Design of a Miniature Series Elastic Actuator for Bilateral Teleoperations Requiring Accurate Torque Sensing and Control

Abstract

Compared with stiff actuators, series elastic actuators (SEAs) can render more accurate output torque and stiffness. Hence, SEAs are suitable for robots that need to interact safely with human or properly with the actual or virtual environment. Many existing rotary SEAs are bulky and not suitable for multiple-degree-of-freedom (DoF) applications. To explore the merits of SEAs in bilateral teleoperations that often require multiple-DoF force feedback, this letter presents a miniature rotary SEA. By using a specifically designed planar spring, the size of the SEA can be minimized while the output torque and stiffness can still be accurately controlled. Dynamic modeling and impedance control experiments show that the torque and stiffness rendering results are better than those of existing SEAs. A master-slave robot system using the proposed SEA demonstrates that both stiff and soft remote environments can be virtually realized. We expect that this miniature SEA can serve as an alternative actuator for robotic teleoperations requiring accurate torque sensing and control.