Generation of dynamic humanoid behaviors through task-space control with conic optimization

Abstract

This paper presents a new formulation of prioritized task-space control for humanoids that is used to develop a dynamic kick and dynamic jump in a 26 degree of freedom simulated system. The demonstrated motions are controlled through a real-time conic optimization scheme that selects appropriate joint torques and contact forces. More specifically, motions are characterized in appropriate task spaces, and the real-time optimizer solves the task-space control problem while accounting for user-defined priorities between the tasks. In contrast to previous solutions of the Prioritized Task-Space Control (PTSC) problem for humanoids, the solution presented here satisfies the ZMP constraint and ground friction limitations at all levels of priority, and is general to periods of flight as well as support. All generated motions include control of the system's centroidal angular momentum, which leads to emergent whole-body behaviors, such as arm-swing, that are not specified by the designer. In addition, compared to a previous quadratic programming solution of the PTSC problem, our approach gains a factor of 2 speedup in its required computational time. This speedup allows the control approach to operate at real-time rates of approximately 200 Hz.