Development of Compensation Logic for EPS in Limit Cornering Condition

This paper proposes steering compensation logic of Electric Power Steering (EPS) system in limit cornering condition. Steering wheel torque is decided by relationships between internal forces and external forces. The internal forces are steering frictions and assist force. The external forces are transferred from tire forces through kingpin axis and steering system. Kingpin moments are analyzed by using vector analysis and tire model. Relations of these forces are defined and used to explain steering disturbance by comparing simulation results and measurement data. Using these relationships, the proposed compensation logic is designed. This logic is verified by simulation models and validated in proto type vehicle.