Robust Unknown Input Observer Design for Linear Uncertain Time Delay Systems with Application to Fault Detection

In this paper, a novel approach is proposed to design a robust fault detection observer for uncertain linear time delay systems. The system is composed of both norm‐bounded uncertainties and exogenous signals (noise, disturbance, and fault) which are considered to be unknown. The main contribution of this paper is to present unknown input observer (UIO)‐based fault detection system which shows the maximum sensitivity to fault signals and the minimum sensitivity to other signals. Since the system contains uncertainty terms, an H_∞ model‐matching approach is used in design procedure. The reference residual signal generator system is designed so that the fault signal has maximum sensitivity while the exogenous signals have minimum sensitivity on the residual signal. Then, the fault detection system is designed by minimizing the estimation error between the reference residual signal and the UIO residual signal in the sense of H_∞ norm. A sufficient condition for the existence of such a filter is exploited in terms of certain linear matrix inequalities (LMIs). Application of the proposed method in a numerical example and an engineering process are simulated to demonstrate the effectiveness of the proposed algorithm. Simulation results show the validity of the proposed approach to detect the occurrence of faults in the presence of modeling errors, disturbances, and noise.     

On the Design of Observer for Nonlinear Time‐Delay Systems

This paper suggests a new method to design observers in a class of nonlinear time‐delay systems with delays in system states. The method is based on an extension of the well‐known state‐dependent Riccati equation (SDRE) technique. The conditions for locally asymptotic stability of the proposed observer are investigated. Some numerical simulations are provided to show the design procedure and the flexibility of the proposed observer.     

An Adaptive and Optimized Switching Observer for Sensorless Control of an Electromagnetic Valve Actuator in Camless Internal Combustion Engines

In this paper, the design and operation of a special electromagnetic actuator as a variable engine valve actuator are presented. Further, this paper describes a feasible approximated velocity switching estimator based on measurements of current and input voltage to achieve sensorless control. The proposed concept allows a reduced‐order observer to be conceived and yields a specific control strategy with an acceptable performance. In general, this approach represents a viable strategy to build reduced‐order observers for estimating the velocity of systems through the measurement of input current and voltage. The robustness of the velocity tracking is explored using a minimum variance approach. The effect of the noise is minimized, and the position can be achieved through an adaptive and optimized structure by combining this particular velocity estimator and an observer based on the electromechanical system. Position control is achieved through an inversion of the model. This approach avoids a more complex structure for the observer and yields an acceptable performance as well as eliminating bulky position‐sensor systems. In addition, a control strategy is presented and discussed. Computer simulations of the sensorless control structure are presented in which the positive effects of the observer with optimized parameter setting are visible in the closed‐loop control.     

马尔可夫跳变系统的鲁棒故障检测与时域优化

研究马尔可夫跳变系统(MJS) 鲁棒故障检测滤波器(FDF) 的设计与优化问题. 基于观测器构建残差发生器, 将相应的FDF 设计问题转化为H_∞ 滤波问题, 以LMI 的形式得到并证明了FDF 存在的充分条件及求解方法. 为进一步改善故障检测系统的性能, 采用一种时域优化方法对其进行优化, 并以矩阵Moore-Penrose 逆的形式给出了该优化问题的最优解. 数值仿真表明该方法具有较好的检测效果.     

PBT/官能化聚烯烃弹性体共混体系的力学性能与相形态

考察了马来酸酐接枝乙烯-辛烯共聚物（POE-g-MAH）和乙烯-丙烯酸甲酯-甲基丙烯酸缩水甘油酯三元共聚物（E-MA-GMA）对聚对苯二甲酸丁二醇酯（PBT）的增韧作用。结果表明，未接枝的POE弹性体对PBT缺口冲击韧性的改善作用不大。两种官能化聚烯烃弹性体（E-MA-GMA、POE-g-MAH）对PBT具有显著的增韧作用。当弹性体用量分别达到8．5％和10％以后，共混物都各自出现明显的脆／韧转变现象。这意味着在达到同样的冲击韧性时，PBT／E—MA—GMA共混体系的拉伸强度损失较小。SEM显示，PBT／E—MA—GMA共混体系中分散相具有更细微的分散，有效地诱导PBT基体产生银纹和剪切屈服，消耗大量的冲击能。     

