Abstract: When an electrification failure occurs in any of the phase of a motor, a control device of an electric power steering device executes current control for generating, in each of two electrification phases other than a phase with the electrification failure, a phase current that changes in the form of a secant curve or a cosecant curve based on an asymptotic line, which is a predetermined rotational angle corresponding to the phase with the electrification failure, to thereby continuously output a motor control signal. The control device of the electric power steering device executes current restriction for restricting the phase current within a predetermined range. The control device of the electric power steering device further executes control for accelerating rotation of the motor during two phase drive, in order to prevent the occurrence of a stuck steering wheel during low-speed steering, which is caused as a result of the execution of the current restriction.

Abstract: An assist gradient Ra and also an F/B gain gradient Rp are inputted to an assist gradient compensation control unit. The F/B gradient Rp is added to the assist gradient Ra in an adder and the sum obtained is inputted into a switching control unit. The assist gradient Ra that has been inputted from a basic assist control unit is directly inputted together with the sum to the switching control unit. When a torque feedback control is executed, the switching control unit outputs the sum of the assist gradient Ra and F/B gain gradient Rp to a filter constant computation unit and an assist gradient gain computation unit.

Abstract: In an electric power steering apparatus which comprises a motor for generating steering assist force, it is judged whether or not the vehicle is in a state of straight forward motion. A mean reference steering angle is determined by dividing total of relative steering angles which are determined when the vehicle is judged to be in a state of straight forward motion by the number of judgments that the vehicle is in a state of straight forward motion. A steering angle is determined by subtracting a steering angle midpoint from a relative steering angle with taking the mean reference steering angle as the steering angle midpoint. The output of the motor for generating steering assist force is corrected in accordance with an output correction value determined on the basis of the determined steering angle. This output correction value is altered so as to have a positive correlation with the number of judgments that the vehicle is in a state of straight forward motion.

Abstract: In an electric power steering apparatus, a steering torque is detected by a torque sensor, and a motor which generates steering assist power is controlled so that steering assist power is generated in accordance with basic assist torque which corresponds to the detected steering torque. The phase of the output signal of the torque sensor is caused to vary by a phase control element. The phase control characteristic of the phase control element is altered in accordance with the judgment results of a steering state judgment element as to whether the steering state is a return steering state or positive steering state, so that, in the frequency response characteristic of the output to input of the torque sensor, the gain at the higher frequency band where the frequency is greater than a set value is reduced in the return steering state in comparison to the positive steering state.

Abstract: The micro computer 17 continue an output of a motor control signal to execute a current control to carry to each of two phases a phase current changing like a secant curve or a cosecant curve at making a predetermined rotational angle according to the phase generated the current-carrying failure as an asymptote at the generation of the current-carrying failure. The micro computer 17 provides a rotational angle compensating section 40 compensating an input rotational angle ? to correct a phase offset between a phase current command value Ix* as a current command value and an actual phase current value Ix as an actual current value in the current control.

Abstract: An ECU determines whether the orientation of the vehicle is deflecting at the time of braking. In addition, in a case where it is determined that the orientation of the vehicle is deflecting, the ECU controls operation of an EPS actuator in order to reduce the assist force provided to the steering system.

Abstract: A steering wheel return compensation component is calculated based on an integrated value obtained by integrating a basic control amount in such a manner that the basic control amount has a property to rotate a steering wheel with a specific steering angle by a greater amount to its neutral position as the absolute value of the steering angle becomes greater. Alternatively, a steering wheel return compensation component is calculated in such a manner that the steering wheel return compensation component has a property to rotate the steering wheel by a greater amount to the neutral position as the absolute value of an integrated value obtained by integrating the steering angle becomes greater.

Abstract: The controller in an electric power steering apparatus stores the relationship between the steering torque and the basic assist torque in which the relationship is stored as assist characteristic, and stores the relationship between the steering angle correspondence value corresponding to the steering angle of the vehicle and the motor output correction value in which the relationship is stored as correction characteristic. The controller corrects the output of the motor, which is required in order to generate the basic assist torque, in accordance with the motor output correction value determined from the steering angle correspondence value and correction characteristic, in which the basic assist torque is determined from the steering torque and assist characteristic.

Abstract: In an electric power steering apparatus, steering torque of a steering wheel is detected by a torque sensor, and a motor 10 for generating steering assist power is controlled so that the steering assist power is generated according to a basic assist torque corresponding to the detected steering torque. A correspondence relationship between the steering torque and the basic assist torque is set such that an assist gradient that is a rate of change of the basic assist torque to the steering torque varies according to variation of the steering torque. A correction amount of an output of the motor 10 varies according to the variation of the assist gradient.

Abstract: An electric power steering apparatus according to the present invention comprises steering torque detecting section for detecting a steering torque applied to an operation member for steering a vehicle, steering state judging section for judging whether or not forward stroke steering for operation the operating member in a direction away from a steering angle midpoint is performed, motor controlling section for controlling the driving of an electric motor on the basis of the steering torque detected by the steering torque detecting section, and phase compensating sections provided in the motor controlling section for performing such phase compensation processing that a gain in a predetermined frequency band in frequency response characteristics is lower than gains in respective frequency bands lower and higher than the frequency band when the steering state judging section judges that the forward stroke steering is not performed.

