Optimal Landing Motions for Legged Robots with Variable Stiffness Joints

Abstract

When a robot performs jumping or other explosive motions, excessive impact forces may be generated during the landing phase that potentially causes damage to the robot. This paper investigates optimal landing motions for a legged robot that exploit the capabilities of variable stiffness joints. Minimum impact postures are first investigated in the redundant case, followed by dissipative stiffness control strategies that reduce oscillations and chattering resulting from landing impact. The two strategies are then combined into a unified strategy for minimum impact landing motions, and validated through detailed dynamic simulations.