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: 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: A current increase-decrease amount (?I?*) computed by a command current increase-decrease amount computing unit is added to an immediately preceding value (I?*(n?1)) of a command current value (I?*) in an adder. The command current value (I?*) obtained by the adder is given to a high/low limit limiter. The high/low limit limiter limits the command current value (I?*), obtained by the adder, to a value between a low limit value (?min (?min?0)) and a high limit value (?max (?max>?min)). A high limit value setting unit obtains the high limit value (?max) corresponding to the vehicle speed detected by the vehicle speed sensor, from a vehicle speed-vs.-high limit value map set by a map creating/updating unit, and sets the obtained high limit value (?max) in the high/low limit limiter.

Abstract: An electric power steering apparatus includes a steering assist section that applies assist force to a steering system of a vehicle to assist operation of a steering wheel performed by a driver. The steering assist section is actuated by a motor. When there is an abnormality in a steering torque sensor, the supply of drive power to the motor is controlled such that a converted steering angle, which is obtained by converting the rotational angle of the motor, follows a target steering angle, which is computed based on the steering angle of the steering wheel by operation performed by the driver.

Abstract: An electric power steering (EPS) apparatus 1 includes a motor 12, an EPS actuator 10, a torque sensor 14, and an ECU 11. The EPS actuator 10 uses the motor 12 as a drive source to apply assist force to a steering system, thereby assisting a steering operation. The torque sensor 14 detects a steering torque ? of the steering system. The ECU 11 controls the operation of the EPS actuator 10. Based on the steering torque ? detected by the torque sensor 14, the ECU 11 computes a basic shift amount ?ts_b of the assist force applied to the steering system. The ECU 11 determines which one of returning, holding, and turning is the state of the steering operation. When the state of the steering operation is returning or holding, the ECU 11 executes compensation control for correcting the steering torque ?, which is used in the computation of the basic shift amount ?ts_b of the assist force, thereby increasing the assist force applied to the steering system.

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 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: A motor is driven by the ?-axis current of a ?? coordinate system that is an imaginary rotating coordinate system. A command current value preparation unit sets the ?-axis command current value based on the command steering torque and the detected steering torque. The command current value preparation unit includes a command current increase/decrease amount calculation unit and an addition unit. The command current increase/decrease amount calculation unit calculates the current increase/decrease amount for the command current value based on the sign of the command steering torque and the deviation of the detected steering torque from the command steering torque. The current increase/decrease amount calculated by the command current increase/decrease amount calculation unit is added to the immediately preceding value of the command current value by the addition unit. Thus, the command current value in the present calculation cycle is calculated.

Abstract: A motor control unit includes a detected steering torque correction unit that corrects the detected steering torque that is detected by a torque sensor and then subjected to a limitation process by a steering torque limiter. When the absolute value of the detected steering torque is equal to or smaller than a predetermined value, the detected steering torque correction unit corrects the detected steering torque to 0. When the absolute value of the detected steering torque is larger than the predetermined value, the detected steering torque correction unit outputs the detected steering torque without correction. A PI control unit calculates the addition angle based on the deviation of the control torque obtained through correction by the detected steering torque correction unit from the command steering torque.

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: 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 motor control signal output unit of an electric power steering system includes a feedback gain calculation unit (52), and a feedback control unit executes a feedback control with the use of a proportional gain (Kp) and an integral gain (Ki) that are calculated by the feedback gain calculation unit (52). The feedback gain calculation unit (52) sets the feedback gains to large values (Kp=P0, Ki=I0) when the absolute value of an assist gradient (?) is equal to or smaller than a predetermined value (?0) (|?|??0). On the other hand, when the absolute value of the assist gradient (?) exceeds the predetermined value (A) (|?|>?0), the feedback gain calculation unit (52) sets the feedback gains to small values (Kp=p1, Ki=I1:P1<P0, I1<I0).

