Comparative evaluation of the selective compliance in elastic joints for robotic structures

After a brief reminder about advantages and problems related to the application of large displacement elastic joints in robotic structures, this paper outlines an approach for quantifying the joint's performance in terms of selective compliance (i.e. capability of providing low stiffness along a single desired direction). Local and global performance indexes are proposed which can be used to discern which joint best suits the application requirements. The approach is validated by comparing two beam-like flexures and two novel compliant joints with non trivial morphology.