抄録
Recent passenger cars have been equipped with electric power steering (PS) for both energy conservation and safe cruise assistance such as lane maintenance and vehicle distance control. However heavy-duty commercial vehicles are still steered with hydro-mechanical PS because of their greater steering torque. It is necessary to develop high efficient electro-hydraulic control PS for hybrid commercial vehicles in order to conserve battery power. The authors present a new type of AC-servomotor drive pump control valveless PS and demonstrate improved efficiency in power consumption compared to current valve-control PS from 2.5kW to 340W at full slalom steering in 14s of a 4-ton payload vehicle. Following this study, steering feel, restoring performance and insensitivity against kickback torque are examined by using a passive type load simulator with maximum torque capacity of 1500Nm on the basis of the Fiala two-wheel tire model.
