Disturbance suppression control with preview action for a linear dc brushless motor

This paper proposes a disturbance suppression control with preview action for a brushless and coreless-type linear dc motor. The brushless and coreless-type linear dc motor is coggingless and has long life. It is suitable for high speed and precise positioning control. Parameter variation and load change are regarded as an equivalent disturbance signal and the compensation action is applied by utilizing the estimated value of the equivalent disturbance inside the inner loop. Next, an optimal preview control system is synthesized including the disturbance suppression control system mentioned in the foregoing. Disturbance suppression, improving phase delay and lowering the input peak value are attained in this control system. These effects are confirmed by applying the linear dc motor.     

Robust adaptive control using a combined approach

Direct control, indirect control and variable structure methods are combined with high-gain feedback in this paper for the robust adaptive control of first-, second- and third-order plants with increasing levels of uncertainty. The latter include external disturbance, unmodelled dynamics, time delay and sensor noise. A judicious combination of the methods is found to result in satisfactory response in most cases.     

Adaptive B‐spline neural network‐based vector control for a grid side converter in wind turbine‐DFIG systems

This paper presents a novel control system design for the grid‐side converter of doubly fed induction generator wind power generation systems. The control method proposed in this work is a vector control based on adaptive B‐spline neural network by using a simple fixed‐gain stabilizing control topology. The adaptive control is designed both for inner current loops and an outer DC‐link voltage loop of the grid side converter control system. To guarantee the control stability, the weights updating rule for the B‐spline neural network is synthesized by utilizing Lyapunov's direct method. To verify the effectiveness of the proposed control system, extensive simulations are performed using MATLAB/Simulink. Based on the simulation results, it is concluded that the proposed controller has improved performance compared to an optimum proportional integral control system. It is also relatively robust against external disturbances and variations of the control parameters. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Robust model reference adaptive control for multivariable plants

A complete procedure for generating and analysing robust model reference adaptive control schemes for multivariable plants is developed. The procedure consists of two parts: the first part involves the characterization of the integral structure of the modelled part of the plant, and the associated parametrization of the controller structure; and the second part involves the development of a general robust adaptive law for adjusting the controller parameters so that the closed-loop plant is globally stable despite the presence of unmodelled dynamics and bounded disturbances. The use of dominantly rich signals for improving convergence and the bounds for the tracking and parameter error is also analysed.     

High‐performance speed control based on an instantaneous speed observer considering the characteristics of a dc chopper in a low speed range

This paper proposes a new high‐performance speed control method for wide speed range, which is based on instantaneous speed observer considering the characteristics of dc chopper. In order to regulate a motor speed for wide speed reference including a very low speed range, this paper designs the instantaneous speed observer which uses the information of an armature current and an armature voltage. This observer has no effect of inertia variation and disturbance torque completely, but it has the effect of electrical parameter variation. Hence, this paper proposes a new identification algorithm to cancel out the estimation error caused by both the resistance variation and the voltage drop. The proposed observer can always estimate an instantaneous value of motor speed. The proposed total system becomes a new robust speed servo system for a wide speed range. © 1999 Scripta Technica, Electr Eng Jpn, 130(3): 77–87, 2000     

Servo motor adaptive speed control under angle-dependent disturbances using an RBF network

It is well known that the angle-dependent disturbance in a servo motor caused by nonuniformity of field windings, armature cogging, rotor imbalance, nonuniform load and so on, may influence the speed control performance greatly. This often leads to large speed fluctuations which are undesired in practical situations. Therefore speed fluctuation reduction techniques in the presence of angle-dependent disturbances are strongly required and have been studied by many researchers. In this paper, the authors propose a new approach to this problem via adaptive control with the aid of a radial basis function (RBF) network composed of Gaussian basis functions. The angle-dependent disturbance, viewed as a periodic non-linear function with a period of 2π radians in the angular domain, is approximated by an RBF network in (0, 2π) radians. Then an adaptive linearization control system employing the RBF network which compensates for the disturbance is proposed. The RBF network has the advantage that it is linear in the parameters and hence parameter adaption is very fast and easy to implement. It is proved through theoretical analysis that the stability of adaptive control is guaranteed by Lyapunov stability theory. Finally, simulation and experimental results are included in the paper to show the excellent performance of the proposed method. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(4): 77–86, 1997     

