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针对考虑位姿耦合的非合作航天器交会对接场景,在没有速度测量情况下为了同时解决安全约束、模型不确定性、执行器故障和输入饱和问题,提出一种基于容积卡尔曼滤波算法(CKF)的自主安全接近方法。首先基于容积卡尔曼滤波器和扩张状态观测器(ESO)分别估计目标航天器的位姿信息和相对速度信息;然后通过将一种新颖的安全包络与人工势函数(APF)结合设计自适应滑模控制器,并设计非奇异辅助系统对执行器故障和输入饱和带来的影响进行集中处理。提出的控制策略在不违反安全约束情况下,能在固定时间内实现位置接近和姿态同步。通过李雅普诺夫方法可以保证闭环系统固定时间稳定。仿真结果表明,所提控制方法具有较高的精度和良好干扰抑制能力。 相似文献
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微小航天器单相流体回路自主热控地面实验研究 总被引:2,自引:0,他引:2
单相流体回路是解决微小航天器热控问题的一种重要手段,但是由于其内热源功率密度高、轨道热环境变化复杂,要求其具有高度自适应控制能力。为满足开展微小航天器单相流体回路自主热控研究的需要,提出了一种单相流体回路核心部件-微机械泵的PWM控制策略及实现算法,设计并搭建了其地面等效模拟实验装置,实现了该单相流体回路包括微机械泵驱动电压-压差输入输出关系、热源载荷变化及微机械泵转速变化的开环动态特性实验研究,并在此基础上完成了所提出的单相流体回路自主控制方法控制效果的地面等效模拟实验研究,达到±0.5℃以内的自主控温效果。该控制策略除了可以实现高精度自主控温以外,由于机械泵功耗基本上与热载荷成正比,还可以减少热控系统运行能耗,因而在能量供应有限的微小航天器上具有广阔应用前景。 相似文献
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Compared to traditional docking systems, spacecraft docking with inter-satellite electromagnetic mechanism has distinct advantages. However, its 6-DOF control problem has not been adequately investigated. From our knowledge, this paper attempts to study the 6-DOF control problem for the first time. Based on the far-field electromagnetic force model and Hill's model, the dynamic model of translational motion is derived; using tracking control strategy, LQR method and estimate of Extended State Observer (ESO), an optimal and robust translational controller is designed to satisfy relative position/velocity requirements of soft docking. Representing the attitude of the docking spacecraft pair by unit quaternion, the attitude dynamic and kinematic models with quaternion expression are derived; using behavior-based coordinated control approach and ESO, a decentralized attitude controller is designed to simultaneously align one spacecraft with its absolute desired attitude and with the other spacecraft of the docking pair, requiring no angular velocity measurement and exhibiting better robust capability. The feasibility and performance of this proposed 6-DOF controller are validated by theoretical deduction and simulation results. 相似文献
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航天器自主运行技术的进展 总被引:6,自引:5,他引:6
阐述了航天器自主运行的概念、目标和任务。对自主运行和传统测控方式进行了比较。最后重点介绍了航天器自主运行技术的进展情况。文章分4个部分介绍自主运行技术。首先介绍了2种自主运行体系结构,它们是自主运行各种功能集成的基础。第2部分介绍了2种智能规划与调度技术。第3部分介绍了基于模型的故障诊断与系统重构技术。第4部分介绍了有效载荷数据自主处理的进展情况。最后进行了总结并介绍了与自主运行相关的其他技术。 相似文献
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Momentum management of spacecraft aims to avoid the angular momentum accumulation of control momentum gyros through real-time attitude adjustment. An attitude control/momentum management controller based on state-dependent Riccati equation is developed for attitude-stabilized spacecraft. The governing equations of the system are formulated as three-axis coupled with full moment of inertia, which fully capture the nonlinearity of the system and are valid for systems with significant products of inertia or strong pitch to roll/yaw coupling. The state-dependent Riccati equation algorithm brings the nonlinear system to a linear structure having state dependent coefficients matrices and minimizing a quadratic-like performance index. The system equations are nondimensionalized, which avoid numerical problems at the same time make the weighting matrix more predictable. To guarantee closed-loop system stability, the state-dependent Riccati equation algorithm is also modified based on pole placement technique. The state-dependent Riccati equation is online calculated through the computational-efficient θ-D technique which reaches a tradeoff between control optimality and computation load. The dynamic characteristics of the system at torque equilibrium attitude are analyzed. Constraints on moment of inertia for successful momentum management are provided. Simulations demonstrate the excellent performance of the controller. 相似文献
