Research of methods on resonant frequency measurement and estimation of vehicle steering system

Presently, requirements for reducing noise, vibration and harshness (NVH) in automobiles are more stringent than ever One form of NVH is the vibration of steering systems which occurs sometimes at high speeds or when the engine is idling, and the other is that of the assistant torque by electric power steering and hydraulic power steering. Effective ways to reduce steering vibration are to reduce the vibration forces and, as far as possible, to keep the resonant frequency of the steering system away from the resonant frequency of the vehicle body and the frequencies of the aforementioned vibration forces. Therefore, accurately assessing the resonant frequency of steering systems is critical. This paper explains a method for achieving this with steering systems mounted in actual vehicles.