纯量反馈系统稳定零极近似相消的积分约束

导出了单输入单输出反馈控制系统误差响应基于名义系统稳定的零、极点近似相消的时间域积分约束，此积分约束是任何反馈控制系统均应满足的．这一约束给出了单输入单输出反馈系统固有折中的新的观点．名义系统稳定的零、极点近似相消的存在导致反馈控制系统的调节时间延长或者误差响应的无穷范数变大．因此，在反馈控制系统设计中，尽量避免补偿器的零、极点与名义系统的极、零点近似相消(即使这些零、极点是稳定的)．     

纯量反馈系统稳定零极近似相消的积分约束

导出了单输入单输出反馈控制系统误差响应基于名义系统稳定的零、极点近似相消的时间域积分约束 ,此积分约束是任何反馈控制系统均应满足的 .这一约束给出了单输入单输出反馈系统固有折中的新的观点 .名义系统稳定的零、极点近似相消的存在导致反馈控制系统的调节时间延长或者误差响应的无穷范数变大 .因此 ,在反馈控制系统设计中 ,尽量避免补偿器的零、极点与名义系统的极、零点近似相消 (即使这些零、极点是稳定的 )     

基于全驱系统方法的高阶严反馈系统时变输出约束控制

针对输出受不对称时变约束的不确定高阶严反馈系统, 提出一种基于全驱系统方法的高阶自适应动态面输出约束控制方法. 所研究的高阶严反馈系统, 每个子系统都是高阶形式, 通过非线性转换函数将原输出约束系统转换为新的无约束系统, 从而将原系统输出约束问题转化为新系统输出有界的问题. 进一步结合全驱系统方法和自适应动态面控制, 直接将每个高阶子系统作为一个整体进行控制器设计, 而不需要将其转化为一阶系统形式, 有效简化了设计步骤; 同时通过引入一系列低通滤波器来获得虚拟控制律的高阶导数, 以代替复杂的微分运算. 基于Lyapunov稳定性理论证明闭环系统所有信号是一致最终有界的, 系统输出在满足约束的条件下能有效跟踪期望的参考信号, 且可通过调整参数使得系统跟踪误差收敛到零附近的足够小的邻域内. 最后, 通过对柔性关节机械臂系统进行仿真, 验证了所提出控制方法的有效性.     

一种多目标多约束问题的优化算法研究

针对优化设计中常见的多目标多约束优化问题,提出了一种求解新方法：利用KS函数的凝聚特性,将优化问题中的全部或部分约束凝聚为一个近似的、逼近精度仅由一个参数控制的约束,然后,再对约束压缩后的优化问题选用适当的约束优化方法求解。仿真结果表明,由于压缩了求解规模,此法收敛稳定且速度快,用于求解一类多目标多约束优化问题具有很好的效果。     

离散时间系统下的积分二次约束方法的几个问题

研究了离散情形下的反馈系统的稳定性问题,利用新近发展起来的积分二次约束(IQC)方法,对离散系统的反馈连接问题,给出了其稳定性分析准则和一些必要条件,这些结果适用于时不变与时变系统.其次,利用已有的结果.得到了离散时变系统MIMO情况下的绝对稳定性问题的一个判据.最后,利用一个较强的IQC定义,给出了判断某一类反馈系统稳定的充分必要条件.     

基于维修时间约束的机群系统可用度的仿真算法

在描述机群系统运行状态的基础上,通过对各结点间结构功能关系的量化处理,给出了描述机群系统中各结点随机变量的概率分布及其抽样方法;然后,依据对故障发生状态和修复状态的识别,确定出各结点的工作状态,从而建立了可用性仿真逻辑关系,得到了机群系统可用度的估计值,为机群系统可用性分析与设计提供了定量依据。     

时间约束混合流水车间调度问题综述

车间调度是智能制造领域中的核心问题之一,在经典流水车间调度中,所有工件按照相同的加工顺序在指定机床上加工.混合流水车间调度(HFS)作为流水车间调度的特例,相比前者增加了机床选择的灵活性,可以显著优化系统目标,但同时也增加了问题求解的难度.由于时间约束HFS相比基本HFS问题更贴近实际生产过程,近年来,综合考虑各类时间相关约束的HFS问题得到了深入研究.因此,本文围绕基本HFS、有限等待时间HFS、带准备时间HFS、模糊/随机加工时间HFS、多时间约束HFS、时间约束相关多目标HFS等问题开展研究.针对每一类时间约束HFS问题,按照问题规模对当前研究成果进行分类描述,按照确定性算法、启发式方法、元启发式方法、算法混合对相关成果进行算法分类,按照实际工业应用对文献进行归类分析.另一方面,围绕交货期、能耗、成本等3类性能指标,分析了在各类时间约束HFS问题中的多目标优化相关成果.最后详细分析了带时间约束HFS问题在问题层面、算法层面和应用层面存在的挑战性问题和未来研究的方向.     