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航天器的自主导航技术 总被引:4,自引:0,他引:4
本文首先总结航天器自主导航技术的发展史,在此基础上分折了目前几种候选的自主导航系统,对比了它们的性能和优缺点。然后介绍了自主导航技术及系统组成规律。着重介绍了载人飞船自主导航系统的组成,自主导航的算法。最后提出了发展我国飞船自主导航系统的建议。 相似文献
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Presented herein is a concept of an Autonomous Navigation & Guidance System for electrically propelled deep space missions, including hardware configuration, algorithms for autonomous navigation and guidance, and estimates of potential guidance precision and mass consumption. This concept is actually a unified Navigation, Guidance and Attitude Control system. The unification is imposed by strong coupling between the orbital motion and the spacecraft attitude characteristic of low thrust space flights. The sensor set of the system consists of an optical instrument (Coupled Sun Star Tracker), and a block of four vector accelerometers. The propulsion subsystem is a set of nearly parallel Hall thrusters rigidly attached to the spacecraft body. The final stage of data processing is combining the thrust and torque programs and generating power and mass rate shares for every thruster. An end-to-end computer simulation provides guidance accuracy estimates versus the navigation data precision, flight time and available maximum thrust. Terminal guidance errors of a few tens of km in position and a few tens of cm/s in velocities are predicted under plausible assumptions on system parameters. Mass expenditures for the control are typically below one percent of total fuel mass budget. 相似文献
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This report deals with the problems of synthesizing algorithms for controlling the attitude manoeuver of a transport spacecraft aimed at injecting the spacecraft into a closed terminal domain of “heading-range” phase coordinates which makes it possible to descend to the landing aerodrome region in accordance with a spiral trajectory tracking pattern. The descent trajectory is controlled by changing the roll angle. The principal distinguishing feature of the suggested method of transport spacecraft lateral motion control resides in guiding the spacecraft to a terminal curve and in providing an automatic transfer from roll control to interacting control of roll angle and angle of attack. The performance of the control algorithm under transient conditions are considered in detail.Algorithms controlling the longitudinal range by varing the magnitude of the roll angle and lateral range by selecting the respective sign of the roll control angle are thereafter synthesized separately. The major problem in designing the angular motion control system of transport spacecraft is the development of a high-rate roll axis turn control algorithm. To ensure high accuracy of lateral manoeuvering of the spacecraft it is expedient to accomplish the spacecraft reorientation in roll in a minimum time. It is therewith necessary to take into account with the sideslip angle limitation associated with the need of complying the design conditions of the spacecraft flowaround and with the spacecraft skin selected temperature conditions. It is expected that the total side slip angle is acceptable for measurement. Within the greater portion of the descent trajectory constant-thrust jet-reaction control engines are employed as actuators. Therefore, together with the high speed of response developed control algorithm provides an adequate efficiency of the system from the viewpoint