Proportional directional valve based automatic steering system for tractors

Most automatic steering systems for large tractors are designed with hydraulic systems that run on either constant flow or constant pressure. Such designs are limited in adaptability and applicability. Moreover, their control valves can unload in the neutral position and eventually lead to serious h...

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Bibliographic Details
Published in:Frontiers of information technology & electronic engineering 2016-05, Vol.17 (5), p.458-464
Main Authors: Liu, Jin-yi, Tan, Jing-quan, Mao, En-rong, Song, Zheng-he, Zhu, Zhong-xiang
Format: Article
Language:English
Subjects:
Check valves
Circuit design
Communications Engineering
Computer Hardware
Computer Science
Computer Systems Organization and Communication Networks
Control valves
Design
Electrical Engineering
Electronics and Microelectronics
Feedback
Flow regulators
Hydraulic equipment
Hydraulics
Instrumentation
Networks
Proportional integral derivative
Steering
Systems design
Tractors
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Summary:Most automatic steering systems for large tractors are designed with hydraulic systems that run on either constant flow or constant pressure. Such designs are limited in adaptability and applicability. Moreover, their control valves can unload in the neutral position and eventually lead to serious hydraulic leakage over long operation periods. In response to the problems noted above, a multifunctional automatic hydraulic steering circuit is presented. The system design is composed of a 5-way-3- position proportional directional valve, two pilot-controlled check valves, a pressure-compensated directional valve, a pressure- compensated flow regulator valve, a load shuttle valve, and a check valve, among other components. It is adaptable to most open-center systems with constant flow supply and closed-center systems with load feedback. The design maintains the lowest pressure under load feedback and stays at the neutral position during unloading, thus meeting the requirements for steering. The steering controller is based on proportional-integral-derivative （PID） running on a 5 1-microcontroller-unit master control chip. An experimental platform is developed to establish the basic characteristics of the system subject to stepwise inputs and sinusoidal tracking. Test results show that the system design demonstrates excellent control accuracy, fast response, and negligible leak during long operation periods.
ISSN:2095-9184
2095-9230
DOI:10.1631/FITEE.1500172