A reactive extension of the OpenMusic visual programming language

Objectives: OpenMusic (OM) is a domain-specific visual programming language designed for computer-aided music composition. This language based on Common Lisp allows composers to develop functional processes generating or transforming musical data, and to execute them locally by demand-driven evaluations. As most historical computer-aided composition environments, OM relies on a transformational declarative paradigm, which is hard to conciliate with reactive data-flow (an evaluation scheme more adequate to the development of interactive systems). We propose to link these two evaluation paradigms in the same and consistent visual programming framework.Methods: We establish a denotational semantics of the visual language, which gives account for its demand-driven evaluation mechanism and the incremental construction of programs. We then extend this semantics to enable reactive computations in the functional graphs.Results: The resulting language merges data-driven executions with the existing demand-driven mechanism. A conservative implementation is proposed.Conclusions: We show that the incremental construction of programs and their data-driven and demand-driven evaluations can be smoothly integrated in the visual programming workflow. This integration allows for the propagation of changes in the programs, and the evaluation of graphically designed functional expressions as a response to external events, a first step in bridging the gap between computer-assisted composition environments and real-time musical systems.     

Observer‐based H ∞ output tracking control for networked control systems

This paper is concerned with observer‐based H _∞ output tracking control for networked control systems. An observer‐based controller is implemented through a communication network to drive the output of a controlled plant to track the output of a reference model. The inputs of the controlled plant and the observer‐based tracking controller are updated in an asynchronous way because of the effects of network‐induced delays and packet dropouts in the controller‐to‐actuator channel. Taking the asynchronous characteristic into consideration, the resulting closed‐loop system is modeled as a system with two interval time‐varying delays. A Lyapunov–Krasovskii functional, which makes use of information about the lower and upper bounds of the interval time‐varying delays, is constructed to derive a delay‐dependent criterion such that the closed‐loop system has a desired H _∞ tracking performance. Notice that a separation principle cannot be used to design an observer gain and a control gain due to the asynchronous inputs of the plant and the controller. Instead, a novel design algorithm is proposed by applying a particle swarm optimization technique with the feasibility of the stability criterion to search for the minimum H _∞ tracking performance and the corresponding gains. The effectiveness of the proposed method is illustrated by an example. Copyright © 2013 John Wiley & Sons, Ltd.     

带有传感器故障的模糊时滞系统的容错控制

针对一类连续非线性时滞系统,在状态不完全可测的情况下,研究了带有传感器故障的容错控制问题。采用T-S模型对非线性系统进行模糊建模,通过构造广义系统设计了观测器,同时估计出系统的状态与故障,进一步利用平行分布补偿算法（PDC）设计基于观测器的模糊容错控制器,给出了保证该模糊容错控制系统稳定的充分条件。仿真例子进一步验证了所提出方法的有效性。     

HP nonlinear guidance law design based on smooth sliding mode control

To eliminate the perturbation of interceptor detection induced by aerodynamic heating,the head pursuit (HP) guidance law for three-dimensional interception was presented. The guidance law positioned the interceptor ahead of the target on its flight trajectory,and the speed of interceptor was required to be lower than that of the target. On the basis of a novel head pursuit three-dimensional guidance model,a nonlinear guidance law was developed based on smooth sliding mode control theory. At the same time,a special observer was designed to estimate the target acceleration,and a numerical example on maneuvering ballistic target interception verified the effectiveness of the presented guidance law.     

基于虚拟弹簧的欠驱动手指的动力学建模和控制

采用虚拟弹簧对2关节欠驱动手指进行了动力学建模。并使用该方法建立实际的3关节欠驱动手指的动力学模型,通过动态控制实验验证了动力学模型的正确性。该方法不仅避免了求解微分几何方程,并且直接派生出可解耦的动力学模型。可直接进行逆动力学分析、仿真和实时控制。同时,建立了基于动力学模型的速度观测器,用于轨迹跟踪,弥补了欠驱动手没有速度传感器的缺点,补偿了欠驱动环节造成的不确定因素。与PID或计算力矩法相比较,其轨迹跟踪误差更小,动态控制效果更好。