A Self-contained 3D Hopping Robot Kale Harbick CS547 - Fall 2000 Project Presentation

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

3 Previous Work Marc Raibert – MIT Leg Lab –Planar hopper pneumatic leg, hydraulic hip –3d hopper pneumatic leg, hydraulic hip Martin Buehler – McGill University –Monopod I and II planar, electrical actuation

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

5 Forward Velocity

6 Body Attitude

7 System Software Architecture

8 Simulation MathEngine physics toolkit Explicit airflow and valve models –sub-critical vs. super-critical flow –valve timings OpenGL front-end Controller-Simulator interface –TCP for control signals –UDP for sensor data

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

10 Pneumatic System

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

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

13 Construction: Current State