Simulation and control of biped walking robots

This PhD thesis covers simulation and control of biped walking robots. Simulations and experiments were performed with the robots Johnnie and Lola developed at the Institute of Applied Mechanics, Technische Universität München, Germany. The chapter on modeling and simulation describes the approach to simulating the rigid multibody dynamics. It includes specialized models for simulating drive friction, nonlinear drive kinematics and the unilateral ground contact. Component models, contact and differential equation solvers are combined to a family of robot simulations with varying modeling depth and computational cost. The thesis also presents a hierarchical system for real-time walking control. Novel aspects include a trajectory generator based on spline collocation and a stabilizing controller based on hybrid position/force control. Lola’s redundant toe and pelvis joints are used to reduce joint speeds and avoid joint limits. All methods were verified on both robots in walking experiments and simulations. In experiments Lola reached a maximum walking speed of 3.34 km/h. Using a computer vision system developed at the Institute of Autonomous Systems Technology at the Universität der Bundeswehr in Munich, Germany, Lola is also capable of safely exploring previously unknown environments.