Patent ID: 6973991
Filing Date: 2005-12-13
Classification: B62D,G01L

Abstract:
1. An electric power steering apparatus for applying rotation force of a motor to a steering system including a steering member and steering wheels for performing a steering assist, the power steering apparatus comprising: an input shaft coupled to the steering member; an output shaft; a torsion bar coupling the input shaft to the output shaft; an input shaft rotation detection unit for outputting a signal in response to rotation of the input shaft; an output shaft rotation detection unit for outputting a signal in response to rotation of the output shaft; a computation unit for obtaining information concerning torque transmitted between the input and output shafts and angular displacement with respect to each of the input and output shafts on the basis of outputs of the input shaft rotation detection unit and the output shaft rotation detection unit; and a driving control unit for generating a steering assist force by driving the motor in response to the torque transmitted between the input and output shafts, wherein the driving control unit determines which of the input shaft and the output shaft is dynamically superior based on the obtained information and when the output shaft is dynamically superior to the input shaft, the driving control unit controls the motor to apply a torque that is smaller than the torque that is transmitted between the input and output shafts in a backward assist direction.