变体飞行器链式平滑切换控制

针对变体飞行器在连续变形过程中的高度保持和姿态稳定问题,提出了一种平滑切换状态反馈控制器设计方法.建立了纵向运动的链式平滑切换系统模型,相比于传统的任意切换律和硬切换方案,所提出的模型能够更准确的反映变形过程的运动特性,且降低了设计的保守性.推导了链式平滑切换系统有限时间有界且具有鲁棒性能指标的充分条件,将增稳控制器设计转化为具有线性矩阵不等式组约束的优化问题.所设计的控制器虽然放宽了对系统渐近稳定性的要求,但能够保证系统状态在变形时间段内有界稳定,且兼顾了实际的舵偏响应.控制算例和非线性仿真验证了所提方法的有效性.     

Stabilization of switched neural networks with time‐varying delay via bumpless transfer control

This paper investigates the stabilization of switched neural networks with time‐varying delay. In order to overcome the drawback that the classical switching state feedback controller may generate the bumps at switching time, a new switching feedback controller which can smooth effectively the bumps is proposed. According to mode‐dependent average dwell time, new exponential stabilization results are deduced for switched neural networks under the proposed feedback controller. Based on a simple corollary, the procedures which are used to calculate the feedback control gain matrices are also obtained. Two simple numerical examples are employed to demonstrate the effectiveness of the proposed results.     

Aggressive Longitudinal Aircraft Path Tracking Using Nonlinear Control

We study the problem of converting a trajectory tracking controller to a path tracking controller for a nonlinear non-minimum phase longitudinal aircraft model. The solution of the trajectory tracking problem is based on the requirement that the aircraft follows a given time parameterized trajectory in inertial frame. In this paper we introduce an alternative nonlinear control design approach called path tracking control. The path tracking approach is based on designing a nonlinear state feedback controller that maintains a desired speed along a desired path with closed loop stability. This design approach is different from the trajectory tracking approach where aircraft speed and position are regulated along the desired path. The path tracking controller regulates the position errors transverse to the desired path but it does not regulate the position error along the desired path. First, a trajectory tracking controller, consisting of feedforward and static state feedback, is designed to guarantee uniform asymptotic trajectory tracking. The feedforward is determined by solving a stable noncausal inversion problem. Constant feedback gains are determined based on LQR with singular perturbation approach. A path tracking controller is then obtained from the trajectory tracking controller by introducing a suitable state projection.     

基于微分几何反馈线性化的高超声速飞行器控制系统实现

为实现对高超声速飞行器横滚角度数值、纵滚角度数值的同步控制,使飞行器元件呈现出相对平稳的运动状态,设计基于微分几何反馈线性化的高超声速飞行器控制系统;利用电源管理模块电路,更改电机驱动器元件的连接形式,根据螺旋桨转动速率,调试IMU惯性传感器、GPS定位、PID控制器三类下级硬件设备的实时运行状态,完成高超声速飞行器控制系统的主体应用结构设计;按照飞行器运动轨迹的微分处理结果,计算控制向量反馈指标的具体数值水平,再通过解析几何信号的处理方式,确定线性化姿态解算表达式,实现基于微分几何反馈线性化的飞行器控制程序设计,结合相关硬件应用设备,完成对高超声速飞行器控制系统的研究;实验结果显示,当实验时间为14 s时,实验组横滚角度数值与理想角度数值之间的差值最大为3°;当实验时间为6 s时,实验组纵滚角度数值与理想角度数值之间的差值最大为4°,微分几何反馈线性化原则能够有效控制横滚角度数值、纵滚角度数值与理想角度数值之间的差值水平,在促进高超声速飞行器平稳运动方面具有较强的可行性价值。     

Robust control of a laboratory aircraft model via fast output sampling

A new multimodel approach to robust controller design is illustrated by a practical application: for a laboratory aircraft model, a robust controller is designed for acceptable performance, in normal operating conditions and under propeller failure, simultaneously. Based on a linear model for each operating mode, linear matrix inequality (LMI) formulation of the problem and convex programming are used to search for a state feedback controller that achieves the objective. This state feedback design is then realized simultaneously in both operating modes by a controller that is based on fast output sampling. Robust performance is demonstrated by experimental results.     

