近红外谱域显微干涉仪的位移传感特性研究

为研究近红外谱域显微干涉仪在近红外波段的位移传感特性,分析了条纹载频对位移量提取的影响,建立了测量光谱中心波长与干涉仪位移传感范围之间关系公式,讨论了光源可见光分量对近红外光栅光谱仪所记录条纹的串扰现象并提出抑制方法。构建近红外迈克尔逊型谱域显微干涉实验系统,单次测量位移量传感精度优于0.02μm。测量标准台阶板的台阶高度(其标称值为7.732μm),测量偏差为0.044μm。采用近红外谱域显微干涉装置,无需轴向扫描即可实现位移量测量,将光谱仪记录的谱域干涉信号转换为随波数线性变化信号处理能有效提高位移传感精度,增大中心波长能够有效提高位移传感范围,在系统中加入短波截止滤光片则能有效抑制可见光分量对近红外光谱域条纹造成的串扰。

Study on Coaxiality Measurement System of Compound Gear Shaft Based on Non⁃contact Optic

Aiming at the shortcomings of traditional contact measurement methods such as low measurement efficiency,high cost and low accuracy,a non-contact optical measurement method based on the laser displacement sensor is proposed.According to the relevant regulations of the coaxiality error evaluation standard and the structural characteristics of the compound gear shaft,we have designed and built a set of supporting software system as well as a hardware test platform.In this paper,the distance difference threshold and scale threshold methods are used to eliminate outlier data.The least squares circle is selected to calculate the center of the circle and the minimum containment cylinder axis method is used as the reference axis of the composite gear shaft.Compensated by the standard step shaft calibration,the coaxiality error of the composite gear shaft can be measured to be within 0.01 mm in less than two minutes.The range value of the multi-section measurement test is 0.065 mm.The average coaxiality error is∅0.476 mm.

Nonlinear correction of photoelectric displacement sensor based on least square support vector machine

A model of correcting the nonlinear error of photoelectric displacement sensor was established based on the least square support vector machine.The parameters of the correcting nonlinear model,such as penalty factor and kernel parameter,were optimized by chaos genetic algorithm.And the nonlinear correction of photoelectric displacement sensor based on least square support vector machine was applied.The application results reveal that error of photoelectric displacement sensor is less than 1.5%,which is rather satisfactory for nonlinear correction of photoelectric displacement sensor.

New Optical Triangulation and Digital Image Processing in Measurement

In this paper,a new direct optical triangulation(DOT) for measuring theout-of-plane displacement is given.In order to state its principle,DOT is used to measure a micro-displacement of a rigid body,and at the same time,the method of digital image processing is also given.

A novel wide-range precision instrument for measuring three-dimensional surface topography

We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface.

A novel wide measuring range FBG displacement sensor with variable measurement precision based on helical bevel gear

A novel fiber Bragg grating(FBG)displacement sensor is proposed,which can achieve wide measuring range displacement detection with variable measurement precision due to its mechanical transfer structure of helical bevel gear.A prototype is designed and fabricated.The maximum detection displacement of this prototype is 1.751 m,and the precision grade changes from 0.2%to 6.7%.Through analyzing the experiment data which is obtained in the calibration experiment,the measuring range of this sensor is from 0 m to 1.532 m,and the wavelength shift errors between experiment data and theory calculation are all less than 5%.

Cylindrical spiral triboelectric nanogenerator

In recent years, triboelectric nanogenerators have attracted much attention because of their unique potential in self-powered nanosensors and nanosystems. In this paper, we report a cylindrical spiral tdboelectric nanogenerator （S-TENG）, which not only can produce high electric output to power display devices, but also can be used as a self-powered displacement sensor integrated on a measurement ruler. At a sliding speed of 2.5 m/s, S-TENG can generate a short-circuit current （Isc） of 30 μA and an open-circuit voltage （Voc） of 40 V. As the power source, we fabricate a transparent and flexible hand-driven S-TENG. Furthermore, we demonstrate a self-powered S-TENG-based measuring tapeline that can accurately measure and display the pulled-out distance without the need for an extra battery. The results obtained indicate that TENG-based devices have good potential for application in self-powered measurement systems.

Micro-Displace Sensor Based on Self-Mixing Interference of the Fiber Laser With Phase Modulation

Micro-displacement measurement based on self-mixing interference using a fiber laser system was demonstrated. The sinusoidal phase modulation technique was introduced into the fiber laser self-mixing interference measurement system to improve the measurement resolution. The phase could be demodulated by the Fourier analysis method. Error sources were evaluated in detail, and the system was experimentally applied to reconstruct the motion of a high-precision commercial piezoelectric ceramic transducer （PZT）. The displacement measurement resolution was well beyond a half-wavelength. It provides a practical solution for displacement measurement based on all optical-fiber sensing applications with high precision.