JP6412475B2 - Vehicle steering system - Google Patents

Description

  The present invention relates to a vehicle steering apparatus including an electric motor that applies an auxiliary torque to a vehicle steering system.

2. Description of the Related Art A vehicle such as an automobile is equipped with a vehicle steering device including an electric motor that applies an auxiliary torque to a vehicle steering system.
For example, Patent Document 1 discloses an electric power steering system in which a steering torque of a steering system is detected by a steering torque sensor, auxiliary torque corresponding to the detection signal is generated by an electric motor, and the generated auxiliary torque is applied to the steering system. A vehicle steering device is disclosed in which a steering angle ratio, which is a ratio of a steering angle of a steered wheel to a steering angle of a steering wheel, is variable according to the vehicle speed.
According to the vehicle steering apparatus according to Patent Document 1, the assisting torque application motor assists the driver's steering intention while making the steering angle ratio variable according to the vehicle speed. Sex can be secured.

Japanese Patent Laid-Open No. 10-250607

As in Patent Document 1, in a vehicle steering apparatus having a steering angle ratio variable function, in general, for example, at a low vehicle speed such as parking, the steering angle ratio is largely changed as compared with a medium and high vehicle speed. Yes.
However, the conventional steering apparatus for a vehicle having a variable steering angle ratio function including Patent Document 1 focuses on the reduction of the steering force by generating the auxiliary torque, and has not been able to reduce the steering amount sufficiently. .

  The present invention has been made in view of the above circumstances, and provides a vehicle steering apparatus that can ensure the comfort of the steering feeling given to the driver by reducing the steering force and the steering amount of the driver. Is an issue.

  In order to solve the above-described problems, a vehicle steering apparatus (1) according to the present invention includes a steering torque detector that detects a steering torque generated in a steering system including a steering member of a vehicle, and an auxiliary torque for the steering system. An electric motor to be applied, an integration processing unit that performs an integration process of the steering torque, a target rudder angular velocity is calculated based on an integral value of the steering torque obtained by the integration process, and a weighted target is calculated based on the target rudder angular speed The main feature is to include a target torque calculation unit that calculates torque and a control unit that performs drive control of the electric motor using a target current value corresponding to the weighted target torque.

In the vehicle steering apparatus (1) according to the present invention, when the driver quickly operates the steering member (abrupt operation in a short time), it is considered that a significant steering request has occurred, and the steering force on the driver And reduce the steering amount. The reduction of the steering force means realizing a required turning with a small steering force. Further, the reduction of the steering amount means realizing a large turning with a small amount of steering. Hereinafter, the quick operation of the steering member is referred to as “flick steering”.
Here, the problem is how to associate the magnitude of the driver's flick steering with the target current value applied to the electric motor.
The inventor first considered that the magnitude of the driver's flick steering and the level of the steering request level can be correlated with each other. Further, the present inventors have found that there is a correlation between the required level based on the driver's flick steering and the integrated value of the steering torque. Furthermore, as a result of finding out that the required level based on the flick steering of the driver and the rudder angular velocity have the same correlation as described above, and carrying out earnest research based on these findings, the present invention was finally completed.

In the vehicle steering apparatus (1) according to the present invention, the target rudder angular velocity is calculated based on the integral value of the steering torque, the weighted target torque is calculated based on the target rudder angular velocity, and the calculated target weight is calculated according to the calculated weighted target torque. The drive control of the motor is performed using the target current value. The weighted target torque is a target torque calculated based on the target rudder angular velocity with the aim of reducing the steering force and the steering amount in order to respond to the flick steering request from the driver (hereinafter the same).
According to the vehicle steering device (1) according to the present invention, it is possible to secure the comfort of the steering feeling given to the driver by reducing the steering force and the steering amount of the driver.

  The vehicle steering device (2) according to the present invention further includes a steering angle detection unit that detects a steering angle with respect to a middle point of the steering system in the vehicle steering device (1), and the control unit Performs control to reduce the target current value when the directivity direction related to the rudder angle and the directivity direction related to the target rudder angular velocity are different from the target current value when both directivity directions are the same. It is characterized by that.

