센서 융합 기반의 배추 수확기 예취부 3축 자세 제어

Abstract

In Korea, Chinese cabbage harvesting is insufficiently mechanized and automated, and this task is typically carried out using manual labor. Thus, research on Chinese cabbage harvesters is required. However, the terrain in cabbage fields is generally rough and comprises many obstacles. Consequently, problems such as overcutting, missed cutting, and side cutting occur while cutting cabbages using a cabbage harvester. Therefore, it is necessary to study the cutting mechanism of the harvester to perform accurate cutting, considering the terrain in the fields. To this end, a three-axis attitude control mechanism was designed in this study; this mechanism controls the cutting device of the Korean cabbage harvester with three cylinders. In addition, an accelerometer, a gyro sensor, and a rotary encoder were designed for sensor fused. The cylinders were controlled such that the measured roll (Φ) and pitch (θ) were level with the ground. In addition, the angle of the guide in the cutting device (θ<SUB>e</SUB>), driven by grounding to the ground, was calibrated using the height data. The cylinder in the sliding (x) axis was controlled to maintain the target height. Further, a proportional-integral-derivative controller was integrated to reduce overshoot and improve stability. To assess the performance of the algorithm, a 2:1 scaled-down model of the cutting device of the Korean cabbage harvester was produced, and the attitude control mechanism was installed on its driving platform and tested. Attitude measurement was performed using a motion capture device (OptiTrack). For quantitative evaluation, data with and without the attitude control system were compared by estimating their root mean square error (RMSE). The RMSE values for the level and height were 0.89° and 2.23 cm, respectively, for attitude control with the posture control system; however, those for attitude control without the posture control system were 2.15° and 4.05 cm, respectively. In addition, improvements of 58% in the level control and 45% in the height control were observed. In further investigations, better results can be obtained using the harvester if the changes in the angle and height are higher than those obtained in this experimental environment.