TO OPTIMIZE THE STATIC PERFORMANCE PARAMETER OF A FOUR-BAR CHAIN FOR FUNCTION GENERATION WITH GREATER NUMBER OF ACCURACY POINTS

Abstract

Mechanism syntheses for three prescribed positions are simple because that number of precision points corresponds to the maximum number of prescribed positions for which a four-bar linkage may be synthesized by linear methods using standard dyad form. In case of three prescribed positions the linear solution can be obtained whereas for the four and five prescribed positions of function generation, the equations are transcendental and linear solutions are not possible. The present work expands on the loop-closure technique and the standard dyad form to investigate the four and five-precision point cases. It is well known that the mechanisms which have low value of transmission angles exhibit poor operational characteristics. Therefore, it is not enough for designers to satisfy the input-output specifications of a synthesis problem, they must also take into account the Transmission Angle. In present work a computer program is developed to synthesize a four-bar function generation to optimize transmission angle for three, four and five Chebyshev precision points. Effect of the number of these precision points on Transmission Angle and Mechanical Advantage has been studied for a given range of input and output link angle for a four-bar function generation mechanism. This study is a step towards optimized synthesis of a four bar chain