【作者】 韩飞；

【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， 2018， 博士

【摘要】 空间失效航天器不具备合作的姿轨控制和信息交互支持能力;轨道处于空间摄动力作用下的自由漂飞状态;姿态处于空间摄动力矩作用下的慢旋或翻滚状态。本文将具备上述三方面特征的失效航天器称为空间非合作漂旋目标。针对此类目标的在轨服务任务面临任务环境高动态强时变、测量不确定性与大时延、复杂多约束等不利条件,使得空间非合作漂旋目标的逼近与跟踪控制成为亟待解决的瓶颈问题和国内外研究的热点问题。针对该问题,本文在动力学特性分析与建模的基础上,重点研究了复杂构型目标多约束下的姿轨同步逼近轨迹规划方法、姿轨耦合逼近与跟踪控制方法。主要包括以下内容:分析了逼近与跟踪非合作漂旋目标的姿轨耦合、多源测量误差传递等问题。通过分析空间漂旋目标的旋转运动特性,得出典型构型漂旋卫星的螺旋章动特性,进而设计了包含姿轨跟踪状态建立和最终逼近两个阶段的任务流程。分别建立了追踪星与目标星质心之间和表面之间的相对姿态和轨道耦合的动力学模型。建立了姿轨测量与导航误差在系统中的传递模型,通过数学仿真分析了从测量与导航误差到控制输入误差的传递影响。针对姿轨跟踪状态建立阶段的逼近轨迹规划问题,研究了多约束下的姿轨同步逼近最优轨迹规划方法。综合考虑安全防撞、视线跟踪、羽流规避、控制受限等约束,构建了复杂构型目标逼近与跟踪的多约束模型。建立了13个状态量的姿轨同步逼近最优控制问题描述方程,基于高斯伪谱法设计了非线性规划求解流程。为提高轨迹规划的运算效率,建立了姿轨同步逼近的虚拟域逆动力学模型、虚拟域与时域之间的状态量转换模型,进而设计了多约束下的轨迹规划解算流程。数学仿真结果表明:两种方法均可获得满足多约束条件的姿轨同步逼近轨迹;高斯伪谱法的时间或能量目标函数更优;虚拟域逆动力学法的计算效率相比高斯伪谱法大幅提升,但只能得到时间或能量次优的轨迹。针对姿轨跟踪状态建立阶段的姿轨同步控制问题,给出了一种双滑模面姿轨耦合控制方法,并分别通过数学仿真和地面微重力试验验证了有效性。为保证系统在不确定性、有界干扰等因素影响下的控制性能,提出了一种双滑模面控制方法,并证明了闭环系统稳定性,进而利用该方法设计了逼近和跟踪漂旋目标的姿轨耦合双滑模控制律。综合考虑有界干扰、测量误差、输入受限、系统不确定等因素,对传统单滑模面控制方法和本文提出的双滑模面控制方法开展数学仿真,结果表明:双滑模面控制方法在控制闭环中引入了状态偏差的积分项,且可自动补偿各种因素影响,使得稳态控制偏差和噪声同时得到明显改善。基于地面微重力半物理试验系统,设计了轨道面内对漂旋目标逼近与跟踪的任务场景,验证了双滑模面控制方法在GNC全系统实时闭环、微重力动力学条件下的有效性。针对最终逼近阶段的相对姿轨耦合控制问题,考虑距离目标过近导致无法直接测量相对姿轨状态的情况,基于所提的双滑模面控制方法,引入图像点坐标信息和期望广义速度,给出了一种间接估计辅助的图像视觉伺服双滑模控制方法。通过任务场景设定和仿真分析,发现基于间接估计信息的控制方案无法满足任务需求,甚至可能导致与目标碰撞。为此,基于图像视觉伺服思想,建立了超近距离姿轨跟踪的成像运动模型,将图像视觉伺服的期望广义速度、图像位置信息引入双滑模面控制闭环,从而提出了一种间接估计辅助的图像视觉伺服双滑模控制方法。数学仿真结果表明:与基于间接估计信息的控制方案相比,该方法的控制性能明显改善,可为空间漂旋目标的最终逼近与跟踪任务提供安全、准确、稳定的相对姿态和轨道条件。更多还原

