Single Channel Instrument for Simultaneous Rotation Speed and Vibration Measurement Based on Self-Mixing Speckle Interference

Abstract

In this paper, a novel method for simultaneous measurement of rotation speed and vibration based on self-mixing speckle interference (SMSI) has been demonstrated. In view of the autocorrelation characteristic of SMSI, the time delay of laser incident during one rotation period is determined, and the rotation speed of the object is calculated according to the mathematical relationship. At the same time, the signal square-wave conversion and the global maximum fringe-counting method are proposed to measure the vibration displacement subject to the rotation. The theory and signal processing means are introduced in detail, and a series of experiments employing computer disk at different positions with various rotation speeds indicate that the proposed method achieves a simple, efficient, and accurate multi-parameter measurement.

High-Precision Laser Self-Mixing Displacement Sensor Based on Orthogonal Signal Phase Multiplication Technique

“…So-called self-mixing interference refers to the fact that a part of the reflected or scattered light feedbacks into the laser cavity and interferes with the original light, resulting in changes in laser output characteristics. Compared with traditional interferometry used to measure the motion of an external target, selfmixing interferometry has been applied in many sensing fields, such as distance [6][7][8][9], angle [10][11][12], displacement [13][14][15][16], velocity [17][18][19], and other fields [20][21][22][23], due to its inherent advantages, such as its simple and compact structure, self-alignment, and low cost.…”

Laser Self-Mixing Interferometer Based on Multiple Reflections and Phase-Modulation Technique

“…Laser self-mixing interferometry (SMI) is an emerging non-contact measurement technology which has been extensively researched. Owing to its intrinsic feature of simplicity, compactness, and easy collimation, SMI has been widely applied in various fields, such as displacement [1,2], vibration [3][4][5], velocity [6,7], angle [8,9], tomography [10], and biomedical signal [11] measurements. In the typical SMI systems, the fringe-counting method is usually used to quickly demodulate the displacement of the vibration.…”