Control Of A Mechanically Compliant Joint With Proportional-Integral-Retarded (Pir) Controller

In this paper, a mechanically compliant joint is designed and a novel proportional-integral-retarded (PIR) controller is adopted. Firstly, the structure of the invariant stiffness joint is introduced in details and linear springs are connected with the output link to obtain flexibility. Secondly, the control programs are built with Simulink and automatically compiled and downloaded into the controller. Thirdly, the physical mechanism and electromagnetic function of permanent magnet synchronous motor (PMSM) are combined to get the transfer function. Fourthly, a direct integration method (DIM) with Simpson method is proposed and used to analyze the stability of PIR controller with the joint. Finally, some compared experiments with conventional proportional-integral-derivative (PID) controller added a low-pass filter in the derivative term in speed loop and position loop are taken, and the results show that PIR controller is better in the speed of settlement and more stable in some condition.