Nonlinear Robust Path Control for a Field Robot Scouting in Strawberry Orchards

In recent years, the interests of introducing autonomous robots by growers into agriculture fields are rejuvenated due to the ever-increasing labor cost and the recent declining numbers of seasonal agricultural workers. Among all the enabling technologies used in robot operations for agricultural products with shallow structures, controlling a robot to traverse throughout a field is challenging. In this study the motion control of a robot, custom-designed for strawberry fields, is separated into multiple phases to deal with the over-bed and cross-bed operation needs. Different sensors are used for different control phases. In particular, nonlinear robust controllers are designed for the cross-bed motion, purely relying on vision feedback. The proposed sensing and control methods are successfully validated in a commercial farm.