Smooth output feedback stabilization for a class of nonlinear systems with time‐varying powers

This paper investigates the global asymptotic stabilization problem for a class of nonlinear systems with time‐varying powers. First, adding a power integrator technique is revamped to design a smooth state feedback controller, which is implementable with only upper and lower bounds of the time‐varying powers. When the system state is not fully available and the time‐varying power is exactly known, a smooth output feedback controller constituted by a state feedback and a nonlinear state observer is constructed to globally stabilize the system. Copyright © 2017 John Wiley & Sons, Ltd.     

一类离散时间切换线性系统的无差拍控制

研究一类带多控制器和多传感器离散时间线性系统的无差拍控制.对能控系统,通过适当的状态坐标变换获得系统矩阵的块三角结构,再设计状态反馈和周期切换策略使得状态反馈矩阵在有限周期内为零,从而保证闭环系统的无差拍稳定.进一步,对能观系统,设计具有有限时间精确估计的动态输出反馈,通过适当的周期切换策略实现闭环系统的无差拍稳定.最后,给出一个例子以验证所提设计方法的有效性.     

State feedback stabilization of discrete linear switching systems subject to nonsymmetrical state and control bounds

Stabilization problem of discrete-time linear switching systems with bounds on the state and control input is solved in this paper.First,the synthesis of state feedback controllers that ensure the stab...     

Disturbance rejection for an aircraft flying in atmospheric disturbances

For an aircraft flying in atmospheric disturbances a static state feedback controller is designed. The design goal is that of rejecting the influence of a rotary gust disturbance to the vertical and forward velocity of the aircraft. The necessary and sufficient condition for this problem to have a solution is derived in terms of simple forms involving only the flight stability derivatives of the aircraft. The general analytical expression of the disturbance rejection controller matrix and the resulting closed, loop system, are derived in forms involving the aircraft parameters as well as arbitrary design parameters. The necessary and sufficient conditions for disturbance rejection with simultaneous stabilizability of the closed loop flight system are also established.     

Controller and observer design for a class of discrete-time nonlinear switching systems

The main contribution of this paper is to present some controller synthesis results for the discrete-time nonlinear (Lipschitz-like) switching systems. Under the assumption that the discrete state of switching systems is known, three related problems are considered, which are full-state feedback controller design, continuous state observer design, and observer-based output feedback controller design. The basic idea of the proposed approaches is to construct the different types of Hybrid Lyapunov function to guarantee the stability, and all of these methods are given in terms of linear matrix inequalities. The results obtained in this paper are only dependent on the Lipschitz-like constant matrices without regard to the specific nonlinear forms. Finally, a numerical example made up of two subsystems is given to show the applicability of theoretical results.     

Reaching condition for variable-structure output feedback controller using a search technique

The aim of this paper is to establish the reaching condition for a variable-structure output feedback controller based on Genetic Algorithms (GA). The design of the variable-structure controller using output feedback provides a technique to compute matrix parameters and guarantees the reaching conditions for a general class of linear systems. A combination of both a modified control law and a simple search technique based on the GA approach is proposed to obtain a good dynamic response. The proposed method is computationally simple and tractable, and guarantees a sliding motion along the switching surface. The efficacy of the theoretical results is illustrated by considering a linearized model of an aircraft control problem.     

Adaptive stabilization of a class of uncertain switched nonlinear systems with backstepping control

In this paper, we focus on the problem of adaptive stabilization for a class of uncertain switched nonlinear systems, whose non-switching part consists of feedback linearizable dynamics. The main result is that we propose adaptive controllers such that the considered switched systems with unknown parameters can be stabilized under arbitrary switching signals. First, we design the adaptive state feedback controller based on tuning the estimations of the bounds on switching parameters in the transformed system, instead of estimating the switching parameters directly. Next, by incorporating some augmented design parameters, the adaptive output feedback controller is designed. The proposed approach allows us to construct a common Lyapunov function and thus the closed-loop system can be stabilized without the restriction on dwell-time, which is needed in most of the existing results considering output feedback control. A numerical example and computer simulations are provided to validate the proposed controllers.     

基于受控拉格朗日函数的垂直起降飞机控制器设计

本文将单欠驱动度力学系统基于受控拉格朗日函数(CL)的控制器设计技术应用到具有输入耦合的垂直起降(PVTOL)飞机的控制问题中. 在显式陀螺力的匹配条件下, 得到的光滑反馈控制律保证了系统几乎全局渐近稳定. 与现有同类方法所得到的结果相比, 该匹配控制器形式更简单而收敛性能得到保持.     

