Abstract: An end determination unit determines that a steering apparatus is in an end touching state when an angle deviation, which is a difference between an actual turning angle and a target turning angle, exceeds a threshold. This angle deviation exceeds the threshold before a large axial force is generated in a steering shaft. Accordingly, is it possible to determine that the steering apparatus is in the end touching state more quickly.

Abstract: An electric power steering system includes a motor control device that controls, based on an assist command value, driving of a motor that gives an assist torque to a steering mechanism. The motor control device computes a first assist component based on a steering torque and a vehicle speed. A steered-angle command value is computed based on the steering torque and the first assist component, and a second assist component is computed by performing a feedback control that matches the steered angle with the steered-angle command value. The motor control device adds the second assist component to the first assist component so as to compute an assist command value. The motor control device includes a road information compensation portion that decreases an absolute value of the second assist component included in the assist command value when a skid is detected by a vehicle state detecting portion.

Abstract: A current command value computing section includes an integration control computing section. Based on an integration of the steering torque ?, the integration control computing section computes a steering torque integration control amount Iint*, which is a compensation component for increasing the assist force. The integration control computing section functions as a determining device that determines whether the vehicle is traveling forward in a straight line. When the determining device determines that the vehicle is traveling forward in a straight line, the integration control computing section outputs the steering torque integration control amount Iint* to an adder. The current command value computing section superimposes the steering torque integration control amount Iint* on a basic assist control amount Ias* computed by a basic assist control section, and outputs the obtained value, as a current command value Iq* corresponding to a target assist force, to an output section.

Abstract: A target pinion angle computation unit computes a target pinion angle on the basis of a basic assist component and a steering torque, and computes the target pinion angle so as to rapidly increase a steering reaction force when it is determined based on the target pinion angle that a rack shaft of a rack-and-pinion mechanism reaches a position near a limit of a movable range of the rack shaft. In an. EPS, a correction component for the basic assist component, which is necessary to increase the steering reaction force rapidly, is computed through execution of PID control for causing an actual pinion angle to coincide with the target pinion angle. Because the correction component is added to the basic assist component, the steering reaction force is increased rapidly when the rack shaft reaches the position near the limit of the movable range.

Abstract: When only one of sensor signals generated by the plural systems and output from a torque sensor is normal, a control variable restriction processing part performs an assist restricting process for setting an upper limit value and a lower limit value of a basic assist control variable in accordance with at least one of the lateral acceleration, the steering angle, the steering speed, or the yaw rate.

Abstract: An electric power steering system includes a motor control device that controls, based on an assist command value, driving of a motor that gives an assist torque to a steering mechanism. The motor control device computes a first assist component based on a steering torque and a vehicle speed. A steered-angle command value is computed based on the steering torque and the first assist component, and a second assist component is computed by performing a feedback control that matches the steered angle with the steered-angle command value. The motor control device adds the second assist component to the first assist component so as to compute an assist command value. The motor control device includes a road information compensation portion that decreases an absolute value of the second assist component included in the assist command value when a skid is detected by a vehicle state detecting portion.

Abstract: An assisting command value calculating unit calculates a first assisting factor on the basis of the value of a torque differential control volume added to a basic assist control volume based on a steering torque value, while increasing or decreasing, on the basis of an assisting gradient, the torque differential control volume based on a torque differential value. The pinion angle F/B control unit calculates a pinion angle command value, capable of being converted to a steering angle of the steering wheel, on the basis of the steering torque and the first assisting factor, and executes rotational angle feedback control. The assisting command value calculating unit calculates an assisting command value on the basis of the value of a second assisting factor, calculated by the pinion angle F/B control unit, added to the first assisting factor.

Abstract: An ECU controls the operation of an EPS actuator in order to periodically apply instantaneous motor torque to a steering system when assist continuation control is executed using a sensor signal (residual sensor signal) that is output by a sensor element in which an abnormality has not been detected, regardless of the application of an assist force. The ECU also detects an abnormality in the residual sensor signal based on whether the application of instantaneous motor torque is reflected in the residual sensor signal, which is the basis of the assist continuation control.

Abstract: An electric power steering system includes short-circuit determination means for determining whether a short-circuit between an energization failure phase and one of the two phases other than the energization failure phase has occurred while assist force is being generated using the two phases other than the energization failure phase as energization phases. When the short-circuit determination means determines that the short-circuit has occurred, generation of the assist force is stopped.

