Abstract
In this paper, the double inverted pendulum having a single actuator is built and the controller for the system is proposed. The lower link of the target pendulum system is hinged on the plate to free for rotation in the specified range($10^{\cire}$) on the x-z plane. The upper link is connected to the lower link through a DC motor. The double inverted pendulum built can be kept upright posture by controlling the position of the upper link even though it has no actuator in lower hinge. The algorithm to control the inverted pendulum consists of a state feedback controller within a linearizable range and a fuzzy logic controller coupled with a nonlinear feedback compensator for the rest of the range. Conventional state feedback control is employed, and the fuzzy controller is responsible for generating the reference joint angle of the upper link for the nonlinear feedback compensator which drives a DC motor to generate an indirect torque to the lower joint. As a result, we can get the upright posture of the proposed pendulum system. Simulations and experiments are conducted to show the validity of the proposed controller.