Position Detection Method of Piezoelectric Driven Spherical Motor Based on Laser Detection

Area of Science:

• Optics and Photonics
• Mechanical Engineering
• Control Systems

Background:

• Accurate measurement of motor speed and position is crucial for effective motor control.
• Spherical motors require precise position information for their complex multi-degree-of-freedom (multi-DOF) operation.
• Existing measurement techniques may have limitations in non-contact, high-accuracy applications.

Purpose of the Study:

• To propose and validate a novel non-contact method for measuring the angular velocity and position of a multi-DOF spherical motor rotor.
• To leverage the Doppler effect of laser light for precise motion sensing.
• To enhance the control capabilities of spherical motors through accurate rotor feedback.

Main Methods:

• Utilizing a laser generator to split a beam into reference and measurement paths.
• Employing the Doppler effect on the measurement beam reflected from the rotating spherical motor rotor.
• Implementing a photoelectric conversion module to detect frequency difference signals.
• Deriving angular velocity and position information from the frequency difference signals.

Main Results:

• Experimental verification confirmed the efficacy of the proposed laser Doppler method.
• Achieved coordinate errors of less than 2 mm for the Z and Y axes.
• Demonstrated a Z-axis error of less than 0.2 mm.
• The method proved effective in accurately measuring the spherical rotor's position information.

Conclusions:

• The developed laser Doppler technique offers a viable non-contact solution for spherical motor control.
• The method provides high accuracy in measuring angular velocity and rotor position.
• This approach has the potential to improve the performance and precision of multi-DOF spherical motors.