  Here, the directivity direction related to the steering angle reflects the current steering position, while the directivity direction related to the target rudder angular velocity reflects the steering position intended by the driver. In short, when the directivity direction related to the steering angle is different from the directivity direction related to the target rudder angular velocity, the current steering position and the steering position intended by the driver are in different directivity directions with reference to the midpoint. Means the case. Further, the case where the two directivity directions are the same means that the current steering position and the steering position intended by the driver are in the same directivity direction with reference to the midpoint.

  In the vehicle steering device (2) according to the present invention, the target current value when the directivity direction related to the steering angle and the directivity direction related to the target steering angular speed are different from the target current value when both directivity directions are the same. Therefore, the target current value when the current steering position and the steering position intended by the driver are in different directivity directions with respect to the midpoint is set to the current steering position and the steering intended by the driver. The position acts to decrease compared to the target current value when the position is in the same directivity direction with the midpoint as a reference.

  According to the vehicle steering device (2) of the present invention, the driving force of the motor when the current steering position and the steering position intended by the driver are in different directivity directions with respect to the midpoint is When the steering angle greatly fluctuates across the middle point, the steering position intended by the driver and the steering position intended by the driver are reduced compared to the driving force of the motor when the middle point is in the same directional direction. In addition, the situation where the behavior of the vehicle is disturbed can be suppressed.

  Further, in the vehicle steering device (3) according to the present invention, in the vehicle steering device (2), the control unit determines the degree of decrease in the target current value when the two directivity directions are different. Control is performed to increase as the middle point is approached.

  In the vehicle steering apparatus (3) according to the present invention, the control unit performs control to increase the decrease degree of the target current value when the two directivity directions are different as the steering angle approaches the middle point. The driving force of the motor when the steering position and the steering position intended by the driver are in different directivity directions with respect to the midpoint can be gradually decreased as the steering angle approaches the midpoint.

  According to the vehicle steering device (3) according to the present invention, when the current steering position and the steering position intended by the driver are in different directivity directions with respect to the midpoint, the motor is driven near the midpoint. Since the vehicle is decelerated (including a temporary stop), a situation in which the behavior of the vehicle is disturbed when the steering angle fluctuates greatly across the middle point can be accurately suppressed.

A vehicle steering apparatus (4) according to the present invention includes a steering torque detector that detects a steering torque generated in a steering system including a steering member of the vehicle, an electric motor that applies an auxiliary torque to the steering system, A standard target torque is calculated based on an integration processing unit that performs steering torque integration processing and a detected value of the steering torque, and a target steering angular velocity is calculated based on an integrated value of the steering torque obtained by the integration processing. And at least one of a target torque calculation unit that calculates a weighted target torque based on the target rudder angular velocity, a standard target current value corresponding to the standard target torque, and a weighted target current value corresponding to the weighted target torque And a control unit that performs drive control of the electric motor using one of them.
The standard target torque is a target torque that is set as a standard based on the steering torque in order to respond to a normal steering request (excluding a flick steering request) by the driver (hereinafter the same).

  According to the vehicle steering device (4) of the present invention, the standard target torque is calculated based on the detected value of the steering torque, while the target rudder angular velocity is calculated based on the integral value of the steering torque, and the target rudder is calculated. A weighted target torque is calculated based on the angular velocity, and drive control of the motor is performed using at least one of a standard target current value corresponding to the standard target torque and a weighted target current value corresponding to the weighted target torque. Therefore, similarly to the vehicle steering device (1), it is possible to secure the comfort of the steering feeling given to the driver by reducing the steering force and the steering amount of the driver.

  Moreover, the vehicle steering device (5) according to the present invention further includes a vehicle speed detection unit that detects a vehicle speed in the vehicle steering device (4), and the control unit includes the vehicle speed and the standard target current value. And setting a target current value used when performing drive control of the motor based on at least one of the weighted target current values, and controlling the drive of the motor using the set target current value. It is characterized by performing.

  According to the vehicle steering device (5) of the present invention, the control unit performs the drive control of the electric motor based on the vehicle speed and at least one of the standard target current value and the weighted target current value. In addition to setting the target current value to be used and performing drive control of the motor using the set target current value, the target current value is set appropriately according to the vehicle speed (the steering force and the steering amount for the driver can be reduced). The drive control of the electric motor can be performed using the target current value.

