空间站姿态控制的一种新算法

以四元数作为定位参数对空间站进行姿态控制。首先给出了以四元数表示的系统动力学西式其次提出了非线性三轴姿态控制方法,该方法是以四元数作为反馈量,控制力矩陀螺作为执行元件,利用李亚普诺夫函数对非线性系统进行控制,为大型航天器的姿态控制开辟了新的途径;最后以一空间粘为例进行了姿态控制仿真计算,从而说明以四元数为定位参数的空间站姿态控制方法具有计算速度快、计算精度高等优点。     

卫星姿态控制系统容错控制综述

主要针对卫星姿态系统容错控制研究领域已有的成果进行了回顾。总结了国内外卫星容错控制的现有成果,主要从卫星姿态控制系统的可重构性、单体卫星容错控制和卫星编队容错控制3个部分对相关的研究成果进行了归纳分析。其中,卫星姿态系统的可重构性从重构目标和系统功能要求两方面进行分析;对单体卫星容错控制现状的介绍主要从自适应技术、滑模理论、预设性能、干扰观测器、故障估计观测器几个方面展开;卫星编队容错控制方法从独立容错、协同容错、拓扑重构和组成重构的角度进行阐述。最后进行总结,并展望了卫星姿态控制系统容错控制领域未来可能出现的新问题和研究思路。     

Stabilization of the attitude of a rigid spacecraft with external disturbances using finite-time control techniques

In this paper, we consider the attitude stabilization problem for a rigid spacecraft with external disturbances. To obtain a better disturbance rejection property, we employ finite-time control techniques. In the absence of disturbances, by employing continuous finite-time control method, a continuous finite-time controller is designed such that the attitude of the rigid spacecraft will converge to the origin in finite time. In the presence of disturbances, by employing terminal sliding mode method, a discontinuous finite-time control law is proposed such that the states will eventually converge to a small region of the origin, which can be rendered as small as desired. Numerical simulation results show the effectiveness of the method.     

飞翼布局无人机反演自抗扰姿态控制

针对飞翼布局无人机模型强非线性、大不确定性及多变量强耦合等问题,设计了基于块控反演控制技术的姿态控制律,并采用自抗扰控制中的线性扩张状态观测器实现了对模型总不确定性的估计。为解决因阻力方向舵舵效非线性以及舵环节指令跟踪延迟造成控制系统动态性能下降的问题,采用函数拟合法解算阻力方向舵舵偏指令,并利用二阶振荡环节对观测器进行抗时滞处理。仿真结果表明,所设计的姿态控制律能够使飞翼布局无人机准确跟踪姿态指令,并具备较强的鲁棒性与良好的动态性能。     

基于RBF网络的质量矩导弹姿态控制

研究了三轴稳定质量矩导弹姿态控制问题.建立了内部带有3个可移动滑块的数学模型.利用RBF(radial basis function)网络的快速自学习、自适应特性, 作为被控对象的模型, 不断调整PID控制器的参数, 协调控制滑块位置, 从而改变导弹的飞行姿态.最后讨论了滑块运动特性对系统性能的影响并对系统稳定性进行了分析.仿真结果表明该控制律在保证系统稳定的情况下有效地实现导弹的姿态调整, 并且提高了系统的动态响应品质.      

喉部不对称对微喷管性能影响

以FLUENT 6.1软件为工具,利用数值计算求解二维稳态可压缩Navier-Stokes(N-S)方程,模拟了微喷管内超声速流体流动,分析了喷管喉部结构不对称对喷管内部的流场和喷管性能的影响.这种喉部结构不对称是由于喉部上下顶点在x方向偏离一定距离所造成的.数值计算结果表明,喷管喉部在流体流动方向的不对称,将导致喷管内部流体流场不平衡性,使得流量增大,喷管出口的x方向推力增加,y方向产生了多余的推力.      

Practical stabilization in attitude thruster control

The attitude stabilization of a spacecraft using thrusters is considered from a practical point of view, i.e., when actuator constraints, uncertainties and failures, measurement noise, fuel consumption, and inertia matrix uncertainty are considered. A variable structure controller based on sliding modes is obtained first, which guarantees global exponential stability under actuator constraints, uncertainties, and failures. The design is based on a continuous average-proportional torque selection function and a set of feasible sliding surfaces, which may be adapted to improve performance. Exponential convergence towards ultimate bounds is guaranteed when all other practical issues arise.     

