Design and Control Aspects of Humanoid Walking Robots

摘要

The research presented in this dissertation discusses the development of a humanoid biped robot from the planning stage to biped walking focusing on low level control. Concepts in hardware design, posture manipulation, and hybrid joint control, that are novel in humanoid robotics, are presented and entirely verified in hardware experiments. Decisive for the future performance of the robot is a careful selection of an appropriate motor-gear-combination during hardware design, as oversized actuators increase the total weight of the robot, thus deteriorating the walking performance. A systematic procedure for actuator selection based on optimal control is discussed. When replaying precalculated trajectories with a humanoid robot, it is often desirable to modify the posture of the robot thus compensating for control errors or adapting the trajectory for new situations. This task can be accomplished by a method termed Jacobi Compensation. A walking controller based on the inverted pendulum method is implemented on the humanoid UT-Theta. This robot is equipped with an innovative knee joint allowing to switch between actuated motion and free swinging. To ensure smooth and reliable operation with this joint, a hybrid, nonlinear, time optimal knee controller has been implemented.