Development of Piezoelectric Actuator by Feedback of Induced Charge

本研究的目的是利用内部电荷产生的感应电荷来估计压电元件(压电体)的位移和发力，以减小压电体的迟滞效应。由于附加元件非常小，因此这种方法有望实现器件的小型化。1997年测量了感应电荷的基本性能，1998年研制了精密定位装置，建立了利用感应电荷的控制方法。(1)测量了感应电荷与压电体位移的关系。测量了压电体位移对感应电荷和外加电压的滞后性。感应电荷对位移的线性度远好于外加电压的线性度。(2)[精确定位]比较了感应电荷反馈控制(ICFC)与开环控制和位移反馈控制的定位性能。位移既可以通过ICFC控制，也可以通过位移反馈控制。这个。采用ICFC与逆传递函数补偿相结合的方法实现了10秒的位移控制。(3)[并联机构定位台设计]研制了一种六自由度Stewart平台式精密定位装置。它的尺寸为160x160x85 mm。定位台的活动范围为100x100x10um。其共振频率在x和y方向为50赫兹，在z方向为190赫兹。采用有源降噪方法降低电力线噪声。(4)[原子力显微镜(AFM)应用]定位平台的俯仰误差比管式压电元件小10倍。在测力曲线中，z运动的重复性为16 nm。可以得到线性度良好的原子力显微镜。

This research aims to estimate displacement and generated force of a piezoelectric element (piezo) by using induced charge caused by internal charge to reduce the hysteresis of the piezo. Miniaturization of devices is expected by this method because additional elements are very small. A control method using the induced charge is established after basic performance of the induced charge is measured in 1997 and a precise positioning device is developed in 1998.(1)[Measurement of displacement and force generated]The relationship between induced charge and the displacement of a piezo is measured. The hysteresis of the displacement of the piezo to the induced charge and to applied voltage is also measured. The linearity of the induced charge to the displacement is much better than the linearity of the applied voltage.(2)[Precise positioning]The positioning performance by induced charge feedback control (ICFC) is compared with open loop control and displacement feedback control. The displacement can be controlled by the ICFC as well as by the displacement feedback control. The. displacement is controlled by combining the ICFC with inverse transfer function compensation for 10 seconds.(3)[Design of positioning table with parallel mechanism]A Stewart platform type device with six degrees of freedom is developed for precise positioning. It measures 160xl60x85mm. The movable range of a positioning table is 100x100x10mum. Its resonance frequencies are 50 Hz in the x and y directions and 190 Hz in the z direction. A noise from power line is reduced by an active noise reduction method.(4)[Application to atomic force microscope (AFM)]The pitching error of the positioning table is 10 times smaller than a tube type piezoelectric element. The repeatablitity of the z motion is 16 nm in the measurement of force curves. An AFM with good linearity can be obtained.