Nonlinear decoupling sliding mode control and attitude control ofspacecraft

Control of a class of uncertain nonlinear systems which can be decoupled by state-variable feedback is considered. A variable-structure-control (VSC) law is derived so that in the closed-loop system the output variables asymptotically track given output trajectories in spite of any uncertainty in the system. On the basis of this result, a control law is derived for the attitude control of an orbiting spacecraft in the presence of uncertainty using reaction jets. The controlled outputs are the three Euler angles which describe the orientation of the spacecraft relative to an orbital frame. Simulation results are presented to show that, in the closed-loop system, precise attitude control is accomplished in spite of the uncertainty in the system     

姿控脉冲发动机点火逻辑优化控制算法

针对拦截弹末制导姿控脉冲发动机组合点火问题,利用吱呀轮优化(SWO)的导向式快速搜索特点,提出了一种基于SWO的点火逻辑优化控制算法。在分析脉冲发动机数学模型和点火控制约束条件的基础上,将脉冲发动机的组合点火问题转化为任务调度问题,并与贪心算法和遗传算法进行比较。仿真结果表明,该算法能够满足控制精度和实时性要求。     

基于综合识别的高速飞行器在线姿态控制方法

针对高速飞行器控制方法中控制模型难以适应大包络飞行和算法中辨识存在收敛性的问题,设计了一种基于综合识别的在线控制方案.首先,由在线直接可测量构成三通道的特征状态量,以特征状态量建立面向控制的特征模型;然后,通过反馈线性化进行通道间的解耦,采用极点配置来进行在线控制参数的实时调节.仿真结果表明,在气动参数拉偏的情况下,三个通道均取得了较好的控制效果,控制器具有快速性和鲁棒性,且易于工程实现.     

基于自抗扰控制的拦截弹姿态控制系统设计

针对采用气动力/直接力复合控制的拦截弹姿态控制问题,提出一种基于自抗扰控制技术的姿态控制系统设计方案。给出俯仰通道短周期扰动运动方程,分别建立了气动力子系统、直接力子系统的二阶积分数学模型。根据建立的数学模型,分别针对气动力子系统、直接力子系统设计了自抗扰控制器。为了有效协调气动力/直接力的复合控制,给出一种加权指令分配方法。仿真结果表明,提出的设计方法能够获得较好的动态响应性能,控制器具有较强的鲁棒性。     

内装式空射火箭箭机分离RCS姿态控制方案研究

采用反作用喷气控制系统(RCS)对内装式空中发射运载火箭箭机分离阶段实施姿态控制的方案进行了研究.根据不同发射条件下的箭机分离运动,确定了RCS启控时运载火箭的飞行状态,设计了发动机点火前的运载火箭俯仰运动程序.在此基础上,给定标准弹道方案,并确定了RCS推力器组合方案.采用脉冲调宽调频(PWPF)调制方法,设计出适合...     

Tethered dual spacecraft configuration: a solution to attitude control problems

A new dual spacecraft configuration comprising of two spacecraft halves judiciously connected through extremely short tethers is proposed. The simple tethered configuration induces stabilizing torques when subjected to attitude disturbances, thus ensuring 3-d pointing stability of both the satellite platforms. The enhanced system performance obtained using tethers enables a much greater flexibility in the choice of satellite mass distribution. Three particular TSS models involving parallel tethers, a `parachute-like' conical tether layout as well as a single tether connection have been considered. A detailed numerical response simulation shows that these modes of tether attachments bring about a radical change in the satellite attitude behavior from the nominal one involving relatively large librational amplitudes or instability to a virtually fixed desired orientation. Of these, the parachute configuration appears to be superior. The passive nature of the proposed mechanisms using tether lengths on the order of merely a couple of meters needed for small and medium size systems makes the concept particularly attractive for future space missions. Finally, it is felt that the proposed tethered dual satellite systems may offer a simple answer to three-axis attitude control problems.     

Fault tolerant attitude control of under-actuated spacecraft: Theory and experiment

This paper investigates fault tolerant attitude control theory and experiment for under-actuated spacecraft with one reaction wheel completely broken and two others suffering actuator faults of partial loss of effectiveness or bias. A non-smooth robust adaptive fault tolerant control law is proposed under the zero-momentum and input saturation conditions. It shows that the available reaction wheels need to produce sufficient control torque for the fault tolerance. Such a new control method is implemented in a semi-physical simulation system of an air-bearing platform. Experimental results show the effectiveness of the proposed method in spacecraft practical engineering.     

空间非合作航天器抓捕后姿态抗干扰控制

针对空间非合作航天器抓捕后存在未知不确定惯性参数的柔性组合体姿态稳定控制问题,基于中间状态观测器设计方法提出了一种新的姿态稳定抗干扰控制方法,同时考虑了诸多扰动及控制输入受限问题。研究结果表明,传统的姿态稳定控制方法需要已知柔性航天器惯性参数信息及状态信息,上述信息未知情况下会使姿态难以高精度稳定控制,且容易导致控制输入不满足受限要求。针对该问题,考虑控制输入幅值及变化率受限前提,提出了一种基于中间状态观测器的抗干扰控制方法,通过引入辅助变量构造新型中间状态观测器,同时估计组合体状态信息及综合干扰,设计出了一种新的组合体姿态稳定抗干扰控制器。通过Lyapunov稳定性分析方法证明了所设计的控制器能够保证闭环系统的全局渐近稳定性。相比于已有的混合H₂/H_∞控制器,所提出的抗干扰控制器在应用时不需要柔性组合体的姿态及模态信息,并且也不需要惯性参数的辨识过程。最后,通过给定参数进行仿真对比,进一步验证了所设计控制器的有效性和优越性。     

