Output signals of a torque sensor include a first output signal used in an assist control and a second output signal used in controls other than the assist control. An adjusting device of an electric power steering device includes an input torque meter for measuring an input torque applied to the input shaft, an output torque meter for measuring an output torque output by the steering mechanism, and a sensor output corrector for correcting an output signal of the torque sensor. The sensor output corrector corrects the first output signal so that a relationship between the input torque measured by the input torque meter and the output torque measured by the output torque meter becomes an ideal characteristic set in advance, and corrects the second output signal so that an input torque detected by the torque sensor coincides with the input torque measured by the input torque meter.

A parking assist system parks a vehicle at a target parking position by automatically steering an EPS. The parking assist system includes a acquiring unit configured to acquire the position of the vehicle, a position determining unit configured to determine the target parking position, a generating unit configured to generate a path from the position of the vehicle to the target parking position, a detecting unit configured to detect the temperature of the EPS, and a assist unit configured to automatically steer the vehicle so as to move along the path generated by the generating unit. The generating unit generates a path in which a degree of stationary steering by which the vehicle is steered in a state where the vehicle stops is small when the temperature of the EPS is high, compared with when the temperature of the EPS is low.

[Problem] An object of the present invention is to provide an electric power steering apparatus that is capable of positively returning a steering wheel to a neutral point in such a running state as to return to a going straight state by calculating a return control current corresponding to a steering angle and a steering speed and compensating a current command value. [Means for solving the problem] An electric power steering apparatus comprising: a steering wheel return control section that calculates a return control current with a steering angle, a vehicle speed and a steering speed, and drives a motor with a compensated current command value left by the subtraction of the return control current from a current command value, wherein the steering wheel return section comprises a base-return control current calculating section that calculates a base-return control current, a target steering speed calculating section that calculates a target steering speed, a return control gain calculating section that calculates a deviation between the target steering speed and the steering speed, performs coding, and at a same time calculates a return control gain by using at least two control calculations among a P-control calculation, an I-control calculation and a D-control calculation, a limiter that limits a maximum value of the return control gain, and a correcting section that corrects the base-return control current with an output gain of the limiter and outputs the return control current.

[Problem] An object of the present invention is to provide an electric power steering apparatus that is capable of positively returning a steering wheel to a neutral point in such a running state as to return to a going straight state by calculating a return control current corresponding to a steering angle and a steering speed and compensating a current command value. [Means for solving the problem] An electric power steering apparatus comprising: a steering wheel return control section that calculates a return control current with a steering angle, a vehicle speed and a steering speed, and drives a motor with a compensated current command value left by the subtraction of the return control current from a current command value, wherein the steering wheel return section comprises a base-return control current calculating section that calculates a base-return control current, a target steering speed calculating section that calculates a target steering speed, a return control gain calculating section that calculates a deviation between the target steering speed and the steering speed, performs coding, and at a same time calculates a return control gain by using at least two control calculations among a P-control calculation, an I-control calculation and a D-control calculation, a limiter that limits a maximum value of the return control gain, and a correcting section that corrects the base-return control current with an output gain of the limiter and outputs the return control current.

A zero turn radius vehicle with a single steered wheel is described. The vehicle may include a pair of power transfer mechanisms driving a pair of wheels, an operator control mechanism for controlling the steering, speed and direction of the vehicle and a controller in communication with the operator control mechanism. A steerable wheel is located adjacent the front of the vehicle frame, on a first side of the vehicle frame and an electric actuator is connected to the controller for steering the front steerable wheel. A second, non-steerable front caster wheel is located on a second side of the vehicle frame. The controller controls the pair of power transfer mechanisms and the electric actuator based on operator input to the operator control mechanism.

A power-steering device includes a steering wheel and an assistance motor controlled by a controller which uses at least one closed-loop control law ensuring an adjustment of the steering wheel torque, the controller including at least one feedback arm which calculates a drift component by measuring or assessing an actual force parameter corresponding to the actual steering wheel torque, by next calculating a time drift value of the actual force parameter, and then multiplying the time drift value by a drift gain, wherein the controller uses three-dimensional cartography to adjust the drift gain according to a portion of the actual force parameter and the longitudinal velocity of the vehicle, according to a first domain, referred to as “parking domain”, which extends from a longitudinal vehicle velocity of zero to a predetermined longitudinal velocity threshold, and a second domain, referred to as “driving domain”, which extends beyond the longitudinal velocity threshold.

An electromechanical power steering system for a motor vehicle may include a driving worm that is driven by an electric motor and acts on a worm gear that is coupled to a steering shaft. The driving worm may be mounted in such a way that it can rotate about its worm axis. More particularly, the driving worm may be mounted in a bearing that is held in a mount. The mount may prestress the driving worm in a direction of the worm gear. In some examples, the mount is torsionally weak about a torsion axis that is positioned perpendicularly with respect to the worm axis.”

An electric power steering apparatus that enables implementation of a desired steering torque without being affected by a state of a road surface by controlling a steering torque so as to become a value corresponding a steering angle and a steering angular velocity. The apparatus includes a SAT compensation value calculating section that calculates a SAT compensation value based on a SAT value; and a steering reaction compensation value calculating section that calculates a steering reaction compensation value based on the SAT compensation value, a steering angle and a steering angular velocity, and corrects the current command value by the steering reaction compensation value. Further, an electric power steering apparatus controls a twist angle of a torsion bar so as to follow a value corresponding to a steered angle.

The steering control device includes: current command value 1 calculation unit 11 which determines current command value 1 based on a vehicle speed and a steering torque; current command value 2 calculation unit 14 which determines current command value 2 based on a filtered differential value of the steering torque; and current drive unit 10 which drives motor 5 so that the value of the motor current matches the sum of current command values 1 and 2. When a first crossover frequency represents the crossover frequency of control open loop characteristics in the steering control device as obtained when current command value 2 is determined using a differential value of the steering torque which has not been filtered, the notch frequency of the notch filter is set to be greater than the mechanical resonance frequency of the steering control device and smaller than the first crossover frequency.

A method for controlling an electric power steering apparatus, the electric power steering apparatus and a vehicle equipped with the same. The method includes detecting an upper-side angle of a torsion bar; detecting a lower-side angle; setting an angle target value of an opposite side by using one of the upper-side angle or the lower-side angle; detecting an actual angle of the opposite side; and performing an angle follow-up feedback control based on a deviation between the angle target value and the actual angle.