压电微动工作台的位移复合控制

为解决稳态精度和稳定性之间的矛盾,提高压电陶瓷执行器的控制性能,进而提高其驱动的微动工作台的定位精度,构造了一种前馈补偿同反馈调节相结合的复合控制算法。其中,前馈补偿为基于压电陶瓷执行器迟滞非线性模型的前馈控制,通过自学习算法来实现,用来补偿压电陶瓷执行器的迟滞非线性,提高对参考位移信号的跟踪能力;反馈调节为PID反馈控制,用来进一步校正前馈补偿没有消除的偏差以及由模型的不确定性所引起的误差,且为了减小积分饱和作用以及微分对扰动的敏感性,对PID算法进行了改进,使之成为一种变系数积分与加权微分的PID算法。试验验证了该算法的有效性,并将该算法同其他控制算法——开环控制、前馈控制、PID 反馈控制进行了对比试验研究,结果表明,复合控制算法比其他控制算法具有更好的性能。     

压电微动工作台的位移自感知控制

使用自感知方法测量压电微动工作台的位移,省去独立传感器,构成位移自感知控制系统.压电陶瓷执行器晶片上的自由电荷中包含执行器的位移信息,据此提出基于积分器的压电执行器位移自感知方法,并设计了获取执行器晶片上自由电荷的积分器电路.该方法使得自感知电路的调节和感知信号的获取变得容易,可克服电桥法自感知电路阻抗不易匹配的不足.将该位移自感知方法作为压电微动工作台控制系统的反馈方式,并为提高工作台的动静态性能,构造一种前馈补偿同反馈调节相结合的复合控制算法,实现了自感知复合控制.试验验证了自感知复合控制的有效性,并将该控制方法同其他控制方法--前馈控制、独立传感器常规PID反馈控制、独立传感器复合控制进行了对比试验研究,结果表明自感知复合控制具有独立传感器复合控制的良好性能.     

五自由度纳米级定位工作台的设计研究

提出一种新型的五自由度精密定位平台的工作原理及其设计方法。工作台采用柔性导向机构实现平移及转动功能,采用压电陶瓷作为驱动元件,外置纳米级电容传感器作为位移量测量反馈元件,采用数字PID控制方法,可以实现纳米级精度的定位。给出了多种形式柔性导向机构刚度计算公式及设计实例。     

直接驱动式共轨系统可控针阀升程的驱动电路研究

针对柴油发动机喷油速率的控制问题,对喷油速率的控制方式进行了归纳总结,对直接驱动式共轨系统的特点和优势,以及直驱喷油器针阀的控制方式进行了分析,对于压电执行器的驱动电路以及充放电控制策略进行了分析,将可变电阻这一思路引入到电压反馈电路中,设计出了驱动电路的可变反馈模块,通过电控单元控制反馈电阻的选取,实现了在燃油喷射过程中对压电执行器驱动电压以及针阀升程的阶梯控制。对驱动电路进行了仿真优化设计,并利用压电执行器来对驱动电路进行了试验验证。研究结果表明,压电执行器完全充放电时间在120μs左右,喷油过程中驱动电压的变化可在100μs内实现,满足共轨系统对针阀的响应要求,所设计的驱动电路能够在燃油喷射过程中通过改变驱动电压来控制喷油速率。     

纯电力加载下压电陶瓷内环迟滞特性的实验研究

以典型压电陶瓷堆叠执行器为研究对象,对纯电力加载作用下压电陶瓷的内环迟滞行为进行了实验研究和分析。实验采用Sawyer-Tower方法获得了执行器的极化强度,利用高精度电容式位移传感器测量了执行器的输出位移,结合外围实验设备,通过计算得到了堆叠执行器在输入电压频繁折返过程中的电压-极化和电压-应变曲线。从压电陶瓷内部晶体的电畴转向角度出发,对其行为特性的产生机理进行了分析,给出了压电陶瓷堆叠执行器的建议工作区域。     

