Fuzzy control of a real time inverted pendulum system

In this study, a real-time control of the cart-pole inverted pendulum system was developed using fuzzy logic controller (FLC). Swing-up and stabilization of the inverted pendulum were implemented directly in the FLC. The FLC designed in the Matlab-Simulink environment was embedded in a dSPACE DS1103 DSP controller board. The FLC for swing-up brings the pendulum near to its inverted position from downward position between 5 and 10 seconds. The FLC for stabilization maintains the pendulum near to inverted position with average +/- 1 degree of error and the cart near to zero position with average +/- 0.02 m of error. In order to test the robustness of the FLC, internal (changing model parameters) and external disturbances (applying external forces) were applied on the inverted pendulum. The maximum errors of the pendulum angle to the impulse force input were obtained between 1.89 degrees and 4.6449 degrees in the internal disturbance tests. The errors obtained from external disturbance tests vary with applied forces. Based on robustness tests, the inverted pendulum system with the FLC was shown to be robust to the external and internal disturbances.