双定子直线振荡电机动子位移自传感技术研究

基于建立的双定子直线振荡电机系统数学模型,提出了电机动子位移自传感算法,通过对于电机端电压及电流信号的处理实现了动子位移的自传感.在此基础上,通过实验对此算法进行了验证.实验结果显示,在有效行程范围(20 mm)内.定频变行程和谐振点变行程控制方式下的估算行程的最大绝对误差分别为0.4 mm和0.3 mm,最大相对误差分别为4.76%和3.7%,可以满足控制要求.此算法可用于直驱压缩机的变行程控制及上死点控制.     

双定子动磁铁式直线振荡执行器的力特性分析

为研究双定子动磁铁式直线振荡执行器的力特性,在分析执行器结构及运行原理的基础上,首先建立执行器的等效磁路模型,推导出一种计算执行器电磁推力及气隙磁链的解析模型,该模型充分考虑了结构参数及永磁体材料对电磁推力的影响;然后采用三维有限元参数化分析方法对执行器的电磁推力进一步分析和计算。结果表明:该执行器的电磁推力与动子位移无关,与定子电流成正比;气隙磁链是定子电流和动子位移的线性函数。研究结果将为该类新型执行器的优化设计及驱动控制提供较好的理论依据。     

自传感介电弹性体执行器的动力学设计及应用

本文提出了一种传感与作动一体化的介电弹性体（DE）软执行器,可用于薄膜结构形面变形的同步测量和控制.首先,建立DE软执行器电致驱动过程的动力学模型,描述其力电耦合行为.其次,通过开展动态作动实验,辨识该动力学模型的参数.第三,分析不同参数对作动器动态响应的影响,以理解其基本动力学特性.第四,建立DE软执行器自传感过程的简化电路模型,并对其电学参数与位移之间的关系进行实验标定.最后,开展平面薄膜结构的形面位移自适应调整实验,并设计相应的控制策略.实验结果表明,该DE软执行器在作动和传感方面均具有较高精度.因此,其在构建高精度空间薄膜天线方面具有较好的应用前景.     

新型Halbach横向磁通直线振荡执行器

结合Halbach阵列永磁电机和横向磁通电机的优点,提出一种Halbach型横向磁通直线振荡执行器。该执行器无需动子铁芯,具有结构紧凑、质量轻、定子叠装方便及力特性良好等特点。首先介绍了该新型直线振荡执行器的基本结构和工作原理,分析了动子磁极的Halbach阵列磁场分布,并采用三维有限元参数化分析方法对执行器的气隙磁链和静态电磁推力特性进行数值计算,建立了考虑气体力负载的执行器系统模型,分析了动子质量、弹簧刚度、气体力负载等因素对执行器谐振特性的影响。研究结论将为该新型执行器的进一步优化设计及其高效率控制提供有效的理论依据。     

Cymbal型复合压电作动器微进给技术研究

针对普通压电作动器行程较短的缺点,提出一种具有Cymbal结构的复合压电陶瓷作动器的结构设计。通过将压电陶瓷微小的径向位移放大,转换成轴向位移,扩大了作动器的行程。在作动器控制系统设计中,一方面在硬件结构设计中引入了高精度的位移传感器闭环反馈系统,另一方面通过对作动器的输出进行软件补偿的方法,消除了Cymbal型复合压电作动器自身存在的输出磁滞性和非线性的缺点,大幅度提高了系统的开环控制特性,实现了对作动器的高精度控制。实验结果证明系统设计有效。     

萤火虫PID算法在电机作动器悬架上的应用

为提高汽车悬架系统的性能,提出了一种萤火虫PID算法。首先在分析萤火虫PID算法原理的基础上,设计了适合于电机作动器悬架的萤火虫PID算法,给出了算法实现的步骤与流程;然后,对传统电机作动器进行改进设计并建立四自由度电机作动器悬架数学模型与仿真模型,以dSPACE为该仿真模型运行载体,设计主动悬架半实物仿真算法测试系统;最后,利用该测试系统,采用不同车型与路面输入对萤火虫PID算法进行了仿真测试实验,结果表明所设计的萤火虫PID算法可以有效降低车身加速度、悬架动行程、轮胎动位移等。     

