复杂环境影响下RLV再入轨迹姿态协同控制策略研究

Due to the aerodynamic heating produced during the flight, RLV is prone to appear the elastic deformation and the failure of partial aero-surfaces which leads to under-actuation problem and shows up the non-minimum phase characteristic; The comprehensive effects of these two characteristics reduce the maneuverability and stability more severely during reentry phase and become the risk of security and stability for RLV. The project intends to suppress unstable zero dynamics and estimate flexible state to solve the bottleneck problem of reentry trajectory and attitude cooperative control for RLV. By the qualitative analysis of flexibility and non-minimum phase as well as the quantitative description of the changes of flexible state and unstable zero dynamics, the stable conditions of flexible state and zero dynamics are found, then control-oriented model is established. Considering the complex environmental effects, three-dimensional real-time trajectory optimization method and trajectory tracking method are studied to achieve fast tracking of the optimized trajectory. The unstable zero dynamics suppression method as well as the integrated flexibility observer and fixed-time robust adaptive controller design method are studied. The trajectory and attitude controller are amended adaptively by evaluation and decision-making to achieve the trajectory and attitude cooperative control. In addition, the project is to establish an all-digital simulation platform. The project can provide new ideas and new ways for RLV reentry trajectory and attitude cooperative control under the complex environmental effects and it has important theoretical significance and application prospects for other aerospace vehicle referred to problem of stable tracking and control.

RLV飞行过程中产生的气动热会引起机身弹性形变，并导致部分气动舵面失效， 出现欠驱动问题，表现出非最小相位特性;弹性与非最小相位的综合影响更严重地降低了RLV操纵性和稳定性，是RLV安全稳定飞行的隐患。项目拟从抑制不稳定零动态、估计弹性状态出发，解决RLV再入轨迹姿态协同控制的瓶颈问题。通过定性分析，定量描述弹性状态和不稳定零动态的变化规律，找到弹性状态和零动态的稳定条件，建立面向控制模型；综合考虑复杂环境的影响，研究三维实时轨迹优化方法和不确定影响下的最优轨迹跟踪方法，实现轨迹精确跟踪；研究不稳定零动态抑制方法，综合设计弹性观测器及固定时间鲁棒自适应控制器，实现姿态稳定控制；通过评估决策自适应修正轨迹与姿态控制器，实现轨迹姿态协同控制。建立实时仿真全数字仿真平台。该项目为复杂环境影响下RLV再入轨迹姿态协同控制提供新思路和新途径，对其他空天飞行器的稳定跟踪控制具有重要理论意义和应用前景。

本基金针对复杂环境影响下RLV再入轨迹姿态协同控制为研究主题，解决RLV再入轨迹姿态协同控制的瓶颈问题。主要开展了以下工作：1）解决了弹性及非最小相位的影响下的RLV面向控制建模问题，找到了弹性状态和零动态的稳定条件，建立了面向控制模型；2）综合考虑复杂环境的影响，研究了三维实时轨迹优化方法和不确定影响下的最优轨迹跟踪方法，解决了飞行器在面临突发事件时的轨迹实时优化问题，确保飞行器在面临突发事件时，能够根据飞行器当前飞行状态，自主获得可行再入飞行轨迹，轨迹实时求解时间优于2秒；3）解决了弹性、非最小相位特性、外界干扰及模型不确定等综合影响下对参考制导指令的稳定跟踪控制问题，研究了不稳定零动态抑制方法，实现了系统零动态的稳定，综合设计了弹性观测器及固定时间鲁棒自适应控制器，实现了姿态稳定控制，控制精度优于5×10^-3度 ，并通过评估决策自适应修正轨迹与姿态控制器，实现了轨迹姿态协同控制；4）开发了RLV全数字化仿真平台，实现了对所提出的RLV再入轨迹姿态协同控制方法的可行性、适用性、有效性的虚拟仿真验证，解决了缺乏实物环境导致算法的可行性无法得到有效验证的问题。该项目为复杂环境影响下RLV再入轨迹姿态协同控制提供新思路和新途径，可以有效地提升RLV高精度姿态控制、在轨服务、巡航机动以及再入返回的能力，且对研究成果对其他类型飞行器制导控制系统的研制具有重要的参考价值。