Trajectory tracking with external disturbance of bionic underwater robot based on CPG and robust model predictive control

Aiming at the 3-D trajectory tracking control problem of underwater bionic robots, a novel trajectory tracking control strategy based on robust model predictive control (RMPC) and central pattern generator (CPG) is designed for underwater bionic robots with external disturbances. Firstly, the overall mathematical model of the robot is established, and a discrete robust model predictive controller is designed for trajectory tracking control, and then its stability is proved. Secondly, according to the mechanical analysis of the pectoral fin and the caudal fin, the transformation functions of the pectoral fin and the caudal fin is designed, and the lower CPG motion controller and the upper RMPC trajectory tracking controller are combined to establish an RMPC-CPG controller. It not only improves the coordination and smoothness of the motion of the bionic robot during the trajectory tracking process, but also incorporates many constraints in the motion process into the rolling optimization, so that the control input meets the actual drive constraints and avoids the problem of drive oversaturation. Finally, the simulation experiment is designed to verify the tracking performance of the bionic underwater robot under external disturbance. Simulation results demonstrate the effectiveness of the controller and its robustness to external disturbances. •The transformation function is designed according to the mechanical model of the robot.•The CPG network and the robust model predictive controller are combined through the transformation function.•Simulations verify the effectiveness of the proposed RMPC-CPG controller.•The RMPC-CPG controller can keep the tracking accuracy within 0.74m in the presence of disturbances.