Application of homogenous transformation matrix to measurement of cam profiles on coordinate measuring machines

A kinematic model is presented to aid the cam profile design task and to determine the NC data required to move an inspection probe to the necessary locations to inspect the surface profile of a spatial cam on a coordinate measuring machine (CMM). The cam profile is designed in accordance with the principles of conjugate surface theory. Homogenous transformation matrices are then employed to derive the CMM ability function matrix and the measuring probe location matrix. The required NC data are obtained by equating the elements in the ability function matrix with the corresponding elements in the probe location matrix in order to solve the CMM link variables. The validity of the proposed approach is verified by carrying out the automatic inspection of a machined cam on a CMM using the NC data computed by the developed algorithm. The methodology presented in this study combines the cam design, machining and inspection activities, and makes possible a flexible and automatic spatial cam design and manufacturing process.