A modified super‐twisting sliding mode control with inner feedback and adaptive gain schedule

In order to deal with the overestimation of matched uncertainty and improve the convergence of sliding variable in sliding mode control, a modified structure of super‐twisting algorithm (STA) with inner feedback and adaptive gain schedule is presented in this paper. The foremost characteristic of the modified STA is that an inner feedback mechanism is built in the standard STA so as to regulate the dynamic behavior of sliding variable effectively. The damping effect produced by the inner feedback can restrain the overshoot and enhance the performance of faster convergence of the sliding variable. Furthermore, the adaptive gain schedule can effectively decrease the chattering amplitude without knowing the upper bound of uncertainty. The numerical simulations and experiments on DC servo system with low speed are carried out to validate the effectiveness and performance advantages of the proposed methodology. Copyright © 2016 John Wiley & Sons, Ltd.     

Variable neural adaptive robust controllers for uncertain systems

A class of variable neural adaptive robust controllers is proposed. Essential components of the proposed controllers are raised‐cosine radial basis function (RCRBF) neural networks that can vary their structures dynamically by adding or removing RBFs online. The compact support of the RCRBFs alleviate the problem of determining the parameters of the RBFs and can, together with a simple adding and removing algorithm, significantly reduce the computational effort in the training process of the network. The stability of the overall closed‐loop system is analyzed using the Lypaunov type of arguments. It is guaranteed that the tracking error of the closed‐loop systems driven by the proposed controller is uniformly ultimately bounded. Copyright © 2007 John Wiley & Sons, Ltd.     

Composite adaptive disturbance observer‐based control for a class of nonlinear systems with multisource disturbance

Antidisturbance control and estimation problem are introduced for a class of nonlinear system subject to multisource disturbances. The uncertain multisource disturbances consist of not only a single harmonic or constant disturbance but also another unexpected nonlinear signal described as a nonlinear function. The composite adaptive disturbance observers are constructed separately from the controller design to estimate the disturbance with partial known information. By integrating disturbance observer‐based controller with robust adaptive control, a novel type of composite adaptive disturbance observer‐based control scheme is presented for a class of nonlinear system with multisource disturbances. Simulations for a flight control system are given to demonstrate the effectiveness of the results compared with the previous schemes. Copyright © 2012 John Wiley & Sons, Ltd.     

A small‐gain approach for adaptive output‐feedback NN control of switched pure‐feedback nonlinear systems

This paper investigates the problem of adaptive output‐feedback neural network (NN) control for a class of switched pure‐feedback uncertain nonlinear systems. A switched observer is first constructed to estimate the unmeasurable states. Next, with the help of an NN to approximate the unknown nonlinear terms, a switched small‐gain technique‐based adaptive output‐feedback NN control scheme is developed by exploiting the backstepping recursive design scheme, input‐to‐state stability analysis, the common Lyapunov function method, and the average dwell time (ADT) method. In the recursive design, the difficulty of constructing an overall Lyapunov function for the switched closed‐loop system is dealt with by decomposing the switched closed‐loop system into two interconnected switched systems and constructing two Lyapunov functions for two interconnected switched systems, respectively. The proposed controllers for individual subsystems guarantee that all signals in the closed‐loop system are semiglobally, uniformly, and ultimately bounded under a class of switching signals with ADT, and finally, two examples illustrate the effectiveness of theoretical results, which include a switched RLC circuit system.     

