Whole-Body Control of Humanoid Robot in 3D Multi-Contact under Contact Wrench Constraints Including Joint Load Reduction with Self-Collision and Internal Wrench Distribution

Abstract

In this paper, we propose an approach for online whole-body control of position-controlled humanoid robot with 3D multi-contact to cope with contact wrench constraints and joint overload. In our method, robots are controlled under contact wrench constraints with three features: 1) internal wrench control to reduce joint load and prolong the time in which the high-load postures can be maintained 2) feasible utilization of self-collision to reduce joint load by turning off joint servo gains 3) handling degenerated degree of freedom by solving a quadratic optimization problem integrating wrench distribution and inverse kinematics in which internal wrench is controlled only in controllable directions.With our methods, HRP2-JSKNTS could pick up an object under a desk with squatting with the back of the upper leg on the back of the lower leg without sliding at the right arm. We also evaluated the effectiveness of our control to reduce joint load with another experiment.