  The vehicle steering device (6) according to the present invention further includes a reverse position detection unit that detects whether or not the select lever of the vehicle is in the reverse position in the vehicle steering device (4). The unit controls driving of the electric motor using the weighted target current value when it is detected that the select lever is in the retracted position.

  According to the vehicle steering apparatus (6) of the present invention, the control unit performs drive control of the electric motor using the weighted target current value when it is detected that the select lever is in the reverse position. It is possible to perform drive control of the motor using a weighted target current value (which can reduce the steering force and the steering amount for the driver) that is appropriate when the vehicle is moving backward.

  Further, the vehicle steering apparatus (7) according to the present invention further includes a selection unit used when the vehicle steering apparatus (4) selects either the standard target current value or the weighted target current value. The control unit performs drive control of the electric motor using a target current value selected by the selection unit.

  According to the vehicle steering device (7) according to the present invention, the control unit performs drive control of the electric motor using the target current value selected by the selection unit from the standard target current value or the weighted target current value. Therefore, the drive control of the electric motor can be performed using the target current value selected by the selection unit (for example, the steering force and the steering amount of the driver can be reduced).

  ADVANTAGE OF THE INVENTION According to this invention, the comfort of the steering feeling given to a driver | operator can be ensured by reducing the steering force and steering amount in a driver | operator.

It is a figure showing typically the whole structure of the steering device for vehicles concerning the embodiment of the present invention. It is a block diagram which represents partially the internal structure of an EPS control apparatus. It is a block diagram showing the internal structure of a 1st target torque calculation part. It is a block diagram showing the internal structure of a 2nd target torque calculation part. It is a block diagram showing the internal structure of a 3rd target torque calculation part. It is a figure with which it uses for description which concerns on the control mode switching operation | movement of an EPS control apparatus.

Hereinafter, a vehicle steering apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.
In addition, in the figure shown below, the common referential mark shall be attached | subjected between the members which have a common function, or between the members which have a mutually corresponding function. Further, for convenience of explanation, the size and shape of the member may be schematically represented by being deformed or exaggerated.

[Configuration of Vehicle Steering Device 11 According to Embodiment of the Present Invention]
A configuration of a vehicle steering apparatus 11 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram schematically illustrating the overall configuration of a vehicle steering apparatus 11 according to an embodiment of the present invention.

  As shown in FIG. 1, the vehicle steering device 11 includes a handle (steering wheel) 13, a steering assist device 15, and a steering device 17.

  A handle (corresponding to a “steering member” of the present invention) 13 is a member that is operated when the driver tries to change the traveling direction of a vehicle (not shown) to a desired direction. One end of a steering shaft 19 is connected to the center of the handle 13. The steering shaft 19 is rotatably supported with respect to the upper casing 21 via bearings 23a, 23b, and 23c provided on the lower, intermediate, and upper portions of the upper casing 21, respectively.

  A magnetostrictive steering torque sensor (corresponding to the “steering torque detector” of the present invention) 25 is provided inside the housing 21 so as to surround the torsion bar portion 20 of the steering shaft 19. The torsion bar unit 20 constitutes a part of the steering torque sensor 25. The steering shaft 19 is provided with a magnetostrictive film (not shown) made of, for example, Ni—Fe plating so as to cover the entire circumference in the circumferential direction of the torsion bar portion 20. The steering torque sensor 25 determines the magnitude of the steering torque (steering torque detection value TRQ) input to the torsion bar portion 20 of the steering shaft 19 via the handle 13, for example, solenoid type first and second coils 25a, 25b. To detect the steering shaft 19 in a non-contact manner.

  The steering torque TRQ detected by the steering torque sensor 25 is, for example, an electric power steering control device (hereinafter referred to as “EPS control device”), which will be described later, via a communication medium 24 such as CAN (Controller Area Network). 51. The steering torque TRQ has, for example, a positive value for the steering torque TRQ acting in the left turning direction of the handle 13, and a negative value for the steering torque TRQ acting in the right turning direction of the handle 13.

