Magnetorheological variable stiffness and damping flexible joint with cam working surface for industrial robot

In order to improve the environmental adaptability and interaction stability of industrial robotic arms, a flexible joint with variable damping and stiffness based on magnetorheological (MR) technology was proposed. The mechanical models for variable stiffness and damping of MR flexible joint were established, and the relationship between cam surface and variable stiffness element was derived based on the energy method. Subsequently, the variation patterns of equivalent stiffness and damping of the prototype under different excitations were experimentally tested, and the test results show that its mechanical properties meet the design requirements. To further verify the performance of the MR flexible joint on the robotic arm, we setup a collision buffering test system and investigated the buffering performance of the system under different working conditions. The buffering test results indicate that when the current of variable stiffness element is 2.0 A, the peak collision acceleration of the system after installing the MR flexible joint decreases by about 40.19% compare with the rigid collision.