Robust nonlinear model predictive control of a bionic underwater robot with external disturbances

Abstract

Aimed at the trajectory tracking control problem of bionic underwater robots, this paper designs a novel two-dimensional trajectory tracking method based on robust nonlinear model predictive control (RNMPC) and a central pattern generator (CPG) for use in the trajectory tracking of a bionic underwater robot with an external disturbance. First, the overall mathematical model of the robot is established, a robust nonlinear model predictive controller based on a tube for trajectory tracking is designed, and then the stability of the controller is proved by the Lyapunov stability analysis method. Second, a transformation function is designed to combine the CPG motion controller at the bottom layer and the RNMPC trajectory tracking controller at the upper layer in order to establish an RNMPC-CPG controller, which improves the coordination and smoothness of the motion of the bionic robot in the trajectory tracking process. Finally, a simulation experiment is designed to verify the tracking performance of the bionic underwater robot with external disturbances. The simulation results demonstrate the effectiveness of the controller.