Wide range and high precision free curved surface measuring method

Abstract

The wide range and high precision free curved surface measuring method includes setting the curved surface on one platform capable of shifting precisely in both X and Y directions, integrating laser displacement sensor and grating displacement sensor and linear coder, installing the laser displacement sensor onto one servo mechanism capable of moving in Z direction, obtaining the Z coordinates of the curved surface with the laser displacement sensor and grating displacement sensor and linear coder, and obtaining the X and Y coordinates with the precisely shifting platform. The present invention fuses several sensors, has the features of high efficiency, wide range and high precision in free curved surface measurement, and will find its wide application in manufacture technology.

Description

Technical field: [0001] The invention relates to an automatic measurement method for free-form surface parts. Background technique [0002] In the aerospace, automobile, mold, shipbuilding and other industrial fields closely related to the manufacturing industry, free-form surface parts have been more and more widely used. At present, the measurement methods for free-form surfaces mainly include coordinate measurement, binocular stereo vision, laser triangulation, interferometry, and layer-by-layer scanning measurement. engineering and high precision requirements. [0003] For the measurement of free-form surfaces, there are generally three main methods: (1) The integration of the contact probe and the non-contact probe of the three-coordinate measuring machine. Due to the wide application of the three-coordinate measuring machine in the industry, this method has been obtained Extensive research by scholars at home and abroad, such as Carbone and V.Chan using stereo vision...

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Problems solved by technology

Although this integrated method has high precision, it still needs to be further studied in terms of realizing intelligent measurement, reducing manual intervention and errors, and improving measurement speed and stability; (2) line structured light method integrating laser and CCD, such as The REPLICA reverse engineering system of the American 3D Scanners company, the line structure laser profiling measurement system based on the CNC system of Huazhong University of Science and Technology, etc., this method has the characteristics of large range, large field of view, and simple light pattern information extraction. Widely concerned by foreign scholars, but the disadvantages are relatively low accuracy and difficult calibration; (3) the integration of laser displacement sensor and CCD, such as Li Jian of Zhejiang University developed a free-form surface laser non-contact measurement system on a CNC milling machine, Ju Hua has conducted research on key technologies such as non-contact measurement planning, data processing and error compensation. The method is to use an open motion control system, use machine vision to guide measurement planning, and use a laser displacement sensor to directly obtain the displacement in the Z direction. This method is expected to realize the integration of fast measurement, surface reconstruction and CNC machining, but due to the nonlinearity of the measurement principle of the laser displacement sensor, it cannot have the characteristics of large range and high precision

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