DESIGN OF HARMONIC MOTION GENERATING RSSR FOUR BAR MECHANISMS FOR HIGH SPEED APPLICATION

摘要

Consideration of a mechanism for high-speed application inevitably poses certain kinematic design requirements that can be cast as a function generation synthesis problem involving the entire motion cycle of the mechanism. This paper addresses such application of RSSR four bar mechanisms for high-speed application. It employs a perturbational kinematic analysis of the mechanism to obtain approximate equations relating the follower and input angular displacements. The follower angular motion is derived, approximately, as a linear combination of two simple harmonic functions, in terms of the first and second harmonics of the crank angle. Albeit the exact mathematical description relating the input and output links exists it is not conducive to a kinematic design for dynamic performance. In contrast the approximate equations derived in this paper enable function generation of RSSR four bar mechanisms in which the higher harmonics of the input link are minimized. This utility of the approximate equations are demonstrated through several mechanism design examples.