A Comprehensive Study of Vibration Suppression and Optimization of an Electric Power Steering System

Electric power steering (EPS) systems have become the most advantageous steering system used in vehicles. They provide better fuel efficiency and a more compact design over traditional hydraulic power steering (HPS) systems. However, EPS systems are afflicted with unwanted noise and vibration that can undermine the safety of drivers. This article presents a mathematical framework for vibration analysis in a column-type EPS system. The steering column is modeled as a continuous clamped column. The equations of motion are derived using Hamilton’s principle, and explicit expressions are presented for the frequency and transmissibility equations. A three-degrees-of-freedom (3-DOF) dynamic model is also presented by an approximation of the stiffness, damping, and mass of the steering column. The results of the proposed analytical models are validated using ANSYS simulation. Parametric studies are conducted to investigate the effect of key design variables on the natural frequency and vibration response of the steering system. An H ₂ optimization method is presented to determine the minimal vibration of the steering wheel, and the results are compared with different order Padé approximations. An optimized Dynamic Vibration Absorber (DVA) and Dynamic Vibration Absorber Inerter (DVAI) are mounted to the steering box to examine the effect of DVA and DVAI systems on vibration mitigation of the steering wheel without increasing the overall weight of the system.