the piezoelectric motor, mostly used on optical zoom of cameras for exemple, it is very small and works following the piezoelectricity principle. This project aim is to create a experimental test bench in order to understand how it is working and controlled and how it is implemented in a displacement control system.
During the education, are designed for DC motors, brushless motors, linear motors moving, the stepping motors, but one that is widely used and little known is the piezoelectric motor. To better understand the technology, we have here studied the motor.
The distortion caused by the compression force generates a separation of the centers of positive and negative charges, hence the appearance of an electric field. This principle wich is reversible, that is used.
We excite the ceramic plates with a PWM which the excitation frequency corresponds to a self mode of stator bending. The combination of two sinusoidal vibrations in quadrature in time and space creates a propagaging wave in the stator causing a displacement of the rotor causing by friction.
Acting on the excitation frequency of the PWM, we can control the engine speed.
Tis motor have the particularity to get the following characteristics:
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After the model creation, here is the final model retained for the motor studies:
Calulation show we can control the displacement with a precision of 7μm.
Synthesis of carried out tasks:
- Model constructionPerspectives:
- PID settings for an optimal functionment
