Robust design of vibration suppression control system for crane using sway angle observer considering friction disturbance

It is desirable for a container crane to operate smoothly and quickly. For this purpose, the control system of a container crane should be capable of antisway control for suppressing vibrations. A vision sensor system is often used to detect the sway angle. However, since a control system with a vision sensor has a delay time when determining the angle, it sometimes leads to deterioration of control performance owing to the delay time. In order to overcome this problem, this paper proposes a new antisway crane control system based on a dual‐state observer with sensor‐delay correction. However, because of nonlinear friction in the crane, the estimation accuracy achieved by using the observer is poor. To overcome this problem, this paper proposes a disturbance observer considering friction disturbance. The control performance and e?ectiveness of the proposed robust control system based on the estimated information are shown to be satisfactory by experimental results. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(3): 36–46, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22412     

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。     

Variable Dynamic Threshold of Jerk Signal for Contact Detection in Industrial Robots without Force Sensor

This study proposes a variable dynamic threshold for a jerk signal for achieving contact detection in industrial robots. Sensorless force control is useful in applications in advanced industrial robots. The external torque of each joint is estimated accurately by using a disturbance observer and by inverse dynamics calculations. However, the phase lag of the disturbance observer and the dynamic parameter error create force estimation errors. These errors hamper quick and reliable contact detection in industrial robots. Therefore, this study proposes a useful approach to contact detection that uses a variable dynamic threshold for a jerk signal. The proposed variable dynamic threshold reduces contact detection failures caused by force estimation errors during the free motion of a robot. The proposed threshold is suitable for robot motion and improves the speed of contact detection. Numerical simulation results show that the proposed method is valid for the parameter variations in an actual industrial robot. In addition, experimental results show that the dynamic threshold is a useful technique for application to general robot systems as well. The dynamic threshold is useful in applications for any industrial sensorless force control system.     

Robust speed control method for dc servomotors using adaptive gain law

The speed control ability of dc servomotors is affected by parameter variations and disturbance torque. In this paper, a robust speed control method for dc servomotors with a disturbance torque observer and a feedback controller is proposed. The disturbance torque observer is used for the compensation of parameter variations and disturbance. The feedback gain is adjusted in the aspect of stability by an adaptive gain law based on Lyapunov's direct method and is used to restrain the influence of estimation error for the disturbance observer. A robust current control scheme for a voltage source PWM inverter with disturbance observer is also presented, since current control ability affects the control performance of dc servomotors. The validity of this control scheme is verified by numerical simulations and experiments. © 1999 Scripta Technica, Electr Eng Jpn, 126(3): 30–40, 1999     

基于鲁棒扰动观测器的弃风供暖系统

针对大范围弃风和全球变暖等问题,考虑风力发电的不确定性,提出了一种基于鲁棒扰动观测器的风机供电系统控制策略。首先针对风机供电系统进行建模并利用基于泰勒级数展开的扰动观测器消弭系统中存在的参数不确定和未知风力发电波动。其次应用了基于PLC和WinCC的分布式电锅炉供暖控制方法。最后通过仿真验证了所提方法的有效性。     

A study on higher‐order disturbance observer and robust stability

In earlier papers, it has been reported that a fast and precise servo system, which has low sensitivity to parameter variation and disturbance, can be realized with simple structure by using a high‐order disturbance observer. However, no clear and simple design method satisfying specifications for robust stability, the influence of measurement noise, and relative stability (damping characteristics) for large parameter variation has been proposed. In this paper, we clarify the class of robust servo systems realized by adjusting the order of the disturbance observer and the control parameters. We apply this strategy to the design of a second delay system, such as a position servo system, and realize a high‐performance robust servo system using a high‐order disturbance observer. © 1999 Scripta Technica, Electr Eng Jpn, 128(1): 37–44, 1999     

基于龙伯格扰动观测器的永磁同步电机PWM电流预测控制

针对传统永磁同步电机(PMSM)PWM电流预测控制中电机参数扰动造成的电流静差及振荡问题,提出基于龙伯格(Luenberger)观测器的PWM电流预测控制。首先,将系统参数扰动引入到电机电压方程,构建在参数扰动中拥有优良性能的Luenberger观测器来观测系统扰动。其次,离散化Luenberger扰动观测器,通过极点配置分析系统稳定性。最后,将观测器估计系统扰动引入含参数扰动项的电压方程中,为PWM电流预测控制算法提供实时性扰动补偿。仿真结果表明,所提算法能够快速无静差地观测出系统扰动,有效避免参数扰动造成的电流静差及振荡问题,提高电流预测算法的鲁棒性。     

基于神经网络的永磁直线同步电机位置控制

针对永磁直线同步电机(PMLSM)伺服系统中的诸多不确定性问题,提出了采用神经网络来实现实时积分-比例IP位置控制器的设计。本文所提出的神经网络结构合理、简单,权值具有明确物理意义和可以在线快速调整的特点,以便进行实时控制。用由模型参考自适应参数辨识器和负载扰动力观测器构成的估计器来估计动子质量和负载扰动力。将观测的负载扰动力前馈,进一步增强系统的鲁棒性。仿真结果表明,系统具有很强的鲁棒性,同时提高了稳态精度。     