误差约束严格反馈系统的迭代学习控制

针对一类严格反馈非线性系统,本文提出误差跟踪学习控制算法,旨在解决状态约束问题和系统的初值问题.文中构造了二次分式型对称障碍Lyapunov函数以及二次分式型非对称障碍Lyapunov函数,并结合反推技术来分别设计学习控制器.两种控制方案里分别采用积分学习律和微分–差分学习律估计未知系数.系统跟踪误差在控制器作用下囿于预设的界内,从而实现迭代过程中对状态的约束;引入期望误差轨迹,经迭代学习后,两种控制方案均能够实现状态误差在整个作业区间上对期望误差轨迹的完全跟踪,并且实现系统输出在预指定作业区间上精确跟踪参考信号.数值仿真结果表明了控制方案的有效性.     

回溯算法在多约束分配问题中的应用

以学生宿舍合理分配问题为背景,对分配中所涉及的学生高考入学成绩、生源地、宿舍类别等诸多约束条件进行充分分析和探讨,给出了解决这类问题的一种新的有效算法--基于矩阵存储的回溯算法,并给出了算法的实现细节.在此基础上,讨论了该算法的时间复杂度,得出了该算法较同类问题的回溯法具有更好的时间效率,说明了该算法在多约束分配问题中更具合理性和有效性.     

带时间约束的多机器人协作规划研究

通过对多机器人协调规划的研究,将协调任务的要求化为混合整数规划的不等式约束。设计出时间性能指标最优的费用函数,规划出各个机器人最优路径。然后,利用反馈控制器,将规划出满足完整性约束的路径转化为满足机器人运动学约束的轨迹。     

Asymptotic tracking control for constrained nonstrict‐feedback MIMO nonlinear systems via parameter compensations

This paper studies the problem of adaptive fuzzy asymptotic tracking control for multiple input multiple output nonlinear systems in nonstrict‐feedback form. Full state constraints, input quantization, and unknown control direction are simultaneously considered in the systems. By using the fuzzy logic systems, the unknown nonlinear functions are identified. A modified partition of variables is introduced to handle the difficulty caused by nonstrict‐feedback structure. In each step of the backstepping design, the symmetric barrier Lyapunov functions are designed to avoid the breach of the state constraints, and the issues of overparametrization and unknown control direction are settled via introducing two compensation functions and the property of Nussbaum function, respectively. Furthermore, an adaptive fuzzy asymptotic tracking control strategy is raised. Based on Lyapunov stability analysis, the developed control strategy can effectually ensure that all the system variables are bounded, and the tracking errors asymptotically converge to zero. Eventually, simulation results are supplied to verify the feasibility of the proposed scheme.     

一类不确定非线性MIMO系统的神经网络输出反馈跟踪控制

针对一类具有外部干扰的不确定仿射非线性MIMO系统提出了一种神经网络输出反馈跟踪控制方法. 在仅输出可测的情况下, 控制律和神经网络权值更新律中仅用到输出误差, 无需设计状态观测器或加入低通滤波器使得估计误差动态满足严格正实条件. 为抑制外部干扰和子系统间的交叉耦合及神经网络逼近误差, 在控制律中加入鲁棒控制项. 基于Lyapunov稳定性定理证明了系统的稳定性及信号的有界性. 仿真例子证实了所提方法的可行性.     

