Study on unknown input reduced-order observer for fault diagnosis

A novel unknown input reduced-order observer (UIRO) design scheme is presented. It is proved that unknown input appearing in measurement can be eliminated by a simple algebraic transformation. Then, a new UIRO design scheme is proposed via a transformation under no unknown input existing in measurement. Compared with other known results, the condition is weaker than others. So it was further reasonable. The design procedure proposed is simple and straightforward enough to be applied. An example is given to show its efficiency in fault diagnosis.     

通信协议一致性测试序列自动生成算法研究

在通信协议的一致性测试领域中,自动生成满足测试需要的一致性测试序列一直是该领域研究的一个重要问题.在对两种基于UIO序列的通信协议的一致性测试序列的自动生成算法进行了研究和比较后,分析了这两种算法各自的测试序列的生成过程及优缺点.实验结果表明,将这两种测试序列的生成算法相结合,能够对通信协议的控制流部分进行充分的测试,使生成的测试序列具有比较高的错误覆盖率,从而提高了一致性测试的效率.     

基于UIO序列的测试方法及UIO生成算法研究

测试序列生成是协议一致性测试的一个重要方面,好的测试序列应该有较大的错误覆盖率且长度越短越好。测试序列构成中的第三部分通常称为状态识别序列,通过比较几种以UIO序列为状态识别序列的协议一致性测试方法,提出了一个更好的UIO序列生成算法,该算法能产生更短的UIO序列。     

A novel unknown input observer-based fault detection with application to a two-stage chemical reactor

This article presents a new method of fault detection for the two-stage chemical reactor system. The process can be carried out effectively in the presence of the time-delay and the unknown inputs and the parameter uncertainties by using the observer-based method technique. In order to detect the actuator fault, a novel unknown input observer is employed as the residual generator. Multi-objective optimization techniques and a new performance index are adopted to ensure the robustness and sensitivity of the fault detection observer. Then the problem of fault detection is reduced to the problem of model matching. Furthermore, sufficient conditions are obtained to guarantee that the error system is asymptotically stable with an performance by means of the Lyapunov function technique. Finally, a two-stage chemical system is borrowed to demonstrate the effectiveness of the obtained methods.     

UIO design for singular delayed LPV systems with application to actuator fault detection and isolation

In this paper, the unknown input observer (UIO) design for singular delayed linear parameter varying (LPV) systems is considered regarding its application to actuator fault detection and isolation. The design procedure assumes that the LPV system is represented in the polytopic framework. Existence and convergence conditions for the UIO are established. The design procedure is formulated by means of linear matrix inequalities (LMIs). Actuator fault detection and isolation is based on using the UIO approach for designing a residual generator that is completely decoupled from unknown inputs and exclusively sensitive to faults. Fault isolation is addressed considering two different strategies: dedicated and generalised bank of observers’ schemes. The applicability of these two schemes for the fault isolation is discussed. An open flow canal system is considered as a case study to illustrate the performance and usefulness of the proposed fault detection and isolation method in different fault scenarios.     

协议一致性测试生成的路径叠加方法

基于UIO序列提出了一种新的协议一致性测试生成方法——路径叠加方法。其核心思想是寻找有限状态机中无重复转换的路径作为路径叠加转换序列,在其后连接该序列尾状态的UIO序列,从而验证该序列中所有转换。理论与实验结果表明,由路径叠加算法生成的测试序列长度要比其他基于UIO序列的算法生成的测试序列明显缩短。特别的,利用路径叠加转换序列来替代OUIO方法中对子序列直接叠加而生成的完全叠加转换序列,在检错性不降低的前提下,大大降低了叠加计算的复杂度。     

A predictive controller for induction motors using an unknown input observer for online rotor resistance estimation and an update technique for load torque

This paper deals with the design of an output feedback predictive controller for induction motors. The fundamental interest of the proposed controller is the capability of decoupling the mechanical speed and the rotor fluxes, without degradation against the variation of rotor resistance and load torque. Hence, the contribution is to apply two estimation procedures in order to achieve this goal. Namely, an unknown input observer (UIO) is used for the constant time estimation whereas a heuristic solution is exploited for the load torque update. Moreover, rotor flux components are recovered as an unavailable state of the system. Effectiveness of the proposed observers and the performance of the controller are confirmed by simulation results.     

A gain-varying UIO approach with adaptive threshold for FDI of nonlinear F16 systems

A discrete gain-varying unknown input observer (UIO) method is presented for actuator fault detection and isolation (FDI) problems in this paper. A novel residual scheme together with a moving horizon threshold is proposed. This design methodology is applied to a nonlinear F16 system with polynomial aerodynamics coefficient expressions, where the coefficient expressions for the F16 system and UIOs may be slightly different. The simulation results illustrate that a satisfactory FDI performance can be achieved even when the F16 system is under the environment of model uncertainties, exogenous noise and measurement errors.     

基于未知输入观测器的直流电机鲁棒故障估计

针对直流电机系统提出一种基于未知输入观测器(UIO)的鲁棒故障估计方法,同时估计系统中的执行器故障和传感器故障。首先,构建包含系统传感器故障的增广状态系统;然后,基于该增广系统提出一种新颖的UIO,并给出了该观测器的存在条件和多故障估计策略;同时,引入H_∞性能指标最大程度地抑制干扰对故障估计结果的影响;接着,给出观测器的设计条件和参数求解过程并将其转化为易于求解的线性矩阵不等式(LMI)的形式;最后,通过算例仿真和实验验证了该方法的有效性和可用性。     

固相萃取-氢化物产生-原子荧光光谱法检测 大米中总砷的含量

目的建立基于UIO66材料分散固相萃取体系的提取大米中总砷,并采用氢化物产生-原子荧光光谱法检测其含量。方法以7 mL 0.06 mol/L HNO_3+3%H_2O_2为消解液,在最大微波功率800 W下, 180℃微波消解20min,提取大米中的总砷,通过金属有机骨架材料UIO66实现大米提取液中总砷的分离净化,最后采用氢化物产生-原子荧光光谱法进行总砷含量测定。结果在10～80μg/kg浓度范围内,总砷的标准曲线方程线性良好(相关性系数r~2=0.9997),最低检出限(limitofdetection,LOD)为0.024μg/kg,样品加标回收率在93.4%～107.8%之间,相对标准偏差2%。7种大米样品中的总砷含量在150～250μg/kg之间,其中糙米中总砷含量最高(244.53±4μg/kg),东北地区产大米与南方地区产大米的总砷含量存在显著性差异(P0.05)。结论基于UIO66分散固相萃取体系的大米中总砷分离分析方法具有高灵敏度、低成本、易操作的特点,可有效实现大米中总砷的净化和定量分析。