Nonlinear model predictive control method for autonomous approach of tanker/receiver

Abstract In order to solve the problems of strong nonlinearity, strong coupling and multivariable constraints of the receiverr’s motion model in the process of the tanker/receiver autonomous approach, a nonlinear model predictive control (NMPC) method is proposed in this paper. By analysing the external forces and torques acting on the receiver, a nonlinear dynamic model of the receiver is established to provide an accurate prediction model for NMPC. An objective function with the terminal state of the receiver is designed, multiple state variable constraints are added, the adaptive gradient descent method is used to solve the optimal control quantity online and finally the stability of NMPC is proved. The numerical simulation results show that the proposed method has good control performance and can quickly and stably control the receiver to fly directly behind the tanker and maintain the same speed and direction.