1. A Self-contained 3D Hopping Robot Kale Harbick Department of Computer Science, USC kale@robotics.usc.edu

2. 2 Objectives Self-contained –Onboard computing –Onboard power –Capable of dynamically stable motion without external support Additional behaviors –Gait transitions (inclined planes) –Sit down, stand up, lean against a wall

3. 3 Static vs. Dynamic Stability Statically stable –Car –Quadruped walking Dynamically stable –Biped walking –Running, hopping

4. 4 Previous Work Marc Raibert – MIT Leg Lab –Planar and 3D hoppers –Planar and 3D bipeds –Quadruped (trot, bound, pace) Martin Buehler – McGill University –Monopod I and II –Scout I and II (bounding quadrupeds)

5. 5 Previous Hoppers

6. 6 Three-part Control System Raibert controller Hopping height –Thrust for specified duration during stance –Exhaust to specified pressure during flight Forward velocity Body attitude

7. 7 Forward Velocity

8. 8 Body Attitude

9. 9 My Design

10. 10 Mechanical System Leg thrust –Pneumatic cylinder (400N) Leg swing –2 Pneumatic cylinders (250N) Power –2 onboard CO 2 tanks (5 min) 9 kg total mass

11. 11 Processing and Communication Processing –486DX133 PC/104 –Solid state disk –A/D Converter –Quadrature Decoder Communication –Radio modem –Infrared

12. 12 Sensors Foot contact 2 encoders for hip angle Leg length 3-axis accelerometer Roll and pitch gyros Compass Pressure sensors

13. 13 Performance Predictions 15 cm foot clearance 1.1 m/s maximum velocity 135 W (mechanical) Specific resistance = 1.4

14. 14 Performance Comparison MassPowerSpecific Resistance MIT 3D Hopper 17 kg250 W1.5 Monopod I 15 kg125 W0.7 Monopod II 18 kg48 W0.22 MIT Quadruped 25 kg2500 W5.0 USC 3D Hopper (predicted) 9 kg135 W1.4

15. 15 Specific Resistance P = mechanical power m = system mass g = acceleration due to gravity v = forward velocity

16. 16 Specific Resistance

17. 17 Additional Behaviors Sitting down, standing up, leaning Joystick control –Turn by changing direction of motion –Yaw is not controllable Inclined terrain –Up vs. Down