A basic study on the development of a cutter-height control system for harvesting
Date Issued
2008
Date
2008
Author(s)
Lin, Jia-Sian
Abstract
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.he 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. he 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.
Subjects
hydraulic
height control
8051 single chip
cutter
Type
thesis
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