ENGINEERING

Stability evaluation of a proportional valve controller for forward-reverse power shuttle control of agricultural tractors

Hyeon-Ho Jeon1   Taek-Jin Kim2   Wan-Soo Kim3   Yeon-Soo Kim4,5   Chang-Hyun Choi6   Yong-Hyeon Kim7,*   Yong-Joo Kim1,4,*   

1Department of Smart Agricultural Systems, Chungnam National University, Daejeon 34134, Korea
2Research and Development Institute, TYM Co., Ltd., Gongju 32530, Korea
3Institute of Agricultural Science, Chungnam National University, Daejeon 34134, Korea
4Department of Biosystems Machinery Engineering, Chungnam National University, Daejeon 34134, Korea
5Smart Agricultural Machinery R&D Group, Korea Institute of Industrial Technology (KITECH), Gimje 54325, Korea
6Department of Bio-Mechatronics Engineering, Sungkyunkwan University, Suwon 16419, Korea
7Gint Co., Ltd., Suwon 16225, Korea

Abstract

Due to the characteristics of the farmland in Korea, forward and reverse shift is the most used. The fatigue of farmers is caused by forward and reverse shifting with a manual transmission. Therefore, it is necessary to improve the convenience of forward and backward shifting. This study was a basic study on the development of a current control system for forward and reverse shifting of agricultural tractors using proportional control valves and a controller. A test bench was fabricated to evaluate the current control accuracy of the control system, and the stability of the controller was evaluated through CPU (central processing unit) load measurements. A controller was selected to evaluate the stability of the proportional valve controller. The stability evaluation was performed by comparing and analyzing the command current of the controller and the actual current measured. The command current was measured using a CAN (controller area network) communication device and DAQ (data acquisition). The actual current was measured with a current probe and an oscilloscope. The control system and stability evaluation was performed by measuring the CPU load on the controller during control operations. The average load factor was 12.27%, and when 5 tasks were applied, it was shown to be 70.65%. This figure was lower than the CPU limit of 74.34%, when 5 tasks were applied and was judged to be a stable system.

Figures & Tables

Fig. 1. A photo of proportional valve controller for forward-reverse power shuttle control of agricultural tractor used in this study. SOC, system on chip; MCU, micro controller unit.