Stability Analysis of an Articulated Vehicle Steering System

A steering system for an articulated vehicle was analyzed to gain an improved understanding of the closed loop stability characteristics. The analysis was applied to an electrohydraulic system and is applicable to more general types of systems. Since the parameters of electrohydraulic valves are well known, a simulation model including the hydraulic system and the vehicle dynamics, was easily derived. Using the simulation, the oil mass resonance was determined to be the most critical parameter and was controlled by adding compensation in the steering system closed loop. The paper describes the steering system, simulation model, and stability criteria.