【作者】 汪洋；

【导师】 李彬；

【作者基本信息】 四川大学 ， 控制工程， 2021， 硕士

【摘要】 大角度姿态机动任务是空间技术中最具挑战性的任务之一,其目标是在满足各种约束条件的情况下,将航天器的姿态驱动到一个期望的值。其关键技术在通信导航组网,太空观测任务,以及空间站建立等航空战略任务中占据重要地位。航天器是典型的非线性系统,如何在满足多种约束的情况下,找出一种合适的控制方法是一个极具挑战性的问题。本文针对这一研究热点,并结合当前航天器姿态控制的主要研究方向,对航天器姿态控制方法展开研究,研究内容分为以下三个部分:第一部分主要对航天器姿态控制的姿态描述方法,运动模型进行阐述,进行系统建模。首先介绍了常用的几个坐标系的定义以及四元数。并且给出了姿态解算以及坐标求取的公式,得出了航天器姿态控制的运动学方程。然后建立了三轴正交的的航天器动力学模型。最后针对本文主要的约束问题,指向约束问题,进行了一系列建模分析,对不同的指向约束类型进行了凸参数化处理。为后文构造控制器,求解最优控制问题提供夯实的理论基础。第二部分尝试用数值计算的方法解决姿态约束下的航天器姿态控制的最优控制问题。使用控制参数化技术来构造控制输入以便解决半无限规划的难题,约束转录技术被用来处理姿态约束,控制约束。并且对最优控制时间点变换问题,本文采用了一种新的处理方式,区间参数化方式,能够缓解传统时间点变换技术(Time scaling transform)计算量随着控制变量攀升的问题。区间参数化的方法,通过选取部分时间节点作为决策变量,对区间内节点进行线性延伸,能够将在只计算数个变量区间的起始点的情况下,使得控制值的时间变换节点更加合理。仿真结果说明,得出的最优解满足姿态约束以及控制有界约束以及区间参数化技术的有效性。第三部分从势函数角度给出了一类带可设计参数的势函数控制器,并且给出了一种普遍适用的势函数最优参数选择方法。在保证控制器稳定性以及指向约束满足的前提条件下,所提出的控制方案又具备一定的最优性。构造的势函数和目前的大多数势函数相比较,具有可自由调节边界排斥力的作用,能够使得更多的姿态角在机动过程中是可达的。控制器通过一种基于梯度的最优参数调整方法来调整控制器参数。此外,保证了角速度约束和控制力矩约束的满足。因此,该控制方案同时实现了稳定性、最优性和可行性。数值模拟验证了在方向约束下的精确重指向机动,蒙特卡洛仿真表明所选的参数具有一定的最优性。针对姿态约束下的航天器姿态控制问题,本文提出了数值计算的方法以及势函数控制方法。数值计算方法解决了航天器姿态控制的半无限规划问题以及约束处理问题,解决了时间变换节点的计算难题。势函数的方法,提出了一种新颖的势函数,能够解决势函数控制器的边界不可达问题,并且针对势函数控制器,系统的提出了最优参数调整方法,能够在额外的控制有界约束以及角速度有界的约束下完成机动过程,并且所选取的控制增益是最优的。更多还原

【Abstract】 The large-angle attitude maneuver mission is one of the most challenging tasks in space technology.Its goal is to drive the attitude of the spacecraft to a desired value under various constraints.Its key technologies play an important role in communication and navigation networking,space observation missions,and space station establishment and other aviation strategic missions.Spacecraft is a typical nonlinear system.How to find an appropriate control method under the condition of satisfying various constraints is a very challenging problem.Aiming at this research hotspot and combining with the current main research direction of spacecraft attitude control,this paper carries out research on spacecraft attitude control method.The research content is divided into the following three parts:In the first part,the attitude description method and motion model of spacecraft attitude control are described,and the system modeling is carried out.Firstly,the definition of several coordinate systems and quaternions in common use are introduced.The equations of attitude solution and coordinate calculation are given,and the kinematics equations of spacecraft attitude control are obtained.Then a three-axis orthogonal spacecraft dynamics model is established.Finally,aiming at the main constraint problem in this paper,pointing constraint problem,a series of modeling analysis is carried out,and different types of pointing constraint are treated with convex parameterization.It provides a solid theoretical basis for constructing the controller and solving the optimal control problem.In the second part,the numerical method is used to solve the optimal control problem of spacecraft attitude control under attitude constraints.Control parameterization techniques are used to construct control inputs to solve semiinfinite programming problems,and constrained transcription techniques are used to deal with attitude constraints and control constraints.In addition,for the problem of optimal control Time point transformation,this paper adopts a new processing method,interval parameterization method,which can alleviate the problem that the calculation amount of traditional Time point transformation technology increases with the control variable.The interval parameterization method,by selecting some time nodes as decision variables,carries on the linear extension of nodes within the interval,which can make the time transformation nodes of control values more reasonable when only the starting points of several variable intervals are calculated.The simulation results show that the optimal solution satisfies the attitude constraint and the bounded control constraint and the effectiveness of the interval parameterization technique.In the third part,a kind of potential function controller with programmable parameters is given from the perspective of potential function,and a general method for selecting optimal parameters of potential function is given.Under the premise of ensuring the stability of the controller and satisfying the pointing constraints,the proposed control scheme has a certain optimality.Compared with most of the current potential functions,the proposed potential function can freely adjust the boundary repulsive force and make more attitude angles reachable in the maneuver process.The controller adjusts the parameters of the controller by an optimal parameter adjustment method based on gradient.In addition,the constraints of angular velocity and control moment are satisfied.Therefore,this control scheme achieves stability,optimality and feasibility at the same time.The numerical simulation verifies the precise repointing maneuver under the direction constraint,and the Monte Carlo simulation shows that the selected parameters have certain optimality.In order to solve the attitude control problem of spacecraft under attitude constraint,the numerical calculation method and potential function control method are proposed in this paper.The optimal control method solves the semiinfinite programming problem and constraint processing problem of spacecraft attitude control,and solves the calculation problem of time transformation node.Potential function method,this paper proposes a novel potential function,can solve the problem of the boundary of the potential function controller is inaccessible,and in view of the potential function controller,the system of the optimal parameter adjustment method is proposed,in the additional control of bounded constraint and the angular velocity of bounded under the constraint of completing the process of motor,and the selection of control gain is optimal.更多还原