Robust adaptive control for non‐linear systems in generalized output‐feedback canonical form

Design of global robust adaptive output‐feedback dynamic compensators for stabilization and tracking of a class of systems that are globally diffeomorphic into systems in generalized output‐feedback canonical form is investigated. This form includes as special cases the standard output‐feedback canonical form and various other forms considered previously in the literature. Output‐dependent non‐linearities are allowed to enter both additively and multiplicatively. The system is allowed to contain unknown parameters multiplying output‐dependent non‐linearities and, also, unknown non‐linearities satisfying certain bounds. Under the assumption that a constant matrix can be found to achieve a certain property, it is shown that a reduced‐order observer and a backstepping controller can be designed to achieve practical stabilization of the tracking error. If this assumption is not satisfied, it is shown that the control objective can be achieved by introducing additional dynamics in the observer. Sufficient conditions under which asymptotic tracking and stabilization can be achieved are also given. This represents the first robust adaptive output‐feedback tracking results for this class of systems. Copyright © 2003 John Wiley & Sons, Ltd.     

基于新型电压控制律的永磁同步电机滑模补偿控制

针对永磁同步电机转矩闭环控制系统中动态耦合项和反电动势项引发弱动态性能的问题,提出一种基于新型电压控制律的永磁同步电机滑模补偿控制方法。首先,基于永磁同步电机模型建立新型电压控制律,保证转矩闭环控制系统的稳定性。其次,利用速度估值与滑模面的函数关系,设计自适应速度观测器,对d、q轴耦合项和反电动势项进行补偿,同时实现系统的速度闭环控制。在此基础上,引入含sigmoid非线性光滑函数的滑模面,构造滑模补偿控制策略,实现控制律在整个运动过程中对参数摄动和外扰动的鲁棒性。最后,搭建Matlab/Simulink仿真模型和由TMS320F28335控制的400 W永磁同步电机的实验平台。仿真和实验结果表明所提控制方法具有转矩和电流波动小、响应快和鲁棒性强的特性。     

先进控制在异步电动机直接转矩控制中的应用

为提高直接转矩定子磁链的观测精度 ,给出了一种新的自适应定子磁链观测器的设计方案 ,它采用正实误差模型下的参数调节率 ,该方案不依赖于定子电阻。最后给出实例 ,仿真结果表明了设计方法的有效性     

Discrete‐time simplified adaptive control of a dc motor based on asymptotic output tracker theory

Simplified adaptive control (SAC) has simple structure and is readily implemented in real systems, but few real applications have as yet been reported. A discrete‐time algorithm for SAC has recently been proposed by one of the authors. Although it solves the problem of unavoidable time delay arising in the discretization of the continuous‐time algorithm, the algorithm generally produces a bounded output error between the controlled plant and the reference model due to a feedforward gain added in parallel to the controlled plant so as to satisfy the positive real (ASPR) property with almost complete rigor. This paper treats the applicability of the SAC algorithm to a real system, that is, the position control of a dc motor with variable load. The algorithm used here is modified, and the feedforward compensator is inserted in parallel not only to the controlled plant, but also to the reference model. The algorithm guarantees that the output error vanishes asymptotically. The control performance is examined by both simulation and testing of an actual system and is compared with that of a conventional PID control. These results illustrate satisfactory control performance and verify the applicability of the modified algorithm. © 2001 Scripta Technica, Electr Eng Jpn, 135(1): 33–42, 2001     

Robust 2DOF fuzzy gain scheduling control for DC servo speed controller

This paper proposes a new design method called “robust 2DOF fuzzy gain scheduling control” for a DC servo speed control system. The proposed technique utilizes the basic concept of 2DOF robust loop shaping, whose time‐domain specifications are combined during the controller design using a reference model. In addition, the local controllers are fixed‐ structure robust controllers whose structure can be specified as for a simple controller. A fuzzy approach is adopted in both system identification process and global control structure to accomplish an entirely robust system. Although the design of robust control in a fuzzy system is not easy, genetic algorithms (GAs) simplify the control design problem to design the fuzzy controller such that the average stability margin is minimized. Implementation of a DC servo speed control was adopted to investigate the effectiveness of the proposed controller. As seen from the results, the proposed controller has more robust performance and can be adopted in applications with a wide operating range. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Robust adaptive output feedback control of nonlinearly parameterized systems

