Study On Motion Of Planar Mechanism Based On CCD Technology

Kinematics and dynamics researching of mechanism is important in analysis and synthesis of mechanism. That acquiring the displacement, locus, velocity and acceleration of points on the component and angular displacement, angular velocity and angular acceleration of components is very necessary because real motion parameters are often requisite for analysis in the researching. Therefore the method, acquiring the motion parameters of components of planar mechanism, based on CCD and digital images processing technology is put forward in this paper. Program for this is also written. CCD (Charge Coupled Devices) is used widely in the area of measurement and testing as a new-style photoelectric device. The researching about manufacturing and applying of CCD is also evolved wonderfully. In this paper, with CCD and digital image processing technology, the time-change-sequence images of slider-crank mechanism which is a kind of typical planar mechanism are processed, and these images are gathered by CCD camera. The coordinate of marks on the component is gotten at different moment and the numerical method is used to calculate the parameters such as velocity and acceleration. Compared with the other detecting methods, this method covers the shortage of other transducers and shows the advantage of non-contact measurement of CCD. At the same time, the researching findings about this method can also be applied in the area of location detecting of components and parts, automatic location, intelligent manufacturing and so on.Based on the theory of digital image processing and numerical analysis, digital image processing program are written by Delphi7 of Borland. Binary processing and post-processing are applied to transform the images gathered by CCD camera to the binary images by the program. In the complex background, interference scenery of images is wiped fully off, foreground is separated and the relative positions of bench marks on the mechanism are determined. After compared with other several numerical analysis methods, Fourier series fitting method is applied to calculate the parameters of motion of the mechanism.In the process of processing the digital images, a modified, easy and valid algorithm between global binarization and local binarization are researched in case that the processing objects are specific in this paper. Digital images algebraic operation and guide line for wiping the discrete offending points are confirmed. Not only the program that can realize the algorithm but also handling system is built. The applicability that the relative processing method is used to solve the practical application problems is discussed.Because the geometry center of the mark is constant in the course of movement, projection method is used in this paper to define exactly the comparative location of the geometry center of the mark. This establishes the basis for the motion analysis of mechanism.