An electric power steering apparatus that driving-controls a motor via inverters based on a current command value, and applies an assist force by the motor to a steering system, includes multi-system driving systems with the inverters for respective system-windings of the motor which is a multi-system motor, wherein respective multi-system current command value characteristics against a steering torque are applied so as to be disproportionate for left and right steering, to the respective multi-system driving systems, and an assist-control is performed in response to the individual current command value characteristics.

The disclosure provides a steering system for a vehicle. The steering system may include a steering rack and an electronic power steering (EPS) system. The EPS system may include an actuator that assists movement of the steering rack, a torque sensor; an angle sensor; and an EPS system controller. The EPS controller may be configured to determine a steering rack center point indicating a center of the steering rack between opposite maximum steering angles. The EPS controller may be configured to determine a vehicle center zero point. The EPS controller may be configured to store the vehicle center zero point in response to determining that the vehicle center zero point is within a threshold of the steering rack center point.

A steered-angle command value calculation circuit calculates a steered-angle command value by adding a steering torque to a first assist component that is a sum of a basic assist control amount, a hysteresis control amount and a damping control amount. A steered-angle feedback control circuit calculates a second assist component by angle feedback control based on the steered-angle command value. A compensation control circuit generates the hysteresis control amount and the damping control amount based on a determination flag generated by a hand release determination circuit and indicating whether or not the steering state corresponds to a hand release state. The hand release determination circuit determines whether or not the steering state corresponds to the hand release state based on signs of a steering angle calculated by a steering-angle calculation circuit, a steering angular velocity that is a differential value of the steering angle, and a steering angle acceleration.

Provided are a steering control device and the like, including the steps of: calculating a steering assist torque to be applied to an actuator for applying the steering assist torque to a steering system of a vehicle in order to improve return characteristics of the steering system; determining a steering state of a driver; correcting the steering assist torque depending on a result of the steering state determination; and controlling the actuator depending on the corrected steering assist torque, in which the step of determining a steering state of a driver includes determining the steering state of the driver based on a combination of at least two of the following: a manually-operating steering state determination; an abrupt steering wheel return determination; a high-acceleration steering wheel return determination; a manual return steering determination; and an additional-steering determination.

A control device (50) for an electric power steering device (10) is configured to: store a basic target return speed (Vrb), which increases in magnitude as the magnitude of a steering angle (θ) increases; calculate, when a steering wheel (14) is being returned to a neutral position, the basic target return speed (Vrb) based on an actual steering angle (Step 10); calculate a transitional target return speed (Vtrt), which gradually increases in magnitude and gradually approaches the basic target return speed as the magnitude of the actual steering wheel decreases; and control, when the magnitude of a difference between the basic target return speed and the transitional target return speed is more than a reference value, a steering assist torque so that a return speed reaches the transitional target return speed (Step 20 to Step 160).

[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.

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.

An electric power steering apparatus is provided which can suppress the difference in steering feel between before and after it is allowed to compute an absolute steering angle and which can improve the steering feel. A basic assist control unit sets a basic assist current value. An assist gain setting unit sets assist gain. The assist gain is fixed to a lower limit value less than one before it is allowed to compute the absolute steering angle, and is gradually increased from the lower limit value to one and is then fixed to one after it is allowed to compute the absolute steering angle. An assist gain multiplication unit corrects the basic assist current value by multiplying the basic assist current value by the assist gain.

A steering device for a motor vehicle is described, the steering device comprising a steering element for steering the motor vehicle, and an actuating element by means of which wheels of the motor vehicle are adjusted as a function of an actuation of the steering element. The steering element has a steering assist unit associated with it, in particular an electronic steering assist unit for active return of the steering element, the steering assist unit comprising a motor and an open- and closed-loop control unit which drives the motor for generating an assist torque. The open- and closed-loop control unit receives data from a first sensor which directly senses the position of the actuating element, and drives the motor as a function of the position of the actuating element. Further described is a method of controlling a steering device.

A steer-by-wire steering system for a vehicle is disclosed, comprising a steering wheel unit, connected with a wheel unit. The steering wheel unit has a steering wheel angle sensor, a steering wheel actuator for setting a steering wheel target torque, and a steering wheel controller for actuating the steering wheel actuator. The wheel unit has a steering sensor for capturing at least one actual steering value, a wheel actuator for setting a target steering value, and a wheel controller. The wheel controller is designed to calculate a virtual torsion rod torque based on the target steering value and the actual steering value, to actuate the wheel actuator based on the calculated virtual torsion rod torque, and to transfer the calculated virtual torsion rod torque to the steering wheel unit. The steering wheel controller is designed to calculate the steering wheel target torque based on the transferred virtual torsion rod torque.