Papers by Keyword: Displacement Measurement

Abstract: In this paper we present a calibration method, which enables a combining of 3D Digital Image Correlation and termographic systems for simultaneous measurements of displacements, strains and temperature. It concerns a model of a calibration target, that works for visible and infrared light spectrum and calibration method. The working system was applied for three interesting cases: monitoring of a tank filled with liquid, a heated plexi board and a human arm during muscle contraction.

Abstract: The eddy current sensor can be used to measure the displacement. It is widely used in petrifaction, electric power, mechanism. The eddy current sensor has fast dynamic response, non-contact measurement, and better adaptability characters. The accuracy of eddy current sensor often is influenced by the environment temperature. The environment temperature effect is analyzed and put forward to a method to compensate to enhance the accuracy.

Abstract: In order to time grating measurement principle application to the field of optical measurement, a uniform scan coordinate system by using photosensitive element of timing driven is presented to convert the displacement detection of the object into measured time difference. According to the conversion principle of relative motion coordinate systems of time grating, when view the photosensitive element of linear CCD as a uniform scanning coordinate system, view the spatial side by side and timing of mutually staggered on the two linear CCD as a stationary coordinate system, after measured the time difference variation of the output electric signal on the different CCD for the same object, size and direction of the relative displacement of the object would be made by multiplying time difference variation and scanning speed. With the calibration of the Renishaw laser interferometer for the developed linear CCD displacement sensor, the measuring errors are controlled within after error correction in the effective measuring range of 600.05mm. This realizes the idea of time measuring space in the field of optical.

Abstract: In order to meet the displacement measurement’s need for high precision and large measuring range, a novel design of optical fiber displacement system is proposed. Optical fiber is applied to the displacement measurement field with its simple structure, light weight, cheap cost and high precision. A displacement measurement model based on transmissive optical fiber is established, and theoretical calculation and simulation are conducted to verify the accuracy of the model. Displacement measuring experiments are completed and the results show that the transmissive optical fiber displacement measurement system has high measuring accuracy with the relative error less than 0.2% over a large range.

Abstract: To improve the measurement accuracy of two-dimensional (2D) precision working stages in the semiconductor manufacturing industry, an error separation and dynamic compensation method based on a planar grating is proposed for a 2D coplanar displacement measurement system. In the system, a planar grating of HEIDENHAIN PP281R is fixed in the center of precision working stage to build coplanar structure and reduce Abbe errors. And the system errors including grating period carved error, temperature effect, vibration effect and mount effect are modeled, calculated and separated. Then the separated errors are dynamically compensated from the corresponding displacement measurement results through data-processing software. Analysis results show that the proposed error separation and dynamic compensation method based on planar grating can improve the measurement accuracy of the coplanar displacement measurement system effectively.

Abstract: An Ionic Polymer-Metal Composite (abbr. IPMC) is a type of a smart materialconsisting of two layers of noble metal and an ion-conducting layer between them. Smart ma-terials are generally capable of actuating and sensing. Mechanical deformation of the IPMCbeam produces an electric potential di erence (in the order of mV) proportional to the tipdisplacement on the electrodes. In this paper, the sensing capabilities of IPMC samples will beinvestigated. The composites are manufactured in a form of a thin (0.3 mm) plate, which arecut into rectangular samples. Tests will be performed on separate samples and two electricallyconnected samples. Response to various frequencies will be tested for each sample and for twomechanically and electrically coupled samples, creating a simple sensor array.

Abstract: The core component of profilometer is a stylus displacement measuring system, whose resolution reaches nanoscale. Since the stylus tip is very small, a variation on probing force has a great impact on the results of high-precision displacement measurements. In this paper, a special flat rectangular voice coil motor is designed to realize a constant probing force for the stylus displacement measuring system. Experimental results show the probing force can be adjusted from 5mg to 1000mg and the resolution can reach 5mg.

Abstract: Comparing to the single aperture imaging system, Artificial Compound-Eye (ACE) imaging system has some nice features, such as small size and stereo vision. Based on the pictures captured by ACE, the displacement of an object can be easily deduced. This paper introduces our multiple-focus ACE imaging system. The system mainly consists of (a) a micro-lens array fabricated by Micro-Electro-Mechanical-System (MEMS) technology, (b) a CMOS chip, (c) a 3D mechanical moving stage, and (d) a software module. It can measure the displacements of an object in 212D space without calibration. The experiment validation is included.

Abstract: This paper introduces a well-used long range displacement measurement system. The advantages of the system are that the sensor's measurement range can be extended by optical linear scale with a simple structure, and the distance between the measured object and the sensor can be automatically adjusted. The feasibility of the measurement system is tested by simulation experiments, and the accuracy performance is evaluated with respect to both repeatability error and linearity error. The experimental results show that the displacement measurement system reaches a level of accuracy which is sufficient for operational requirements.

Abstract: The error of displacement measurements by digital image correlation method is examined from a pratical perspective. Different from previous research, this study focuses on external factors influencing the accuracy of displacement measurement in the study of cooperative mark recognition and camera placement. Our major objectives of this research include indentificating the chief error sources and assessing their influences on the testing results. There are 5 parts in this paper. We start with a brief introduction of the necessity of analyzing the errors. After reviewing the principles of digital image correlation method, an detailed discussion of error soureces of this method is provided. Then we design a pratical experiment measuring the characteristics of a spring vibrator using the digital image correlation mesurement systems and laser displacement sensor. By comparing the results from two ways of measurment, we end the study with the conclusion that the accuracy of displacement measuring by digital image correlation method is tightly related to the choice of cooperative mark and camera intersection angle.