Abstract: A microcomputer is provided with an extracting section capable of extracting a specific frequency component from an input signal. The extracting section extracts, from a pinion angle corresponding to a signal indicating a state of the steering system, a frequency component corresponding to a vibration of a steering system caused by stress applied to steerable wheels. The extracting section outputs an effective value of the extracted frequency component as a power spectrum to a second computing section. In the case that the power spectrum output from the extracting section is equal to or more than a predetermined threshold value, the microcomputer enhances a torque inertia compensation control so as to suppress vibration of the steering system caused by the stress. In other words, the microcomputer increases a torque inertia compensation amount corresponding to a compensation component based on a steering torque differential value.

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: The rotational angle correction controller includes a second correction amount-computing part that computes a second correction amount ?2 for correcting the rotational angle ? such that the phase is shifted in the steering operation direction, and the rotational angle correction controller performs the rotational angle correction by adding the computed second correction amount ?2 to the rotational angle ?. Further, the rotational angle correction controller includes a stuck steering wheel determining part that detects the significant reduction in the follow-up performance of the motor with respect to the steering operation that occurs due to the existence of the deceleration section caused by execution of the above-described electric current restriction, that is, the occurrence of the stuck steering wheel. When the occurrence of the stuck steering wheel is detected, the second correction amount-computing part changes the second correction amount ?2 to a value (?2?) larger than the normal value.

Abstract: A current command value computing section includes an integration control computing section. Based on an integration of the steering torque ?, the integration control computing section computes a steering torque integration control amount Iint*, which is a compensation component for increasing the assist force. The integration control computing section functions as a determining device that determines whether the vehicle is traveling forward in a straight line. When the determining device determines that the vehicle is traveling forward in a straight line, the integration control computing section outputs the steering torque integration control amount Iint* to an adder. The current command value computing section superimposes the steering torque integration control amount Iint* on a basic assist control amount Ias* computed by a basic assist control section, and outputs the obtained value, as a current command value Iq* corresponding to a target assist force, to an output section.

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: The rotational angle correction controller includes a second correction amount-computing part that computes a second correction amount ?2 for correcting the rotational angle ? such that the phase is shifted in the steering operation direction, and the rotational angle correction controller performs the rotational angle correction by adding the computed second correction amount ?2 to the rotational angle ?. Further, the rotational angle correction controller includes a stuck steering wheel determining part that detects the significant reduction in the follow-up performance of the motor with respect to the steering operation that occurs due to the existence of the deceleration section caused by execution of the above-described electric current restriction, that is, the occurrence of the stuck steering wheel. When the occurrence of the stuck steering wheel is detected, the second correction amount-computing part changes the second correction amount ?2 to a value (?2?) larger than the normal value.

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: A microcomputer is provided with an extracting section capable of extracting a specific frequency component from an input signal. The extracting section extracts, from a pinion angle corresponding to a signal indicating a state of the steering system, a frequency component corresponding to a vibration of a steering system caused by stress applied to steerable wheels. The extracting section outputs an effective value of the extracted frequency component as a power spectrum to a second computing section. In the case that the power spectrum output from the extracting section is equal to or more than a predetermined threshold value, the microcomputer enhances a torque inertia compensation control so as to suppress vibration of the steering system caused by the stress. In other words, the microcomputer increases a torque inertia compensation amount corresponding to a compensation component based on a steering torque differential value.

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 variable gear ratio hydraulic power steering device 1 is provided with a variable ratio transmission mechanism 7 having a drive motor 70; a flow volume control valve 41 for controlling the discharge flow volume of an oil pump 10 which circulates operating fluid; and a steering angle sensor 310 for measuring a handle steering angle input to a steering handle 31. A valve controlling controller 50 is constructed to take thereinto a measured ACT angle which is the rotational angle of the drive motor 70 and to calculate a target ACT angle for the drive motor 70 based on the handle steering angle. Further, the valve controlling controller 50 controls the flow volume control valve 41 to make the discharge flow volume equal to or greater than a predetermined flow volume when the magnitude of a difference ACT angle which is the difference between the target ACT angle and the measured ACT angle is equal to or greater than a threshold value.

Abstract: In a neutral position detection error protecting apparatus, vehicle wheel velocities of right/left driven wheels are detected and a right/left wheel velocity difference is obtained. Then, when a right/left wheel velocity difference is less than a predetermined velocity a steering rotation angle is more than a predetermined value and a vehicle wheel velocity is more than a predetermined velocity in a predetermined period, it is determined that there is an abnormality in the vehicle wheel velocities.