【作者】 王俊；

【导师】 李传江；

【作者基本信息】 哈尔滨工业大学 ， 控制科学与工程， 2016， 硕士

【摘要】 未来航天任务越来越复杂,对卫星的指向精度和稳定度提出的要求也越来越高。采用合适的隔振技术削弱振动是提高卫星姿态控制精度的关键技术。载荷扰动隔离(Disturbance-free Payload,DFP)卫星从结构上将卫星分为载荷舱与平台舱,两舱通过非接触磁浮机构连接,将卫星有效载荷与振动源从物理结构上完全隔离,从而保证载荷的高精度高稳定度姿态控制。目前针对DFP卫星的研究主要集中在数学建模、隔振性能验证以及结构设计方面,并取得了可观的成果。与此同时,结合工程实际问题设计性能良好的控制器,对于实现DFP卫星的高精度姿态控制也有重要的意义。本论文研究内容来源于航天八院某研究课题“动静隔离式超高指向精度、超高稳定度卫星控制技术研究与仿真软件开发”,在考虑了DFP卫星的结构特性、执行机构输出能力受限以及环境扰动等工程实际问题的情况下,设计了完整的DFP卫星一体化控制方案,在避免两舱发生碰撞的同时实现了载荷舱高精度高稳定度姿态控制。主要包括以下几方面内容:首先,对DFP卫星进行了数学建模。对DFP卫星工作模式及控制系统进行了分析,在总结DFP卫星的运动特性及控制系统特点的基础上给出了DFP卫星运动学及动力学方程,给出了DFP卫星两舱相对位置及相对姿态解算方法。然后,针对DFP卫星的姿态控制问题,针对卫星平台舱和载荷舱的不同控制需求及结构特点,分别设计了姿态控制器。针对载荷舱,在充分考虑空间环境干扰和转动惯量不确定性的条件下,设计了一种满足输入有界条件且不依赖载荷舱转动惯量的非线性姿态控制器。该控制器结构简单、易于实现,同时具有较强的鲁棒性。针对平台舱的太阳帆板存在抖振的问题,基于经典控制理论和频域分析的方法,设计了结构滤波器及PD控制器使得平台舱能够有效抑制帆板振动并跟踪载荷舱的运动。接着,针对DFP卫星两舱相对位置控制问题,设计了两种相对位置控制器。首先充分利用每个磁浮机构线圈与磁轭的间隙,考虑磁浮机构线圈与磁轭的相对运动情况,设计了基于逻辑的离散相对位置控制器,在实现两舱避碰的同时有效降低了相对位置控制的频次。为了进一步提高两舱避碰的安全性,在考虑两舱受到空间环境摄动影响以及执行机构输出能力受限的条件下,设计了具有L2增益干扰抑制能力的连续相对位置控制器,并从理论上证明了控制系统的稳定性。最后,结合姿态控制器做了六自由度联合仿真分析,验证了本文所设计的姿态控制器及相对位置控制器的有效性,并能实现DFP卫星载荷与卫星平台的高精度高稳定度一体化控制。更多还原

【Abstract】 As the future space missions is becoming more and more complex, the high accurancy and stability of satellit attitude control is becoming more and more important. Using appropriate satellite vibration isolation technology to weaken vibration is the key to improving the precision of satellite attitude control. Disturbance-free Payload satellite structure contains the payload module and the platform. The two modules are connected by the non-contact magnetic actuators. The structure of a satellite with Disturbance-free Payload(DFP)architecture can isolate satellite payloads from virbration sources in the physical structure, which can guarantee the precision and stability of the payload attitude. At present, the research of DFP satellite which is mainly focused on mathematical modeling, vibration isolation performance verification and structure design has gained considerable achievements. Meanwhile, designing controllers with good performance combined with the practical engineering problems is of great significance for the realization of the high precision attitude control of the DFP satellite. The content of this paper comes from a project “Dynamic Isolation Type Super High Pointing Accuracy, Super High Stability of Satellite Control Technology Research and Simulation Software Development”. Considering engineering practical problems such as the DFP satellite structure character, actuators output limited, environmental disturbnace and so on, this paper designs integrated control method for DFP satellite to achieve high precision high stable attitude control for payload module while avoiding the collision. The main contents of this dissertation are as follows:Firstly, establish mathematical model for disturbance-free payload and satellite platform. Analysis the work pattern and control system of DFP satellite, on the basis of summarizing the characteristics of DFP satellite and control system, present the kinematics and dynamics models. The relative position and attitude calculation method of the two modules are introduced in detail.Then, design attitude controlers for payload moduel and platform respectively according to attitude control problems and their different control demands and the structure features. For payload module, considering the influence of environmental disturbance, uncertainty of moment of inertia, and actuators output limited, propose a saturate nonlinear attitude control menthod without moment of inertia. For the platform, based on classical control theory and frequency domain method, design filter and PD controller to track payload moduel and suppress the chattering phenomenon of flexible appendagesLater, two kinds of relative position controllers are proposed. Making full use of the clearance between the yoke and coil of non-contact magnetometric actutors, considering the relative motion of the coil and the yoke, design the discrete logic position controller to avoid collision of the two modules and reduce the times of control. In order to further improve the safety, considering the two modules are in the conditon of environmental disturbance and limited output capacity of the actuators, design L2 gain disturbance suppress continuous controller, and theoretically proved that the control system is stable.Finally, the six degrees of freedom simulation combined with the attitude controllers is involved to illustrate the effectiveness and feasibility using the proposed control methods. The results show that high precision and high stability of integrated control for disturbance-free payload and satellite platform can be achieved.更多还原