Development of Rotating Workspace Ground Contact Force Observer for Legged Robot

Abstract

Legged robots have opened their way to more stable and practical mobile robot applications. However, their locomotion strategies are limited to similar patterns, and dynamic running at high speed still is not successfully realized. One of the key technology required for the realization of the dynamic running of the legged robot is to estimate the ground contact force and control it in real-time. This paper tackles this problem in two ways: the derivation of the observer algorithm based on the leg dynamics and the simplification of the observer design using the Rotating Workspace motion description. To this end, two novel coordinate systems are introduced to describe the joint space motion and the workspace differently, and the ground contact force observer is designed in the novel coordinate systems. The performance of the proposed observer is verified through experimental results.