Further, the steering shaft 19 is provided with a steering angle sensor 26 (corresponding to the “steering angle detection unit” of the present invention) that detects the steering angle of the handle 13. As shown in FIG. 1, the steering angle sensor 26 is provided on the side of the steered wheels 41 a and 41 b described later than the torsion bar portion 20 that constitutes a part of the steering torque sensor 25.
The steering angle STR detected by the steering angle sensor 26 is supplied to the EPS control device 51 via the communication medium 24. The steering angle STR is, for example, a positive value for the steering angle STR in the left turning direction of the handle 13 and the steering angle in the right turning direction of the handle 13 with respect to the neutral position of the handle 13 (the midpoint of the steering system). STR takes a negative value.

  The steering assist device 15 has a function of providing an assisting force related to steering of the handle 13 by the driver. The steering assist device 15 is provided with a steering assist motor 27 that supplies an assisting force (steering reaction force) for reducing the steering force of the handle 13 by the driver (including adjustment of response), and an output shaft of the steering assisting motor 27. A worm wheel gear 31 that meshes with the provided worm gear 29 is included. The steering assist motor 27 corresponds to the “motor” of the present invention.

  The worm wheel gear 31 is provided on the other end of the steering shaft 19 opposite to the end on which the handle 13 is provided, with the steering shaft 19 as a rotation center. The worm wheel gear 31 serves to transmit the rotational force of the steering assist motor 27 to the steering wheel 13 via the steering shaft 19 and to the steered wheels 41a and 41b via the steering device 17.

  A pinion shaft 35 is connected to the other end of the steering shaft 19 via a pair of universal joints 33 in series. The pinion shaft 35 is rotatably supported with respect to the lower casing 37 via bearings 39a and 39b provided in the lower and intermediate portions of the lower casing 37, respectively.

  The steered device 17 has a function of transmitting the driver's steering force input via the handle 13 and the steering shaft 19 to the steered wheels 41a and 41b. The steering device 17 includes a pinion gear 43 provided on the pinion shaft 35, a rack shaft 47 having rack teeth 45 that mesh with the pinion gear 43 and reciprocating in the vehicle width direction, and both ends of the rack shaft 47. Tie rods 49a and 49b provided, and steered wheels 41a and 41b that are rotatably provided via the tie rods 49a and 49b, respectively.

[Configuration of EPS control device 51 and its peripheral parts]
Next, the configuration of the EPS control device 51 that controls the drive of the steering assist motor 27 and its peripheral portion will be described with reference to FIGS. 1, 2, 3A, and 3B. FIG. 2 is a block diagram partially showing an internal configuration of the EPS control device 51. FIG. 3A is a block diagram illustrating an internal configuration of the first target torque calculation unit 209A. FIG. 3B is a block diagram illustrating an internal configuration of the second target torque calculation unit 209B. FIG. 3C is a block diagram illustrating an internal configuration of the third target torque calculation unit 209C.

  The EPS control device 51 is connected to the communication medium 24 as shown in FIG. In the communication medium 24, in addition to the steering torque sensor 25 and the steering angle sensor 26, a vehicle speed sensor (corresponding to the “vehicle speed detection unit” of the present invention) 53 that detects the speed (vehicle speed V) of the host vehicle. A reverse position sensor (corresponding to the “reverse position detection unit” of the present invention) 55 for detecting whether or not a select lever (not shown) mounted on the host vehicle is in the reverse position, and a first target described later. Select switches (corresponding to the “selection unit” of the present invention) 57 used when selecting either the current value or the second target current value are respectively connected.

  The EPS control device 51 refers to various values such as the steering torque TRQ detected by the steering torque sensor 25, the steering angle STR detected by the steering angle sensor 26, and the vehicle speed V detected by the vehicle speed sensor 53. The steering steering device 11 has a function of controlling the steering assist force of the handle 13 that is exhibited. The EPS control device 51 includes a microcomputer that performs arithmetic processing and various peripheral circuits including a drive control circuit for the steering assist motor 27.

