基于高增益观测技术的高精度感应电机磁链观测器研究

针对感应电机磁链观测的一般方法具有观测精度不高、使用的电机参数多、易受影响等问题,利用非线性微分同胚变换对感应电机强耦合非线性系统进行转化,提出一种基于高增益观测技术的感应电机磁链观测器.该观测器不需要满足状态能观的条件且计算量小,通过调节增益能够达到任意精度误差.对非线性规范型的高增益观测器进行了稳定性分析,证明了收敛性.仿真和实验结果验证了该观测器的高观测精度和所提方法的可行性和有效性.     

High gain observer based on a triangular structure

A high gain observer based on a triangular structure of nonlinear systems is proposed. An algorithm capable of calculating a gain of the observer is given. This observer synthesis is then extended to a class of multi‐output nonlinear systems which contains the model of binary distillation columns. Finally, we illustrate the performance of the estimator using numerical simulations of a methanol–ethanol distillation column. Copyright © 2002 John Wiley & Sons, Ltd.     

High performance sensorless speed vector control of SPIM Drives with on-line stator resistance estimation

The aim of this paper is to implement a sensorless Indirect Stator Field Oriented Control (ISFOC) of Single-Phase Induction Motor Drive (SPIMD) with stator resistance tuning. The proposed method for the estimation of speed is based only on measurement of stator currents. A very simple identification algorithm using d-axis stator current error for identifying the stator resistance is proposed. Experimental results for SPIMD are presented and analyzed by using a dSpace system with DS1104 control board based on the Digital Signal Processor (DSP) TMS320F240. Simulated results are compared with experimental results on a test 1.1 kW SPIM setup. The agreement between simulated and experimental results proves the validity of the proposed method.     

High gain observer for a class of non-triangular systems

This paper presents a high gain observer for a class of MIMO nonlinear systems involving some uncertainties. The latter is particularly composed of cascade subsystems where each subsystem is associated with a subset of the output variables, and assumes a triangular dependence on its own state variables and may depend on the state variables of all other subsystems. The main contribution consists in extending the available results to allow more interconnections between the subsystems. Of fundamental interest, it is shown that the underlying observation error exponentially converges to zero in the absence of uncertainties. Moreover, the observation error can be made as small as desired by properly specifying the observer design parameter in the case where uncertainties are considered.     

High gain estimation for nonlinear systems

This work is a continuation of [4] where the third author exhibits a high gain exponential observer for MISO nonlinear systems affine in the input and observable for any input with continuous dynamics and measurements. In this paper, we establish stability results for continuous-continuous and continuous-discrete extended Kalman filters derived from the observer of [4].     

High gain observer with updated gain for a class of MIMO nonlinear systems

A high gain like observer with an updated gain is proposed for a class of MIMO nonlinear systems that are observable for any inputs. The main contribution of this article lies in the nature of the observer gain that involves a scalar time-varying design parameter governed by some scalar Riccati equation. This time-varying design parameter, chosen constant in standard high observer, allows to get an acceptable tradeoff between state reconstruction speed on the one hand versus amplification of noise on the other. Simulation results are given in order to highlight the performances of the proposed observer, namely its exponential convergence and its good behaviour in dealing with noise measurements.     

A nonlinear observer for on-line estimation of the cerebrospinal fluid outflow resistance

Accurate estimates of the outflow resistance of the human cerebrospinal fluid system are important for the diagnosis of a medical condition known as hydrocephalus. In this paper we design a nonlinear observer which provides on-line estimates of the outflow resistance, to the best of our knowledge the first method to do so. The output of the observer is proven to globally converge to an unbiased estimate. Its performance is experimentally verified using the same apparatus used to perform actual patient diagnoses and a specially-designed physical model of the human cerebrospinal fluid system.     

High gain observer based extended generic model control with application to a reactive distillation column

This article aims at synthesizing an estimator based hybrid control scheme that consists of a high gain nonlinear observer and the extended generic model controller (EGMC) that is developed by the application of differential geometry theory. The model-based EGMC control system demands the knowledge of some physical state variables of the process and therefore, the development of a suitable algorithm to perform the state estimation has captured the attention. Here, we design a high gain observer so that it estimates a limited number of states which are solely required for the controller simulation. As a consequence, there exists a significant structural discrepancy. Despite this large mismatch, the state observer performs satisfactorily in converging the estimation error for the case of an example ethylene glycol reactive distillation system. With the same reduced-order predictor model, a comparison is also made between the high gain observer and the extended Kalman filter (EKF). Finally, the high gain observer based EGMC control structure shows promising performance in regulating the ethylene glycol column.     

基于奇异观测器的连续系统传感器故障估计

研究连续系统的传感器故障估计问题,提出一种奇异观测器来进行故障估计,所提方法不需要假设故障、故障导数和干扰的上界已知.通过HB∞性能指标抑制了干扰对故障估计的影响;采用线性矩阵不等式来获得奇异观测器的增益阵;利用Lyapunov泛函得到了观测误差动态系统的鲁棒渐近稳定性;最后通过飞行器仿真实例验证了所提方法的有效性.     

A weighted variable gain super-twisting observer for the estimation of kinetic rates in biological systems

The knowledge of kinetic reaction rates is important for monitoring and controlling biotechnological processes. However, the lack of on-line sensors for this purpose and the inherent problems with numerical differentiation make observers indispensable. In this work, we propose the use of a weighted variable gain super-twisting observer (WVGSTO), applicable to a class of second-order nonlinear systems that include a measurable weight on the unmeasured variable and the possibility of bounding the perturbations with measurable functions. This estimation method is illustrated with an academic example and then applied to a fed-batch bioprocess.     