of fuel consumption. The possibilities offered by the suggested algorithms controlling the lateral motions of the center of masses and around the center of masses during the descent stage and in the course of landing approach manoeuvering are illustrated by an example considering a hypothetical transport spacecraft featuring variable aerodynamics and a low frequency of natural oscillations of the angular motion loop. The suggested algorithms make it possible to fully employ the transport spacecraft maneuverability and to meet the terminal heading and velocity requirements within a wide class of disturbances. 相似文献
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针对传统脉冲避障算法在航天器轨迹规划应用中存在对瞬时推力依赖性强且燃料消耗量大的问题,提出能量最优的连续动态避障算法。该算法首先基于线性相对运动方程与有限时间的能量最优模型,建立了相对运动能量最优模型,同时验证了模型最优性;其次将动态障碍物的 y 向运动误差偏移与正态分布概率引入避碰安全距离模型,修正了追踪航天器动态避障的范围,确定了安全距离矢量长度,增强了规避障碍的可靠性;最后通过障碍物速度矢量与追踪器航天器速度矢量夹角确定动态避障点方向,减少燃料消耗的同时提高了避障的有效性、准确性。通过仿真验证,该算法可以自适应选取规避障碍点,有效规避动态障碍;工质燃料消耗较小,有效延长航天器在轨寿命。 相似文献
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There is suggested an algorithm of the autonomous tracking of a minor celestial body (comet, asteroid or satellite) by the photo-TV-camera of the spacecraft during its flyby in the vicinity of the celestial body, investigated by the data of images obtained by this camera. This algorithm allows prediction of the celestial body angular position in order to point the onboard camera to the body. The field of applicability for the suggested algorithm taking into account various errors is being investigated. The problems of the optimization of the program of the autonomous tracking in order to decrease the prediction errors or to increase the prediction time interval are considered. The results obtained are illustrated by the example of the autonomous tracking of Halley's comet nucleus. 相似文献
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针对地球中高轨道卫星导航信号不可用或不可信赖情况下的航天器编队自主相对导航问题,提出一种基于星载数据链仅测距的航天器相对导航新方法。首先,在地球非球形J2引力摄动条件下建立适用于椭圆轨道的线性化相对运动动力学模型,并建立基于星载数据链的飞行时间测距模型。然后,通过理论推导与数值仿真结合的方式对建立的仅测距相对导航系统进行可观测性分析,得出至少存在三种镜像模糊轨道的结论。接着,建立可用于提升系统可观测性的几何拓扑一致性约束模型,设计基于一致性无味卡尔曼滤波的分布式估计策略,并研究对应的相对导航误差传播规律。最后,通过标准蒙特卡洛打靶对所提算法进行仿真校验。仿真结果表明,相比于Tschauner Hempel(TH)动力学模型,利用建立的J2摄动相对运动动力学模型设计的仅测距相对导航系统能达到更高的相对导航精度,一致性无味卡尔曼滤波算法也能够有效提高编队导航的可观测性。 相似文献
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应用压电材料实现大型柔性空间结构的振动控制引起了广泛关注。针对上下表面粘贴压电层的复合层梁结构,采用高阶位移场模型,利用线性热压电本构关系和Hamilton原理导出了层梁结构的高阶有限元模型。电势和温度沿厚度方向的分布均采用线性模型。采用常增益速度负反馈控制、Lyapunov反馈控制和基于独立模态的线性二次型调节器(LQR)设计主动控制器,实现了层梁结构脉冲激励和热载荷作用下的振动主动控制。仿真结果表明,LQR方法更能有效的实现结构振动控制,其振动衰减时间较短,作动器峰值电压更低,但不能消除热载荷引起的结构静变形。 相似文献
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The capacity to acquire the relative position and attitude information between the chaser and the target satellites in real time is one of the necessary prerequisites for the successful implementation of autonomous rendezvous and docking. This paper addresses a vision based relative position and attitude estimation algorithm for the final phase of spacecraft rendezvous and docking. By assuming that the images of feature points on the target satellite lie within the convex regions, the estimation of the relative position and attitude is converted into solving a convex optimization problem in which the dual quaternion method is employed to represent the rotational and translational transformation between the chaser body frame and the target body frame. Due to the point-to-region correspondence instead of the point-to-point correspondence is used, the proposed estimation algorithm shows good performance in robustness which is verified through computer simulations. 相似文献
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