Modelling and control for a bipedal robot on slopes

Abstract

This paper presents a systematic trajectory generation method for a bipedal robot walking on slopes. A suitable offline walking pattern based on an inverted pendulum model is designed and the planning is parameterized by step lengths, step period and other walking parameters. Meanwhile, a slight unevenness of a slope can cause serious instability for bipedal walking robots. Therefore, this paper also proposes an online control algorithm for a bipedal robot even walking on the unevenness slope, and the robot can adapt to the floor conditions. The control algorithm includes a landing time controller, landing direction controller, zero moment point (ZMP) regulation controller and attitude correction controller. During the process, accurate attitude information for these controllers is achieved through an adaptive filtering method and the ZMP position is measured through force sensing register sensors, which are attached to the robot’s feet. Finally, the experiment is carried out on a SCUT-I humanoid robot. The result proves that the method described in this paper can successfully control a robot walking on slopes.