pressure sensitive piezoelectric sensor

                                   pressure sensitive piezoelectric sensor

As a new type micro-motor, its own technological development of piezoelectric ring transducer can not be separated from the electronic control and drive. The advantages and disadvantages of the control technology are directly related to whether the excellent performance can be fully exerted, and will affect the application and promotion. Therefore, the research of control technology of wholesale piezo ring has received more and more attention from scholars at home and abroad. About the history of development of ultrasonic motor:

The development of ultrasonic motor has gone through four stages in the 1961, the elastic body was used to stimulate the elastic body for the first time, and the vibration of the hifu ultrasound piezo was used to drive the clock gear. This watch is accurate, only one minute per month error, it is breaking the record at the time,which is causing a sensation, but also opened the prelude to ultrasonic motor.

Principle machine prototype stage. From 1972 to 1973, ultrasonic motors with practical prospects were developed by Siemens and Matsushita. However, due to piezoelectric materials ,piezo ceramic cylinder is operating at a driving frequency of several tens of kHz, the amplitude is too small and the materials are not shut, and large torques cannot be obtained.Barth proposed a standing wave type ultrasonic motor, which has a large torque, it is high speed, but low life. Several kinds of ultrasonic motors with the same principle have also been developed.In 1978, the piezo disc element successfully is constructed an ultrasonic motor.which is capable of driving large loads.

Its characteristic is that it uses the transducer principle to reduce the resonance frequency and increase the resonance amplitude. However, it failed for various reasons. Based on the study of Vasiliev in 1980, a wedge-shaped standing type ultrasonic motor was proposed. Its operating frequency is 27.8kHz, input power 90W, but the motor has two disadvantages: First, the rotor of piezo electric disc has contact with a serious wear and tear, and second, the rotor speed calibration is more difficult to control, only one direction rotation, it is developed in 1982 travel wave type.