Research on control allocation based on improved fixed-point for reusable boosted vehicle

To satisfy the control accuracy and reliability demands of reusable boosted vehicles (RBV), there appears a number of different kinds of redundant actuators. However, the limitations of the deflection angle, angular rate and non-continuous working mode affect their control effect. To meet the real-time demands of control systems and control precision, it is imperative to study control allocation (CA) algorithms with higher calculation accuracy and efficiency. This paper makes a comparison of the computational efficiency of control allocation algorithms based on quadratic programming by using the number of flops required at each iteration, First, the conventional fixed-point (FP) algorithm is transformed to quadratic programming, and the satisfying conditions of the optimal solutions for the conventional fixed-point method are given. Secondly, according to actuator saturation, an improved fixed-point (IFP) control allocation algorithm is proposed to improve calculation efficiency, and its detailed proof is given. Based on the characteristics of iteration constant mapping, the norm of the control variable errors between two adjacent moments must meet the related requirements before the termination conditions of the iteration are reached. Finally, simulation based on various control allocation algorithms verifies the validity and rationality of the proposed algorithm.