基于电流控制的压电陶瓷驱动电源及其试验研究

压电陶瓷致动器在电场驱动下会产生迟滞和蠕变现象,降低了定位精度。根据压电陶瓷致动器的位移与电荷量之间具有线性关系,研制了基于电流控制的压电陶瓷驱动电源。通过控制压电陶瓷的充电电流来控制其运动速度,从而控制其位移量。设计特殊电路和有针对性的控制算法,实现对压电陶瓷的快速驱动与高精度定位的结合。试验结果表明,利用该电源可实现对压电陶瓷的线性驱动和快速精密定位。     

采用压电陶瓷元件进行智能板振动控制

将分布的压电传感器／驱动器运用于智能板结构的主动减振控制中,分布的压电传感器能感知结构的局部应变状态,并通过控制回路反馈给驱动元件,构成闭环控制。建立了智能板闭环控制的分析模型,揭示在应变率反馈下,主动控制的机理是增加了结构的阻尼。用两对压电陶瓷元件仿真了柔性板的闭环控制,获得了令人满意的结果。     

基于神经网络的压电自感知主动控制仿真试验

由于传统的自感知电桥电路难以有效地实现自感知执行器传感与执行之间的信号分离,因此,提出了一种采用神经网络分离出压电自感知执行器传感信号的新方法,用神经网络直接估算结构的振动速度来得到振动控制时控制器的反馈信号.将嵌入在复合材料悬臂梁中的压电陶瓷片作为自感知执行器,采用基于Filter-X LMS算法的自适应滤波控制器对悬臂梁的振动进行主动控制.结果表明神经网络估算得到的振动速度和用传感器直接测得的完全吻合,将神经网络的输出作为控制器的反馈信号可以取得理想的减振效果.     

基于Dahl模型的压电陶瓷微夹钳控制研究

针对微零件装配工艺的需要,开发了一套基于压电陶瓷驱动的微夹钳,建立了压电陶瓷驱动微夹钳位移与电压的关系模型,针对压电陶瓷迟滞现象提出了基于Dahl模型的前馈补偿控制和PID混合控制算法,微装配实验证明该模型结构控制效果好,能达到控制要求。     

压电陶瓷驱动电源的研究现状及进展

压电陶瓷驱动器在电场作用下存在压电效应,从理论上讲,压电陶瓷器件可以获得无限小的位移分辨率,但是由于电源的稳定性和压电陶瓷本身的特性而产生迟滞和蠕变现象,从而降低其定位精度.采用不同方式的驱动电源和控制模型将直接影响压电陶瓷致动器的输出性能.文中从驱动电源的发展和驱动器模型2个角度,总结了国内外不同的驱动方案,进而提出应该优先选用电流源驱动压电陶瓷,并得出根据应用场合不同选择相应驱动电源和控制模型的结论.     

以压电陶瓷为作动器的主动隔振研究

本文讨论了压电陶瓷作动器的性能和基于共振情况下的柔性结构的高频窄带主动隔振技术。由压电陶瓷作为作动器，激振器作为干扰源，铝制悬臂梁作为结构组成了系统装置。由力传感器将结构的信号经补偿器补偿后作用于作动器组成了闭环主动隔振系统，最后给出了经典的二阶补偿下的闭环隔振实验结果。     

Beam vibration control using cellulose-based Electro-Active Paper sensor

Cellulose based Electro-Active Paper (EAPap) has recently shown a great potential as an environment-friendly smart material due to its biodegradability, biocompatibility and flexibility. Lots of studies have been conducted to investigate the basic smart characteristics of EAPap, but its application has not yet developed well. In this paper, the possibility of cellulose-based Electro-Active Paper (EAPap) as a piezoelectric sensor was investigated by the vibration control of the cantilevered beam. The EAPap sample was attached at the root of the cantilevered beam and used as a vibration sensor. The piezoceramic patch was also attached at the root of the beam and played as an actuator. The voltage output of EAPap showed exact dynamic characteristics of the cantilevered beam. The frequency bandwidth and quality factor of EAPap were similar to those of piezoceramic patch, which results EAPap has similar sensing capability of piezoceramic patch. To find the application of EAPap sensor, beam vibration control was performed. EAPap sensor output was considered as a position error of the cantilevered beam and a simple PID controller was designed to suppress the vibration of the beam. The EAPap sensor output provided clear time response of the beam. The controlled system showed good vibration control performance of the beam. The results provided that the piezoelectric characteristic of EAPap has a great potential as a sensor and also as a new smart material.     

