Design of joint variable stiffness actuation system of service robot

LIN A-bin， ZHOU Jian-jun， ZHANG Ya-ping
（School of Mechanical Engineering，Hangzhou Dianzi University， Hangzhou 310018， China）

Abstract： Aiming at solving the safety and reliability problem generated from human-robot interactions，a variable stiffness joint actuation system was proposed. A kind of parallel adjustable compliance flat torsional spring for achieving variable stiffness was employed. Stiffness of the flat torsional springs was analyzed，and the relationships between stiffness of the flat torsional spring and deflection angle，preload were built，which provides a theoretical basis for the performance optimization of the joint actuation system. The simulation results indicate that the flat torsional spring's essential deflection angle，having a large stiffness variation，approximately from 0° to 7°，which meets the stiffness requirements for service robot joints. The system not only retains the characteristics of the variable rigidity，and reduces the volume of space for the elastic module，and greatly simplifies the system structure， it is easy to maintain.
Key words： service robot； joint actuation system； variable stiffness； flat torsional spring