Development of Servo-Units for a Compliantly Actuated Quadruped Prototype

Abstract

This master thesis deals with the development of servo-motor-units as part of the quadruped project at the Institute of Robotics and Mechatronics, German Aerospace Center (DLR). To be able to perform highly dynamic motions such as jumping, the servo-motor-units of a quadruped robot require to produce high torque and velocity peaks on the one hand while being of compact size and light weight on the other hand. This is achieved by means of taking an off the shelf servo-motor-unit and replacing the electronics by a custom electronics which requests the maximum power of the motors. The developed servo-motor-unit provides a compact powerful motor with a good position sensor and a real-time USB link. The firmware enables to command the motor with a frequency of 1 kHz. The frequency of control loop and the communication can be set independently from each other. In a second part the development of an automated test system for motors is described. The measurements showed that performance factors and the efficiency of the developed servo-motor-unit are almost on the same level of a high-end motor, specially designed for application in robotic systems. It is interesting that the servo-motor-unit is almost as efficient as a high-end robot motor, but is about factor 10 cheaper.