基于Duhem前馈逆补偿的压电陶瓷迟滞非线性 自适应滑模控制

针对压电陶瓷的动态迟滞非线性,研究了基于Duhem逆模型前馈补偿的滑模自适应控制策略。首先,利用多项式逼近Duhem模型中的未知分段函数ｆ(.)和ｇ(.),采用递推最小二乘法进行系统辨识,并求取逆模型,将其作为前馈控制器,考虑压电陶瓷迟滞非线性随输入信号频率变化,且难以完全抵消,模型参数存在不确定性等问题,设计一种自适应滑模控制律。利用Lyapunov稳定性定理及仿真实验证明了该控制律可以使系统全局渐进稳定。最后,进行了压电陶瓷迟滞补偿实验和位移跟踪实验。实验结果表明,前馈逆补偿控制下的压电陶瓷位移迟滞量减小了96.1％,与直接控制相比,前馈逆补偿控制下位移跟踪的最大绝对误差减小了27.0％,平均绝对值误差减小了17.9％,具有更好的跟踪精度和动态性能。     

基于压电陶瓷微位移执行器的精密定位技术研究

阐述了压电陶瓷微位移执行器的驱动原理,介绍了执行器的性能与应用情况;利用自行设计的输出特性测试系统,对WTYD0808042压电陶瓷微位移执行器进行了相关实验研究,分析了执行器的非线性和迟滞特性;采用Duhem算子建立了压电执行器的迟滞模型,利用建立的Duhem模型作为PID反馈控制的前馈环节进行闭环精密定位控制的研究。实验结果表明:该模型能够有效降低非线性和迟滞特性对压电执行器位移输出精度的影响,提高执行器的动态响应特性。     

微位移系统中压电陶瓷驱动器迟滞建模

针对超精密微位移系统中压电陶瓷驱动器的迟滞非线性问题,提出了一种基于遗传反向传播(BP)神经网络的压电陶瓷迟滞非线性建模方法.通过电涡流位移传感器获取压电陶瓷驱动器不同电压值下所对应的位移值;利用六次多项式拟合获得迟滞的数学模型,从而建立基于遗传BP神经网络的迟滞,模型.实验结果显示:该迟滞模型在神经网络测试下的最大误差为0.082 1 μm,平均绝对误差为0.0158 μm.表明,所建的迟滞模型能够较精确地反映出压电陶瓷驱动器的迟滞特性,同时为微位移控制系统设计提供了一定的理论基础.     

基于径向基神经网络的压电作动器建模与控制

针对压电作动器(piezoelectric actuator,PEA)的率相关迟滞非线性特性,构建了Hammerstein模型对压电作动器建模.采用径向基(radial basis function,RBF)神经网络模型表征迟滞非线性,利用自回归历遍模型(auto-regressive exogenous,ARX)表征频率的影响,并对模型参数进行了辨识.此模型可以在信号频率在1～300 Hz范围内时,较好地描述压电作动器的迟滞特性,建模相对误差为1.99%～4.08%.采用RBF神经网络前馈逆补偿控制,结合PI反馈的复合控制策略实现跟踪控制,控制误差小于2.98%,证明了控制策略的有效性.     

压电陶瓷驱动器迟滞非线性误差的建模与分析

压电陶瓷驱动器的最大迟滞非线性误差可以超过输出行程的15%,而快刀伺服系统(FTS)要求重复定位精度优于10 nm,相对线性度误差优于0.5%,压电陶瓷驱动器的误差无法满足该精度要求;首先对压电陶瓷迟滞非线性误差进行实验分析,将迟滞非线性误差分为频率无关迟滞现象和频率相关迟滞现象;接着对Bouc-Wen(BW)和Prandtl-Ishlinskii(PI)的频率无关迟滞模型进行修正和对比,确定了采用PI模型描述本文的频率无关迟滞现象,PI模型对频率无关迟滞曲线的辨识精度为0.392%;然后设计基于Hammerstein模型的频率相关迟滞模型,Hammerstein模型对频率相关迟滞曲线的辨识误差相比PI模型时,其均方根值降低了88.068%;提出了压电陶瓷驱动器迟滞非线性误差的建模方法,并分析了其有效性和准确性,给FTS伺服控制提供了一种实用的前馈控制器。     

压电微定位平台神经网络与专家模糊复合控制方法

为了消除压电微定位平台的迟滞非线性特性,实现高精度定位控制,采用具有两个隐含层的BP神经网络建立压电微定位平台的迟滞模型,以精确描述驱动电压与输出位移的迟滞关系;设计一种基于BP神经网络迟滞逆模型的前馈控制器,对迟滞非线性进行补偿,将迟滞非线性近似线性化.为进一步提高定位系统的精度,提出基于迟滞逆模型前馈补偿和专家模糊控制的复合控制方法.仿真结果表明,该复合控制方法可以将压电微定位平台的定位误差控制在0.091μm以内,从而有效地消除迟滞非线性对压电微定位平台定位精度的影响.     

