基于伪谱法的固定采样实时最优制导方法研究

摘要

针对具有过程约束和终端状态约束的高超声速飞行器再入制导问题,给出了一种固定采样非线性实时最优制导算法,该算法通过连续在线计算开环最优控制的方式提供闭环反馈,避免了内环跟踪控制器的设计过程.利用通用伪谱优化软件包实现多约束非线性系统最优控制问题的在线求解.在考虑计算误差、预报误差、模型参数不确定性和干扰的情况下,对采用该算法构成的闭环控制系统的有界稳定性进行了理论分析与证明.仿真结果表明,该实时最优制导算法能有效地抑制飞行过程中不确定性和扰动的影响.%For hypersonic reentry guidance problems under process constraints and terminal states constraints, a nonlinear real-time optimal guidance algorithm with fixed sampling frequency is proposed. A closed-loop feedback method is designed by successively generating real-time open-loop optimal controls, thus avoiding the design procedure of inner-loop feedback controller. Nonlinear optimal control problems with constraints are solved on-line by using general pseudo-spectral optimization software (GPOPS). Considering computational errors, propagation errors, model parameters uncertainties and disturbances, the theoretical analysis for the bounded stability of the closed-loop system is given. Simulation results show that the method can deal with uncertainties and disturbances during flight effectively.