Gait planning method of a hexapod robot based on the central pattern generators: Simulation and experiment

Biomimetic robots such as biped, quadruped, hexapod and fish robots become the research hot of robotics in recent decades. Hexapod robots can adapt to the rugged ground and complex environment, which are usually difficult for wheeled and tracked robots. Controlling the locomotion of biomimetic robots by central pattern generators (CPGs) is a new method developed recently. In this paper, we apply the CPGs based on Matsuoka oscillators for the gait planning of a hexapod robot to produce rhythmic locomotion. The mathematic model of Matsuoka oscillator is fourth-order nonlinear coupled. We use the state observation method and phase plane method to analyze the relation between the parameters of the mathematic model of the Matsuoka oscillator and its output waveform. Then we design a CPGs network based on six Matsuoka oscillators to control the hexapod hip joint angle respectively. For the knee joint angle and ankle joint angle, we establish the mapping relation between them and the hip joint angle. The CPGs based strategy is first verified through the simulation using ADAMS software, and then is implemented and tested through practical experiments using the hexapod robot in our lab.