复杂耦合环境下电动力绳离轨系统动力学模糊建模与数字控制研究

Recently, deorbiting electrodynamic tether systems have received considerable attention from a lot of countries due to the characteristics of high efficiency and cleanliness. However, there still remain many challenging problems to be solved in the research of dynamics and control. Especially, the highly non-linear dynamics of deorbiting systems will lead to difficulties in modeling under the effects of multi-physics coupling, rigid-flexible coupling, fast-slow coupling, and so on; Moreover, it is also unclear that how the widely used digital/sampled-data control method affects the dynamics of deorbiting systems. For the purpose of overcoming the problems aforementioned, this project firstly makes use of Takagi-Sugeno (T-S) fuzzy modeling approach to describe the dynamics of deorbiting systems under complex coupling constraints. The established T-S fuzzy model not merely is capable of depicting nonlinear dynamics accurately, but also is convenient for controller design. Additionally, the effects of sampling signals on the dynamics and stability of the system will be revealed on the basis of T-S fuzzy model. Instead of using continuous-time signals, the robust control laws with input restrictions are designed according to sampling signals. Finally, the effectiveness of research results is verified in ground-based experiments. The achievements of this project will open a new window for the solutions to dynamic modeling and control of deorbiting electrodynamic tether systems, and provide the foundation of theory and technology for the applications of aerospace engineering.

目前，高效、清洁的电动力绳离轨系统受到各国密切关注，其动力学与控制问题极具挑战性。特别地，在空间多物理场、刚-柔、快-慢时变等复杂耦合因素的影响下，离轨系统的强非线性特征给动力学建模带来了显著困难；此外，工程实践中广泛应用的数字采样控制方式对离轨系统动力学的作用机理也尚未明确。本项目针对上述关键问题及技术难点展开创新性研究，内容包括：依托模糊逻辑表征复杂非线性关系的突出优势，建立离轨系统的Takagi-Sugeno（T-S）模糊动力学模型，克服传统模型不能同时兼顾非线性动力学刻画和控制器设计的缺陷；以模糊模型为基础，阐明数字采样现象对系统动力学行为及稳定性的作用规律；打破连续时间反馈惯例，直接基于采样反馈信号设计含约束的鲁棒控制律；根据天-地动力学相似，构建地面实验平台以验证研究结果。项目研究成果将为电动力绳离轨技术的研究提供新思路与新方法，进而为航天工程实践提供理论支撑与技术指导。

电动力绳离轨技术具有清洁无污染、效率高等突出优点，具有广泛的应用前景并受到各国密切关注，其动力学与控制问题极具挑战性。本项目通过理论分析、数值仿真和地面物理实验相结合的手段，开展了电动力绳离轨系统动力学模糊建模与数字控制研究。已按计划开展项目研究，主要成果如下：开展了绳系卫星系统非线性动力学分析，研究了由大气阻力和地球扁率摄动引起的混沌行为，建立了混沌发生的参数域，并设计了一种滑模控制律以实现系绳长度控制并抑制混沌运动；以姿态四元数、角速率为模糊前件变量，通过单点模糊化、乘积推理和“中心-平均值”解模糊方法建立了绳系卫星系统端部卫星的姿态T-S模糊动力学模型，并基于该模糊模型，分别提出了含控制量饱和约束的采样反馈鲁棒控制律和事件触发反馈鲁棒控制律；以绳系卫星系统非线性动力学方程中的关键非线性项为前件变量，基于局部扇形非线性准则，通过单点模糊化、乘积推理和“中心-平均值”解模糊方法构建了绳系卫星系统的T-S模糊动力学模型，以该模糊模型为基础，依托不变集理论，提出了一种含系绳张力非对称约束的鲁棒模糊控制律；面向杠铃型电动帆的姿态动力学与控制问题，采用非奇异动力学模型刻画电动帆的姿态动力学，并据此提出了一种非线性模型预测控制律；构建地面物理仿真实验平台，验证了相关理论研究结果。本课题研究结果为电动力绳离轨系统的动力学与控制提供了新的理论和技术。