Software Description USyCaMs: A Software Package Introduction

Kinematics of Cam Mechanisms

The synthesis procedure is based on the minimization of power losses, which is achieved, in turn, by minimizing the magnitude of the sliding velocity along the contact surfaces. To this end, the contact surfaces are designed as ruled surfaces, and motion is transmitted along a common line, the contact generatrix, which gives rise to a higher kinematic pair. Two more kinematic pairs arise, namely, the cam-frame and the follower-frame pairs, which belong to the class of lower kinematic pairs, and can be either revolute or prismatic [Ang82]. USyCaMs thus allows the synthesis of cam mechanisms not only with rotating, but also with translating cams or followers.

One objective of USyCaMs is to synthesize the contact surfaces of all the elements involved for two cases: (a) mechanisms comprising the frame, the cam, and the follower, henceforth termed three-link mechanisms; and (b) mechanisms similar to the former, but with an intermediate fourth element, the roller, henceforth termed four-link mechanisms. As a matter of fact, we are here following the established terminology in the realm of cam mechanisms, but, properly speaking, the intermediate element between cam and follower is not always a `roller'. Indeed, when minimizing the magnitude of the sliding velocity between cam and `roller' and between `roller' and follower, the `roller' turns out to be a hyperboloid of revolution that both slides and rotates with respect to the cam and the follower, in the most general case in which the axes of rotation of the cam and the follower are skew. In this case, we have a spatial mechanism. If the same axes intersect, we have a spherical mechanism and the roller takes the form of a cone of revolution and rotates without slipping about both the cam and the follower. Therefore, in the case of three-link mechanisms, two ruled surfaces are synthesized, while three are synthesized in the case of four-link mechanisms. The shape of the foregoing surfaces is determined so as to produce a given input-output function between cam and follower.

Software Description USyCaMs: A Software Package Introduction