挠性飞行器飞轮姿态控制系统设计

针对带有大型太阳帆板的挠性空间飞行器动力学特性十分复杂的特点，通过合理的假设，采用单轴解耦分析姿态控制系统稳定性问题。采用极点配置法，按照刚体卫星设计系统PID参数，利用根轨迹，确定按刚体卫星参数设计的系统能使挠性空间飞行器控制系统具有渐近稳定性的充分条件；推导系统参数间的关系式，分析挠性空间飞行器主轴姿态控制系统稳定性问题。最后，通过仿真验证了系统的性能。     

基于伪谱法的欠驱动航天器实时最优控制算法设计

针对欠驱动刚性航天器提出了时间最优的闭环状态反馈控制算法。首先,利用直接Legendre 伪谱法规划出航天器开环的姿态机动轨迹,并验证了所得最优控制输入的可行性。然后,以航天器实际运行轨迹与开环轨迹间的偏差为变量构造偏差方程,并提出了基于间接Legendre 伪谱法的最优姿态稳定控制算法。最后,采用实时重规划策略实现了稳定控制器状态的反馈,从而完成了对参考轨迹的闭环跟踪。仿真结果表明所提算法运算量小,计算速度快,可以实时获取解析形式的控制输入修正量,而且对初始姿态存在扰动的情况具有一定的鲁棒性,运算精度较高。     

太阳帆板故障模式展开动力学仿真

基于ADAMS软件，对柔性太阳帆板展开与锁定过程进行了动力学仿真分析，详细地研究了太阳帆板展开与锁定过程对航天器本体姿态运动的影响，并且重点研究了两种典型故障模式下太阳帆板展开与锁定过程对航天器本体姿态运动的影响，一种故障模式为一侧两块太阳帆板故障，另一侧太阳帆板正常展开；另一种故障模式为有一块太阳帆板展开机构故障，由同步机构协调展开。给出了航天器本体姿态运动以及太阳帆板展开过程动力学特性等仿真结果，并初步提出了故障模式下的动力学辅助展开策略的建议，对航天器姿态控制系统的设计以及地面试验提供了参考和依据。     

编队飞行挠性航天器的输出反馈姿态协同控制

研究了在姿态调节和时变参考姿态跟踪情况下,且挠性模态变量和角速度不可测量时的编队飞行挠性航天器的姿态协同控制问题。针对姿态调节问题,在挠性模态不可测量的情况下,将文献中已有的用于刚体航天器编队飞行的比例〖CD*2〗微分协同控制器,推广到了挠性航天器编队的情形。然后,针对姿态跟踪问题,通过构造关于挠性模态的期望动态系统,并利用无源滤波器,提出了一种仅利用姿态测量信息的无速度反馈协同控制器。仿真结果表明了所提出控制方案的有效性。     

STABILIZATION OF A KIND OF PREY-PREDATOR MODEL WITH HOLLING FUNCTIONAL RESPONSE

The stabilization problem of a kind of prey-predator model with Holling functional responseis investigated.By approximate linearization approach,a feedback control law stabilizing the closed-loop system is obtained.On the other hand.by exact linearization approach,a suitable change ofcoordinates in the state space and a feedback control law render the complex nonlinear system to bea linear controllable one such that the positive equilibrium point of the closed-loop system is globallyasymptotically stable.     

Tracking control for air-breathing hypersonic cruise vehicle based on tangent linearization approach

This paper is focused on developing a tracking controller for a hypersonic cruise vehicle using tangent linearization approach. The design of flight control systems for air-breathing hypersonic vehicles is a highly challenging task due to the unique characteristics of the vehicle dynamics. Motivated by recent results on tangent linearization control, the tracking control problem for the hypersonic cruise vehicle is reduced to that of a feedback stabilizing controller design for a linear time-varying system which can be accomplished by a standard design method of frozen-time control. Through a proper model transformation, it can be proven that the tracking error of the designed closed-loop system decays exponentially. Simulation studies are conducted for trimmed cruise conditions of 110 000 ft and Mach 15 where the responses of the vehicle to step changes in altitude and velocity are evaluated. The effectiveness of the controller is demonstrated by simulation results.     

准坐标系下的弹性飞行器飞行动力学建模

结合有限元思想和拉格朗日方程推导了准坐标系下的弹性飞行器飞行动力学模型,与通常采用的平均轴系建模方法相比,该方法克服了变量难在相同坐标系下表示等缺点,而且该模型包含了自由度之间所有的耦合,能够更充分的反映刚性自由度与弹性自由度间的交叉耦合特性,更全面的从本质上体现飞行器结构动力学、空气动力学以及飞行动力学这种多学科之间相互影响的非线性飞行动力学特性。该动力学模型可用于弹性飞行器非线性稳定性分析、弹性飞行器飞行动力学与控制理论分析等。

Abstract：

As the frequency separation between the rigid body modes and the structural dynamics becomes tighter, the traditional aircraft flight mechanics treatment, there is, the rigid body approximation, may be not efficient. A complete coupled equation of motion for fully flexible aircrafts were derived, without any constraint relationship, which was done by employing Lagrange’s equations and the finite element method in terms of quasi-coordinates. This model includes automatically all six rigid-body degrees of freedom and elastic deformations, as well as the gravity, propulsion, aerodynamics, and control forces, in addition to forces of an external nature, such as gusts. Different from the modeling method based on ＂mean axes＂ coordinate system, the seamless integration was achieved by using the same reference frame and the same variables to describe the aircraft motions and the force acting on it, including the aerodynamic forces. The formulation is modular in nature, in the sense that the structural model, the aerodynamic theory, and the controls method can be replaced by any other ones to better suit different types of aircraft, provided certain criteria are satisfied.     

