【作者】 宋婷；

【导师】 张迎春；

【作者基本信息】 哈尔滨工业大学 ， 控制科学与工程， 2009， 硕士

【摘要】 随着当今航天科技的发展,国内外对低轨道小卫星的需求逐渐增大。姿态控制系统是保证卫星稳定运行和基本功能的关键,本文针对低轨道小卫星,系统的研究三轴稳定卫星姿态控制系统,并在星敏感器在轨标定以及控制器设计两方面进行深入研究。描述卫星常用坐标系以及姿态描述方法,建立动力学与运动学模型,引入H_∞控制理论,介绍H_∞控制理论的主要思想及基本理论,为在轨标定及控制器设计奠定理论基础。应用H_∞滤波算法,利用高精度陀螺实现对星敏感器常值误差的在轨标定。采用高精度陀螺获得连续的三轴姿态角速度信息,结合卫星姿态运动学方程,针对星敏感器的常值误差建立星敏感器在轨标定模型,分别应用H_∞滤波算法与卡尔曼滤波算法,完成在轨标定,以确保星敏感器的在轨工作精度。并应用仿真手段对两种算法进行仿真验证。针对低轨道卫星,设计状态反馈H_∞控制器。根据低轨道卫星的特点以及在轨环境,详细分析系统的不确定性以及环境干扰,根据H_∞控制理论针对所选卫星设计状态反馈H_∞控制器,并应用线性矩阵不等式方法求解控制器参数,以简化计算过程。基于以上研究,完成低轨道卫星的高精度三轴稳定姿态控制系统设计。利用高精度陀螺和星敏感器的测量值,通过H_∞滤波算法得到姿态信息,将此姿态信息输送给状态反馈H_∞控制器得出控制指令,利用零动量飞轮根据控制指令对卫星施加相应的控制力矩完成高精度姿态控制任务。同时建立姿态控制系统的闭环仿真环境,对前文设计的姿态控制系统进行验证与分析。仿真结果均验证算法的有效性,证明针对低轨道卫星设计的三轴姿态稳定控制系统可以达到高精度、高稳定度的姿态控制要求。更多还原

【Abstract】 With the development of the aerospace technology, the demand of low-orbit micro-satellite is increasing. The attitude control system is the key to ensure the stable operation and the basic functions of the satellite. This dissertation designs a high precision attitude control system of the three-axis stabilized satellite. Besides the controller, further research on the on-orbit calibration of the star sensor also be done.This paper firstly describes the common attitude coordinate system, then establishes the dynamics and kinematics model, introduces the H_∞control theory at last. The introduction of H_∞control theory sets a foundation for the in-orbit calibration and the design of controller.A system that can identify the constant error of the star sensor through high-precision gyro with H_∞filter is designed. High-precision gyro can give the attitude angle of satellite. This dissertation uses the star sensor’s constant error as state variables to get an identify model of the star sensor’s constant error, then uses two different filters and compares their results.H_∞state feedback controller of the low-orbit satellite is designed. Then based on the analysis of the system uncertainty and the environment disturbance, the attitude controller of the satellite is proposed. To make the computation easier, the LMI method is adopted to find out the coefficient of the controller.After all the works above, a high-precision control system of the low-orbit satellite need to be built. We can get the attitude data. We need by the high-precision gyro/star sensor and the attitude determination based on the H_∞theory. Then the controller get the data to compute the control instructions which are put into the fly-wheels, the fly-wheels putout the control torque, finally the whole system can finish the task of the attitude control. Simulation proves the design satisfies the demands.The simulation proves the algorithms useful, and the low-orbit satellite attitude control system can achieve the requirements.更多还原