电容式位移传感器在电控液动执行器中的应用

本文详细的讲述了电容式传感器在电控液动执行器中的应用，包括传感平的结构、原理以及检测电路的原理和有关的实验数据，在使用过程中证明本传感器完全符合电控液动执行器的技术指标。     

改进UKF算法在PMLSM无位置传感控制中的应用

针对永磁直线同步电机(PMLSM)的无位置传感控制,提出了一种基于改进无迹卡尔曼滤波(UKF)算法的永磁直线同步电机的动子速度和位置估计方法,对永磁直线同步电机的动子速度和位置进行估计.相比于传统的UKF算法,改进UKF算法在采样点的获取上进行了改进,在采样点的获取上运用了球形采样策略,而非传统的平方根对称采样策略,极大减少了采样点的数量,减少了状态估计过程中算法的计算量,在估计性能相当的情况下,改进的球形采样策略UKF算法较传统的平方根对称采样UKF算法在永磁同步直线电机无位置传感实时控制系统中有明显优势,取得良好的控制效果.     

基于新型压电致动器的微隔振平台系统

为实现微隔振平台的自适应控制,设计了具有驱动和传感功能的第三代压电致动器,针对其直接应用于微隔振系统隔振效果不是很理想的现状.从理论上分析了导致结果不理想的原因,提出一种改进方法,通过理论建模分析和试验研究,结果表明:该方法虽然降低了致动器位移增益.但具有较好的隔振效果.     

浅水动边界问题的位移法模拟

为精确模拟浅水波非线性演化过程中的动边界,提出一种基于位移的Hamilton变分原理,并进而导出一种基于位移的浅水方程（Shallow Water Equation based on Displacement,SWE D）.SWE D以位移为基本未知量,可以精确满足动边界处的零水深要求并精确捕捉动态边界位置,且解具有协调性.在Hamilton变分原理的框架下,分别采用有限元和保辛积分算法对该浅水方程进行空间离散和时间积分,可有效地处理不平水底情况,保证对非线性演化进行长时间仿真的精度.数值算例表明该方法适用于浅水动边界问题的数值模拟.     

Design and control of a single-stage dual-actuator system for high-precision manufacturing

This paper proposes a design for the linear state feedback control of the dual-actuator system, which is a dual-input single-output system for the high-precision manufacturing stage. The proposed control prevents saturation or reduces the unnecessary movement of the piezoelectric (PZT) actuator at the transient response by tracking the error between the estimated and actual positions of the coarse-actuator system at each control sample. Also, a new mechanism of the single-stage dual actuator is introduced. The axes of the stepper motor and the PZT actuator are co-axial. The coupling effects between the stepper motor and the PZT actuator are considered. Both the simulation and experiment results show that the proposed algorithm successfully prevents unwanted motions of the PZT actuator at the transient response. The experiment results show that the settling time and overshoot were enhanced by 45.7 and 95.9 %, respectively, for the proposed algorithm when the reference distance was 10 μm, which exceeds the stroke of the PZT actuator.     

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.     

Integration of displacement sensor into bulk PZT thick film actuator for MEMS deformable mirror

Bulk PZT thick film actuator integrated with displacement sensor, the so-called self-sensing actuator, is presented in this paper. The PZT film is used as not only an actuating layer but also a displacement sensor, which is achieved by dividing the electrode on the top surface of the PZT film into two parts: central top electrode for actuating and outer annular sensor electrode for piezoelectric displacement detection. When the actuator moves, the piezoelectric charge is induced in the outer annular PZT due to the piezoelectric effect. The total amount of accumulated charge is proportional to the stress acting on the PZT, which is in turn proportional to the actuator displacement. By collecting the piezoelectric charge, the actuator displacement can be detected. A theoretical model is proposed to determine the structure parameters of the sensor and predict the sensor sensitivity. Experiments were performed on the micro-fabricated sensor integrated PZT thick film actuator, and the measured piezoelectric charge is close to the theoretical predictions. The integrated piezoelectric sensor has a displacement sensitivity of approximately 4 pC/nm. In addition, the integration of displacement sensor into the actuator needs no additional fabrication process and has no influence on the actuator performances.     