基于高增益观测器的AUV水平面轨迹跟踪控制

通过研究欠驱动自治水下机器人（AUV）在水平面的运动规律,针对欠驱动AUV水平面轨迹跟踪控制中的非完整约束、模型中的耦合性和非线性、海流干扰、跟踪精度问题进行了深入的研究,运用高增益观测器结合反步控制方法对欠驱动AUV轨迹跟踪进行有效控制。定义了AUV的地面坐标系和船体坐标系,并完成了地面坐标系向船体坐标系的转换,建立了欠驱动AUV的水平面运动学模型和动力学模型。为欠驱动AUV所提出的高增益观测器结合反步控制方案,在保证跟踪系统稳定性的前提下,可以有效地提高跟踪精度,能够消除外界干扰对控制效果的影响,并使得控制输入满足实际工程的应用约束条件。控制方法的稳定性均采用Lyapunov稳定性理论加以证明,并通过数值仿真验证了所设计控制器的有效性。     

Integrated observer based fault estimation for a class of Lipschitz nonlinear systems

The fault estimation for a class of nonlinear systems with Lipschitzian nonlinearities and faults is studied in this article. An integrated estimation observer that covers the robust estimation observer (REO) and adaptive estimation observer (AEO) is proposed to improve the accuracy of fault estimation. Compared with the traditional AEO, the designed observer does not involve the output derivatives and can be more suitable for practical applications. Furthermore, based on the designed observer, the coupling term emerging in the obtained error dynamics can be eliminated reasonably and less conservative stability conditions for the error dynamics can be obtained, whereas the case is hard to be achieved based on the existing intermediate estimator approach in the literature. Compared with the traditional REO and AEO, the fault can be estimated with a good accuracy by using the proposed integrated estimation observer. Numerical examples test the effectiveness and advantages of the proposed method.     

基于新型转子磁链辨识方法的多电机系统同步控制

磁链观测是多电机闭环控制系统性能的重要环节,而电机参数的变动通常使磁链观测的精度难以满足要求.针对3台异步电机和3台逆变器组成的三电机同步系统,提出了局部模型网络磁链辨识方法.将电机参数变化当作干扰项来处理,解决了因电机参数变动影响磁链准确观测的难题.在此基础上,采用神经网络逆构建由速度、磁链、张力子系统组成的伪线性复合系统,实现了三电机同步系统中速度、磁链和张力的解耦.分别对各子系统设计线性闭环控制器,实现了三电机系统的同步控制.仿真结果验证了磁链辨识的准确性和控制系统良好的动静态性能.     

Nonlinear observer design for state and disturbance estimation

A new systematic framework for nonlinear observer design that allows the concurrent estimation of the process state variables together with key unknown process or sensor disturbances is proposed. The nonlinear observer design problem is addressed within a similar methodological framework as the one introduced in [N. Kazantzis, C. Kravaris, Nonlinear observer design using Lyapunov's auxiliary theorem, Systems Control Lett. 34 (1998) 241; A.J. Krener, M. Xiao, Nonlinear observer design in the Siegel domain, SIAM J. Control Optim. 41 (2002) 932.] for state estimation purposes only. From a mathematical standpoint, the problem under consideration is addressed through a system of first-order singular PDEs for which a rather general set of solvability conditions is derived. A nonlinear observer is then designed with a state-dependent gain that is computed from the solution of the system of singular PDEs. Under the aforementioned conditions, both state and disturbance estimation errors converge to zero with assignable rates. The convergence properties of the proposed nonlinear observer are tested through simulation studies in an illustrative example involving a biological reactor.     

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.     

Adaptive observer design for robust fault estimation

In this article, fault diagnosis for a class of linear systems based on adaptive observer is investigated. Linear systems without model uncertainty are first considered, and two adaptive observers are designed for fault identification. The first one uses optimal design for minimizing the estimation error. The second one can achieve asymptotic fault estimation. The general situation where the system is subjected to either model errors or external disturbance is then discussed. Robust adaptive control techniques are applied to guarantee the convergence to a bounded set. Simulation of sensor fault diagnosis for an induction motor is presented to verify the effectiveness of the proposed method.     

基于广义未知输入观测器的鲁棒故障估计方法

当干扰存在时,有效地估计故障且放松故障的限制条件需要进一步的研究,为此针对含未知干扰的非线性连续系统的鲁棒故障估计问题提出一种广义未知输入观测器方法。首先,将执行器故障向量和传感器故障向量与原系统状态向量组成广义系统,放松对故障类型的限制,对此广义系统设计未知输入观测器解耦干扰,保证鲁棒性的同时估计出状态变量、执行器故障及其一阶微分和传感器故障。然后通过解线性矩阵不等式（LMI）给出估计误差渐近收敛的条件。最后,在MATLAB 的simulink平台上用三叶片水平轴风力模型仿真验证本文观测器的故障估计有效性鲁棒性。     

Fault estimation for T-S fuzzy Markovian jumping systems based on the adaptive observer

The adaptive fault estimation problem is studied for a class of stochastic Markovian jumping systems (MJSs) with time delays and nonlinear parameters. By means of Takagi-Sugeno fuzzy models, the dynamics of observer error generator and the fuzzy error dynamical system are constructed. Based on the selected Lyapunov-Krasovskii functional framework, the adaptive fault estimation algorithm is proposed to enhance the rapidity and accuracy performance of fault estimation. In terms of linear matrix inequalities techniques, a sufficient condition on the existence of the adaptive observer is presented and proved. Moreover, the presented results are also extended to multiple time-delayed nonlinear MJSs. A numerical example is given at last to illustrate the effectiveness of the proposed approach.