46results about How to "Good steering feel" patented technology

The invention provides a safe electric power-steering device that produces a good steering feel, has the ability to disengage steering-wander suppression or steering-pull suppression, and produces an increased driver-burden reduction effect during steering wander or steering pull. [Solution] A motor-current correction-value computation unit that uses a motor-current correction value based on a motor correction signal to correct a current command value comprises the following: a straight-line-movement determination unit (110, 120) that determines whether a vehicle is moving in a straight line; an adaptive calculation unit that calculates the aforementioned motor correction signal (SG4) in accordance with the result of the straight-line-movement determination, a steering angle (theta), and an applied force (SAT estimate), at least, and outputs said motor correction signal (SG4); a vehicle-speed-sensitive gain unit (133) that outputs a vehicle-speed gain (Ga) that depends on the speed (V) of the vehicle; and an output calculation unit (105, 106) that multiples the motor correction signal (SG4) by the vehicle-speed gain (Ga) and outputs a motor-current correction value (Imc). The motor-current correction-value computation unit also has the ability to set thresholds for the motor correction signal and steering information and disengage steering-wander suppression or steering-pull suppression depending on the result of a condition determination performed on said motor correction signal and steering information and said thresholds.

In an electric power steering system, multiple cutouts (45) are formed in a flange portion (36) formed on an axial end portion (23a) of a ball screw nut (23) of a ball screw device that drives a rack shaft. In addition, a motor shaft (6) has a thin-plate portion (44) that extends on the radially outer side of the ball screw nut (23). When the thin-plate portion (44) that extends from the motor shaft (6) is swaged into the cutouts (45) that serve as engagement recesses that have side walls in the circumferential direction, the rotation of the ball screw nut (23) relative to the motor shaft (6) is restricted.

A steering torque shift control amount calculation unit (31) calculates the steering torque shift control amount (εts) by multiplying the basic shift amount (εts_b) used as the basic compensation component by the transition coefficient (Kss). Then, the steering torque shift control amount (εts) is subjected to the low-pass filter process in an abrupt change prevention processing unit (32). An abrupt change prevention processing unit (40) is provided in the steering torque shift control amount calculation unit (31). The transition coefficient (Kss) is subjected to the low-pass filter process in the abrupt change prevention processing unit (40). The cutoff frequency of the low-pass filter that forms the abrupt change prevention processing unit (40) is set to a value lower than the cutoff frequency of the low-pass filter that forms the abrupt change prevention processing unit (32) that executes the low-pass filter process on the torque shift control amount (εts).