Robust tracking control for a class of MIMO nonlinear systems with measurable output feedback

This paper proposes a robust output feedback controller for a class of nonlinear systems to track a desired trajectory. Our main goal is to ensure the global input-to-state stability (ISS) property of the tracking error nonlinear dynamics with respect to the unknown structural system uncertainties and external disturbances. Our approach consists of constructing a nonlinear observer to reconstruct the unavailable states, and then designing a discontinuous controller using a back-stepping like design procedure to ensure the ISS property. The observer design is realized through state transformation and there is only one parameter to be determined. Through solving a Hamilton–Jacoby inequality, the nonlinear control law for the first subsystem specifies a nonlinear switching surface. By virtue of nonlinear control for the first subsystem, the resulting sliding manifold in the sliding phase possesses the desired ISS property and to certain extent the optimality. Associated with the new switching surface, the sliding mode control is applied to the second subsystem to accomplish the tracking task. As a result, the tracking error is bounded and the ISS property of the whole system can be ensured while the internal stability is also achieved. Finally, an example is presented to show the effectiveness of the proposed scheme. Copyright © 2007 John Wiley & Sons, Ltd.     

Distributed output‐feedback finite‐time tracking control of nonaffine nonlinear leader‐follower multiagent systems

The distributed output‐feedback tracking control for a class of networked multiagents in nonaffine pure‐feedback form is investigated in this article. By introducing a low‐pass filter and some auxiliary variables, we first transform the nonaffine system into the affine form. Then, the finite‐time observer is designed to estimate the states of the newly derived affine system. By applying the fraction dynamic surface control approach and the neural network‐based approximation technique, the distributed output‐feedback control laws are proposed and it is proved that the tracking errors converge to an arbitrarily small bound around zero in finite time. Finally, some simulation examples are provided to confirm the effectiveness of the developed method.     

Finite‐time tracking control of uncertain nonholonomic systems by state and output feedback

This paper studies the finite‐time tracking control of nonholonomic systems in chained form with parameter uncertainties, unknown output gains, and mismatched uncertainties. To achieve the finite‐time tracking control of uncertain nonholonomic systems, we propose 2 types of controllers by state and output feedback, respectively. Both of the proposed 2 types of controllers can achieve the finite‐time output tracking control of the nonholonomic systems even in the presence of mismatched uncertainties and/or unknown gains. The effectiveness of our proposed controllers are illustrated with simulation examples.     

Output feedback preview tracking control for discrete-time polytopic time-varying systems

This paper focuses on the problem of static output feedback preview tracking control for discrete-time systems with time-varying parameters subject to a previewable reference signal. We develop a design method of a robust controller with integral and preview actions achieving robust tracking performance. First, an augmented error system including future information on reference signal is constructed by introducing two new related auxiliary variables to the original system state and input. This leads to a tracking problem being transformed into a regulator problem. Then, a previewable reference signal is fully utilised through reformulation of the output equation for the augmented error system while considering a static output feedback. Meanwhile, the static output preview control gains are solved explicitly by the proposed conditions. Finally, a numerical example is given to demonstrate the effectiveness of the proposed method.     

Discrete time output feedback sliding mode tracking control for systems with uncertainties

This paper describes a method for designing discrete time static output feedback sliding mode tracking controllers for uncertain systems that are not necessarily minimum phase or of relative degree one. In this work, a procedure for realizing discrete time controllers via a particular set of extended outputs is presented for systems with uncertainties. The conditions for existence of a sliding manifold guaranteeing a stable sliding motion are given. A procedure to synthesize a control law that minimizes the effect of the disturbance on the sliding mode dynamics and the augmented outputs is given. The proposed control law is then applied to a benchmark aircraft problem taken from the literature that represents the lateral dynamics of a F‐14 aircraft under powered approach. Copyright © 2013 John Wiley & Sons, Ltd.     

力反馈装置控制及伺服频率分析

本文研究力反馈装置的电机选取与力控制方法。通过分析力反馈系统特点,提出了电机最大电气时间常数指标与控制电机堵转转矩的方法。通过一维力反馈装置验证了该方法,并进行了虚拟墙的实验研究。     

A‐Orbital feedback linearization of multiinput control affine systems

This article deals with transformations of multiinput nonlinear control systems into linear controllable systems. For multiinput control affine systems, the notion of A‐orbital feedback linearizability is introduced which generalizes the notion of orbital feedback linearizability and is based on input‐dependent time scalings. A necessary and sufficient condition for A‐orbital feedback linearizability is derived for multiinput control affine systems. On the basis of this condition, an A‐orbital feedback linearization algorithm is developed. It is revealed that the proposed concept extends the existing approaches to orbital feedback linearization. More precisely, it is proved that if a system is A‐orbitally feedback linearizable in a neighborhood of some point, the dimension of the state is greater than that of the input by at least three, and the time scaling essentially depends on the input, then the system cannot be orbitally feedback linearized around that point.