Nonlinear Output Feedback for Autonomous U-turn Maneuvers of a Robot in Orchard Headlands

This paper is devoted to the navigation of a robot in orchard headlands using embedded sensors such as lasers, Lidars or cameras. The main idea is to consider a differential robot model directly in polar coordinates and not in Cartesian coordinates which makes it possible to obtain simpler expressions of the outputs. Then two nonlinear output state feedback controllers are proposed to track two shapes based on spirals allowing to go from one row of fruit trees to another. These controllers are based on an input to output linearization and proved to be very efficient on simulations.