Design and analysis of a novel variable stiffness joints with robots

This paper presents the design of a symmetric variable stiffness joint that employs worm gear and sliding helical transmissions to adjust the effective length of the leaf springs. Firstly, the design concept and working principle of the variable stiffness joint are presented, along with two different assembly methods. Secondly, the stiffness equations and characteristics of the variable stiffness joint are then derived and analyzed. Next, the dynamics of the variable stiffness joint are modeled and simulated visually using Simulink. Finally, a prototype of the variable stiffness joint is constructed and its stiffness characteristics are experimentally verified. The experimental results demonstrate that both assembly methods are capable of adjusting the stiffness and position of the joint within a certain range. This study contributes to the understanding and development of symmetric variable stiffness joints by presenting a comprehensive design, analysis, simulation, and experimental evaluation. The proposed joint has potential applications in various fields that require adaptability, adjustability, and safety.