Ultralow rotation speed control method of ultrasonic motor

Abstract

The invention discloses an ultralow rotation speed control method of an ultrasonic motor, which comprises the following steps of: establishing interval excitation signals as ultrasonic motor excitation signals for controlling the rotation speed of the ultrasonic motor, and taking excitation signal frequency, the number of the excitation signals and excitation time interval as control parameters; recording the conversion relationship among the rotation speed of the ultrasonic motor and the three control parameters, and forming a parameter conversion mapping table; receiving the rotation speed instructions, and acquiring the three control parameters corresponding to the rotation speed instructions through the conversion mapping table for correcting the previous parameters; and calculating through the ultrasonic motor rotation speed signals and the rotation speed instructions which are monitored in real time so as to obtain excitation signal frequency correction, adding with the excitation signal frequency in the previous corrected parameters as the novel excitation signal frequency, taking the number of the excitation signals and the excitation time interval in the previous corrected parameters as the corrected ultrasonic motor control parameters, and controlling the rotation speed of the ultrasonic motor. The interrupted-type excitation adopted by the method can control the ultrasonic motor to run under the ultralow rotation speed, and the ultralow rotation speed control method of the ultrasonic motor has favorable rotation speed control performance.

Description

technical field [0001] The invention relates to a control method of an ultrasonic motor, which has good speed control performance and precision. Background technique [0002] Since the appearance of the ultrasonic motor (USM) in the early 1980s, it has attracted the attention of many people with its novel working principle and unique performance characteristics. Ultrasonic motors are widely used in low-speed direct drive mechanisms, such as optical lens drive devices, nuclear magnetic resonance instruments, etc., due to their small and compact size, light weight, and high output torque density. [0003] At present, the existing method mainly achieves the purpose of controlling the speed of the ultrasonic motor by controlling the frequency of the sine wave. The specific method is to adjust the speed of the ultrasonic motor by adjusting the frequency of the high-voltage and high-frequency sine wave that is passed into the piezoelectric ceramic sheet. According to the working ...

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Problems solved by technology

[0005] The problem solved by the present invention is: to overcome the deficiencies of the prior art, to provide a method for controlling the ultra-low speed of the ultrasonic motor, which can control the operation of the ultra-low speed of the ultrasonic motor, and has good speed control performance and precision, and solves the problem of existing control problems. Method restricts the problem of small speed range of ultrasonic motor

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