参数不确定SGCMG系统的自适应操纵律设计

在单框架控制力矩陀螺(SGCMG)系统操纵律的设计中,如果考虑框架伺服特性,往往假设系统的物理参数是确切已知的.为消除参数的不确定性对操纵性能的影响,设计了一种自适应操纵律.该操纵律可对系统物理参数进行在线估计,并能根据航天器姿态控制给出的角动量(或力矩)指令,直接计算出每个框架驱动系统所需的控制力矩.由于操纵律没有算法奇异,在SGCMG系统不出现运动奇异的情况下,可使操纵误差渐近收敛至零.同时,该操纵律对系统参数变化具有良好的适应性,且形式简单,易于实现.对应用在航天器上的某SGCMG系统的仿真结果表明,上述操纵律是可行的.     

敏捷卫星SGCMG群姿态机动测试用例设计研究

针对SGCMG群敏捷姿态机动这一新技术,研究一种SGCMG群姿态机动测试用例设计方法。在分析SGCMG运动特性的基础上,建立了SGCMG群卫星姿态动力学模型和SGCMG群力矩输出矩阵,由此开展了SGCMG群操纵律研究及奇异性分析;结合SGCMG群卫星姿态动力学模型、运动学模型和PID控制器设计,搭建了敏捷卫星姿态控制闭环仿真系统,采用不考虑奇异规避的广义操纵律进行闭环仿真,通过遍历搜索的仿真运算,寻找分别经历无奇异、显奇异和隐奇异的典型目标姿态角组合,完成了敏捷卫星SGCMG群奇异规避算法的测试用例设计与验证,实现了对SGCMG群敏捷机动能力与系统指标的全面考核,极大提高了测试用例覆盖的全面性和有效性,具有现实的工程意义。     

近空间无尾飞行器解耦与控制分配方法研究

关于飞行器稳定性优化控制问题,由于近空间无尾飞行器具有典型的通道间强耦合且多个操纵面介入单个通道控制,执行机构的复杂化和非线性导致控制系统设计实时性和响应性差,精度达不到要求。为提高姿态控制器控制精度,减小力矩分配误差,提出通过解耦控制系统和控制分配逻辑来分别解决对象的耦合和多操纵面的力矩分配问题。通过将动态逆设计方法与变结构控制理论相结合,设计了一种强鲁棒性的解耦控制律,并在加权伪逆算法的基础上,提出采用舵面偏角修正操纵面的效率矩阵,从而实现了强耦合非线性对象的高精度控制。仿真结果表明,控制器解耦效果良好且具有较强鲁棒性,控制分配算法减小了80%力矩分配误差,满足了飞行器的控制需求。     

用单框架控制力矩陀螺的大型航天器姿态控制系统实物仿真研究

利用三轴气浮台模拟航天器空间力学环境,进行了单框架控制力矩陀螺(SGCMG)姿态控制/动量管理系统全实物仿真研究.推导了大型航天器姿态控制/动量管理系统数学模型.设计调试了实物仿真系统.研究了单框架控制力矩陀螺奇异回避问题、失效操纵问题和动量管理优化问题.证明了系统构形分析、奇异性分析和操纵律设计的正确性和有效性.通过大型航天器姿态控制/动量管理系统实物仿真,检验了设计方案的可行性和系统硬、软件的可靠性.     

面向新颖成像模式敏捷卫星的联合执行机构控制方法

为满足新颖成像模式对卫星姿态快速机动或对规划姿态的高精度跟踪控制需求,本文针对金字塔构型控制力矩陀螺（Control moment gyroscopes,CMG）群与反作用飞轮为联合执行机构的挠性敏捷卫星,提出一种融合以Legendre伪谱法实现卫星姿态及CMG群框架角速度最优规划的前馈控制、以非线性模型预测控制（Nonlinear model predictive control,NMPC）实现最优轨迹反馈跟踪的复合控制方法.在前馈控制律设计中,充分考虑了CMG群的力矩输出能力、奇异性及振动抑制性能等约束,规划获得了最优的CMG群框架角速度、卫星的姿态角及角速度.在反馈控制律设计中,以飞轮输出力矩能力、姿态机动快速性及能量为约束,设计了具有滚动优化思想的跟踪算法,补偿由于初始状态及转动惯量偏差等带来的控制误差.研究结果表明,在转动惯量存在偏差情况下,本文的控制方法仍是有效的,且表现出较强的鲁棒性.     

