Abstract: In the vehicle power steering system, a first assist torque component is computed based on a steering torque and a vehicle speed. A target steered angle is computed based on the first assist torque component and the steering torque, and a second assist torque component is set based on the target steered angle and an actual steered angle. Then, the vehicle power steering system assists a steering operation by applying an assist torque Tas corresponding to the first assist torque component and the second assist torque component. Further, an ideal steered angle at which a vehicle is able to keep travelling in a lane is set based on image information on the lane captured by a camera, and a correction value is computed based on the deviation between the ideal steered angle and the actual steered angle. Then, the target steered angle is corrected by the correction value.

Abstract: In an electric power steering system, a vehicle reactive force model computes a correction spring reactive torque in such a manner that an elasticity component included in a steering reactive force is increased with an increase in a lateral acceleration. As the lateral acceleration increases, an increase in a basic drive torque is suppressed by a larger amount. By an amount by which the magnitude of the basic drive torque is suppressed, a target pinion angle computed by a target pinion angle computing unit decreases and a correction component for a basic assist component is decreased. A steering assist force is decreased, and a steering reactive force is increased with a decrease in the steering assist force. Thus, it is possible to obtain an appropriate steering reactive force based on the magnitude of the lateral acceleration.

Abstract: An EPS includes a first rack and pinion mechanism that converts rotation of a pinion shaft due to a steering operation, to reciprocating motion of a rack shaft; and a steering force assist device that applies a motor torque of a motor as an assist force by using a second rack and pinion mechanism; and an ECU that controls an operation of the steering force assist device. Rack teeth of the rack shaft constituting the first rack and pinion mechanism are formed so that a steering gear ratio is changed depending on a steering angle. The ECU computes a motor neutral point by subtracting a conversion value from a motor angle detection value. The conversion value is computed based on a steering angle detection value by referring to a conversion map that is set taking into account the steering gear ratio corresponding to the steering angle.

Abstract: A control device in an electric power steering device calculates a first assist component based on steering torque and a vehicle speed. The control device also calculates a compensation component associated with an reverse input and calculates a steered angle command value based on an addition value of the compensation component and basic drive torque that is an addition value of the steering torque and the first assist component, produces a second assist component by performing steered angle feedback control that causes the steered angle of a vehicle to follow the steered angle command value. The control device controls drive of a motor based on an assist command value that is an addition value of the first assist component and the second assist component.

Abstract: A controller of an electric power steering system includes: a basic assist component computing unit (60) that computes a first assist component (Ta1*) based on a steering torque (Th); a steered angle command value computing unit (61) that computes a steered angle command value (?t*) based on the sum of the steering torque (Th) and the first assist component (Ta1*); and a steered angle feedback controller (62) that computes a second assist component (Ta2*) through feedback control on an actual steered angle (?t). The controller further includes: a correction component computing unit (65) that computes a correction component (Tc*) based on a steering angle (?s); and an assist command value computing unit (50) that computes an assist command value (Ta*) by subtracting the correction component (Tc*) from the sum of the first assist component (Ta1*) and the second assist component (Ta2*).

Abstract: A zero point change model executes banked road correspondence control when a vehicle travels on a banked road. By this control, a target turning angle when the total torque is zero can be changed from a neutral turning angle to a lower side of an inclined road surface. Thus, a steering angle of a steering wheel according to a banked road can be realized even if the driver does not apply steering torque during traveling on a banked road. Accordingly, the driver can obtain a suitable steering feeling when traveling on a banked road while achieving the target turning angle according to the total torque.

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: In an engine of a direct-injection type, a split injection (a fuel injection in an intake stroke and a fuel injection in a compression stroke) is carried out. A compression-stroke injection amount is gradually decreased or increased when the split injection is carried out. Engine rotational speed, which varies by combustion of such injected fuel, is detected for respective fuel injection amounts, which are varied (decreased or increased) as above. Such a fuel injection amount, with which the engine rotational speed becomes maximum, is calculated and set as a basic injection amount for the compression-stroke injection. The fuel injection in the compression stroke is then controlled based on the basic injection amount.

Abstract: In the vehicle power steering system, a first assist torque component is computed based on a steering torque and a vehicle speed. A target steered angle is computed based on the first assist torque component and the steering torque, and a second assist torque component is set based on the target steered angle and an actual steered angle. Then, the vehicle power steering system assists a steering operation by applying an assist torque Tas corresponding to the first assist torque component and the second assist torque component. Further, an ideal steered angle at which a vehicle is able to keep travelling in a lane is set based on image information on the lane captured by a camera, and a correction value is computed based on the deviation between the ideal steered angle and the actual steered angle. Then, the target steered angle is corrected by the correction value.

Abstract: In an electric power steering system, a vehicle reactive force model computes a correction spring reactive torque in such a manner that an elasticity component included in a steering reactive force is increased with an increase in a lateral acceleration. As the lateral acceleration increases, an increase in a basic drive torque is suppressed by a larger amount. By an amount by which the magnitude of the basic drive torque is suppressed, a target pinion angle computed by a target pinion angle computing unit decreases and a correction component for a basic assist component is decreased. A steering assist force is decreased, and a steering reactive force is increased with a decrease in the steering assist force. Thus, it is possible to obtain an appropriate steering reactive force based on the magnitude of the lateral acceleration.

Abstract: A controller of an electric power steering system includes: a basic assist component computing unit (60) that computes a first assist component (Ta1*) based on a steering torque (Th); a steered angle command value computing unit (61) that computes a steered angle command value (?t*) based on the sum of the steering torque (Th) and the first assist component (Ta1*); and a steered angle feedback controller (62) that computes a second assist component (Ta2*) through feedback control on an actual steered angle (?t). The controller further includes: a correction component computing unit (65) that computes a correction component (Tc*) based on a steering angle (?s); and an assist command value computing unit (50) that computes an assist command value (Ta*) by subtracting the correction component (Tc*) from the sum of the first assist component (Ta1*) and the second assist component (Ta2*).

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: There is provided an electric power steering system that makes it possible to improve the driver's steering feel, and that includes a controller that controls driving of a motor. The controller computes a first assist component based on a steering torque. The controller computes a torque command value based on a basic drive torque that is the sum of the steering torque and the first assist component, and computes an assist compensation component through feedback control based on the torque command value. The controller computes a steered angle command value based on a value obtained by adding the assist compensation component to the basic drive torque, and computes a second assist component through feedback control based on the steered angle command value. The controller controls driving of the motor based on an assist command value that is the sum of the first assist component and the second assist component.

Abstract: An EPS includes a first rack and pinion mechanism that converts rotation of a pinion shaft due to a steering operation, to reciprocating motion of a rack shaft; and a steering force assist device that applies a motor torque of a motor as an assist force by using a second rack and pinion mechanism; and an ECU that controls an operation of the steering force assist device. Rack teeth of the rack shaft constituting the first rack and pinion mechanism are formed so that a steering gear ratio is changed depending on a steering angle. The ECU computes a motor neutral point by subtracting a conversion value from a motor angle detection value. The conversion value is computed based on a steering angle detection value by referring to a conversion map that is set taking into account the steering gear ratio corresponding to the steering angle.

Abstract: A zero point change model executes banked road correspondence control when a vehicle travels on a banked road. By this control, a target turning angle when the total torque is zero can be changed from a neutral turning angle to a lower side of an inclined road surface. Thus, a steering angle of a steering wheel according to a banked road can be realized even if the driver does not apply steering torque during traveling on a banked road. Accordingly, the driver can obtain a suitable steering feeling when traveling on a banked road while achieving the target turning angle according to the total torque.

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: 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.