应用分力合成方法改善柔性系统性能的研究

提出了将柔性结构的分力合成主动振动抑制方法和反馈控制方法结合使用来提高控制系统性能指标的方法，应用该方法仅需要知识闭环系统及柔性振动的频率及阻尼，而且可以同时抑制任意多个振动模态，分力合成方法可以对频率和阻尼系数的不确定性具有较强的鲁棒性，这使该方法更易于工程实现，本文对单柔性杆，将分力合成主动振动抑制方法和反馈控制相结合，设计了不同形式的大角度机动控制律，数值仿真和试验结果充分验证了方法的有效性。     

具有航向保持非线性的舵鳍非线性鲁棒控制

针对给定的线性舵鳍联合系统,考虑船舶航向保持的非线性,建立了一个舵鳍联合系统的非线性数学模型,然后采用精确反馈线性化对该非线性模型进行线性化,最后基于闭环增益成形算法设计出非线性鲁棒控制器.通过Matlab的Simulink工具箱分别对6级风浪和8级风浪作用下考虑舵机、鳍机特性的非线性舵鳍联合控制系统进行仿真,仿真结果表明所设计的控制器在保持航向控制的同时,能达到较好的减摇效果,并且该控制器具有较强的鲁棒性.本研究具有设计简单、物理意义明显的优点.     

柔性航天器自适应多层神经网络跟踪控制方法

针对柔性航天器的姿态跟踪以及振动抑制问题,提出了一种自适应多层神经网络控制方法。利用自适应多层神经网络来补偿系统的非线性项,利用光滑变结构项来补偿神经网络逼近误差及外部干扰。柔性航天器为典型的一个中心刚体加柔性附件的结构,假设模型参数未知并且具有任意的有限维。控制器只利用姿态角和角速度信息进行反馈控制,不需柔性附件振动信息。最后,实验表明该方法可以有效地完成姿态跟踪和振动抑制。     

一种Backstepping模型参考鲁棒飞行控制律的设计

提出了一种Backstepping模型参考鲁棒飞行控制律的设计方法。方法的主要特征是：在仅需要输入输出信号的情况下，即使系统参数未知且存在未建模动态和非线性因素干扰，系统仍能保证较强的鲁棒性，获得良好的跟踪效果。具体给出了飞机纵向通道短周期控制的设计方案，同时讨论了其他复杂模态下该方案的扩展方法。对上述方案的数值仿真显示了该方法良好的跟踪性能。     

Longitudinal Control for Balloon-Borne Launched Solar Powered UAVs in Near-Space

Aiming to improve the pull-up control performance in the process of releasing balloon-borne solar powered UAVs (Unmanned Aerial Vehicles), this paper establishes the full flight mechanics equations with flexible modes, and proposes the control method suitable for engineering application. To be specific, the authors first calculate the real aerodynamic force on horizontal stabilizer by comparing the fuselage deformation in ballooning test with that in static loading test. Furthermore, considering fuselage elastic deformation, the pitching moment coefficient is obtained and the influence of airspeed and elevator angle on pitching moment coefficient and control surface efficiency are analysed. Second, the authors establish a complete flight mechanics model, including elastic structural dynamic model and rigid flight dynamic model, by comprehensively considering the aerodynamic data, the relationship between fuselage deformation and load, as well as the ballooning test. Third, the authors perform the numerical simulation and comparison study on control performance between rigid model and flexible model. Moreover, the authors implement model modification based on the low altitude flight test and steady-state point analysing. Finally, a scaled UAV is used to complete the balloon-borne launching test. The results show that the longitudinal control method can analyse the longitudinal aerodynamics and control characteristics accurately, and could be effectively utilized in the pull-up control of the balloon-borne solar powered UAV.

