Cam profile analysis and simulation using synthetic curves

Cam follower mechanisms are used for obtaining complex motion outputs at follower end with different profile curve inputs at cam end. The kinematic behaviour of follower establishes basic suitability of cam for a given application and it is decided by the cam profile curves, which is main input of cam follower system. In this paper synthetic curves, that are generated parametrically through a set of known data points with desired number of curve segments, are studied for their effect on the kinematic behaviour of follower and are proved to be a major improvement over the traditional trigonometric and polynomial cam profile curves. Different synthetic curves are generated by varying their different parameters. The kinematic behaviour of follower is, then, simulated for cam profiles using these synthetic curves. The resulting follower displacements, velocities, accelerations and jerks are analysed and a comparative study is performed with the kinematic behaviour of cycloidal cam profile. It is observed that the Hermite curve, when used as a cam profile, has caused up to 28.32% reduced maximum acceleration of follower than that obtained for cycloidal curve. The Bèzier curve has facilitated continuous jerk of follower, which is not, at all, possible by using a cycloidal curve. So, they provided additional versatility to suit more complex / high speed applications. It is concluded that the synthetic curves are providing better control on kinematic behaviour of cam follower mechanism, with adjustable values of maximum velocities, maximum accelerations, and maximum values of jerks in different regions of cam rotation due to flexibility of shape control.