Kinematic Optimization of Cam Mechanisms with Variable Input Speed

The motion characteristics of the follower can be adjusted flexibly by varying the input speed of cam, not changing the cam profile. An optimum design of variable input speed for the cam mechanism is aimed at improving the kinematic performance of the traditional cam mechanism by reducing the peak angular acceleration and angular jerk. The transfer functions of cam mechanisms with variable input velocity, the normalized displacement, angular velocity and acceleration and jerk of the followers corresponding to the normalized time, are firstly inferred in this paper. The B-spline curve, as the uniform mathematics expression, can be differently shaped depending on its control points. So speed function is described as a non-uniform B-spline curve and therefore, the corresponding control points are considered as the design variables. The method to confirm the knot vector is discussed. The kinematic optimization of variable-speed cam mechanisms and its constraints are then developed. Finally, two examples are given to illustrate the proposed method and also to show its feasibility and validity.