受油机指定时间姿态稳定控制

针对空中加油任务受油阶段受油机姿态稳定的需求,考虑受油机时变转动惯量、不确定转动惯量和风干扰的影响,提出了一种受油机指定时间姿态稳定控制策略.首先,建立了含时变转动惯量、内部不确定性和外部扰动下的受油机姿态动力学和运动学模型;其次,为了提高姿态稳定的快速性和确定性,使用指定时间稳定理论作为基础,设计了受油机姿态稳定鲁棒...     

Anti-disturbance attitude control of combined spacecraft with enhanced control allocation scheme

In this paper, we propose a novel anti-disturbance attitude control law for combined spacecraft with an improved closed-loop control allocation scheme. More specifically, a saturated approach is adopted to guarantee the global asymptotic stability under control input saturation. To enhance the robustness of the system, a nonlinear disturbance observer is constructed to compensate the disturbances caused by inertial parameter uncertainty and unmodeled dynamics. Next, the quadratic programming algorithm is used to obtain an optimal open-loop control allocation scheme, where both energy consumption and actuator saturation have been considered in the allocation of the virtual control command. Then, a modified closed-loop control allocation scheme is proposed to reduce the allocation error under the actuator uncertainty. Finally, stability analysis of the closed-loop system with the proposed allocation scheme is provided. Simulation results confirm the effectiveness of the proposed control scheme.     

基于新型快速Terminal滑模的高超声速飞行器姿态控制

为了提高Terminal滑模的收敛速度,避免滑模控制器奇异,首先分析Terminal滑模控制器出现奇异的原因,提出了一种新型非奇异快速Terminal滑模,其收敛速度在任意点均快于双幂次形式的Terminal滑模,并给出收敛时间公式。基于此,又改进了一种结构更为简单的非奇异快速Terminal滑模。针对高超声速飞行器姿态模型,利用新型快速Terminal滑模,采用干扰观测器逼近姿态的复合干扰,设计了高超声速飞行器内、外回路Terminal滑模控制器。采用一阶滤波器,消除了由Terminal滑模所导致最终控制器的奇异问题;基于Lyapunov稳定性理论,严格证明了飞行器姿态内、外回路系统的有限时间稳定。最后,通过飞行器在气动参数标称与拉偏情况下的数字仿真,验证了设计方案的有效性。     

Channelization: the two-fault tolerant attitude control functionfor the Space Station Freedom

The Space Station Freedom was, from the mid-1980's through 1993, the design for an international orbiting laboratory facility. The Space Station Freedom was comprised of “utility” systems, such as power generation and distribution, thermal management, and data processing, and “user” systems such as communication and tracking, propulsion, payload support, and guidance, navigation, and control. These systems are required to work together to provide various station functions. To protect the lives onboard and the investment in the station, the systems and their connectivity had to be designed to continue to support critical functions after any single fault for early assembly stages, and after any two faults for later stages. Of these critical functions, attitude control was the most global, incorporating equipment from nearly all major systems. The challenge was to develop an architecture, or integration, of these systems that would achieve the specified level of fault tolerant attitude control and operate, autonomously, for the three-month unmanned periods during the assembly process. Additionally, this architecture had to maintain the desired utility of the station for each stage of the assembly process. This paper discusses the approach developed for integrating the systems such that the fault tolerance requirements were met for all stages of assembly. Some of the key integration issues are examined and the role of analysis tools are described. The resultant design was a highly channelized one, and the reasons and the benefits of this design will be explored. The final design was accepted by the Space Station Control Board as the design baseline in July 1992     

基于ATSUKF算法的卫星姿控系统故障估计

针对卫星姿态控制过程中可能发生的执行机构或敏感器故障,提出了一种基于无损卡尔曼滤波（UKF）及偏差分离原理的自适应二阶无损卡尔曼滤波（ATSUKF）算法。首先,提出TSUKF算法,通过UKF处理姿态机动时的非线性并通过偏差分离原理将非线性系统的状态及故障分别估计,避免非线性模型的线性化过程同时降低了计算过程中的矩阵维度。然后,在TSUKF算法的基础上提出了ATSUKF算法,通过滑动窗口内的残差计算自适应矩阵,使滤波器在统计特性不准确的情况下仍然具有较快的收敛速度,特别适用于卫星快速机动过程中的姿态与故障估计。数值仿真结果表明,ATSUKF算法相较于TSUKF算法能有效降低统计特性不准对系统造成的不利影响,实现卫星姿态、执行机构/敏感器故障的快速估计。