Papers by Author: Qian Cheng Zhao

Abstract: Tool path is usually described by means of continuous small linear segments. It results in large number of programming points in order to achieve high precision. A construction method of tool path based on arc-cell is presented in this paper, and the tool path is G¹ continuous. The construction method is applied to describe the tool path of wave shape specimen and hill shape specimen. For the two specimens, when their tool paths are described based on continuous small segments, 128212 and 184954 linear segments are necessary, respectively. But when their tool paths are described based on arc-cell, 15838 and 21669 arc-cells are necessary, respectively. And its more important that these arc-cells include information of curvatures and arc-lengths to control acceleration and deceleration.

Abstract: In this paper a radius correction method called 4 points co-sphere and simulation for rotor measurement are discussed. The error of rotor end profile after compensation is evaluated by approaching the minimum zone condition successively. Normal vector bound method determines the theoretical curve segment, searching theoretical corresponding point with dichotomy. The evaluation results have shown that the radius correction method of 4 points co-sphere can be used in rotor measurement, and have more applied value in project.

Abstract: In vision detection system of mobile phone keyboard, images coming from product line are often slant. Those images have to be corrected in order to facilitate match and recognition in further image processing. This paper proposes an effective slant correction method based on the characteristics of mobile phone keyboard image. In this method, straight line edge detection is done only by horizontal Sobel operator. The angle parameter of straight line is tested by multiresolution Hough transform. Then the angle relation is deduced between the tested line and slant mobile phone keyboard image. The slant image is corrected by rotation algorithm which combines the fast rotation algorithm with bilinear interpolation algorithm. The results of experiment indicates that the method and its algorithm are effective and accurate.

Abstract: In condition monitoring of train, because of load change, speed fluctuation and other effect factors, it may cause vibration frequency spectrum migration. If using the common vibration signal acquisition and spectral analysis method to this fault, there will be a result of characteristic spectral smearing, which will lead to misdiagnosis or missed diagnosis. To solve this problem, the vibration mechanism of spectrum-varying fault was discussed. This paper studies a pulse-triggered sampling method of integral periodic signal, the equal angle re-sampling method and other appropriate signal processing method. The feasibility and validity of this method and technology has been verified by the application in Liuzhou Railway Bureau .

Abstract: The important parts of a screw compressor are the two rotors. At present, generally use a CMM to check the form and other parameters of the rotors to ensure its function. Among the all geometrical parameters of a rotor, the form of traverse section profile is the most important one. In the process of measurement, the key technology problem is the probe radius correction because of the complexity of 3D helical surface. When the nominal values of the rotors are unknown, the radius correction is more difficult than that is known. This paper presents a method to evaluate the precision of measuring screw rotors by simulation. Suppose a referenced helical surface, first select the probe ball radius and sampling density, calculate the coordinate values of the probe ball centers along a fixed plane, then calculate the values of measured contour by radius correction, finally compare the reconstructed contour with the referenced surface to evaluate the selected measuring parameters such as probe ball radius, sampling density, the algorithm of radius correction and so on. This simulation process is necessary for actually measuring a screw rotor.

Abstract: A new style micro-force sensor based on a 3-RRR parallel micro-motion stage which had been researching recent years was introduced in this paper. The sensor can be used in micro-force and micro-torque detection in precision engineering. The result and experience from 3-RRR micro-motion stage research bring this new idea. In the first place, the branched chain structure in motion stage needs to be simplified and improved to adapt to the requirement of sensor. Secondly, a mechanics model is constructed according to the sense organ structure. The Jacobin Matrix which is the most important matrix on parallel structure is analyzed and deduced. The relationship among key dimension is worked out through isotropy parameters. With the theory analysis, the final structure of sense organ is determined. The elastomeric sensor body was pasted with electrical-resistance strain gauges, after it was manufactured by Wire-EDM. Strain gauges employed Wheatstone bridge and amplifier AD620 to produce measuring data. Experiment has indicated that the new sensor is competent for micro-force detecting in X, Y direction and micro-moment around Z direction with high stability and reliability.