Abstract: In an electric power steering apparatus, a phase control characteristic for a signal corresponding to detected steering torque is changed according to the judgment whether the steering is in a return steering state or a feed steering state, so that a response of a variation of target output value of a motor for generating steering assist power to a variation of the detected steering torque decreases in the return steering state in comparison with that in the feed steering state. An output control characteristic of the motor is changed according to the judgment synchronously with the change of the phase control characteristic, so that a response of a variation of the output command value to a variation of deviation between the target output value and actual output value decreases in the return steering state in comparison with that in the feed steering state.

Abstract: In an electric power steering apparatus, a steering torque is detected by a torque sensor, and a motor which generates steering assist power is controlled so that steering assist power is generated in accordance with basic assist torque which corresponds to the detected steering torque. The phase of the output signal of the torque sensor is caused to vary by a phase control element. The phase control characteristic of the phase control element is altered in accordance with the judgment results of a steering state judgment element as to whether the steering state is a return steering state or positive steering state, so that, in the frequency response characteristic of the output to input of the torque sensor, the gain at the higher frequency band where the frequency is greater than a set value is reduced in the return steering state in comparison to the positive steering state.

Abstract: The controller in an electric power steering apparatus stores the relationship between the steering torque and the basic assist torque in which the relationship is stored as assist characteristic, and stores the relationship between the steering angle correspondence value corresponding to the steering angle of the vehicle and the motor output correction value in which the relationship is stored as correction characteristic. The controller corrects the output of the motor, which is required in order to generate the basic assist torque, in accordance with the motor output correction value determined from the steering angle correspondence value and correction characteristic, in which the basic assist torque is determined from the steering torque and assist characteristic.

Abstract: In an electric power steering apparatus which comprises a motor (10) for generating steering assist force, it is judged whether or not the vehicle is in a state of straight forward motion. A mean reference steering angle is determined by dividing total of relative steering angles which are determined when the vehicle is judged to be in a state of straight forward motion by the frequency of judgments that the vehicle is in a state of straight forward motion. A steering angle is determined by subtracting a steering angle midpoint from a relative steering angle with taking the mean reference steering angle as the steering angle midpoint. The output of the motor (10) for generating steering assist force is corrected in accordance with an output correction value determined on the basis of the determined steering angle. This output correction value is altered so as to have a positive correlation with the frequency of judgments that the vehicle is in a state of straight forward motion.

Abstract: The present invention provides an electric power steering device enabled to compensate for the influence of the inertia of a steering-assisting-force generating motor on steering with accurate timing even when a steering direction is reversed at high speed. Based on steering torque and a rotation angular speed of a steering-assisting-force generating motor, a steering angular acceleration correspondence value is obtained. The device has means for regulating a gain, which is multiplied to a change acceleration of the steering torque. The motor is controlled so that the steering assisting force is corrected according to a motor output correction value obtained on the basis of the relation between the motor output correction value and the steering angular acceleration correspondence value, which is preliminarily determined and stored in such a way as to compensate for the influence of the inertia on steering, and the obtained steering angular acceleration correspondence value.

Abstract: An electric power steering apparatus has a motor controlled so as to generate steering assist power according to the steering torque required to operate a steering wheel. As a result of correction of the output of the motor in accordance with a value correlating with the rotation angular velocity correspondence value of the steering wheel, in the frequency response characteristic represented by the steering frequency of the steering wheel and the amplitude ratio of the steering torque relative to the steering angle of the steering wheel, the amplitude ratio is set within a setting range, at least within the steering frequency range when a person operates the steering wheel.

Abstract: An electric power steering apparatus has a motor controlled so as to generate steering assist power according to the steering torque required to operate a steering wheel. As a result of correction of the output of the motor in accordance with a value correlating with the rotation angular velocity correspondence value of the steering wheel, in the frequency response characteristic represented by the steering frequency of the steering wheel and the amplitude ratio of the steering torque relative to the steering angle of the steering wheel, the amplitude ratio is set within a setting range, at least within the steering frequency range when a person operates the steering wheel.

Abstract: The present invention provides an electric power steering device enabled to compensate for the influence of the inertia of a steering-assisting-force generating motor on steering with accurate timing even when a steering direction is reversed at high speed. Based on steering torque and a rotation angular speed of a steering-assisting-force generating motor, a steering angular acceleration correspondence value is obtained. The device has means for regulating a gain, which is multiplied to a change acceleration of the steering torque. The motor is controlled so that the steering assisting force is corrected according to a motor output correction value obtained on the basis of the relation between the motor output correction value and the steering angular acceleration correspondence value, which is preliminarily determined and stored in such a way as to compensate for the influence of the inertia on steering, and the obtained steering angular acceleration correspondence value.