Design of controllers for the rotary inverted pendulum

Abstract

The rotary inverted pendulum is a typical nonlinear control object in automatic control research, commonly used to test and evaluate various control algorithms. Due to its inherent instability and strong nonlinearity, controlling this system poses significant challenges, requiring effective control methods to maintain the pendulum’s equilibrium at the upright position. Various control approaches have been applied to this system, including classical control algorithms such as PID, state feedback, and LQR, as well as modern control methods like fuzzy control and model predictive control. This study focuses on the design, simulation, and performance comparison of two primary controllers: LQR and a PID controller with tuned parameters using fuzzy logic. The control algorithms are validated through simulations in MATLAB Simulink and experiments on the Quanser QUBE-Servo2 module. Evaluation criteria include stability, adaptability, and sensitivity to disturbances. The results show that the LQR controller achieves high performance with minimal oscillations and a short settling time, while the PID controller with tuned parameters using fuzzy logic demonstrates better adaptability to changing environmental conditions and unexpected disturbances.