【作者】 张烽；

【导师】 段广仁；

【作者基本信息】 哈尔滨工业大学 ， 控制科学与工程， 2013， 博士

【摘要】 航天器的姿态与轨道控制是空间任务成功与否的关键。随着空间需求的日益增多，特别是对于以在轨服务、编队飞行、行星软着陆过程的终端着陆和空间拦截等为代表的空间近距离运动任务，航天器在受控飞行过程中，其位姿需要快速地、同时地满足高精度的控制要求。传统的航天器姿轨独立控制方式已逐渐不能满足这些新型空间任务的控制精度及机动性能的需求。相比之下，航天器的姿轨联合控制方式能够充分考虑并利用姿态动力学与轨道动力学之间的耦合关系，将两者视为整体，采用统一的控制算法同时调整星体位姿，从系统和全局角度来处理问题，能够从本质上提高任务的控制精度和机动性能。因此，研究航天器近距离运动的姿轨联合控制具有非常重要的理论意义与工程应用价值。本论文以航天器的两类近距离运动任务——空间近距离操作和空间相对轨道机动为研究背景，对航天器近距离运动的姿态轨道一体化建模与控制进行了研究，主要内容包括：建立了面向两类空间近距离运动任务的航天器姿轨耦合动力学模型。根据空间近距离操作和空间相对轨道机动的任务特点，分别提出了控制机构的配置方案，在此基础上，分析航天器姿态与轨道之间的耦合关系，建立了对应的姿轨耦合动力学模型。根据执行机构配置方式的不同，两类动力学模型分别表现为全驱动系统和欠驱动系统。针对空间近距离操作任务，为充分利用执行机构全驱动控制特点，以提高系统的机动性能及控制精度，研究了航天器姿轨联合有限时间控制问题。针对这一问题，本文提出了基于轨迹跟踪思想的鲁棒姿轨联合有限时间控制律，通过设计一类动态性能良好且有限时间收敛的运动轨迹，将有限时间控制问题等价地转化为对设计轨迹的跟踪问题，并利用自适应Backstepping技术设计了控制律，使得航天器的位姿在星体质量特性未知，推力器安装误差和外界干扰存在的情况下，在预定的时间内达到期望值。另外，考虑到控制算法中对执行机构安装误差的补偿项使得控制输入指令不易求取，提出了一种基于优化思想的控制输入计算方法，保证推力输入指令的在线实时解算。随后针对系统中可能出现的“振颤”现象进行了分析，并改进了控制算法，给出了严格的稳定性分析。数值仿真验证了所设计的有限时间控制律的有效性。同样针对空间近距离操作任务，考虑到实际中执行机构幅值受限，研究了含有控制饱和的航天器姿轨联合控制问题，并进一步研究了含有控制饱和的有限时间姿轨联合控制问题。首先，基于抗饱和控制思想，结合自适应Backstepping技术，提出了具有抗饱和能力的鲁棒姿轨联合控制律，通过在虚拟控制中引入一个辅助信号，并对其动力学的巧妙设计，有效补偿了控制饱和误差带来的系统性能损失。随后，为兼顾抗饱和能力及有限时间控制律的强机动性和高控制精度，将已设计的鲁棒有限时间控制律和抗饱和控制律结合，基于切换思想，提出了抗饱和鲁棒有限时间姿轨联合控制律，并基于切换系统理论给出了闭环系统的稳定性分析。仿真结果表明，初期运行的抗饱和控制律能够有效处理执行机构饱和问题，当系统退饱和且满足给定的切换条件时，控制律切换至有限时间控制律，能够保证航天器相对位姿以较小的方法误差快速收敛于期望状态，较好地吸取了两者的优势。针对空间相对轨道机动任务，提出了基于滤波Backstepping技术的鲁棒姿轨联合控制律，解决了欠驱动情形下的航天器姿轨联合控制问题。由于这类任务中，单台轨控发动机的固连安装导致轨控推力矢量与星体姿态角呈非线性耦合关系，使得现有的非线性控制技术很难直接使用，这成为该类任务的姿轨联合控制问题的一个设计难点。本文基于三角函数性质，提出了一种向量分解技术，巧妙地处理了这种非线性级联关系，使得Backstepping思想得以成功应用。由于系统阶次较高，在利用Backstepping技术进行控制律设计时，每一步设计均引入一阶滤波器以避免“级数膨胀”现象。随后，从理论上给出了严格的闭环稳定性分析，其中，利用奇异扰动理论证明了标称情形下闭环系统的指数稳定性，并利用Lyapunov理论证明了一般情形下闭环系统的最终一致有界性。最后，通过对月面软着陆最终着陆段的仿真验证了所提出控制律的有效性。最后，研究了一类特殊的空间相对轨道机动任务——近圆轨道目标交会的姿轨联合控制问题。需要指出的是，利用本文所提出的向量分解技术可以将该控制问题转化为对一类推广的半严反馈系统的输出镇定问题，该系统具有低阶子系统呈线性形式、高阶子系统呈半严反馈形式且整体系统呈现级联形式的结构特点。因此，首先针对这类非线性系统，根据其结构特点，提出了一种基于H∞技术的鲁棒自适应Backstepping控制方法，解决了这类推广的半严反馈系统的鲁棒自适应控制问题，所设计的控制律不仅能够保证闭环系统的稳定性，而且能够按给定水平实现对系统不确定性的抑制。随后，利用所提出的控制算法针对近圆轨道目标交会任务构造了航天器鲁棒姿轨联合控制律，以保证轨控发动机推力受限情形下，主动航天器与目标之间的相对轨道沿着参考轨迹运行，完成最终交会，并能以给定水平抑制系统中的各种不确定性。最后，通过空间拦截任务的仿真验证了所提出控制律的有效性和优越性。更多还原

