Characterization of an Electrohydraulic Valve to Control Auto-steered Off-road Vehicles
The majority of off-road vehicles, including agricultural, forestry and construction vehicles are typically equipped with a hydraulic steering. An efficient way of automating the steering mechanism of these vehicles is by controlling the hydraulic valve that operates the steering cylinder. Electronically-controlled hydraulic valves often behave nonlinearly and, consequently, they introduce certain complexities in the analysis of the hydraulic system. Therefore, it is necessary to understand their behavior before designing a control system that is able to auto-steer an off-road machine safely and efficiently. The objective of this work was to characterize the performance of an electrohydraulic valve with a hardware-in-the-loop electrohydraulic simulator. The operation of the valve was classified in four types (Ⅰ,Ⅱ,Ⅲ,and Ⅳ) according to the valve characteristic curves and the properties of the input signal. The phenomena of deadband, hysteresis, and saturation helped to discriminate between types. The input signal, especially its frequency, was crucial in studying the functioning of the valve. The simulator was fed with signals that imitated the auto-steering action. The outcomes obtained from this research provide some critically supporting information for designing high performance steering controllers for agricultural vehicles steered using an electrohydraulic steering system.
Flow curves valve characteristic curves control systems hardware in-the-loop simulator
F. Rovira-Más Q. Zhang A.C. Hansen
Polytechnic University of Valencia, Campus Camino de Vera, 46022, Valencia,Spain Department of Ag. and Bio. Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
国际会议
北戴河
英文
180-185
2007-06-06（万方平台首次上网日期，不代表论文的发表时间）