More specifically, the EPS control device (corresponding to the “control unit” of the present invention) 51 includes a dead zone processing unit 201, an integration processing unit 203, an adjustment gain calculation unit 207, and a target torque calculation unit 209. ing.
The target torque calculation unit 209 includes at least one of the first target torque calculation unit 209A and the second target torque calculation unit 209B, and a third target torque calculation unit 209C. The first to third target torque calculation units 209A, 209B, and 209C will be described later in detail.

  As shown in FIG. 2, the dead zone processing unit 201 is in a dead zone region (a region where the value of the steering torque TRQ becomes −CTRQ to + CTRQ with 0 being sandwiched) with respect to the steering torque TRQ detected by the steering torque sensor 25. The value of the steering torque TRQ to which it belongs is converted to “0” and output. In addition, the dead zone processing unit 201 outputs a value obtained by multiplying the steering torque TRQ deviating from the dead zone region by a predetermined proportional coefficient (a value that is appropriately set including 1).

  The integration processing unit 203 has a function of performing an integration process on the steering torque TRQ after the dead zone processing by the dead zone processing unit 201. More specifically, the integration processing unit 67 includes an adding unit 211, a holding unit 213, a limiting unit 215, a delay unit 219, and a multiplying unit 221.

  The addition unit 211 adds the steering torque TRQ after the dead zone processing by the dead zone processing unit 201 and the output value of the multiplication unit 221, and outputs the addition result to the holding unit 213. The holding unit 213 holds the output value of the adding unit 211 at a predetermined sampling period (set as appropriate), and outputs the held value to the limiter 215. The limiting unit 215 performs a limiting process of truncating a predetermined minimum value and maximum value among the output values of the holding unit 213, and outputs the output value after the limiting process to the target rudder angular velocity calculating unit 205 and the delay unit via the branch point 217. To 219.

The delay unit 219 outputs the value of the previous sampling period among the output values after the limit processing. The multiplication unit 221 multiplies the output value of the delay unit 219 and the adjustment gain (described later in detail) calculated by the adjustment gain calculation unit 207, and outputs the multiplication result to the addition unit 211.
The target rudder angular velocity calculation unit 205 calculates the target rudder angular velocity TSTRV by multiplying the output value after the restriction processing by the restriction unit 215 by a predetermined gain GTSTRV, and outputs the target rudder angular velocity TSTRV that is the calculation result. .
The target rudder angular velocity TSTRV takes, for example, a positive value for the rudder angular velocity directed in the left turning direction of the handle 13 and a negative value for the rudder angular velocity directed in the right turning direction of the handle 13.

  The adjustment gain calculation unit 207 is based on the steering angle STR related to the steering angle sensor 26, the steering torque TRQ related to the steering torque sensor 25, the target steering angular velocity TSTRV calculated by the target steering angular velocity calculation unit 205, and the like. The adjustment gain for adjusting the steering torque integral value is calculated, and the calculated adjustment gain (real value belonging to the range of 0 to 1) is output to the multiplier 221.

  More specifically, the adjustment gain calculation unit 207 includes an absolute value processing unit 231, a steering angle ratio calculation unit 233, and a gain allocation unit 235.

  The absolute value processing unit 231 performs absolute value processing on the steering angle STR and outputs the steering angle STR after the absolute value processing to the steering angle ratio calculation unit 233.

  The rudder angle ratio calculation unit 233 converts the rudder angle STR after the absolute value processing into the rudder angle ratio SRTO based on a conversion table (preliminarily set as appropriate) of the rudder angle ratio SRTO with respect to the change in the rudder angle STR. The rear rudder angle ratio SRTO is output to the gain allocation unit 235. Here, the steering angle ratio SRTO refers to the steering torque integrated value of the integration processing unit 203 when the predetermined condition described below (the condition for assigning “1” as the adjustment gain of the gain assignment unit 235) is not satisfied. This is a correction coefficient (a real value belonging to a range of 0 to less than 1) for correcting in consideration of the size of STR.

  The gain allocation unit 235 includes a steering angle STR related to the steering angle sensor 26, a steering torque TRQ related to the steering torque sensor 25, a target steering angular velocity TSTRV calculated by the target steering angular velocity calculation unit 205, and a steering angle ratio calculation unit 233. Based on the calculated steering angle ratio SRTO, a predetermined adjustment gain for adjusting the steering torque integrated value of the integration processing unit 203 is assigned.

