【作者】 吉莉；

【导师】 刘昆；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2012， 博士

【摘要】 内编队重力场测量卫星系统是测量地球引力场的一种创新方案，由外卫星和内卫星组成并构成紧密飞行编队，外卫星屏蔽内卫星所受的非保守力，使内卫星按纯引力轨道飞行，精密测量它的轨道就可以反演计算出地球重力场分布。对外卫星的轨道和姿态控制，是确保内卫星的纯引力轨道飞行从而决定重力场测量水平的关键技术。论文针对内编队重力场测量卫星系统面临的控制问题，系统研究了相对轨道保持和姿态稳定一体化控制所涉及的动力学建模与分析、控制精度需求与分析，提出了约束非线性模型预测控制方法、扰动补偿控制和全推力器控制方案等。论文主要研究内容和成果如下：建立了内编队系统稳态运行期间的相对轨道和姿态动力学模型，完成了内编队系统扰动分析。通过分析主要扰动源对相对轨道和姿态的短时影响和长期效应，确立以大气阻力补偿为首要控制目标的内编队系统相对轨道保持控制策略。确立了内编队重力场测量卫星系统相对轨道保持和姿态稳定控制的精度需求。基于内编队系统重力测量原理和相对位置测量原理，建立相对轨道保持和姿态稳定控制与重力测量任务、相对位置测量和精密定轨三者的联系，通过理论建模、误差传播分析和仿真实验，完成了控制系统精度需求分析，为控制系统设计提供合理规范。开展了三种内编队相对轨道保持和姿态稳定控制方法研究，提出了约束非线性模型预测控制方法，实现了内编队轨道与姿态的一体化控制。针对相对轨道和姿态动力学共有的非线性特征和参数不确定问题，基于自适应全状态反馈控制实现了内编队系统相对轨道保持和姿态稳定。为提高控制精度、缩短调节时间并消除输入振颤，提出了适合处理MIMO系统的非线性模型预测控制方法，获得了对模型参数不确定和外部扰动的鲁棒性。考虑内卫星活动范围和执行机构能力约束，提出了约束非线性模型预测控制方法，其干扰不变性适应内编队系统强相对位置约束、高姿态稳定性的任务需求。设计了基于UKF扰动估计的内编队系统扰动补偿控制方案。针对内编队系统相对轨道保持的扰动消除问题，基于相对位置和姿态观测数据，设计了基于UKF（Unscented Kalman Filter）的扰动实时估计方法。利用估计结果，通过扰动估计和反馈控制实现了对内编队的扰动补偿控制，改善了相对轨道保持控制性能。设计了基于连续微推力器的内编队系统轨道与姿态一体化控制方案。通过采用阻力补偿加平衡控制的推力器配置，完成了全推力器控制方案设计。论文以实现内编队系统精密控制为目标，研究取得的约束非线性模型预测控制、扰动估计与补偿控制和全推力器控制方案设计等成果对提高内编队重力场测量卫星系统控制性能具有重要的理论意义和工程价值，对其它卫星的控制也具有理论和技术参考价值。更多还原

【Abstract】 The Inner-formation gravity field measurement satellite system (IFS) is a novelprogram aiming to measure the Earth’s gravity field. It consists of the outer-satellite andthe inner-satellite and hereby turns out to be a compact formation. Completely enclosedin the outer-satellite, the inner-satellite is shielded from non-conservative forces andfollows a purely gravitational orbit. With measurement of the orbit, the Earth’s gravityfield can be reconstructed. One of the key techniques determining the measurementlevel of gravity field is the outer-satellite control used for keeping the inner-satelliteflying in a pure gravitational orbit stably. To resolve the control problem for IFS, thisdissertation studies the integrated relative orbit maintenance and attitude stabilizationcontrol, which involves dynamics modeling and analysis along with control accuracyrequirements and analysis, and proposes constrained nonlinear model predictive control(CNMPC) method, disturbance compensation control and all-propulsion control scheme.The main issues and results of this dissertation are summarized as follows.The relative orbit and attitude dynamic models are constructed and thedisturbance environment is analyzed for IFS in steady-state phase. Based onanalysis of short-term and long-term effects of main disturbances on the relative orbitand attitude, drag compensation is established as the primary control object to maintainthe relative orbit.The accuracy requirements of relative orbit maintenance and attitudestabilization control of IFS are specified. Based on the principles of gravity fieldmeasurement and relative position measurement of IFS, the relationships betweenrelative orbit maintenance and attitude stabilization control and gravity fieldmeasurement, relative position measurement and POD are formulated. The accuracyrequirements of control system are analyzed to provide specification for the controlsystem design, using theoretical modeling, error propagation analysis and simulationexperiments.Three techniques are developed for the relative orbit maintenance andattitude stabilization control, and the CNMPC method is proposed to implementthe integrated orbit and attitude control for IFS. An adaptive full-state feedback lawis taken to account for the nonlinearity and parameter uncertainty behaved by both therelative orbit and attitude dynamics. To improve control accuracy, shorten regulationtime and remove input chattering, a general nonlinear model predictive controlalgorithm is developed to deal with multi-input-multi-output system, achievingrobustness against the model parameter uncertainty and exogenous disturbance. Takingthe territory of inner-satellite and performance restrictions of the actuator into account,the CNMPC algorithm is proposed. The invariance with respect to uncertainties and disturbances applies to the mission requirements of IFS, namely the strong constraintson relative position and high attitude stabilization.A disturbance compensation scheme based on UKF (Unscented Kalman Filter)and disturbance estimation is put forward. To achieve disturbance rejection for therelative orbit maintenance, a real-time estimation of disturbance using UKF is projectedbased on observation of relative position and attitude. Making use of the estimationresults, the disturbance compensation is realized by means of disturbance estimation andfeedback, improving the control performance of relative orbit maintenance.An all-propulsion design using continuous micro-thruster to perform theintegrated orbit and attitude control of IFS is brought forward. The all-propulsionscheme is realized by a thruster configuration adapting to playing drag compensationand balance control simultaneously.This dissertation aims to figure out the precision control problem of IFS and hasimportance theoretical significance and engineering values in improving the controlperformance of IFS, embodied by proposing the CNMPC algorithm and the real-timeestimation method of disturbances using UKF. It can also provide theoretical andtechnical references on the control system design for satellites.更多还原