Reduce the Waveform Distortion Using High-Order Harmonical Driving Current for a Vibrator

Yuntao Qiu,Ning Zhang,Liang Chen,Lu Zhang,Xikai Liu,Xiangdong Liu

doi:10.1109/access.2021.3071194

Yuntao Qiu, Ning Zhang + Show 4 more

Open Access

https://doi.org/10.1109/access.2021.3071194

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Abstract

A method to reduce waveform distortion is proposed and experimentally verified for vibrators driven by voice coil motors. In this method, a current including high-order harmonics is synthesized to drive the vibrator. The amplitudes and phases of the high-order harmonics are calculated based on the measured parameters which are correlated with the distortion. These parameters include the displacement dependence of the vibrator stiffness and that of the magnetic force per unit current. The calculation model is built on the nonlinear vibrator dynamic equation. By minimizing the lower order harmonics of the output acceleration, a series solution is obtained to synthesize the driving current. The feasibility has been demonstrated by Simulink simulation. Applying this strategy to a home-made vibrator, the waveform distortion of vibration acceleration has been reduced from 9.60% to 1.22%. The proposed method provides an alternative technology to reduce the distortion. This technology is especially useful in case that it is difficult to reduce the nonlinearity of the vibrator.

Highlights

Vibration exciters are widely used in the test of inertial sensors
One always hopes that the harmonic distortion can be as small as possible [4]
The vibrators are frequently designed as a forced springmass oscillator, and voice coil motors fed with sine current are always adopted to drive the oscillators

Summary

Introduction

Vibration exciters are widely used in the test of inertial sensors. For example, they are used to calibrate accelerometers and velocimeters [1]–[3], to measure the frequency-dependent transfer function, and to evaluate the common-mode rejection ratio of gravity gradiometers. Harmonic distortions are always observed for the output acceleration due to the displacement-dependent stiffness for the oscillator or the displacement-dependent electromagnetic force for unit applied current for the motor [5], [6]. Y. Qiu et al.: Reduce Waveform Distortion Using High-Order Harmonical Driving Current for Vibrator distortion of the output acceleration based on the measured vibrator parameters.

Results

Conclusion