【Abstract】 The failed spacecraft cannot provide cooperative and controlled attitude and orbit state for the On-Orbit Service satellite,and mantains floating in space with their orbit only affected by perturbative forces.Meanwhile,the space perturation moments will finally cause slowly rotating or tumbling.In this dissertation,the failed spacecraft with these three characteristics is named the floating and tumbling target in space.The On-Orbit Service(OOS)mission is faced with serious challenges,such as the high-dynamic and time-varying mission scenarios,measurement uncertainty and time-relay,multi-constraints,and so on.As one of the enabling technologies for the OOS mission,the control method for approaching and tracking the floating and tumbling non-cooperative target in space becomes the worldwide research hotspot and one of the most pressing problems.For this problem,after the dynamic characteristic modelling and analysis,this thesis focuses on two detailed problems,which are the planning of the safe approaching trajectory to the complex shaped tumbling target with multiple constraints,and the relative attitude and orbit coupled control for approaching and tracking the tumbling target.To solve the dynamic problems of approaching and tracking the typical tumbling satellite,the spiral nutation motion of the target is firstly analyzed,according to which,the mission procedure is designed containing two main phases,those are the attitude and orbit tracking state establishing phase,as well as the final approaching phase.The relative attitude and orbit coupled dynamic models are separately established for the motions between the centroids and surfaces of the chaser and target,then the coupled relationships between the relative attitude and orbit are analyzed.The propagation of measurement and navigation errors in the control system is also modelled,with their influences to control input errors analyzed by numerical simulation.Aiming at the safe approaching trajectory planning problem in the phase of the attitude and orbit tracking state establishing,two attitude and orbit trajectory planning methods are proposed respectively based on the Gaussian pseudo-spectral and the inverse dynamics in virtual domain.The multi-constraint models are established,comprehensively considering the constraints of collision avoiding,sight line tracking,thrust plume interference,limited control input,and so on.By solving the non-linear optimized control problem by using the Gaussian pseudo-spectral method(GPOPs),the planning method of safe approaching trajectory to the tumbling target is designed.Then,in order to increasing the trajectory planning and calculation efficiency,a rapid planning method is designed,which is based on the inverse dynamics in virtual domain(IDVD).Numerical simulations are implemented to demonstrate their capacities to obtain the time or energy optimized trajectory synchronously satisfying multiple constraints.The IDVD method shows significant advantage in computational efficiency,while it can only obtain the suboptimal trajectory.For the relative attitude and orbit coupled control problem in the phase of the attitude and orbit tracking state establishing,a dual sliding-mode surface control(DSMSC)method is proposed,with its efficiency verified by numerical simulations and ground micro-gravity tests.To improve the control performance impacted by bounded disturbance and parameter uncertainty,a dual sliding-mode surface control method is designed,with the closed-loop system stability is also proved.An attitude and orbit coupled DSMSC control method is then designed for approaching and tracking the floating and tumbling target.Comprehensively considering impacts from bounded disturbance,measurement errors,limited control input,parameter uncertainty,numerical simulations are carried out to compare the performances of the single sliding-mode surface control(SSMSC)law and the DSMSC.The second sliding-mode surface of the DSMSC is indicated to remarkably lower the steady statue control bias and noise,which is mainly because of introducing the statue bias integration into the control quantity and its ability to auto-compensate influences from negative factors.Furthermore,a set of ground micro-gravity semi-physical verification system is established,and a mission scenario is designed with the motion constrained in the orbit plane.Then,the efficiency of the DSMSC is verified in the real-time GNC close-loop system with micro-gravity dynamics.In order to solve the approaching and tracking control problem in the situation of direct relative measurement losing efficacy caused by the ultra-short distance during the final approaching mission phase,an indirect estimation assisted IBVS(IEA-IBVS)control scheme is proposed based on DSMSC method.Through the mission scenario analysis and numerical simulations,the control scheme using indirect estimation of the relative attitude and orbit is proved to be deficient,even may cause crash to the target.According to the image based vision servo(IBVS)method,the imaging and motion model is established.By introducing the IBVS expected generalized velocity and image coordinates’ information into the DSMSC control close-loop,an indirect estimation assisted IBVS(IEA-IBVS)control scheme is proposed.The numerical simulation results indicate that,the IEA-IBVS can remarkably promote the relative attitude and position control accuracies,provide more safe,accurate,and stable relative attitude and orbit condition for final approaching and tracking the tumbling target in space.更多还原