The ideas of adaptive nonlinear damping and changing supply functions were used to counteract the effects of parameter and nonlinear uncertainties, unmodeled dynamics and unknown bounded disturbances. The high-gain observer was used to estimate the state of the system. A robust adaptive output feedback control scheme was proposed for nonlinearly parameterized systems represented by input-output models. The scheme does not need to estimate the unknown parameters nor add a dynamical signal to dominate the effects of unmodeled dynamics. It is proven that the proposed control scheme guarantees that all the variables in the closed-loop system are bounded and the mean-square tracking error can be made arbitrarily small by choosing some design parameters appropriately. Simulation results have illustrated the effectiveness of the proposed robust adaptive control scheme. Translated from Journal of Sichuan University (Engineering Science Edition), 2006, 38(4): 136–140 [译自: 四川大学学报 (工程科学版)]     

无速度传感器异步电机转子磁场定向自适应鲁棒控制

针对无速度传感器异步电机矢量控制系统,为了提高系统对电机参数变化和转矩扰动的鲁棒性,提出一种基于自适应观测器的鲁棒控制策略。研究了一种改进全阶自适应状态观测器设计方法,将静止坐标系下状态观测误差系统变换到同步旋转坐标系以克服系统的复杂非线性,通过分析单输入单输出误差系统获得了观测器稳定条件,并采用一种增强型定子电阻自适应率以降低观测器对电机参数变化的敏感性。为了提高异步电机磁场定向控制系统的抗负载转矩扰动能力,在分析扰动转矩对控制系统动态模型影响基础上,提出了一种自适应扰动转矩前馈补偿控制策略。通过11kW无速度传感器异步电机矢量控制系统进行实验,实验结果验证了所提出方法的有效性。     

Robust direct torque and flux control of adjustable speed sensorless induction machine drive based on space vector modulation using a PI predictive controller

A Direct torque and flux control design for a sensorless induction motor, following a Lyapunov-based stator flux observer is presented. In this control scheme, the torque error signal and the amplitude of the stator flux reference vector are delivered to a PI predictive controller. The predictive controller also uses information on the amplitude and position of the actual stator flux vector and measured stator currents to determine the voltage command vector for space vector modulation inverter. In addition, a conventional PI speed controller is used to generate the torque reference signal. Using the fifth order model of the three-phase induction machines in a stationary two axes reference frame, a nonlinear stator flux observer is developed in order to estimate the rotor speed, rotor and stator resistances simultaneously. The stability of this observer is proved by Lyapunov theory. It is shown that if the persistancy of excitation condition is satisfied, the estimated quantities converge to their real values. The effectiveness of the proposed control scheme is verified by computer simulation and experimental results.     

A robustification tool for adaptive non‐linear control

This paper presents a conceptually simple robustification approach for the adaptive control of a class of non‐linear systems with static and dynamic uncertainties. This approach generates a new class of robust adaptive non‐linear controllers and is based upon a combined application of the well‐known adaptive backstepping and recent non‐linear small‐gain techniques. The presented method is illustrated via a third‐ order chemical reactor with only temperature information, and under relaxed conditions. An adaptive output‐feedback stabilizer is obtained without resorting to any state observer. Copyright © 1999 John Wiley & Sons, Ltd.     

交直流互联系统非线性自适应控制规律设计

针对舍有多台发电机的交直流互联系统,为了提高交直流输电系统的稳定性,应用非线性自适应控制设计方法,通过递推法得到了应用于交直流互联系统直流功率调制的非线性自适应控制策略,该控制规律包含了对系统中未知参数的动态估计,用以阻尼交直流互联系统的区域间功率振荡。最后,获得了交直流互联系统的非线性自适应直流附加控制器的一般表达式。4机系统的仿真结果表明,与传统的线性直流功率调制相比较,所设计的控制器对联络线的功率振荡具有良好的阻尼功能;特别是当系统中出现大的扰动时,更能体现该控制器的良好性能。