基于EAM的控制分配设计策略在控制律设计中的应用

针对现代先进飞机的多操纵面气动布局和传统特征结构配置方法(EAM)设计控制律时存在的问题,提出了一种基于EAM的多操纵面控制分配设计策略.通过模块化设计,使控制律与分配律分别独立设计.首先,基于传统EAM设计三轴指令跟踪控制的传统控制律,得到三轴虚拟控制指令.然后,用控制分配方法对多操纵面进行协调分配,发挥冗余操纵面的...     

应用控制力矩陀螺的小卫星姿态控制技术

本文介绍一种基于控制力矩陀螺(CMG)的新型姿态控制系统。CMG可以在不增加功耗、质量和体积的条件下为小卫星提供独特的控制力矩、角动量和姿态机动能力，这将有助于小卫星变得更加机动灵活。灵活性可以显著地扩大航天器的应用范围，提高航天器的效能并且可以大大增加地球观测和科学任务的数据返回率。在接下来的章节中介绍CMG的基本特性，分析了一种为增强型微小卫星设计的低成本、小型化单框架控制力矩陀螺(SGCMG)方案。文中建议的一个SGCMG参数表明，使用CMG有许多优点。该SGCMG能够产生9．82mNm的控制力矩，并且已经通过了气浮台试验验证。对SGCMG和反作用轮(RW)的对比证明，使用SGCMG可以降低整星的重量和功耗。     

基于非线性动态逆的大迎角飞行控制律设计

研究飞机大迎角飞行优化控制问题。为了用非线性动态逆方法进行大迎角飞行控制律设计,首先建立具有大迎角条件下强非线性、非定常迟滞、不对称的力与力矩等气动特性的六自由度非线性飞机模型。然后将非线性动态逆方法与奇异摄动理论相结合,并将飞机状态划分为快慢回路,分别应用非线性动态逆方法进行了飞行控制律设计。最后,通过控制分配将计算得到的三轴力矩指令转化为相应的舵面与推力矢量偏转指令,并进行了仿真验证。仿真结果表明,设计的飞行控制律具有优良的大迎角控制效果。     

多操纵面飞机全局集合稳定非线性自适应动态控制分配

针对多操纵面飞机具有冗余操纵面的特点,考虑包含操纵面偏转角的位置约束和速率约束以及未知有界参数时的非线性控制分配问题,设计一种由上层虚拟控制律和自适应控制分配更新律组成的非线性角速度跟踪控制器.当系统满足充分激励条件时,基于集合稳定性理论,分别证明了上层虚拟控制子系统、控制分配子系统和整个闭环系统的全局一致渐近稳定性.对某多操纵面飞机的仿真结果验证了所提出方法的有效性,并且该方法能使参数估计收敛至真实值.     

基于变速趋近律的机电伺服系统自适应滑模控制

针对带有摩擦力矩、负载力矩以及扰动力矩等不确定性的机电伺服系统,提出一种基于变速趋近律的自适应滑模控制方法.首先,构造双曲正切型辅助函数并设计新的变速趋近律,用以调节滑模变量的收敛速度,使其在到达减速点之前具有较快的收敛速度,而在到达减速点以后则能有效削弱抖振.在此基础上,构造自适应滑模控制器,保证系统位置输出能够快速...     

