Mechatronics Design of a Novel Variable Stiffness Joint Designed with Antagonistic Actuation

In this paper, a novel variable stiffness joint (VSJ) with antagonistic actuation is presented. The actuation is designed with two nonlinear compliance mechanisms (NCMs). This makes it possible for us to control the position and stiffness of the joint independently. In the paper, the designs of the VSJ and the NCM are introduced. Position and stiffness control of the joint is realized using a PID controller based on the dynamics of the compliant actuation system. Experiments are performed to validate the feasibility of VSJ in controlling position and stiffness.