Application Cases

Experiment Name: Application of Power Amplifier in the Design of a Voice Coil Motor Test System

Experiment Objective:
Based on the developed voice coil motor (VCM) direct-drive water hydraulic control valve, the structure of the direct-drive valve was improved. A dynamic mathematical model of the VCM direct-drive water hydraulic valve was established, and experimental studies were conducted.

Experimental Equipment: Linear bearing, signal generator, power amplifier, displacement sensor, voice coil motor, force sensor, spring

Experimental Content:
The air viscous resistance coefficient of the voice coil motor was identified through experiments. A Simulink model of the VCM direct-drive water hydraulic valve was also developed.

Experimental Procedure:

(1) Simulink Modeling of the VCM Direct-Drive Water Hydraulic Valve
An open-loop simulation model from the VCM coil voltage to the spool displacement was established in MATLAB/Simulink, as shown in the figure.

(2) Design of the Voice Coil Motor Test System and Identification of the Damping Coefficient

A VCM system with an elastic load is a single-degree-of-freedom mass-spring-damper system. The mass refers to the mass of all moving parts (including the coil, motor shaft, force sensor, etc.). During motion, the coil experiences air resistance, and the resulting damping force acts on the mover of the voice coil motor.

Experimental Results:
A sinusoidal signal was output by the signal generator to the power amplifier, which drove the motor to perform oscillatory motion. After the oscillation stabilized, the signal generator was turned off. The vibration curve of the VCM position signal over time was then acquired. MATLAB was used to fit the vibration curve into an analytical equation form, as shown in the figure. The identified air damping coefficient was 10.96 N·s/m.