A Novel Theoretical Approach for Hexapodal Gait Generation of the CPG Controller by Using the Delay-Coupled VDP Oscillators

In order to adopt different locomotion gaits for complex environments, the bioinspired central pattern generator (CPG) controller is proposed to steer legged robots to have a variety of different gaits. In this article, for hexapodal robot we construct a new type of CPG controller by using the delay-coupled Van der Pol (VDP) oscillators. The theoretical method is proposed to obtain multiple locomotion gaits. The structure topology is scheduled as a unidirectional ring network consisting of six oscillators. Employing the Hopf bifurcation theory of the delayed differential equation, we propose parameter conditions to guarantee the existence of periodic rhythm with multiple types of spatiotemporal patterns. Then we assign connection order of the CPG units to link the hexapod’s legs and produce different locomotion gaits. The delayed CPG controller possesses almost all types of the hexapodal gaits with the adjustment of the coupling delay and connection orders. The Simulink/ADAMS cosimulations and prototype experiments are implemented to validate gaits of the proposed CPG controller. The main features of the controller are: 1) the delayed CPG system exhibits more types of hexapodal locomotion gaits; 2) the parameter modulation is achieved by a theoretical method; 3) fewer parameters can steer more types of gait patterns; and 4) it does not rely heavily on unit model.