Tracking control of a rotary flexible joint robot: a comparative study

Abstract

Conventional PID controller is very common for industrial processes because of their simplicity and acceptable performance. However, the PID controller cannot effectively manage the large disturbances and has limitations of its own. This study aims to develop sophisticated controllers for the Rotary flexible joint, such as Fuzzy Logic Controllers (FLC) and Internal Model Controllers (IMC). The mathematical modeling of the Rotary Flexible Joint (RFJ) is theoretically investigated and developed in MATLAB and SIMULINK to design a Fuzzy logic-based IMC controller. Gaussian membership functions and the Mamdani method were used to design the FLC. Furthermore, an IMC controller is also desigend for the same model. In this paper, the performance of the PID, FLC, and IMC was compared through simulations. The objective was to keep track of a desired position angle and minimize the vibration of the joint. Simulation results show that the IMC controller performs better than the other two controllers since it successfully manages the disturbances and tracks the set point efficiently.