基于μ综合的压电柔性结构振动主动控制

利用模态理论和μ综合方法,对智能柔性悬臂梁进行振动主动控制研究。以压电陶瓷为作动器,电阻应变计为传感器,采用有限元方法和实验模态测试方法建立结构动力学模型,对两种方法所得结果进行比较分析可知有限元模型与实际系统存在误差。考虑外部扰动和量测噪声的不确定性,同时考虑系统固有频率、阻尼比和作动器参数的不确定性,选择模态位移信号为评价量,根据信号的频率特性选择合适的加权函数,利用μ综合方法设计振动控制器。从频域角度分析控制器的有效性,结果表明该控制器能抑制不确定干扰对输出应变的影响,能在系统不确定性情况下满足控制要求,说明控制器具有鲁棒性。进行了振动主动控制实验研究,结果表明,所设计的控制器能有效抑制结构的振动响应。     

动态非线性压电驱动机电耦合动力学系统建模及其宽带高精度位移控制系统研究

摘要：研究了压电陶瓷驱动器的复杂非线性滞回动力学系统建模及其位移跟踪控制问题。首先采用状态空间方程，建立了一种新型压电驱动机电耦合动力学系统集总参数（Piezo-actuated Electromechanical Coupling Lumped Parameter－PECLP）模型。该模型首次将动态本征非线性集成到压电叠堆的滞回特性中，并兼顾考虑了驱动器中弹性和运动部件的动力学特性。在此基础上，利用微分几何的输入输出线性化方法，导出了一个简化的线性规范型子系统。根据该子系统，设计了一种基于LQ方法的非线性位移跟踪控制系统。与现有控制系统的对比仿真结果表明，本文提出的控制系统不仅消除了驱动器的稳态定位误差，有效的实现整体动态性能的最优化, 而且将其在-3dB的截止频率从638Hz扩展到5217Hz，频带宽度提高了将近一个数量级。较好的改善了驱动器的高速频响特性。     

压电陶瓷执行器的神经网络实时自适应逆控制

目的：为了提高压电陶瓷执行器执行精度,提出消除压电陶瓷的非线性、非光滑的迟滞特性的方法。 方法：提出了基于内积的压电陶瓷动态神经网络非线性、非光滑的迟滞逆模型,采用反馈误差学习方法,避免了求取压电陶瓷的Jacobian信息,快速地在线得到压电陶瓷的逆模型,并结合PID反馈控制,在dSPACE系统平台上,实现压电陶瓷的神经网络自适应逆控制,为了提高实时性,程序采用效率高、速度快的C-MEX S Function编程。结果：实验结果表明：神经网络自适应逆控制的控制精度为：0.13μm,而PID控制精度为：0.32μm 。结论：所提出方法有效地消除了迟滞的影响,控制精度高。     

RBF neural networks hysteresis modelling for piezoceramic actuator using hybrid model

An radial basis function (RBF) neural networks rate-dependent hysteresis hybrid model for piezoceramic actuator is proposed. The piezoceramic actuator cannot be described by neural networks like the back propagation (BP) static neural networks because of its multi-valued hysteresis non-linearity. The proposed hybrid hysteresis model consists of hysteresis-like non-linearity in series with a dynamic RBF neural networks used for implementing non-linear transformations of the phase lag and non-linear magnitude. The hysteresis-like non-linearity model, which is composed of the previous output of piezoceramic actuator and input signal, differs from the hysteresis behaviour of piezoceramic actuator in only ways of their phase and magnitude, and it is used to describe the non-smooth behaviour of piezoceramic actuator. The results of both simulation and experiment show that the new modelling approach is very effective and of higher precision under a decayed input signal with the varying frequency.     

