【作者】 程颢；

【导师】 沈毅； 葛升民；

【作者基本信息】 哈尔滨工业大学 ， 控制科学与工程， 2009， 博士

【摘要】 本论文研究用于卫星姿态控制系统的飞轮的控制。飞轮是卫星姿态控制系统的力矩执行元件,理想的飞轮输出力矩应该严格复现输入指令。但是,实际工程使用的飞轮一直存在诸多非理想因素,严重制约卫星姿态控制系统的精度。本论文从工程实际提出的问题出发,应用现代控制理论解决工程问题。论文首先从工程角度出发介绍了飞轮的结构、工作原理、国内外发展现状,指出目前工程应用的飞轮存在的问题,提出改进飞轮性能的方法。论文详细研究了飞轮控制系统存在的干扰和噪声,为深入研究飞轮控制系统奠定良好的基础。通过分析表明,在飞轮中存在两个影响飞轮性能的关键因素:一是非线性摩擦力矩干扰,二是大范围变速率运行造成的参数变化。这两个因素的存在严重制约了飞轮的性能。飞轮内部的摩擦力矩在零转速附近具有非线性特性,干扰飞轮输出力矩。论文提出了基于速率反馈的飞轮控制系统结构方案,目的在于消除飞轮系统内部非线性摩擦力矩干扰对输出力矩的影响。飞轮控制系统采用脉宽调制和线性调整组合的驱动结构,避免了惯用的脉宽调制结构存在的切换扰动。论文指出目前工程实践中的速率模式飞轮和力矩模式飞轮都可以通过速率反馈的方式抑制干扰从而提高飞轮性能,这一思想是飞轮各种模式的控制系统设计的基础,通过在飞轮系统中引入积分输出反馈,将系统内存在的干扰包括在反馈环内,从而抑制系统内部干扰。这个构造性工作具有重要的理论和工程意义。由于飞轮运行速率范围很宽,参数变化大,在全速率范围内保证速率反馈控制系统的性能具有挑战性。针对飞轮参数变化特性,论文设计了基于增益调度理论的飞轮控制器,使控制系统的动态特性得到提高。该控制器应用于速率模式和力矩模式的飞轮,有效克服了低速非线性摩擦干扰,使飞轮的速率/力矩在全速度工作范围内的动态性能得到有效保证。论文最后给出一个设计的飞轮控制系统在某一卫星应用的例子。比较分析显示,应用本文设计的带有速率反馈飞轮的卫星姿态控制系统性能有明显提高。本论文的研究成果已经直接应用在前不久成功发射的“风云三号”气象卫星和“神舟七号”伴随卫星中,遥测数据显示应用新型飞轮明显提高了卫星的性能,论文工作的工程意义得到实践的验证。更多还原

【Abstract】 This thesis is on the study of flywheel control used in satellite attitude control system. Flywheel is used as torque executive component in attitude control system. Ideal flywheel torque output is identical with torque instruction. Unfortunately, there are some undesirable factors in flywheel applied in engineering, which limit satellite attitude control system accuracy. In this thesis, this problem is solved with control theory in an engineering way.Firstly, the state of art, the structure and principle of flywheel are introduced. The problems in flywheel engineering are pointed out, and the way to improve flywheel performance is put forward.A deeply analysis of noise and disturbance in flywheel control system gives a sound foundation of flywheel control system study. Analysis reveals there are two factors playing key role in depressing flywheel performance, nonlinear friction torque disturbance and parameters varying with flywheel velocity changing in large range.The friction torque in flywheel is nonlinear in the vicinity of zero velocity which disturbs flywheel output. A velocity feedback control scheme is adopted to eliminate this disturbance. To avoid jitter in flywheel working state change, the control system is constructed with pulse width modulation and linear adjusting. Flywheels are used as velocity mode or torque mode in satellite engineering. It is proven in this thesis that the performance of flywheel in these two modes could be improved by suppressing unavoidable disturbance with velocity feedback, this theory is a new type of flywheel control system foundation. Using integral of output as feedback in flywheel system, including disturbance in feedback loop to suppress disturbance effect, is an important constructive work.Flywheel operates in a wide range of velocity, which induces parameters to vary greatly, to keep feedback system stable and performance in large velocity range is a challenge. In this thesis, a Gain Scheduling Controller is designed to cope with parameters varying, and the designed system has desirable dynamic performance. The controller is used in velocity mode or torque mode flywheel, as a result the effect of friction torque is greatly suppressed especially in low velocity band, and the dynamic performance and static accuracy of flywheel torque/velocity output are met in full velocity range. An application of designed flywheel system in a satellite is given in the thesis; comparative analysis shows the performance of attitude control system with velocity feedback flywheel is distinctly improved.The study result was used in“FY-3”satellite and“SZ-7”companion satellite lunched lastly, remote data showed the designed flywheel contributed a lot in satellites attitude performance, this proved the thesis work is valuable in engineering point of view.更多还原