CP-DGPS based combine harvester control without orientation sensor

摘要

Mobile robot control is a classic problem in the roboticrncornrnunity. It is particularly true in the agricultural fieldrnwhere repetitive tasks can be handled using AGV.rnIn this paper, we address the problem of combinernharvester control using a single CP-DGPS receiver, withoutrnany attitude measurement unit. A non linear, velocityrnindependent control law has been designed. It relies uponrnthe kinematic model of the combine harvester.rn‘llvo approaches aimed at estimating the heading of thernfarm vehicle have been investigated. One uses GPSrnvelocity measurements: the kinematic model of thernharvester imposes that its linear velocity is directed alongrnthe vehicle axle. So the heading of the vehicle canrnbe roughly estimated from raw velocity measurements.rnThe other relies upon a Kalman state reconstructor andrnproduces an indirect measurement of the heading. Thernreconstructor has been designed thanks to the kinematicrnmodel of the harvester, and taking into account for thernsensor noise.rnThe control law has been implemented on a combinernharvester. Experiments have been carried out using bothrnkinds of heading estimations on an almost flat ground. Thernstandard deviation from the mean of the lateral positionrnis about three centimeters, and the bias smaller thanrnfive centimeters. Both methods are compared an somernconclusions are drawn.