Abstract:A low-complexity optimal predictive control method is developed for the reentry attitude control of reusable launch vehicles. First, the attitude dynamics model of reusable launch vehicles is established. Second, the attitude tracking optimal predictive controller is designed based on the rolling horizon control framework and mode insertion gradient, and the optimal control action triplet containing the optimal rudder deviation control input, application time and duration is solved. Then, the stability of the closed-loop attitude tracking control system is proved based on the Lyapunov stability principle. Compared with existing predictive control methods, the proposed method significantly reduces the computational complexity of optimal attitude control law due to its prominent advantage without solving complex nonlinear programming problems. Finally, the effectiveness of the proposed method is verified by two sets of numerical simulation cases. The simulation results demonstrate that the proposed method achieves an attitude tracking control accuracy of 10-3 degrees, representing a two-order-of-magnitude improvement compared to the nonlinear model predictive control method. Additionally, the single-step sampling control solution time is reduced by approximately 29.3%, indicating significantly enhanced computational efficiency.