Abstract: A steering torque shift control amount calculation unit (31) calculates the steering torque shift control amount (?ts) by multiplying the basic shift amount (?ts_b) used as the basic compensation component by the transition coefficient (Kss). Then, the steering torque shift control amount (?ts) is subjected to the low-pass filter process in an abrupt change prevention processing unit (32). An abrupt change prevention processing unit (40) is provided in the steering torque shift control amount calculation unit (31). The transition coefficient (Kss) is subjected to the low-pass filter process in the abrupt change prevention processing unit (40). The cutoff frequency of the low-pass filter that forms the abrupt change prevention processing unit (40) is set to a value lower than the cutoff frequency of the low-pass filter that forms the abrupt change prevention processing unit (32) that executes the low-pass filter process on the torque shift control amount (?ts).

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: A motor control unit controls a motor including a rotor and a stator facing the rotor. A current drive unit drives the motor at an axis current value of a rotating coordinate system that rotates in accordance with a control angle that is a rotational angle used in a control. An addition angle calculation unit calculates an addition angle to be added to the control angle. A control angle calculation unit obtains, at every predetermined calculation cycle, a present value of the control angle by adding the addition angle that is calculated by the addition angle calculation unit to an immediately preceding value of the control angle. A torque detection unit detects a torque that is other than a motor torque and that is applied to a drive target driven by the motor. A command torque setting unit sets a command torque to be applied to the drive target.

Abstract: An electric power steering apparatus including a steering torque detecting section configured to detect a steering torque applied to an operation member for steering a vehicle, a steering state judging section configured to determine whether forward stroke steering that steers the operating member away from a steering angle midpoint is performed, a motor controlling section configured to control the driving of an electric motor based on the steering torque detected by the steering torque detecting section, and a phase compensating section provided in the motor controlling section for performing phase compensation, such that, when the forward stroke steering is not performed according to the steering state judging section, a gain in a predetermined frequency band in frequency response characteristics of the phase compensation is lower than gains in frequency bands lower and higher than the predetermined frequency band, and is lower than a gain in the predetermined frequency band when the forward stroke steerin

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: An inventive load apparatus for performance evaluation of a steering system has a simple construction and yet is capable of faithfully reproducing a tire load observed when the steering system is actually mounted on a motor vehicle. A compression load spring device (12) includes a piston (18) which is axially movable within a cylinder (17), and a pair of springs (20, 21) which resiliently urge the piston (18) to hold the piston (18) in a force balanced state at a neutral position in the cylinder. The piston (18) is connected to a rod (19) having one end (19a) serving as a load output portion. A load outputted from the load output portion (19a) is multiplied by a preset factor by means of a lever mechanism (13), and the resulting load is applied to the steering system (30).

Abstract: An electric power steering (EPS) apparatus 1 includes a motor 12, an EPS actuator 10, a torque sensor 14, and an ECU 11. The EPS actuator 10 uses the motor 12 as a drive source to apply assist force to a steering system, thereby assisting a steering operation. The torque sensor 14 detects a steering torque ? of the steering system. The ECU 11 controls the operation of the EPS actuator 10. Based on the steering torque ? detected by the torque sensor 14, the ECU 11 computes a basic shift amount ?ts_b of the assist force applied to the steering system. The ECU 11 determines which one of returning, holding, and turning is the state of the steering operation. When the state of the steering operation is returning or holding, the ECU 11 executes compensation control for correcting the steering torque ?, which is used in the computation of the basic shift amount ?ts_b of the assist force, thereby increasing the assist force applied to the steering system.

Abstract: An electric power steering apparatus includes a steering assist section that applies assist force to a steering system of a vehicle to assist operation of a steering wheel performed by a driver. The steering assist section is actuated by a motor. When there is an abnormality in a steering torque sensor, the supply of drive power to the motor is controlled such that a converted steering angle, which is obtained by converting the rotational angle of the motor, follows a target steering angle, which is computed based on the steering angle of the steering wheel by operation performed by the driver.