Hopf oscillator based adaptive locomotion control for a bionic quadruped robot

Abstract

This contribution aims to construct an adaptive locomotion controller for legged robots based on learning animals' rhythmic behaviors. The design of locomotion control method, different from traditional ones, is inspired from biological term of Central Pattern Generators (CPG), used to produce rhythmic motions. A symmetrically netted CPG structure consisting of coupled oscillators is presented to simply generate stable and natural gait patterns for legged robots. Moreover, gait transition among different gaits with locked phase relation is realized by introducing rotation matrix as coupling term that arbitrary phase difference can be obtained. Thus, smooth and prompt gait switching is achieved so as to perform dynamic walking. Also, in order to enhance adaptability to uneven terrains like slope, we adopt body attitude as sensory feedback to CPG network and the control signals for locomotion are modulated to accomplish dynamic walking on slope. The results from simulations and physical prototype experiment validate the feasibility of proposed control strategy.