Computer Aided Testing Technology And Device For Symmetric Cams

As a mechanical part that can directly produce slave movement, it is essential for cam to have a higher precision, which make the enhancement of cam test system essentially. Comparing with the normal cam, the symmetric cam has characteristics of its own, which has both profile tolerance and symmetric tolerance requirement. There are many cam test systems in the market, but specific system for the symmetric cam has not been developed yet. In this dissertation, a computer aided testing system for profile and symmetry has been designed for symmetric cams, which the encoder and linear grating are used as measurement components in it. Encoder is used to measure the angular displacements and the linear grating is used to measure the line displacements produced by the rotation of cams. The principle of cam testing with single gauge head and double gauge heads is analyzed and the measurment method with single gauge head in engineering practice is determined. A computer aided testing instrument for profile and symmetry of a cam together with corresponding control software are developed, which can be used to process the measurement data and obtain the profile curve , the starting angle, the profile tolerance and symmetry of a cam, then the corresponding assessment can be done. The advantages and disadvantages of many test methods of cam are analyzed, and the mechanical part of the CAT is introduced. The method of curve fitting of cam profile with cubic B-spline curve is presented and the causes of errors are analyzed. As an attachment, the design of Horizontal Articulated Scarab Robot is introduced in detail, and the HAR 0400 has been produced.