Application of Rigid Body Linkage Static Balancing Techniques to Reduce Actuation Effort in Compliant Mechanisms

Abstract

There are analytical methods in the literature where a zerofreelength springloaded linkage is perfectly statically balanced by addition of more zerofreelength springs. This paper provides a general framework to extend these methods to flexurebased compliant mechanisms through (i) the well know smalllength flexure model and (ii) approximation between torsional springs and zerofreelength springs. We use firstorder truncated Taylor's series for the approximation between the torsional springs and zerofreelength springs so that the entire framework remains analytical, albeit approximate. Three examples are presented and the effectiveness of the framework is studied by means of finiteelement analysis and a prototype. As much as 70% reduction in actuation effort is demonstrated. We also present another application of static balancing of a rigidbody linkage by treating a compliant mechanism as the spring load to a rigidbody linkage.