空间交会近程导引段的滑模变结构控制

发布时间：2018-03-27 20:52

本文选题：空间交会　切入点：变结构控制　出处：《哈尔滨工业大学》2015年硕士论文

【摘要】：空间交会是一项广泛应用于在轨服务、在轨装配与编队飞行等复杂航天任务的基础性技术,由于其中的控制问题是保证自主交会成功的关键而吸引了许多研究者们的关注。在研究空间交会控制问题时会受到许多现实工程因素的制约,如在轨航天器除受中心引力作用外还会受到许多外部摄动力的作用,航天器执行机构的故障与时变特性等。滑模变结构控制是一种具有强鲁棒性的非线性控制；相比于其他控制方法,滑模控制在抑制或消除模型不确定性与外部扰动上具有很强的能力。因而本学位论文的主要内容是利用滑模变结构控制理论在考虑必要工程约束的情况下提出适用于航天器自主交会的控制方案。现实中绝大多数空间交会的参考轨道呈近圆形,因而本文将着重研究近圆轨道上航天器自主交会的控制方法。在动力学建模部分,本文由含摄动的非线性二体模型出发,通过拉格朗日与泰勒级数展开进行线性化,在并保留关于参考轨道偏心率的一阶展开项后得到用于描述近圆轨道空间交会的动力学模型,其中参考轨道的非圆性与两航天器所受摄动力的差值分别以时变参数项与外部扰动项的形式存在与模型中。针对存在摄动力扰动与执行器饱和的空间交会,本文提出一种固定增益滑模抗饱和控制器,利用滑模控制抑制外部扰动,通过固定增益避免推力器陷入饱和。此后针对执行器输出上限时变的情形,提出一种增益自适应滑模抗饱和控制器,利用白适应的控制器增益避免了固定增益控制器由于预设增益过小造成的执行器性能浪费或过大引起的执行器饱和。针对存在摄动力扰动与推进系统故障的空间交会,本文提出一种复合型鲁棒容错控制方案。该方案由积分滑模辅助控制器与鲁棒容错保性能控制器复合而成。其中,积分滑模辅助控制器能够消除摄动模型中的外部扰动项并对推力器故障具有容错能力,鲁棒容错保性能控制律则能够以最小成本镇定含故障及时变参数的空间交会标称系统。在含有摄动的非线性二体模型中,本文对固定增益与增益自适应滑模抗饱和控制器以及独立鲁棒容错保性能与复合鲁棒容错控制器进行了对比仿真。仿真结果显示,增益自适应控制器与复合鲁棒容错控制器较其余控制器在航天器自主交会任务中具有稳定性好、收敛速度快以及能量消耗小等优点。
[Abstract]:Space rendezvous is a basic technology widely used in complex space missions such as in-orbit service, in-orbit assembly and formation flying. Since the control problem is the key to ensure the success of autonomous rendezvous, it has attracted the attention of many researchers. In studying the control problem of space rendezvous, it will be restricted by many practical engineering factors. For example, the in-orbit spacecraft will also be subjected to many external perturbation forces in addition to the central gravity force, and the fault and time-varying characteristics of the spacecraft actuator, etc. Sliding mode variable structure control is a nonlinear control with strong robustness. Compared with other control methods, Sliding mode control has a strong ability to suppress or eliminate model uncertainty and external disturbance. Therefore, the main content of this dissertation is to use sliding mode variable structure control theory to propose a suitable method considering the necessary engineering constraints. Control scheme for spacecraft autonomous rendezvous. In reality, most of the reference orbits of space rendezvous are nearly circular. Therefore, this paper will focus on the control method of spacecraft autonomous rendezvous in near-circular orbit. In the part of dynamics modeling, the nonlinear two-body model with perturbation is linearized by Lagrangian and Taylor series expansion. After preserving the first-order expansion term of the reference orbit eccentricity, a dynamic model for describing the space rendezvous of the near-circular orbit is obtained. The difference between the non-circularity of the reference orbit and the perturbation force of the two spacecraft is in the form of time-varying parameter term and external disturbance term, respectively. In this paper, a fixed-gain sliding mode anti-saturation controller is proposed. The sliding mode control is used to suppress the external disturbance and to avoid the thruster falling into saturation through the fixed gain. A gain adaptive sliding mode anti-saturation controller is proposed. The white adaptive controller gain is used to avoid the actuator saturation caused by the fixed gain controller which is caused by too small preset gain. In view of the spatial rendezvous between the perturbed disturbance and the propulsion system fault, the performance of the actuator is wasted or too large due to the presupposition gain. In this paper, a composite robust fault-tolerant control scheme is proposed, which is composed of an integral sliding mode auxiliary controller and a robust fault-tolerant guaranteed cost controller. The integral sliding mode auxiliary controller can eliminate the external disturbance in the perturbation model and has fault tolerance ability to the thruster fault. Robust fault-tolerant guaranteed cost control law can stabilize space rendezvous nominal systems with fault and time-varying parameters at minimum cost. In this paper, the fixed gain and gain adaptive sliding mode anti-saturation controller and independent robust fault-tolerant guaranteed cost controller and composite robust fault-tolerant controller are compared and simulated. The gain adaptive controller and the composite robust fault-tolerant controller have the advantages of better stability, faster convergence speed and less energy consumption than the other controllers in the autonomous rendezvous mission.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V526;V448.2

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