压电主动元件设计与实验研究

为自适应调节和改善空间结构动力学性能 ,利用压电材料的正逆压电效应 ,研制了一种具有传感和驱动双重功能的压电主动元件。该主动元件由压电驱动器、微位移传感器、压力传感器等组成 ,具有输出和实时检测微位移和力的功能。提出了压电主动元件的设计理论 ,并给出其工作机理及组成结构。针对其关键部件——压电驱动器进行了静态实验研究 ,包括位移输出情况、重复精度和稳定性实验。实验结果表明该驱动器输出位移可达 63 .2 μm、重复精度± 0 .0 5μm、稳定性 <0 .1μm,能够用于空间可展结构的精密微位移控制     

压电陶瓷执行器的类Hammerstein模型及其参数辨识

针对压电陶瓷执行器的迟滞非线性对压电陶瓷精密定位的影响,提出了应用类Hammerstein模型对压电陶瓷执行器进行建模的方法.建立了压电陶瓷执行器的迟滞模型并且描述其频率相关性.利用类Hammerstein模型把压电陶瓷执行器看成静态迟滞模型和动态二阶系统的串联,其中静态模型由分类排序的Preisach模型进行描述,二阶系统应用遗传算法辨识其参数.实验结果表明:加入二阶系统后,类Hammerstein模型对频率的相关性有较大增强,其误差相应地大幅降低,在800 Hz时平均绝对误差为0.339 2 μm;丽由Prcisach建立的迟滞模型的误差随着频率的增大而大幅增大,在800 Hz为0.888 1 μm.     

Control of a dual stage magnetostrictive actuator and linear motor feed drive system

A dual stage feed drive system is well suited to satisfying current demands of high performance machining with tight position control under high feed rates in the presence of disturbances. It does this by integrating an actuator with high position resolution and fast response together with a conventional linear drive. A magnetostrictive actuator (MA) with a bandwidth in the kHz range capable of several kN of force output is an ideal candidate for use as the fine positioning element in such a dual stage system. However, MAs display significant hysteresis in their performance. This makes the effective implementation of real-time fast servo control challenging. In this paper, a dynamic Preisach model is utilized to reduce the undesired nonlinearity. A sliding mode controller (SMC) is designed to deal with uncertainties such as the Preisach modeling error as well as external disturbances so as to ensure a robust stable system. Experimental results show the servo performance improvement during a feed step test for single axis control and a single axis component of a sharp path interpolation test.     

Experimental optimization of power-function-shaped drive pulse for stick-slip piezo actuators

Motion of a stick-slip piezo actuator is generally controlled by the parameters related to its mechanical design and characteristics of the driving pulses applied to piezoceramic shear plates. The goal of the proposed optimization method is to find the driving pulse parameters leading to the fastest and the most reliable actuator operation. In the paper the method is tested on a rotary stick-slip piezo actuating system utilized in an atomic force microscope.The optimization is based on the measurement of the actuator response to driving pulses of different shapes and repetition frequencies at various load forces. To provide it, a computer controlled testing system generating the driving pulses, and detecting and recording the corresponding angular motion response of the actuator by a position sensitive photo detector (PSPD) in real time has been developed. To better understand and interpret the experimental results, supportive methods based on a simple analytical model and numerical simulations were used as well.In this way the shapes of the single driving pulses and values of the load force providing the biggest actuator steps were determined. Generally, the maximal steps were achieved for such a combination of the pulse shapes and load forces providing high velocities at the end of the sticking mode of the actuator motion and, at the same time, lower decelerations during the slipping mode.As for the multiple driving pulses, the pulse shapes and values of repetition frequency ensuring the sticking mode of the actuator motion during the pulse rise time together with the maximum average angular rotor velocity were specified. In this way the effective and stable operation conditions of the actuator were provided.In principle, the presented method can be applied for the testing and optimization of any linear or angular stick-slip actuator.