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, steering system dynamics, and a variety of other factors including vehicle dynamics 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 steering system, an actual E/H steering actuator and control interface, and an independently controlled steering loader. This article describes the design 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 interface characteristics of E/H steering systems and evaluating real-time steering controller performance in a laboratory recreated environment for off-road vehicles with loading conditions representative of the field application. The HIL simulator provided an effective tool for E/H steering dynamics research, E/H steering system design and E/H steering controller development.