Time-varying feedback control of nonaffine nonlinear systems without drift

Sufficient conditions are presented under which a general nonlinear system without drift is globally asymptotically stabilizable by time-varying state feedback. A novel approach is developed for the design of a time-varying smooth state feedback controller. The controller is explicitly constructed by using the bounded state feedback strategy (Lin, 1995, 1996) combined with Lyapunov technique as well as lossless systems theory. This work incorporates earlier global stabilization results (Coron, 1992; Pomet, 1992) for controllable affine systems without drift, which are known not to be smoothly stabilizable via any time-invariant state feedback.     

Smooth switching LPV controller design for LPV systems

This paper presents a method to design a smooth switching gain-scheduled linear parameter varying (LPV) controller for LPV systems. The moving region of the gain-scheduling variables is divided into a specified number of local subregions as well as subregions for the smooth controller switching, and one gain-scheduled LPV controller is assigned to each of the local subregions. For each switching subregion, a function interpolating two local LPV controllers associated with its neighborhood subregions is designed to satisfy the constraint of smooth transition of controller system matrices. The smooth switching controller design problem amounts to solving a feasibility problem which involves nonlinear matrix inequalities. To find a solution to the feasibility problem, an iterative descent algorithm which solves a series of convex optimization problems is proposed. The usefulness of the proposed controller design method is demonstrated with a control example of a flexible ball-screw drive system.     

含有非线性参数化的非完整系统的鲁棒自适应控制

针对一类含有强非线性漂移项和未知非线性参数的非完整系统, 提出了一种全局自适应状态反馈控制策略. 首先通过引入参数分离技术, 将非线性参数化系统转换为似然线性参数化系统. 然后引入反馈支配方法设计全局自适应稳定控制器, 同时, 为了避免系统出现不可控性, 设计了一种开关策略. 所设计的控制器能保证系统状态全局收敛到原点, 且其它信号保持有界. 仿真例子验证了算法的有效性和鲁棒性.     

变体飞行器平滑切换LPV 鲁棒控制

针对一类变体飞行器控制问题, 提出一种平滑切换线性变参数(LPV) 鲁棒控制器设计方法. 建立变体飞行器切换LPV 模型, 设计平滑切换控制器, 其中偶数子系统控制器由相邻两个子系统控制器线性插值得到. 给出保证切换LPV 系统指数稳定且具有一定鲁棒性能的充分条件, 由于考虑了调参变量的渐变特性, 所得切换律没有平均驻留时间的限制. 仿真结果表明, 所提出方法使得飞行器系统既具有良好的稳定性和鲁棒性, 又能实现平滑切换.

     

一种近似解耦方法在飞机侧风减缓中的应用

采用一种基于输出反馈,部分状态反馈和奇异摄动理论的近似解耦方法设计一个高增益比例积分控制器来实现对多变量系统的解耦控制.所得控制器结构简单,且解耦后的系统能得到良好的动态响应和较强的鲁棒性.文中以经改装后具有直接侧力操纵面的某型飞机为例,对其侧向平移模态进行了解耦控制设计,并将其应用于该飞机的阵风减缓.最后与不具有直接侧力操纵面的原飞机进行仿真对比.仿真结果表明,其产生的均方根阵风加速度比原飞机减少了约55%.     

Feedback control and output feedback control for the stabilisation of switched Boolean networks

This paper presents the feedback control and output feedback control for the stabilisation of switched Boolean network. A necessary condition for the existence of a state feedback controller for the stabilisation of switched Boolean networks under arbitrary switching signal is derived first, and constructive procedures for feedback control and output feedback control design are provided. An example is introduced to show the effectiveness of this paper.     

基于平均驻留时间切换离散线性系统的降阶输出反馈控制

模型降阶作为简化大规模系统的重要工具,一直受到控制界的高度重视.另外,由于在H∞理论指导下所设计的控制器具有维数过高的特点,这将导致控制器的实现和维护受到限制.基于此本文提出了一种平均驻留时间切换离散线性系统降阶输出反馈控制方法.该方法由一个降阶的切换输出反馈控制器和一个对切换控制器在每个切换时刻的状态执行复位规则的监控器组成,该控制器对切换控制器在每个切换时刻的状态进行降阶控制.仿真结果验证了该方法的有效性.