基于扰动观测器的广义风/光一体化控制策略研究

随着光伏、风电等分布式可再生能源高比例接入微电网,其发电出力不确定性给微电网的安全稳定运行带来显著的压力。提出了一种基于广义风/光同构模型的扰动观测器。首先通过建立风机接口整流器状态方程与光伏接口Boost电路状态方程的类比模型,提出了单输入单输出的风/光同构等效模型,使风机和光伏可以达到广义模型一致性。其次,针对光伏、风机等分布式能源出力不确定所造成的状态变量部分未知问题,通过引入连续时间模型的扰动观测器对等效的广义Boost模型进行控制,在光照或风速变化时,可以实现迅速跟随变化,同时随着时间的推移,扰动观测器可以实现无差调节,从而达到消除扰动而带来的部分状态未知的目的。更进一步,利用电压-电流双扰动观测器可以获得稳定的风/光混合系统的输出电压、电流及功率,并且输出量迅速达到给定值。最后通过仿真验证了所提出方法的有效性和可靠性。     

基于鲁棒非线性控制的无刷直流电机调速系统

设计了一种基于鲁棒非线性控制的无刷直流电机速度伺服系统。控制律中包含线性反馈、非线性反馈和扰动补偿三部分,分别实现快速响应、抑制超调和消除稳态误差的功能,采用一个降阶观测器对系统的不可量测状态和未知常值扰动进行估计。通过Matlab/Simulink进行仿真研究,结果表明所设计的控制系统可以对目标转速进行快速平稳和准确的跟踪,且对负载扰动和系统参数差异具有较好的性能鲁棒性。     

Running stabilization control of electric vehicle based on cornering stiffness estimation

In this paper, novel direct yaw moment control (DYC) with road condition estimation and anti‐slip control is proposed for electric vehicles. An inner‐loop observer controls the vehicle traction, and an outer‐loop observer stabilizes the yawing motion of the vehicle. An immeasurable parameter known as cornering stiffness is estimated from the detected yaw‐rate, steering angle, wheel speed and yaw moment observer output in real time. Thus, the accurate control input can be generated with the estimated parameters. The proposed adaptive control is compared with a conventional robust control method under dry and snowy terrain conditions. Experimental results show that the proposed control algorithm properly attenuates the yaw‐rate error. ©2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 97–104, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20569     

基于改进内模控制的永磁同步电机电流环设计

永磁同步电机(PMSM)作为一种高阶非线性系统,由于参数摄动和外部干扰的原因,传统内模控制器不能保证其精确的控制要求。在传统内模控制的基础上,设计了一种基于指数收敛的误差干扰观测器。在解耦和反电动势补偿情况下,建立内模控制器,然后由内模控制器的输出和反馈电流,构造误差干扰观测器的状态方程,输出误差补偿信号,补偿电机运行过程中参数变动和干扰因素,实现PMSM的高精度控制。建立MATLAB/Simulink仿真模型,仿真中人为增加不确定量和扰动。仿真结果表明,在存在不确定信号和负载扰动时,采用改进的内模控制可以实现电流补偿,降低电流纹波,减小电流稳态误差,同时提高转速响应速度,降低扰动误差。     

Extended disturbance observer for nonlinear system with time-varying disturbance gain

In control engineering, the disturbance is a major problem that deteriorates system robustness. To address this problem, a disturbance observer (DOB) has been proposed and developed. In particular, a general method of estimating high-order disturbance, expressed as a time series expansion, was studied (H-DOB). However, systems to which H-DOB are applicable are limited to those in which disturbance gain is constant. This constraint degrades the generality of H-DOB because applicable systems are limited. Therefore, by expanding to a system with a time-varying disturbance gain, we propose a more general H-DOB. The DOB proposed in this paper redesigns the dynamics of the observer based on the structure of the H-DOB. The proposed DOB is applicable even if the system is highly nonlinear. This paper verifies the convergence of the proposed DOB through proof. Using this proof, the same characteristic error dynamics can be obtained, so the same design method can be applied. The simulation for the verification of the proposed method performs disturbance estimation of the extension system. This simulation proves that, compared to H-DOB, the proposed DOB has good disturbance estimation performance.     

