Optimal control of inverted pendulum on cart system

Abstract

In this paper, a PID and PID-liked fuzzy logic controller is designed for optimal control of inverted pendulum. An inverted pendulum is highly a nonlinear and unstable system. Thus, in this paper, the system is modeled, linearized and controlled. The control objective is to keep the pendulum in an upright position despite external disturbances. The stability analysis of the system is performed, which proves the instability of the system. Two separate controllers were developed to cater for the nonlinear behavior of the system. In the PID controller, the PID gains were fine-tuned through trial and error in MATLAB to obtain optimal control of the system. On the other hand, fuzzy logic is used to tune the PID in the PID-like fuzzy logic controller. Control performances of the system by PID and PID-like fuzzy control method were compared. The result indicated PID-like fuzzy control method performs better in respect of rise time, settling time, peak overshoot and steady-state error.