal to each other.

21. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics CCD Camera  Unibrain Fire-i Digital Board Camera

22. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics CCD Camera  OpenCv the image processing  Color Filter  Template match

23. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics End Thank you Sensors for Humanoid Robot Daniel Baptista 1 Filipe M. T. Silva 1 Vítor M. F. Santos 2

24. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Power Management  Low Dropout Linear Regulator UCC283-5 3A (Texas Instrument)  PCB Design