Evaluation and Experimental Validation of Steering Efforts Considering Tire Static Friction Torque and Suspension and Steering Systems Characteristics

Predicting steering efforts at parking speed condition is critical to achieve ergonomically efficient steering system. The most important factor in calculating steering effort is the static friction torque of tires, which are affected by tire loads, kingpin axis geometry such as camber, caster and kingpin offset. In this research a multi-body approach to calculate steering effort and rack-bar force as a function of tire contact patch friction torque is proposed. For validation, the computed rack-bar force and steering effort are compared to the measured values obtained through actual vehicle test, and they showed good correlation.