Nsk Corporation

Tetsuya Kitazume

Shoya Maruyama

Takahiro Tsubaki

Keita Yoshida

Satoshi Shimokawabe

Toru Sakaguchi

Yoshiki Ninomiya

In a detection method for detecting an end position of a mechanism portion of a turning device, detection of a limit position of a steering angle in a direction of a torque value is started when the torque value of the mechanism portion loaded by at least one of a drive force from an actuator and steering torque to the mechanism portion exceeds a first threshold. The limit position continues to be detected by storing a peak value of the steering angle in the mechanism portion as the limit position while the torque value of the mechanism portion is between the first threshold and a second threshold. The stored limit position is regarded as the end position indicated by the torque value when the torque value of the mechanism portion exceeds the second threshold.

Detection device, detection method and program for detecting end position of turning device

Provided is a control device for an electric power steering device including a first control portion that derives a first command value based on a steering torque and a second control portion that derives a second command value based on a target command value for a driving support function, where the first control portion generates the first command value by extracting a command value corresponding to a vibration suppression component from a command value including the vibration suppression component derived from the steering torque, adjusting the derived command value according to an operating state of a function of the second control portion, and adding the extracted command value to the adjusted command value.

Control device for electric power steering device and control method for the same

A turning angle detecting device includes: a first storage unit configured to store a turning angle neutral point correction value being a difference between a median of the turning angles at respective limits in right and left steering and the turning angle in a straight traveling state; a second storage unit configured to store an initial position of a movable portion of an actuator of a wheel turning mechanism in the straight traveling state; a first turning angle calculating unit configured to calculate a first turning angle with respect to the median of the turning angles at the respective limits based on a detection value of a position of the movable portion; and a second turning angle calculating unit configured to calculate a second turning angle based on the detection value, the turning angle neutral point correction value, the initial position and the first turning angle.

Turning angle detecting device and electric power steering device

A control device includes a current command value calculation unit configured to calculate a first current command value causing an actuator to generate steering assist torque, a correction value calculation unit configured to, when an absolute value of steering angle is greater than or equal to a threshold value, calculate a correction value for suppressing increase in an absolute value of the steering angle by correcting the steering assist torque, a correction unit configured to calculate a second current command value obtained by correcting the first current command value by the correction value, and a driving unit configured to drive the actuator, based on the second current command value. The correction value calculation unit calculates the correction value, based on first torque, the first torque changing nonlinearly with respect to steering angular velocity.

Control device and electric power steering device

A turning control device includes a terminal position learning unit configured to learn a terminal position of the turning mechanism, based on a steered position of the turning mechanism detected by a position detection unit, a command value correction unit configured to, when a steered position detected by the position detecting unit is in a vicinity of a learned terminal position, correct a current command value for an actuator providing a turning mechanism with steering assist force, and a correction amount limiting unit configured to limit a correction amount of the current command value by the command value correction unit, based on a comparison result between the learned terminal position and a predetermined position and a comparison result between stroke length of the turning mechanism calculated from the learned terminal positions and a predetermined length.

Turning control device and turning device

A terminal position learning unit includes a first storage unit configured to store a steered position positioned farthest from a neutral position of a turning mechanism within a range of a steered position detected by a position detection unit when rotational force applied to the turning mechanism is less than or equal to a first predetermined value, a second storage unit configured to store a steered position positioned farthest from the neutral position within a range of a position to which a steered position detected by the position detection unit is shifted in a direction toward the neutral position by a second predetermined value, and a third storage unit configured to store, as a terminal position stored by the terminal position learning unit, one of the steered positions stored in the first storage unit and the second storage unit positioned farther from the neutral position than the other.

A hands-off detection device includes: a first steering angle acquisition unit configured to acquire a first steering angle of a steering wheel; a second steering angle acquisition unit configured to acquire a second steering angle of a steering mechanism connected to the steering wheel via a torsion bar; a steering angle estimation unit configured to obtain an estimation angle of the first steering angle in a state where the steering wheel is not being grasped on a basis of the second steering angle; and a grasping state determination unit configured to determine a grasping state of the steering wheel on a basis of the frequency component of a angle difference between the first steering angle and the estimation angle and a reference frequency component being the frequency component of the angle difference in the state where the steering wheel is not being grasped.

Hands-off detection device and steering device

An electric power steering device including: a control rotational displacement calculation unit configured to calculate a control rotational displacement when a steering angle of the steering system is in an angular range from a maximum allowable steering angle for the steering system to a predetermined threshold steering angle; a control steering angle shifting unit configured to calculate the control rotational displacement corrected by a correction amount based on one of the steering torque and rack axial force and a sign of one of the control rotational displacement and the steering angle as a shift control steering angle; and a feedforward control unit configured to output a second current command value based on the shift control steering angle and steering velocity. An assist control is controlled with a third current command value calculated by adding the second current command value to the first current command value.

