HyQ - Design and Development of a Hydraulically Actuated Quadruped Robot

Legged machines promise greater mobility in rough and unstructured terrain then wheeled vehicles. In the future, especially quadruped robots are expected to be employed for a variety of dangerous and dirty tasks in fields like search and rescue, humanitarian demining etc. The objective of this dissertation is to make a significant contribution toward the development of a highly dynamic quadruped robot. This versatile platform is intended to serve as a tool to deepen the understanding of terrestrial locomotion, to assess the applicability of different hydraulic actuation systems to legged robots and to facilitate the future construction of useful robots for various tasks. To this end, this dissertation: 1. presents several design studies aimed at the creation of a quadruped robot. 2. describes the design and experimental testing of a hydraulically powered prototype leg with a focus on its actuator units. 3. explains the construction of the quadruped robot platform including all electric and hydraulic system components. The developed quadruped robot called HyQ features 12 active degrees of freedom and is designed to perform highly dynamic tasks like jumping and running. Therefore, the robot’s joints are either powered by hydraulic or electric actuators, depending on their particular performance and property requirements. While hydraulic cylinders have an excellent power to weight ratio and naturally absorb impact force peaks during running and jumping, electric motors have compact overall dimensions and exhibit a constant output torque profile. Therefore, hydraulic cylinders actuate the hip and knee