空间四星绳系闭合系统自旋平衡构型保持控制

Spin equilibrium configurations keeping control of four-body closed tether system

针对空间四星绳系闭合系统自旋平衡构型的不稳定特性,建立四星绳系闭合系统动力学模型并设计构型保持控制器,使系统始终处于稳定自旋状态.提出以Golay-3分布的空间四星绳系闭合系统,分析该系统的动力学特性,利用拉格朗日方程推导动力学模型的数学形式.根据动力学方程得出自旋平衡构型,分析表明,系统自旋时在系绳拉力作用下构型平面内的运动具有稳定性,构型平面指向会发散.推导构型平面指向的非线性调节器方程,考虑到研究对象受外界干扰的不确定性,为了增强系统的鲁棒性,设计基于符号函数和基于饱和函数的滑模变结构控制器.仿真表明,两种控制器都具有较强的鲁棒性,可以保持四星闭合系统自旋构型,采用基于饱和函数的软变结构策略可以明显地减少控制系统抖振.

A kinetic model was established and a controller was designed to keep the spin configuration system stable aiming at the unstable problem of four-body closed tethered system.A tethered satellite system（TSS）model with the distribution of Golay-3 was proposed.The dynamics of the system was analyzed and the mathematical model was deduced based on Lagrange equations.Spin equilibrium configurations were obtained based on kinetic equations.The analysis results show that there is a stable state in configuration plane and an unstable state out of configuration plane when the four-body closed tethered system spins.A sliding mode control method based on sign function and saturation function was designed in order to enhance the robustness of the system.Simulation results show that the controllers can keep the spin configurations stable.The soft variable structure method based on saturation function can effectively decrease tremor of the system.