Turning Performance of Combine Robot by Various Compasses

The study aims to examine turning performance of a combine robot by various sensors such as GPS compass and geomagnetic compass. A multi global navigation satellite system (GNSS) with a built-in geomagnetic compass is used as navigation sensors. A GPS compass is used for comparison of the geomagnetic compass. These sensors provide the combine robot with the position and heading information required to steer along a target path. To control steering, we applied a Kalman filter that estimates the lateral and heading errors contained in the position, heading, and traveling-speed data while the combine robot is travelling along straight paths. We also applied a switchback turn method when the robot turns at corners. Through field experiments, we demonstrated that the combine robot is capable of automatically following a target spiral path and harvesting rice crops. In addition, the turning performance of the combine robot was evaluated using the GPS compass or the geomagnetic compass. Though the turning performance by the geomagnetic compass is lower than that by the GPS compass, both compasses can provide the combine robot with sufficient accuracy for harvesting rice crops.