Electric power steering device

A turning control device includes: a target steering angle calculation unit configured to calculate a target steering angle of a turning mechanism, based on a second steering angle of a steering mechanism; a steering angular displacement calculation unit configured to, when a third steering angle, the third steering angle being either a first steering angle of the turning mechanism or the second steering angle, is in a range from a maximum steering angle that the third steering angle can take to a first threshold steering angle, calculate a steering angular displacement of the third steering angle with the first threshold steering angle used as a reference; a steering angle correction value calculation unit configured to calculate a steering angle correction value according to at least the steering angular displacement; and a corrected target steering angle calculation unit configured to correct the target steering angle with the steering angle correction value.

Turning control device

A turning control device includes: a steering angular displacement calculation unit configured to, when a third steering angle that is either a first steering angle of a turning mechanism or a second steering angle of a steering mechanism, is in an angular range from a maximum angle to a threshold steering angle, calculate a steering angular displacement of the third steering angle with the threshold steering angle used as a reference; a steering angle correction value calculation unit configured to calculate a steering angle correction value according to at least the steering angular displacement; a steering angle correction value limiting unit configured to limit the steering angle correction value according to at least a steering state, the third steering angle, and angular velocity thereof; a corrected target steering angle calculation unit configured to correct the target steering angle of the turning mechanism with a limited steering angle correction value.

The present invention is the electric power steering apparatus that drives a motor based on the current command value and assist-controls a steering system by a driving-control of the motor, comprising: a handle-returning control section to calculate the target steering angle velocity for handle-returning based on the steering torque, the current command value, a vehicle speed, a steering angle, calculate the handle-returning control current based on a deviation between the steering angle velocity and the target steering angle velocity, and interpose a filter, which motion characteristic, in a calculation path of the target steering angle velocity, wherein the motor is driven by the corrected current command value by using the handle-returning control current.

Electric power steering apparatus

[Problem] An object of the present invention is to provide a high-performance electric power steering apparatus that can smoothly switch a steering control mode with a simple structure and does not make a driver uncomfortable when the driver steers a handle in an automatic steering control. [Means for Solving the Problem] The present invention is the electric power steering apparatus that has a function, which switches between a manual steering control which drives a motor by the first motor current command value calculated based on at least a steering torque and an automatic steering control which drives the motor by the second motor current command value calculated at a steering angle control section so that an actual steering angle follows-up a target steering angle, comprising: a target steering angle correcting section that performs a calculation process for the steering torque depending on a steering state and vehicle speed and outputs a target steering angle correction value, and a correction outputting section that corrects the target steering angle by using the target steering angle correction value and inputs a corrected correction target steering angle into the steering angle control section.

An electric power steering apparatus that drives a motor based a current command value and assist-controls a steering system by a driving-control of the motor. The apparatus includes a handle-returning control section that calculates a target steering angular velocity by using a steering angle, the vehicle speed, the steering torque and the current command value, calculates a handle-returning control current by using a limit-target steering angular velocity which is obtained by limiting the target steering angular velocity depending on steering angular velocity, and drives the motor by a compensated current command value which is obtained by adding the handle-returning control current to the current command value.

An electric power steering apparatus that includes a function to perform a handle-returning control being consistent with an intention of a driver by using, for a calculation of a target steering angular velocity, only a steering input due to the intention of the driver which is included in a steering torque and the assist current or only vehicle motion characteristics based on the steering input, in the handle-returning control which performs a PID-control depending on a deviation between the target steering angular velocity and a steering angular velocity.

[Problem] An object of the present invention is to provide an electric power steering apparatus that gradual-changes a steering angle control command value, an assist control command value and also a steering angle speed command value, suppresses an excessive accumulation of an integral value in a speed control by being provided a steering speed command value with a limiter, and does not give the driver an uncomfortable feeling. [Means for solving the problem] The present invention is the electric power steering apparatus that has a function to switch between an assist control mode and a steering angle control mode, wherein the steering angle control section comprises a position control section that inputs a target steering angle and an actual steering angle and outputs a first steering angle speed command value; a gradual-changing limiting section that limits an upper limiting value and a lower limiting value by gradual-changing a first steering angle speed command value corresponding to a steering angle control gradual-changing gain; a speed control section that processes a second steering angle speed command value, which is outputted from the gradual-changing limiting section, based on an actual steering angle speed and a steering angle control gradual-changing gain; and a first gradual-changing section that gradual-changes the first steering angle control command value, which is outputted from the speed control section, corresponding to a steering angle control gradual-changing gain and outputs a second steering angle control command value, further comprises a second gradual-changing section that gradual-changes a first assist control command value, which is outputted from an assist control section, with an assist control gradual-changing gain and outputs a second assist control command value, wherein a steering angle control section, and a motor current command value is generated based on the second steering angle control command value and the second assist control command value.

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Maebashi, Japan

Tetsuya Kitazume