Simulation, Analysis and Application for Electromechanical Behavior of Piezoceramic Actuators

• Main Authors: Fuh-Liang Wen, 溫富亮
• Other Authors: Minsun Ouyang
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/40728552652887606681

博士 === 國立清華大學 === 工程與系統科學系 === 92 === Pervious art of ultrasonic motors (USM) or actuators are made of piezoelectric bulky material or piezoelectric stacked disc; however, the cost is so high that the commercial ultrasonic motor is quite expensive. In current study, all ultrasonic actuators are primarily bought from the hardware stores or commercial market available, such as piezoceramic buzzers and Langevin vibrators. The buzzer is composed of piezoelectric ceramic of zirconium-titanium-acid-lead material (PZT or called as piezoceramic) and bound a metal thin-disc in which is added on the constraint condition, called as a thin-disc vibrator. A Langevin vibrator comprises two PZT disks abutting against each other with two copper rings as electrodes. At the end sides of a vibrator, an aluminum block and a stainless block were screwed to the ceramic disk and the copper electrode respectively, as far from each other. When an ultrasonic AC power is applied onto a piezoceramic, the piezoceramic and its attached metal will be forced to generate mechanically extended-contracted phenomena. Electromechanical energy is transferred in wave-form-like. The piezoceramic can work within an ultrasonic frequency with the amplitude of several micrometers, which is controllable by input voltages. Therefore, it can be used as a driving actuator of a compact structure or system. In this paper, the dynamic behaviors of piezoceramic vibrators would be patterned by means of carbon powder observation and simulated via commercial finite element software ANSYS to identify the compound mode shapes in longitudinal and transverse for the driving purpose in thin-disc actuators. Otherwise, an elastic-bouncing tester was designed to estimate the dynamic mechanism in levitated objects for an ultrasonic transportation system using Langevin vibrators. A design philosophy for piezoceramic actuators is adopted that it would be maximized in its probability of success by reducing repeatable and non-repeatable errors. Motion errors of actuators in mechanism design have to be measured and evaluated in terms of preload adjustment due to power transmission via friction contact. The successful control of ultrasonic actuator depends on the interaction of all elements that compose the system and its environment. The advanced closed-loop servo positioning control i.e. Sliding-Mode Control (SMC) is used to compensate automatically for nonlinearly mechanical behaviors such as dry friction, ultrasonic vibrating, slip-stick phenomena. In this study, in comparison of proportional-integral-derivative (PID) controller, SMC scheme has been successfully applied to position tracking to prove the excellent robust performance in noise rejection.