SYNTHESIS OF THE RSCR MECHANISM FOR 4 PRECISION POSITIONS WITH RELAXED SPECIFICATIONS

Abstract

The maximum number of precision positions that can be achieved by the RSCR mechanism is known to be three. However, in many practical applications, for example in pick-and-place tasks on an assembly line, four precision positions are usually preferred. That is, the second and third precision positions are used to control the departure and arrival motion of the first and the fourth precision positions through their first derivatives. This paper presents an efficient technique for synthesizing the RSCR spatial mechanism to satisfy a set of two exact precision positions plus two relaxed precision positions, thereby allowing two degrees-of-freedom of variability in the motion specifications.