压电作动器的动态迟滞建模与H∞鲁棒控制

压电作动器具有率相关动态迟滞非线性特性,给传统建模和控制技术提出了挑战.本文针对压电作动器,提出了一种基于Bouc-Wen的Hammerstein率相关迟滞非线性模型,其中Bouc-Wen模型和线性动态模块分别用于描述系统的静态迟滞非线性特性和率相关特性.同时,构造了一个基于Bouc-Wen模型的迟滞补偿器,将迟滞补偿器与被控对象串联使系统线性化;并建立了不确定性系统模型,提出了一种H∞鲁棒跟踪控制方案,可以实现给定频率范围内单频率和复合频率参考信号的良好跟踪.实验结果表明,所建动态模型具有良好的泛化能力,跟踪控制相对误差小于8%,证明了所提出方法的有效性.     

压电陶瓷执行器的动态迟滞非线性特性建模

针对精密定位系统中压电陶瓷执行器的迟滞非线性特性建模问题,提出了一种基于Hammerstein迟滞模型的建模方法。通过引入一个Backlash类的算子来描述迟滞非线性的轮廓。在利用"扩展输入空间法"将迟滞特性的多值映射转换为一一映射的基础上,采用引力搜索算法优化的支持向量回归机建立静态迟滞模型。为体现迟滞的动态特性,用ARX模型表征迟滞环的率相关性,从而建立了Hammerstein级联模型。并从精密定位系统中采集了实测数据,通过电容传感器获取压电陶瓷执行器给定电压下的位移值,对所提出的模型进行了实验。实验表明:该模型具有较好的性能,辨识过程简便且易于工程实现。     

基于变比模型的AFM扫描器迟滞建模与控制

针对迟滞非线性引起的压电扫描器定位不准确问题,提出一种基于变比模型的迟滞前馈控制方法.通过分析原子力显微镜(AFM)扫描图像数据,利用变比模型,对压电扫描器的迟滞非线性进行了准确建模,在此基础上,针对原子力显微镜纳米级表面成像过程中压电扫描器的周期性运动轨迹,设计一种基于逆的前馈控制策略.将所提出的迟滞补偿算法应用于本原CSPM5500系列原子力显微镜系统,实验结果表明这种方法明显减弱了迟滞非线性的影响,有效抑制了图像畸变,提高了AFM系统的成像性能.     

基于PREISACH模型的压电陶瓷定位控制

压电陶瓷的迟滞非线性特性是影响其定位精度的主要因素之一。本文采用Preisach模型对压电陶瓷进行建模,并采用不完全微分的PID控制策略,通过实验比较其不同控制策略下的定位误差,证明此方法适用于对压电陶瓷进行高精度定位。     

基于单神经元PID控制器的压电陶瓷控制方法

卫星地面综合测试是卫星研制过程中的重要环节,对系统功能验证及性能评估具有重要作用。传统的卫星地面综合测试系统存在研制周期长、投入较大、自动化流程不够完整、可重用性较差等不足。而北斗导航卫星地面综合测试系统采用分布式、高实时性、可配置、多主机的集成体系结构,是集计算机通讯、实时控制、实时数据处理、事后分析等功能于一体的测试系统,适用于从卫星总装集成到发射各个阶段的电气测试。通过卫星系统级的各项接口、功能、性能指标测试,表明该系统满足支持系统论证、状态确认、问题排查等测试需求,有力支撑了北斗导航卫星的成功发射和在轨运行。     

Decoupling and control of micromotion stage based on hysteresis of piezoelectric actuation

