Hardware-in-the-loop simulator of an off-road vehicle electrohydraulic steering system

The design of electrohydraulic (E/H) steering control systems for off-road vehicles should consider the characteristics of physical components, steeri ng system dynamics, and a variety of other factors including vehicle dynami cs and soil stiffness. A computer-controlled hardware-in-the-loop (HIL) E/H steering simulator has been developed as a tool for steering dynamics and controller research. The HIL simulator integrated a dynamic model of the st eering system, an actual E/H steering actuator and control interface, and a n independently controlled steering loader This article describes the desig n of the HIL, simulator, the development of dynamic model of a tractor E/H steering system, and the validation of this system. Results indicated that the HIL simulator was a valuable tool for investigating the dynamics and in terface characteristics of E/H steering systems and evaluating real-time st eering controller performance in a laboratory recreated environment for off -road vehicles with loading conditions representative of the field applicat ion. The HIL simulator provided an effective tool for E/H steering dynamics research, E/H steering system design and E/H steering controller developme nt.