基于改进定点二乘的重复使用助推飞行器控制分配研究

为适应重复使用助推飞行器(RBV)控制精度和控制可靠性等要求,导致多异类执行机构数量的急剧增加,而各执行机构偏转角、偏转角速率和非连续工作方式的限制影响控制效果。为满足该类飞行器控制系统实时性和控制精度等需求,需要研究计算精度、计算效率更高的控制分配(CA)方法。根据每次迭代所需的浮点运算量,在比较基于二次规划的控制分配算法计算效率的基础上,首先,利用最小代价函数关系将传统定点(FP)二乘优化算法转化为二次规划问题,并给出传统定点二乘优化方法最优解应满足的条件;然后,针对执行机构饱和情况,提出了改进定点(IFP)二乘的控制分配算法以提高计算效率,同时给予详细的推导证明,并基于迭代常数映射的特性,以相邻时刻控制量差的范数达到相关要求给出改进算法的迭代终止条件;最后,基于多种控制分配算法,对所提出的控制分配算法进行了比较仿真,验证该算法的有效性和合理性。

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.