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推力分配是推力系统冗余配置时航天器姿态控制系统的必备组成单元。针对传统直接搜索法以及单纯形法在分配过程中在线计算量大、工程实现较难的不足,提出了一种基于最优推力锥的级联分配方法。该算法首先进行无约束分配,搜索出实现目标控制量的准最优推力锥,然后用推力器喷气时间上限对无约束问题的最优推力组合进行饱和处理,更新推力器喷气时间上限,计算当前推力组合的控制误差,并作为下一步的目标控制量,更新推力锥,重复迭代,直至控制误差为0或当前目标量的可行锥不存在。文中以空间站核心舱为例进行了仿真,结果显示:与传统单纯形法相比,该方法能在保持计算量优势的前提下,在目标量可实现时能优化推力组合,精确实现目标量;目标量不可实现时,能在可达集内最大限度地实现目标控制量,充分利用了推力系统的控制能力。
Thrust distribution is an integral part of spacecraft attitude control system when the thrust system is redundantly configured. Aiming at the shortcomings of the traditional direct search method and the simplex method, which are computationally expensive in the distribution process and difficult to be realized in the project, a cascade distribution method based on the optimal thrust cone is proposed. Firstly, the algorithm searches for the quasi-optimal thrust cone that achieves the target control volume by unconstrained distribution. Then, the optimal thrust combination of the unconstrained problem is thickened by the thruster jet upper bound, the upper limit of the thruster jetting time is updated, and the current Thrust combination of the control error, and as the next target control volume, update the thrust cone, repeated iterations, until the control error is 0 or the current target volume of feasible cone does not exist. The simulation of the core station of the space station is taken as an example. The results show that this method can optimize the thrust combination and achieve the target precisely when the target volume can be achieved, compared with the traditional simplex method. When the quantity is not achievable, the target control quantity can be maximally achieved in the reachable set, and the control ability of the thrust system is fully utilized.