A Comprehensive Dynamic Model of Vehicle Steering System

This paper describes a comprehensive dynamic model of a vehicle steering system that calculates the angular displacements of cornering wheels when the driver applies steering torque to the steering wheel to counteract the steering resistance torque, which is a combination of tire-road friction torque and aligning torque. The modeling process was primarily based on CAD software, such as Solidworks, to create a 3D model of a specific vehicle steering system including alignment angles such as Kingpin-, Caster-, and Camber-angle. The 3D model was later converted into a 3D multibody dynamic model with corresponding links and joints in MATLAB/Simscape environment. The tire-road friction torque considered the effects of the kingpin axis and the road friction coefficient. The aligning torque was induced by the lateral force given by the Magic Formula (Pacejka) tire model. This modeling method's effectiveness was demonstrated for a rack-and-pinion steering system. Self-alignment behavior, steering response, and vehicle maneuvers at various vertical loads and vehicle speeds were numerically obtained and analyzed. This method was revealed to significantly simplify the modeling process while producing realistic results for developing active steering systems and autonomous vehicles.