IDENTIFYING SINGULAR POINTS AND THEIR NEIGHBORS IN THE WORKSPACE OF PLANAR CLOSED-LOOP MECHANISMS BASED ON MOTION TRANSMISSION INDEX

Abstract

Singular configurations in the workspace of planar closed-loop mechanism or parallel robot attracts intensive attention of researchers since this is the direct cause of uncontrolled phenomenon as the sudden changes (gain or lose) in the degree of freedom (DoF) of mechanisms when then they encounter these configurations. This paper presents a novel method to identify singular points and their neighbors in the workspace based on pressure angle. In addition, this method also allows us to evaluate the performance of the areas in the task space through motion transmission index (MTI). The method is demonstrated by 2 examples with a four-bar linkage mechanism and 2 DoFs parallel robot. The results shown are important and being used as the first step in the design and control of the closed-loop mechanisms.