Hybrid control for vision based Cart-Inverted Pendulum system

This paper presents a vision based cart-inverted pendulum (CIP) system under a hybrid feedback configuration: the continuous cart´s position measured by encoder and the delayed & sampled inverted pendulum´s upper coordinates, obtained from a visual sensor. The challenge here is to stabilize the CIP from a big inclined initial angle by using a low cost CCD camera. Under this scheme, we propose a hybrid control which consists in a jumping-up (bang-bang) control and a two causal stabilization loops control: the first one (inner loop) realizes a linearization and the stabilization control of the pendulum based on an innovative piecewise continuous reduced order Luenberger observer (PCROLO) coupled with a linearization module, the second one (the outer loop) realizes a Lyapunov based control for the unstable internal system with lower dynamics than that of the pendulum. This hybrid control method is capable of balancing the CIP system within small cart´s displacement. Performances issues of the proposed method are illustrated by the experimental figures and videos.