Control of Rotary Inverted Pendulum Using Model-Free Backstepping Technique

Abstract

This paper presents control studies of a rotary inverted pendulum (RIP) by applying a model-free backstepping (MFBS) control technique. We first discuss the new MFBS technique, which does not rely on the detailed model of the system, and makes use of only the system structure and measurements of the state. The MFBS technique makes use of a normal form of the system model and estimates the unknown dynamics. An approach is also proposed to deal with the unknown control coefficient. The equivalence of the control designed with the proposed method to the control designed with the knowledge of the control coefficient is established. The control designed with the proposed MFBS technique is compared with the LQR control in various settings. It is found that for the RIP control problem, the proposed control performs as good as, or better than the LQR control, but has an advantage of being model-free.

Keywords

• Model-free backstepping (MFBS)
• normal form
• under-actuated systems
• estimation of unknown dynamics