Design and Modeling of A Trapezoidal Leaf Spring-Based Actuators with Valid Arm Length and Bending Deformation for Stiffness Adjustment

This paper proposes a design and modeling of a trapezoidal leaf spring actuator (TLSA) with variable stiffness. The mechanical mechanism of the actuator for stiffness adjustment consists of a flexible trapezoidal leaf spring and two grooved bearing followers (GBFs). The relationship between each GBF and the leaf spring always maintains line contact through the preload generated by the tension spring. Stiffness adjustment is achieved by changing the position of the contact point between the leaf spring and GBF. Such design ensures that only rolling friction ispresent and contributes to the improved stiffness adjustment performance of the actuator. The synchronous belt transmission system is used to change the pivot position accurately and suppress the vibration. Simulation results indicate that the proposed TLSA has the characteristics of a wide stiffness range, rapid stiffness response capability and large maximum load torque value.