Analysis and Synthesis of the Bidirectional Antagonistic Variable Stiffness Mechanism

Variable stiffness actuation promises many benefits regarding mechanism robustness, energy efficiency, and dynamic performance. Here, we analyze the bidirectional antagonistic variable stiffness (BAVS) joint. A comprehensive overview of several aspects is given with a focus on the stiffness and torque characteristics of the joint. First, the functionality and properties of the abstract joint model are considered. Then, implementation details influencing the stiffness properties are discussed based on cam disc variable stiffness mechanisms. In general, an analytic approach is chosen to enable a generalization of the results. Experiments conducted on a BAVS joint of the variable stiffness actuated robot DLR Hand Arm System verify the theoretical findings.