Design and Analysis of a Novel Variable Stiffness Joint for Robot

¹ Master student, Department of Mechanical Engineering, FAMU/FSU College of Engineering, Tallahassee, FL32310, USA
² PhD student, Department of Mechanical Engineering, FAMU/FSU College of Engineering, Tallahassee, FL32310, USA
³ Associate professor, Department of Mechanical Engineering, FAMU/FSU College of Engineering, Tallahassee, FL32310, USA

Abstract

As people pay more attention to the safety of human-robotic interaction, the flexibility of machine joints is becoming more and more important. To address the needs of future robotic applications, many kinds of variable stiffness mechanisms have been designed by scientists. But most of the structures are complex. By studying and comparing many different mechanism designs of variable stiffness joint, we recognize the need to miniaturization and reduce weight of variable stiffness joints with high frequency operation. To address this, need a continuously Variable Compliant Joint (CVCJ) was designed. The core of the joint is based on the structure of the spherical continuously variable transmission (SCVT) which is the catalyst to change the stiffness continuously and smoothly. In this paper, we present a compact variable stiffness joint structure to meet the volume and weight requirements of the future robotic systems. We show the connection between the joint stiffness coefficient and the structure parameters by making mathematical analysis, modelling and simulation for the system to verify the ability to satisfy the base application requirements of the compliant joint.