不确定条件下控制分配问题的鲁棒优化方法

针对具有冗余执行机构的过驱动系统, 在考虑控制效率不确定性的条件下, 提出了一种基于鲁棒优化理论的控制分配算法. 研究了原始不确定鲁棒优化模型的建立和基于椭球不确定集的鲁棒对等式的转化问题, 并推广到可由锥二次不等式表示的不确定集的情况. 讨论了鲁棒优化控制分配算法的求解方法及其计算复杂度. 最后, 针对多操纵面飞机的最优控制分配问题与传统算法进行了仿真比较, 结果表明鲁棒优化算法能有效降低控制效率不确定性的影响, 使分配结果更为合理, 从而具有更好的鲁棒性, 同时能有效提高操纵面故障情况下闭环系统的控制重构能力, 很好地改善了飞控系统的性能.     

多操纵面飞机交叉耦合鲁棒控制分配策略

针对多操纵面飞机气动效能的交叉耦合不确定性, 基于混合优化提出一种鲁棒控制分配策略.将交叉耦合效应描述为控制效能结构不确定性, 建立分配 误差最小的单目标鲁棒最小二乘控制分配模型, 给出等价线性矩阵不等式构型.进一步, 考虑操纵面偏转能量约束, 建立鲁棒混合优化控制分配模型, 以避免单目标 优化下操纵面易饱和的问题.仿真结果表明, 所提出的方法可容忍交叉耦合效应不确定性, 实现操纵面协调控制分配, 具有较好的鲁棒性.     

Contour Tracking of a Redundant Robot Using Integral Variable Structure Control with Output Feedback

This work examines the contour tracking problem of redundant robot on a path with singularity. Using an optimal quadratic programming method is to solve the singularity problem and the computing load of motion planning is reduced by a novel hybrid motion planning method. To achieve contour tracking with output feedback, an integral sliding mode control with a high-gain observer is employed to eliminate the chattering due to discontinuous switching control of the sliding-mode control and maintain robustness of the ideal sliding mode.     

A Singularity-free Steering Law of Roof Array of Control Moment Gyros for Agile Spacecraft Maneuver

In this paper, a singularity-free steering law for single gimbal control moment gyros (CMGs) is addressed for agile spacecraft. The geometrical array considered particularly in this work is a roof array due to the simplicity of singularity envelope. A feasible angular momentum chart which can provide a singularity-free bound is employed. The chart allows a guaranteed maximum torque output and angular momentum at any time without concerning the geometrical singularity of the array. Furthermore, a new deterministic allocation algorithm, called half-leading steering logic, of gimbal angular rates, is also suggested instead of the well-known pseudo-inverse technique to meet control torque commands required and to keep away from the singularity. It is noted that a momentum vector recovery to the initial direction is also an important task for the CMG array to overcome the singularity and for the reliable operation of CMGs. An optimization technique is addressed to restore the gimbal vectors back to their original angular position after the attitude reorientation mission. The techniques proposed are demonstrated using illustrative numerical simulations.

     

Singularity avoidance of CMGs by virtual actuators

An implementable and practical steering law of control moment gyros (CMGs) to avoid singularity is addressed in this paper. The singularity strategy of CMGs revised in this paper is based on a simple but practical virtual actuator methodology. It is known that in a special case of singularity and torque requirement, the virtual CMGs can provide perfect command torque without torque error, which can be proven analytically. In this paper, much extensive analysis is accomplished to provide the performance of the virtual actuator concept, which can avoid the singular configuration of CMGs with possibly smaller control torque error than the conventional singularity robustness method. Finally, the steering law based on the virtual actuator concept is demonstrated by numerical simulations.     

不确定网络结构下的应急物资鲁棒配置模型

灾害发生前的应急物资配置问题具有两个重要的不确定性, 即交通网络中受自然灾害影响而阻断的道路以及受灾点的应急物资需求量. 通过引入两个控制水平参数建立了不确定网络结构下的两阶段应急物资鲁棒配置模型, 并在线性化第2 阶段的回溯问题后提出了求解模型的Benders 分解算法. 数值实验结果表明了所提出的模型的有效性以及所得配置方案的鲁棒性.

