Fuzzy Control of an Inverted Pendulum using AC Induction Motor Actuator

Abstract

It has been proven that fuzzy controllers are capable of controlling non-linear systems where it is cumbersome to develop conventional controllers based on mathematical modeling. This article describes designing fuzzy controllers for an inverted pendulum. It compares performance of two controllers designed based on Mamdani and Takagi-Sugeno in a short track length, following a high disturbance. The work then focuses on the AC electrical motor that produces the torque required for the horizontal movements of the inverted pendulum. A simplified control model for the AC motor is used which includes the motor's time constant as the crucial parameter in producing rapid responses to the disturbances. In the currently modeling of fuzzy controllers for the inverted pendulum, the input to the pendulum block is a torque. This torque is produced by an electrical motor which is not included in the model. A disadvantage in this modeling is that the electrical motor dynamics is not built-in in the control system independently. Here, a simplified model of an AC electrical motor is incorporated to the system. The electrical motor receives its inputs as current or voltage and produces a torque as output to control the balance of the inverted pendulum. The new approach in modeling a fuzzy control system assists in 1) examining use of AC motors in producing rapid response, 2) selecting sensitive parameters for an optimum high performance electrical motor capable to stabilize the inverted pendulum system and 3) designing a Takagi-Sugeno type fuzzy controller