Papers by Author: Xing Hua Qu

Abstract: This paper presents a new method for the calibration of conical thread gauges. The procedure involves scanning of conical thread profiles, extracting all the thread main parameters, reconstructing the conical thread model. The metrologies model compared to the Standard one that is established on the basis of theoretical data. Thereby, the actual state of the threads can be fully identified by means of Screwing into the threaded length, which is good for control of the thread quality

Abstract: A technique to compensate the geometry errors of industrial robot using Laser Tracker System (LTS) has been presented in this paper. A Spherically Mounted Retro-reflector (SMR) is mounted on the end-effector of industrial robot. The positions of SMR are measured by LTS and compared with the nominal value of industrial robot to get geometry error database of robot. The updated error database, together with real-time measuring of the positions on the robot’s end-effector can be used to compensate the geometric errors of the robot. Using this technique to compensate the industrial robot, the geometry errors can be decreased from 0.1mm to 0.04mm.

Abstract: This paper describes a method to characterizing the digital camera. The nonlinear relationship between the RGB signals generated by a digital camera and original image CIEXYZ values was obtained using the polynomial regression procedures. The reasonable structures of the polynomial were found for two digital cameras. The better number of polynomial terms was 19, yielding a modeling accuracy typically averaging 2.1~2.2 E ∆ units and maximally 9.5~10.9 E ∆ units. The experiments results showed that the polynomial regression could be used to characterize commonly digital camera.

Abstract: The computer aided measuring system is established to evaluate geometrical information of the structure in subsection manufacture. The cloud points data of surface are collected by laser tracker so as to explore continuing data processing software and evaluate the error of dimension and shape, and then the real measuring model, matched by the corner information, is compared with CAD through the best-fit algorithm. The lack of fitting information which will cause the low measuring precision is solved by the least square method constrained by radius in structure with large radius and small central angle. As the research object, the tunnel structure is used in the quality control of manufacturers.

Abstract: Rapid progress in modern manufacturing demands for better measurement technique with on-line characteristics. This paper presents a systematic visual solution for on-line industrial 3D measurement. The solution comprises two parts, a multi-sensor visual inspecting station (MSVIS) and a digital close-range visual inspecting station (DCVIS). MSVIS is an integrated system with many sensors. It can meet the requirement of application with sparse measuring points distributed within a large volume. DCVIS only contains two digital cameras with one or more projectors. It has high relative accuracy and a small set up volume and is suitable for applications with dense measuring points. The combined use of MSVIS and DCVIS can provide a general solution for on-line industrial 3D measurement.

Abstract: This paper describes a system that detects and categorizes workpieces with random defects on electrodeposits glossy metal surface. The system is developed on the basis of combination CCD photoelectricity inspection technology, image processing and automatic control technology. In the system, a special illumination apparatus with a light source of diffused light is designed. Workpieces with defects are automatically selected through measurement with image enhancement retreatment, gray scale analysis, image binaryzation, feature extraction and image recognition. Hardware comprises sections of optics, image collection, and control circuits. Software is programmed in Visual C++ and assembly language. The system can resolve the difficulty of detecting random defects on surface under the conditions of high reflection and complex surfaces.

Abstract: Porous silicon with pore size in the range of a few nanometers can be used as multifunctional material in different MEMS applications. Via an electrochemical etching method, porous silicon is fabricated on the silicon substrate and removed as a sacrificial layer by using KOH solution to form a micro structure. This technique is typical in micro fabrication. Three-dimensional size is the basic geometric feature to describe microstructure surface characteristics. It is important to investigate measurement methods for it. UBM Microfocus Measurement System based on defocusing error detection is adopted to measure eroded depth of silicon cup. The measured data in the experiments are analyzed. The influence of etching time, current density and silicon type on etching depth can be acquired. Effective reference data can be provided for studying micro fabrication methods.