     

Control allocation technology based on fault diagnosis for the unmanned aerial vehicle system subject to physical constraints and fault reconfiguration mismatch

The problem of the system robustness subject to physical constraints and mismatched fault reconstruction is discussed in this paper. In order to facilitate the design, a four-rotor unmanned aerial vehicle (UAV) system model was selected for research. First, the control allocation model of the nonlinear UAV system with disturbances is shown in the paper. Secondly, a weighted pseudo-inverse method based on adaptive weights is proposed, which reduces the impact of physical constraints on the system. After that, a dynamic weight control allocation method based on the fault efficiency matrix is designed. The weight matrix can dynamically adjust the control distribution law according to the fault estimation value provided by the observer. Then, a dynamic adaptive control allocation method for faults and physical constraints is carried out by combining adaptive weights and dynamic weights. Finally, a simulation example is presented to further illustrate the effectiveness of the algorithm proposed in this paper.     

Fixed-time dual sliding mode control for linear synchronous motor maglev systems

A dual fixed-time terminal sliding mode control strategy is proposed to address the problems of magnetic coupling, end effects and unknown disturbances in linear synchronous motor maglev systems, which ensures that the system tracking trajectory achieves fixed-time convergence and high accuracy. First, a fixed-time integral terminal sliding mode surface is designed to obtain the desired dynamic properties and avoid the singularity problem. Second, based on the dynamic sliding mode theory, a second fixed-time terminal sliding mode surface is designed to weaken the chattering problem in the controller by replacing the discontinuous switching signal with a continuous switching rule. The proposed controller is theoretically proved to be fixed-time convergent and the convergence time is independent of the initial conditions by means of the Lyapunov function and the fixed-time convergence theorem. Finally, simulations and experiments are carried out on a linear maglev experimental platform. Compared with the fixed-time sliding mode control, the simulation and experimental results show that the proposed strategy improves the tracking accuracy by 37.5%, the convergence speed by 33.3%, and the robustness by 42.1%, which has the advantages of fast convergence speed, strong robustness, and weak chattering.     

Integral Sliding Mode Fault‐Tolerant Control for Spacecraft With Uncertainties and Saturation

An integral sliding mode fault‐tolerant control method is proposed to deal with faults with matched uncertainties, unmatched uncertainties, and input saturation. Integral sliding mode, control allocation, and parameter identification are included in this method. The Lyapunov stability conditions of the integral sliding mode control for uncertainties and input saturation, respectively, are obtained, which denote the robustness extent of the controller. The direct method for control allocation is improved by adding a judgement before calculating for each facet. Finally, the fault‐tolerant scheme is applied to a six‐wheel spacecraft and simulations are given to show its effectiveness.     

推力矢量飞行器的自抗扰控制设计及控制分配

推力矢量飞行器往往需要在大功角等具有大不确定性和强非线性的区域高质量地完成飞行动作,因此,如何应对大范围不确定性是推力矢量飞行器控制设计的关键问题.另一方面,推力矢量飞行器包含多种控制输入并且不同控制输入具有不同物理特性.因此,控制输入分配也是推力矢量飞行器控制设计的关键问题.为了对付大范围的不确定性,本文引入虚拟控制量的概念,采用自抗扰控制技术实现对飞行过程中的总扰动的实时估计和补偿.进一步,考虑控制输入的物理约束条件,提出了保证虚拟控制量达到设计值并使得发动机能耗最小的控制输入分配方案.通过建立对应的优化问题,严格分析其最优解的性质并提出了有限步求解最优控制分配输入量的算法.在仿真环境下,提出的控制算法有效实现了推力矢量飞行器大功角区域的机动动作,并能应对大范围的气动参数不确定性.