Modeling and Controller Designing of Rotary Inverted Pendulum (RIP)-Comparison by Using Various Design Methods

_ Inverted pendulum control is one of the fundamental and interesting problems in the field of control theory. This paper describes the steps to design various controllers for a rotary motion inverted pendulum which is operated by a rotary servo plant, SRV 02 Series. Nonlinear model of the rotary inverted pendulum and linear model (Upright) in the neighborhood of an equilibrium state are described. In this paper the controller consists of three parts: a swing-up controller, a catch controller, and a state feedback stabilizing controller. Designing the control system using PID is quiet challenging task for the rotary inverted pendulum because of its highly nonlinear and open-loop unstable characteristics. Modern control techniques are analyzed to design the controllers for linear model of rotary inverted pendulum, are called stabilization controllers. The paper describes the two Modern Control techniques those are Full State Feedback (FSF) controller and Linear Quadratic Regulator controller (LQR). Designed a swing up controller that raises the pendulum to the inverted position in a controlled manner, where the stabilization controller can stabilize it (Self-erecting pendulum). Here FSF and LQR control systems are tested both for the Upright and Swing-Up mode of the Pendulum. Digitalization of the plant is done by designing discrete 2DOF(Two Degree of Freedom) pid controller using root locus technique. MATLAB based simulation results are described and compared based on the above control methods which are designed to control the Rotary Inverted Pendulum.