【Abstract】 The attitude and orbit control of spacecraft is the key technology in space missions.With the development of worldwide space activities, especially for the proximity mis-sions such as on-orbit maintenance, formation flying, astroid soft landing and space in-terception, the position and the attitude of spacecraft are often required to simultaneouslyachieve the desired states with high maneuverability and control accuracy. To this extent,traditional separated position and attitude control strategy is hard to meet the increas-ing requirements of these future space missions. In contrast, integrated translation androtation control scheme fully takes into consideration the mutual couplings between thetranslation dynamics and the rotation dynamics, and can simultaneously control the posi-tion and attitude motion, which is able to essentially improve the system performance andguarantee high control accuracy and maneuverability. The present dissertation focuses onthe integrated translation and rotation modeling and control of spacecraft in space prox-imity operations and space orbit maneuver, both of which are based on spacecraft relativemotion in proximity. The main researches are listed as follows.Two kinds of coupled relative attitude and orbit dynamics of spacecraft are formulat-ed for two type proximity missions mentioned above. The mutual couplings between theorbital dynamics and the attitude dynamics are analyzed. During the modeling, accordingto the requirements of both missions, two actuator configurations are given to providecontrol force and control torque. Due to the diferent actuator layout, the coupled dy-namics for proximity operations performs a full-actuated system, while the one for orbitmaneuver missions possesses an under-actuated system.Considering space proximity operations, in order to make full use of full-actuatedsystem such that the system maneuverability and control precision can be improved, westudy the robust integrated translation and rotation finite-time control problem of a s-pacecraft. To do so, by designing a class of well-behaviored trajectory with finite-timeconvergence, the finite-time control problem is equivalently transformed into a trajectorytracking problem, and thus a robust finite-time control law is developed via adaptive back-stepping technique. In addition, an approach for computing the thrust input is addressedsince it cannot be evaluated explicitly and directly from the developed control law. Fur-thermore, the control scheme is modified to eliminate potential chattering phenomenonand the stability analysis is given as well. The following numerical simulation shows that the position and the attitude of spacecraft are able to converge to their desired values ina pre-determined time, despite of unknown mass properties, thruster misalignment andexternal disturbances, which demonstrates the efectiveness of the proposed control law.In the sequel, based on the same mission, since the actuator outputs are limited inapplications, the integrated translation and rotation control problem of a rigid spacecraftwith control saturation is considered, and further, the integrated finite-time control prob-lem with control saturation is studied. To solve the first problem, based on anti-windupphilosophy and adaptive backstepping method, an anti-windup robust integrated transla-tion and rotation control law is proposed, where an auxiliary signal is introduced into thevirtual control to compensate for the influence caused by control saturation. Then, in or-der to obtain the high control accuracy and maneuverability from the designed finite-timecontroller and simultaneously deal with control saturation, based on switched control phi-losophy, the proposed finite-time controller and the anti-windup controller are synthesizedand thus the robust integrated translation and rotation anti-windup finite-time control lawis developed, which solves the second problem. The closed-loop stability is guaranteed byusing switched system theory. It can be demonstrated from numerical simulations that,the anti-windup controller takes efect initially to deal with input constraints, and oncethe control saturation no longer happens and the given switch condition is satisfied, thefinite-time controller takes over the system such that the relative position and the attitudeof spacecraft are able to accurately converge to the desired values in a fast response.After that, we focus on the integrated translation and rotation control for relativeorbit maneuver, whose dynamics possesses an under-actuated system. In these missions,a single orbital thruster is often fixed on the spacecraft body and thus the orbital thrustvector for orbit control performs nonlinear with respect to the attitude angles, which be-comes the chief difculty of the control problem. To deal with this nonlinear cascadedrelationship, based on transformations of trigonometric functions, a vector decompositionis proposed such that the backstepping philosophy is applicable. It follows that the fil-tered backstepping technique is used to construct the robust integrated control law, wherea first-order filter is introduced in each design step to facilitate the derivation of the vir-tual controls. Then, the rigorous closed-loop stability analysis is given by using singularperturbation theory and Lyapunov theory. Numerical simulation of a lunar soft landingscenario shows the efectiveness of the proposed control law.Finally, we study the spacecraft rendezvous mission with a target in near-circularorbit, which is a special-type relative orbit maneuver mission. For this mission, by us- ing the proposed vector decomposition, the integrated translation and rotation controlissue can be equivalently transformed into the output stabilization of a class of extend-ed semi-strict feedback systems, whose structure holds the features that1) the low-orderdynamics perform linear systems,2) the high-order dynamics take the semi-strict feed-back form, and3) the whole system possesses the cascaded structure. Thus, accordingto these features, a H∞-based robust adaptive backstepping control law is proposed suchthat the robust adaptive control problem of this type nonlinear system can be solved. Theproposed control scheme is able to not only guarantee the ultimate uniform boundednessbut also attenuate the system uncertainties with a given level. Based on the proposed con-trol scheme, a robust integrated translation and rotation control law is constructed suchthat the spacecraft is able to rendezvous with target along the reference trajectory andsimultaneously attenuate various system uncertainties. The following numerical simula-tion of a space interception scenario is given to illustrate the efectiveness of the designedintegrated controller.更多还原