MINIMUM TIME SWING UP AND STABILIZATION OF ROTARY INVERTED PENDULUM USING PULSE STEP CONTROL

Abstract

This paper proposes an approach for the minimum time swing up of a rotary inverted pendulum. Our rotary inverted pendulum is supported by a pivot arm. The pivot arm rotates in a horizontal plane by means of a servo motor. The opposite end of the arm is instrumented with a joint whose axis is along the radial direction of the motor. A pendulum is suspended at the joint. The task is to design a controller that swings up the pendulum, keeps it upright and maintains the arm position. In the general intelligent hybrid controller, a PD controller with a positive feedback is designed for swinging up and a fuzzy balance controller is designed for stabilization. In order to achieve the swing up in a minimal time, a controller named Minimum Time Intelligent Hybrid Controller is proposed which is precisely a PD controller together with a pulse step controller for swinging up along with the fuzzy balance controller for stabilization. The impulsive control action is tuned by trial and error to achieve the minimum-time swing-up. An energy based switching control method is proposed to switch over from swing up mode to stabilization mode. Extensive computer simulation results demonstrate that the swing up time of the proposed minimum-time controller is significantly less than that of the existing general hybrid nonlinear controller.