无传感器内置式永磁同步电机低速运行转子位置鲁棒观测器

低速运行控制是无位置传感器内置式永磁同步电机(interior permanent magnet synchronous motor,IPMSM)控制系统的关键技术。为了改善无传感器IPMSM矢量控制系统的低速性能,研究了一种基于高频信号注入的转子位置鲁棒观测器,以使位置观测环节具有较强的抗负载扰动能力。在分析扰动转矩可能导致观测器收敛到磁极相反位置问题基础上,针对扰动转矩特性对转子位置鲁棒观测器的结构进行设计。根据阶跃式和斜坡式扰动转矩特性及位置观测误差期望指标,采用极点配置的方法对观测器反馈增益矩阵参数设计进行分析。通过IPMSM无传感器矢量控制系统验证了该转子位置鲁棒观测器的有效性。     

基于龙伯格扰动观测器的PMSM模型预测控制

受工作条件及自身结构影响,永磁同步电机电感参数不是确定的,当采用离线电感参数实现模型预测控制算法时,容易产生参数失配问题,进而导致控制性能下降,为解决该问题,提出了一种基于龙伯格扰动观测器的模型预测电流控制策略。依靠包含扰动的永磁同步电机模型,构建了龙伯格扰动观测器,并根据期望极点配置原理设计了反馈系数,保证观测器的稳定性,创新性体现在利用龙伯格观测器实时估算得到的扰动值补偿由电感参数失配带来的预测精度损失,进而提高系统的控制性能。实验结果表明,提出的基于龙伯格扰动观测器补偿的模型预测控制算法具有较强的鲁棒性,在电感参数失配时,保证电流仍具有良好的稳态性能。     

Robust disturbance attenuation with unknown input observer and sliding mode controller

For a linear system with mismatched disturbance, a robust sliding mode control algorithm using only output feedback is developed in this paper. Although the system with intrinsic issues of unknown input and nonminimum phase is inherited, an improved reduced-order unknown input observer is to be presented in estimating the state of the system. The manipulation of H _∞ control theory along with the implementation of estimated system state can result in robust stabilization with disturbance attenuation when designing integral sliding surface of a system in the sliding mode. A controller is also designed to satisfy the reaching and sliding condition in line with the estimated system state. Finally, a numerical example is explained for showing the applicability of the proposed scheme.     

Robust hybrid estimation and rejection of multi‐frequency signals

We consider the problem of output regulation for LTI systems in the presence of unknown exosystems. The knowledge about the multi‐frequency signals exosystem consists in the maximum number of frequencies and their maximal value. The control scheme relies on two main components: an estimation algorithm, to reconstruct the signal generated by the exosystem, and a controller, to enforce the output regulation property to the closed‐loop system. To tackle the first task, we propose a hybrid observer for the estimation of the (possibly piece‐wise continuous) number and values of the frequencies contained in the exogenous signal. The hybrid observer is particularly appealing for numerical implementations, and it is combined with a self‐tuning algorithm of the free parameters (gains), thus improving its performance even in case of noisy measurements. Semi‐global exponential convergence of the estimation error is provided. As far as the second task is concerned, a robust hybrid regulator is designed for practical rejection of the multi‐frequency disturbance signal acting on the plant. The result is achieved by exploiting the frequencies estimated by the hybrid observer. The effectiveness of the proposed control scheme is shown by means of numerical simulations. Copyright © 2016 John Wiley & Sons, Ltd.     

永磁直驱风力发电机非奇异终端滑模控制

为提高永磁直驱风力发电系统的抗扰能力和控制精度,提出了一种扰动观测器与非奇异快速终端滑模控制相结合的最大功率跟踪控制策略。利用扰动观测器得到风力发电机的转矩变化,对控制器进行前馈补偿;采用非奇异快速终端滑模面提高控制器的动态性能,实现系统快速收敛,减少因扰动引起的抖振。仿真结果表明,所提策略在随机风速的情况下可以准确估计转矩变化,提高最大功率跟踪过程中的转速跟踪精度和风能利用率。     

Sliding mode control for a class of uncertain nonlinear system based on disturbance observer

In this paper, a sliding mode control (SMC) scheme is proposed for a class of nonlinear systems based on disturbance observers. For a nonlinear system, the disturbance that cannot be directly measured is estimated using a nonlinear disturbance observer. By choosing an appropriate nonlinear gain function, the disturbance observer can well approximate the unknown disturbance. Based on the output of the disturbance observer, an SMC scheme is presented for the nonlinear system, and the stability of the closed‐loop system is established using Lyapunov method. Finally, two simulation examples are presented to illustrate the features and the effectiveness of the proposed disturbance‐observer‐based SMC scheme. Copyright © 2009 John Wiley & Sons, Ltd.     

Vibration control of flexible arm by multiple observer structure

This paper describes vibration control of a flexible arm by multiple‐observer structure using the accelerations of the arm. In general, a flexible arm has several oscillation modes. In the model of a flexible arm described as a two‐mass resonant system, the reaction torque feedback makes the flexible arm system stable. In the N‐mass resonant system, it is known that the reaction torque feedback makes all oscillation modes, only the reaction torque feedback is not enough to make the system stable. Resonance ratio control with the arm disturbance observer has been proposed. The arm disturbance observer is able to suppress the disturbance applied to the tip, but it is not sufficient for the disturbance applied to other points on the arm. The aim is to make the control system robust to arm inertia variation and disturbance. This paper proposes vibration control of flexible arm by acceleration feedback, and disturbance rejection by multiple‐observer structure using the acceleration of the arm. The validity of the proposed method is shown by simulations and experiments. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(2): 68–75, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20175