Electro Hydraulic Hitch Control

This paper present and discusses R&D results on electro hydraulic hitch control for off-road vehicle, in particular active damping of oscillation occuring on tractors. The research deals with analysis and control of the oscillations occuring on tractors which are design without any susspection system for agricultural applications and driving for transportation. During tranport phases, the lack of suspension causes the vehicle to bounce and pitch, and makes it difficalt to control. Many systems have been proposed to cope with the oscillatory behavior, and different solutions exist. Common for most of the systems are that they operate on the hydrailc actuators generally providing the motive forces for moving the implement and/or attachment, typically a plough. The basic idea and physical working principle are to use the implement, moveable relative to the vehicle, as a damper mass. The paper includes results on the phenomenon mention above on investigation with special focus on agricultucal tractors. For this purpose a mathematical model and its simulation model descibing the performance of the tractor with its mechanical linkages, and an attached implement. The model is in use as the basis for a parameter research study with emphasis on the requirements to the hitch control by use of hydraulic pressure compensated proportional control valve.