     

基于分段Lyapunov函数方法的柔性卫星姿态模糊控制

提出了一种基于分段Lyapunov函数方法的带太阳帆板柔性卫星的姿态模糊控制方法。对于柔性卫星姿态动力学系统而言,强耦合、非线性以及较强的不确定性是其姿态系统的基本特征,本文针对这类被控对象,采用T-S模型作为万能逼近器,设计一种分段状态反馈控制方案。仿真结果表明,该方案可以保证卫星的姿态控制精度、结构振动抑制和控制系统鲁棒性。     

Near time optimal control with perturbation estimation for flexible spacecraft slewing maneuvers

1.INTRODUCTION Inrecentyears,therehasbeenconsiderableinterest inmodelingandcontrolofflexiblespacecraft.Thisis contributabletotheuseoflightweightandslender materialsforthespeedandfuel efficiencypurposes. Inmanyapplications,sophisticatedcontrolalgo rithmsarerequiredtomakeoptimaluseofmaximum torqueavailablefortimeminimizationmaneuvers, thistimeminimizationcontroloftenresultsinabang bangcontrolthatcanbeimplementedinaerospaceap plicationsusingon offthrusterjetstechnology.But unfortunately,t…     

基于自适应滤波的压电智能挠性悬臂板振动控制研究

针对航天器上悬臂外伸的薄板挠性结构附件，如太阳帆板与天线等，在存在建模参数不确定及外部扰动条件下所引起的振动问题，采用压电智陶瓷片作为敏感器执行器根据优化配置准则粘贴布置在挠性悬臂板上，组成压电智能挠性悬臂板控制及测量系统，进行了主动振动控制研究。基于分布式压电敏感器和驱动器的悬臂板包括弯曲和扭转柱动模态的压电控制方程，在控制算法上采用基于自适应滤波的前馈控制策略，即滤波-xLMS算法，并进行了抑制扰动及振动控制计算机数字仿真研究，结果表明，采用的控制律对于振动快速控制是可行的。     

双柔臂空间机器人运动、振动一体化抗死区控制

探讨漂浮基双柔臂空间机器人存在关节力矩输出死区与外部干扰时的姿态角度运动跟踪及柔性抑振的控制问题。引入含有刚性运动与柔性模态的混合轨迹概念,提出基于运动、振动一体化的积分滑模神经网络自适应控制方案。此方案的优点是不但通过补偿项消除了死区斜率与边界参数不确定及最优逼近误差上确界未知的影响,确保了刚性运动的鲁棒性,而且能同时主动地抑制两臂杆的柔性振动,从而提高轨迹跟踪性能。仿真算例结果表明方案能有效地实现运动、振动一体化控制。     

欠控制方向非线性系统的鲁棒自适应控制

针对一类控制方向未知且具有未建模动态的非线性系统,提出了一种鲁棒自适应控制策略.算法推广了已有的鲁棒自适应非线性控制方法.控制算法保证闭环系统所有信号是一致终值有界的.同时,通过调整控制器设计参数,闭环系统能够实现期望的性能要求.仿真结果进一步说明了理论分析的有效性.     

Robust Chattering-Free Finite Time Attitude Tracking Control with Input Saturation

This paper addresses the attitude tracking control problem of a rigid spacecraft in the presence of the modeling uncertainty, external disturbance, and saturated control input by designing two robust attitude tracking controllers. The basic controller is formulated using an integral sliding mode surface which is continuous and provides an asymptotic convergence rate for the closed-loop system. In this case, only the external disturbance with the prior information is considered. Then, to provide a finite time convergence rate and further improve the robustness of the control system under the unknown system uncertainty containing both the modeling uncertainty and external disturbance,a novel integral terminal sliding mode surface(ITSMS) is designed and associated with the continuous adaptive control method. Besides, a command filter is utilized to deal with the immeasurability problem within the proposed ITSMS and an auxiliary system to counteract the input saturation problem. Digital simulations are presented to verify the effectiveness of the proposed controllers.     

Pose Synchronization of Multiple Rigid Bodies Under Average Dwell Time Condition

This paper considers the pose synchronization problem of a group of moving rigid bodies under switching topologies where the dwell time of each topology may has no nonzero lower bound. The authors introduce an average dwell time condition to characterize the length of time intervals in which the graphs are connected. By designing distributed control laws of angular velocity and linear velocity, the closed-loop dynamics of multiple rigid bodies with switching topologies can be converted into a hybrid dynamical system. The authors employ the Lyapunov stability theorem, and show that the pose synchronization can be reached under the average dwell time condition. Moreover, the authors investigate the pose synchronization problem of the leader-following model under a similar average dwell time condition. Simulation examples are given to illustrate the results.     

Polytopic LPV modeling and gain-scheduled switching control for a flexible air-breathing hypersonic vehicle

A novel gain-scheduled switching control method for the longitudinal motion of a flexible air-breathing hypersonic vehicle (FAHV) is proposed.Firstly,velocity and altitude are selected as scheduling variables,a polytopic linear parameter varying(LPV) model is developed to represent the complex nonlinear longitudinal dynamics of the FAHV.Secondly,based on the obtained polytopic LPV model,the flight envelope is divided into four smaller subregions, and four gain-scheduled controllers are designed for these parameter subregions.Then,by the defined switching characteristic function,these gain-scheduled controllers are switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a given tracking error performance criterion.The condition of gain-scheduled switching controller synthesis is given in terms of linear matrix inequalities(LMIs) which can be easily solved by using standard software packages.Finally,simulation results show the effectiveness of the presented method.