Multiphase Scouting Control of an Agricultural Field Robot With Reachability Analyses

Abstract

Accurate path scouting control of an autonomous agricultural robot is substantially influenced by terrain variability, field patterns, and uncertainties in sensed information. Based on conventional farming techniques, the targeted test crop of strawberries grows in semi-structured environments. Thus in this study, the proposed scouting control architecture comprises of three distinct portions and in each portion different sensors are used. Based on range finder (RF) information, the first region uses a proportional-integral-derivative (PID) controller with logic steps to account for undesirable pop-up events. In the other two portions, vision-based robust controllers are developed, in which a new bound is derived for the focal length uncertainty in vision. Stabilities of the controllers are proven and the reachabilities are analyzed to guarantee that the final state of each portion is within a desired initial region of the next portion controller. The proposed multiphase scouting control is successfully validated for our custom-designed robot in a commercial strawberry farm.