Multistable Behaviors of Compliant Sarrus Mechanisms

Multistable mechanisms providing spatial motion could be useful in numerous applications; this paper explores the multistable behavior of the overconstrained spatial Sarrus mechanisms with compliant joints (CSMs). The mechanism analysis is simplified by considering it as two submechanisms. The kinetostatics of CSMs have been formulated based on the pseudorigid-body method for compliant members at any combination of joints. The kinetostatic results show that a CSM is capable of exhibiting bistability, tristability, and quadristability. The type of behavior is found to depend on the initial (as-fabricated) position and the relative limit positions of the two submechanisms. Possible applications of multistable CSMs include deployable structures, static balancing of human/robot bodies, and weight compensators.