收穫用割刀位置控制系統之基礎研究

Abstract

本研究主要目的為開發一割刀高度位置控制系統，包含了高度位置感測器、高度位置調整機構和8051單晶片控制器。 實驗共分為六個階段：第一階段為高度位置感測器位移量實驗，第二階段為電磁閥延遲時間測試之實驗，第三階段為單晶片控制器訊號對高度位置調整機構反應之實驗，第四階段為油壓系統與控制信號之實驗，第五階段為模擬高度感測器與割刀距離之實驗，第六階段為高度感測器位置與油壓缸位置關係之實驗。 實驗結果顯示，高度位置感測器其位移與力量呈線性關係，且本研究之設計高度位置感測器可以根據不同情形下，改變光遮斷器陣列之距離，避免系統過度的運作。電磁閥延遲時間約為0.1386秒。在手動模式下，高度位置調整機構在多次試驗中，可看出其各組上升速度與下降速度都相當接近。在自動模式下發出不同延遲時間的控制信號，所得結果為要上升1公分時，所需要的作動時間約0.117秒，而要下降1公分，所需要的作動時間則為0.09秒。第四階段比第三階段之實驗推論之作動時間較多，故若要使控制高度位置位移較小的情形下，則只要改變其作動時間即可達成控制目的。第五階段實驗中可知當車速越慢或高度感測器位置與割刀距離越靠近時，則電磁閥延遲時間需要考慮於系統中。高度感測板所接收到的高度變化，經由控制器發出控制訊號給電磁閥，油壓缸能正確動作且有不錯的追隨能力。

The purpose of this study was to develop a cutter-height control system for plucking leaves. This system included a height-sensor, a mechanism which could be adjusted for height, and an 8051 controller. The experiment was divided into six parts. In the first part, the displacements of the height-sensor were tested. In the second part, the delay time of the solenoid for the directional valve was tested. In the third part, the relationship between the reaction of the height-adjustment mechanism and the signals from the controller was investigated. In the fourth part, the relationship between the hydraulic system and the control signals was tested. In the fifth part, the relationship of the distances between the height-sensor and the cutter was tested. In the sixth part, the relation of the positions between the height-sensor and the hydraulic cylinder was tested. The experimental results showed that there was a linear relation between the displacements of the height-sensor and the applied forces. The distances of an array of the photo interrupter could be adjusted to meet the different requirements in order to avoid the system’s overload. The delay time of the solenoid was about 0.1386 sec. In the manual mode, the upward speed and the downward speed of the hydraulic cylinder were very close. In the automatic mode, the control signal was transmitted by a controller, and the working time of the signal was about 0.117 sec when the cylinder rod moved a distance of 1cm upward. The working time of the signal was about 0.09 sec when the cylinder rod moved a distance of 1cm downward. The working time tested in the fourth part was more than that obtained in the third part. The control purpose could be achieved by changing the working time if the displacement was smaller. In the fifth part, the results showed that either when the speed of the vehicle was slow or when the distance between the height-sensor and cutter was getting closer, the delay time of the solenoid for directional valve had to be considered in the system. When the height-sensor receives the signals for height, these signals were transmitted to the solenoid by the controller. The cylinder could then move correctly and also had an acceptable ability.