微电热驱动器中偏置层的分析

设计了一种电热微驱动器,根据几何关系、泰勒公式和材料力学求得偏置层结构末端的位移公式,并验证了采用镍作为偏置层材料的合理性.通过Coventorware软件中的有限元模块进行仿真分析,得出施加驱动电压为5 V,响应时间为5 ms,驱动器的初始温度为300 K时,得出偏置层宽度W1与驱动器位移d的曲线关系.通过验证驱动器的最大应力为235 MPa,小于镍的许用应力,确定驱动器在W1=20μm可以进行可靠的工作.分析偏置层厚度和宽度的加工误差对驱动器末端位移的影响,可得在对偏置层进行加工时要严格控制偏置层厚度H1的加工误差.     

Thin-Film PZT Lateral Actuators With Extended Stroke

Many microelectromechanical system applications require large in-plane actuation forces, with stroke lengths ranging from submicrometer to tens of micrometers in distance. Piezoelectric thin films are capable of generating very large actuation forces, but their motion is not easily directed into lateral displacement in microscale devices. A new piezoelectric thin-film actuator that uses a combination of piezoelectric unimorph beams to generate lateral displacement has been developed. The piezoelectric actuators were fabricated using chemical-solution-derived lead zirconate titanate thin films. These actuators have demonstrated forces greater than 7 mN at displacements of nearly 1 $muhbox{m}$, with maximum stroke lengths at 20 V greater than 5 $muhbox{m}$ in a 500- $muhbox{m}$-long by 100-$mu hbox{m}$-wide actuator. Force and displacement capabilities can be manipulated through simple changes to the actuator design, while actuator nonlinearity can produce dramatic gains in work capacity and stroke length for longer actuators.$hfill$[2007-0298]      

Fuzzy algorithm and structural stiffness in error attenuation of intelligent toolpost

Vibration suppressions techniques in cutting tools can save old machines and enhance design flexibility in new manufacturing systems. The finite element method is employed to investigate structural stiffness, damping, and switching methodology under the use of smart material in tool error attenuation. This work discusses the limitations of using lumped mass modeling in toolpost dynamic control. Transient solution for tool tip displacement is obtained when pulse width modulation (PWM) is used for smart material activation during the compensation of the radial disturbing cutting forces. Accordingly a Fuzzy algorithm is developed to control actuator voltage level toward improved dynamic performance. The required minimum number of PWM cycles in each disturbing force period is investigated to diminish tool error. Time delay of applied voltage during error attenuation is also evaluated. Toolpost static force–displacement diagram as required to predict voltage intensities for error reduction is tested under different dynamic operating conditions.This revised version was published in June 2005 with corrected page numbers.     

Comparing orthogonal force and unidirectional strain component processing for tool condition monitoring

Signal processing using orthogonal cutting force components for tool condition monitoring has established itself in literature. In the application of single axis strain sensors however a linear combination of cutting force components has to be processed in order to monitor tool wear. This situation may arise when a single axis piezoelectric actuator is simultaneously used as an actuator and a sensor, e.g. its vibration control feedback signal exploited for monitoring purposes. The current paper therefore compares processing of a linear combination of cutting force components to the reference case of processing orthogonal components. Reconstruction of the dynamic force acting at the tool tip from signals obtained during measurements using a strain gauge instrumented tool holder in a turning process is described. An application of this dynamic force signal was simulated on a filter-model of that tool holder that would carry a self-sensing actuator. For comparison of the orthogonal and unidirectional force component tool wear monitoring strategies the same time-delay neural network structure has been applied. Wear-sensitive features are determined by wavelet packet analysis to provide information for tool wear estimation. The probability of a difference less than 5 percentage points between the flank wear estimation errors of above mentioned two processing strategies is at least 95 %. This suggests the viability of simultaneous monitoring and control by using a self-sensing actuator.     

移动质量激励悬臂梁振动主动控制系统

利用压电材料的正逆压电效应,实现了移动质量激励悬臂梁振动主动控制;建立了压电元传感方程和作动方程,进一步将其转化为状态空间模型中的状态方程和输出方程;设计了基于线性二次型最优控制(LQR)策略的振动主动控制器,以TMS320VC33 DSP芯片为核心组建了相应的硬件电路。实验结果表明:采用压电自感作动器可很好地抑制移动质量激励引起的悬臂梁振动。