The Spiral Bevel Gear Contact Area Based On Stereo Vision Detection Technology

Spiral bevel gears are widely used in the mechanical transmissionsystem of aviation and motor industry. Their working performances havea vital influence over the whole transmission system. The contact zoneof gear tooth surface, including its position, size and shape, is consideredone of important indexes when gears' working performances areevaluated.The majority of the traditional methods of detecting the contactzone are classified as qualitative analysis, so their precision iscomparatively lower. According to the detecting principle and features,the thesis explores the application of stereovision technology in it, andpresents a new method which is included in quantitative analysis andcharacterized by higher precision, faster speed and non-contact.Firstly, in the thesis, the present situation of measurementtechnology of spiral bevel gear's contact zone and the development ofstereovision technology are introduced. Secondly, the common cameramodels and their calibration are studied and also a calibration method isbrought forward by least squares techniques. Then some algorithmicmethods, such as image smoothing processing, edge detection andGray-Scale transformation, are introduced, and a method, whichpreprocesses the gear contact zone with Gray-Scale's gradual change byusing partial transformation, is presented, and moreover, the edgeextraction process through multiple experiments is determined. Finally,the stereo matching and 3D reconstruction technology, which contains3D information by restoring the tooth surface contact zone edge withtwo images, is discussed, and the computer graphics transformation andcurve fitting technology for creating axial plane graphics of contact zoneis also studied.The experimental results indicate that the method mentioned in thethesis can make an overall measurement of the contact zone of gearsurface, as of its position, size and shape, can offer reference foramending the gear tooth surface, and thus it bears important scientific and practical Values for actual design and manufacture.