This paper presents the mechanism and control design of a micro-motion stage, which employs the right-angle flexure hinges and piezoelectric actuators (PZT). Aiming at the mechanism with the characteristics of a large stroke and three degrees of freedom, analytical models of statics and dynamics are established; especially the coupling motions of stage are investigated, which are verified by finite element analysis simulation. Via open-loop experiment, the decoupling property is well certified. Owing to the hysteresis of PZT, the dynamic equation of system with Bouc–Wen hysteresis model is proposed, which is identified through the Least squares. Moreover, a closed-loop controller of proportion integral derivative combined with the inverse hysteresis model-based feedforward is developed to reduce the nonlinearity and uncertainty, which can improve the positioning accuracy. Besides, the single-axis and multi-axis motions are tested. Experimental results reveal that the stage has a well-decoupling performance, and the effectiveness of proposed Bouc–Wen model is validated under open-loop control. Furthermore, the micro-motion performance in single- and multi-axis motions can be achieved as well.

     

Hysteresis Compensation and Adaptive Controller Design for a Piezoceramic Actuator System in Atomic Force Microscopy

This paper presents an indirect adaptive controller combined with hysteresis compensation to achieve high accuracy positioning control of piezoceramic actuators and illustrates the results with an atomic force microscope (AFM) application. A dynamic model of a piezoceramic actuator system in AFM is derived and analyzed. A feedforward controller based on the Preisach model is proposed to compensate for the nonlinear hysteresis effects. Then an indirect adaptive controller is designed to achieve desired tracking performance as well as deal with the uncompensated nonlinearity from hysteresis and the system parameter variation due to creep. Experimental results indicate that the proposed controller can significantly improve the positioning control accuracy of the piezoceramic actuator as well as achieve high image quality of the AFM system. The maximum scanning error was reduced from 2µm to 0.3µm in comparison with a proportional‐integral‐derivative (PID) controller. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Accounting for hysteresis in repetitive control design: Nanopositioning example

This paper deals with designing a repetitive controller (RC) for tracking periodic reference trajectories for systems that exhibit hysteresis, such as piezoelectric actuators used in nanopositioning systems. Hysteresis can drastically limit the performance of an RC designed around a linear dynamics model, and thus the effect of hysteresis on the closed-loop stability of RC is analyzed and the allowable size of the hysteresis nonlinearity for a stable RC is quantified. But when the hysteresis effect exceeds the maximum bound, an inverse-hysteresis feedforward controller based on the Prandtl–Ishlinskii hysteresis model is used to compensate for the nonlinearity. The control method is implemented on a custom-designed nanopositioning stage. Experimental results show that by incorporating hysteresis compensation the stability margin and the rate of error reduction improve. Likewise, the maximum tracking error reduces by 71%, from 13.7% (using industry-standard integral control) to 3.9% (using RC with hysteresis compensation), underscoring the benefits of RC with hysteresis compensation.     

A hysteresis compensation method of piezoelectric actuator: Model,identification and control

A major deficiency of piezoelectric actuators is that their open-loop control accuracy is seriously limited by hysteresis. In this paper, a novel mathematical model is proposed to describe hysteresis precisely. Based on the hysteresis model, an adaptive inverse control approach is presented for reducing hysteresis. The weights of the main hysteresis loop are identified by using least mean square (LMS) algorithm. The realization of an inverse feedforward controller for the linearization of a piezoelectric actuator is formulated. Experiments were performed on a micro-positioning system driven by piezoelectric actuators. The experimental results demonstrate that the positioning precision is noticeably improved in open-loop operation compared to the conventional open-loop control without any compensation.     

SVD‐Based Accurate Identification and Compensation of the Coupling Hysteresis and Creep Dynamics in Piezoelectric Actuators

In this paper, the coupling hysteresis and creep in piezoelectric actuators are identified and compensated for accurate tracking. First, we present the coupling hysteresis and creep model in smart actuators. Next, a complete identification strategy is designed according to the properties of the Preisach model. Then, an approach for parameter updating of the coupling model is provided. With the identified hysteresis and creep, the model‐based inversion compensation is designed. Finally, we apply the model identification and compensation to a piezoelectric stage to demonstrate the effectiveness of the proposed approaches. Significant reduction of the tracking error is achieved with the model‐based inversion feedforward compensator in which the relative errors at 10 Hz and 50 Hz are reduced to 1.85% and 4.53%, respectively. In addition, the model‐based feedforward is augmented with an integral feedback controller. With the composite controller, the relative errors at 10 Hz and 50 Hz are reduced to 0.42% and 3.04%, respectively.