  More specifically, the gain allocation unit 235 has the same directivity direction (symbol) related to the steering angle STR and the directivity direction (symbol) related to the target steering angular speed TSTRV, or the steering torque TRQ When the absolute value | TRQ | exceeds the dead zone threshold value CTRQ (that is, the predetermined condition is satisfied), “1” is assigned as the adjustment gain.

The adjustment gain “1” calculated by the adjustment gain calculation unit 207 is sent to the multiplication unit 221, and the multiplication unit 221 multiplies the output value of the delay unit 219 (the value of the previous sampling cycle). . In this case, the multiplication result of the multiplication unit 221 is the output value of the delay unit 219 (the value of the previous sampling period).
As a result, the integration processing unit 203 adds (integrates) the steering torque TRQ at a certain sampling period and the steering torque TRQ at the previous sampling period, and then performs a value (steering) on which the limiting unit 215 performs the limiting process. Torque integral value) is output to the target rudder angular velocity calculation unit 205.

  Further, the gain allocating unit 235 has a different directivity direction (symbol) related to the steering angle STR and a directivity direction (symbol) related to the target steering angular speed TSTRV (different sign), and an absolute value of the steering torque TRQ | TRQ | Is equal to or less than the dead zone threshold CTRQ (that is, the predetermined condition is not satisfied), the adjustment gain is “steering angle ratio SRTO (a real value belonging to a range of 0 to less than 1 depending on the size of the steering angle STR)”. Assign.

The adjustment gain “steering angle ratio SRTO” calculated by the adjustment gain calculation unit 207 is sent to the multiplication unit 221, and the multiplication unit 221 outputs the output value of the delay unit 219 (the value of the previous sampling cycle). Is multiplied. In this case, the multiplication result of the multiplication unit 221 takes a value obtained by multiplying the output value of the delay unit 219 (the value of the previous sampling cycle) by the steering angle ratio SRTO.
As a result, the integration processing unit 203 calculates the steering torque TRQ in a certain sampling cycle and the steering torque TRQ in the previous sampling cycle (however, the value after being adjusted according to the magnitude of the steering angle STR). After the addition (integration), the value (steering torque integral value) subjected to the restriction process of the restriction unit 215 is output to the target rudder angular velocity calculation unit 205.

  The target rudder angular velocity TSTRV calculated by the target rudder angular velocity calculation unit 205 includes a first target torque calculation unit 209A (see FIG. 3A) that calculates a first target torque TT1OUT that is an FF (feed forward) target torque, and FB ( Feedback) At least one of the second target torque calculation units 209B (see FIG. 3B) that calculates the second target torque TT2OUT that is the target torque is converted into the target torque.

  As shown in FIG. 3A, the first target torque calculation unit 209A includes an absolute value processing unit 301, a first target torque conversion unit 303, a code acquisition unit 305, and a multiplication unit 307.

  The absolute value processing unit 301 performs absolute value processing on the target rudder angular velocity TSTRV, and outputs the target rudder angular velocity TSTRV after absolute value processing to the first target torque converting unit 303.

  The first target torque conversion unit 303 uses the conversion table (preliminarily set as appropriate) of the first target torque TT1OUT with respect to the change in the target rudder angular velocity TSTRV to set the target rudder angular velocity TSTRV after absolute value processing to the first target torque TT1OUT. And the converted first target torque TT1OUT is output to the multiplier 307.

  The code acquisition unit 305 acquires a code (plus or minus) related to the directivity direction of the target rudder angular velocity TSTRV, and outputs the acquired code to the multiplication unit 307.

  The multiplication unit 307 multiplies the first target torque TT1OUT converted by the first target torque conversion unit 303 by the sign of the target rudder angular velocity TSTRV acquired by the sign acquisition unit 305, and the multiplication result is used as the first target torque TT1OUT. Output as.

  On the other hand, the second target torque calculation unit 209B includes a subtraction unit 311, an amplification unit 313, and a limiting unit 315 as illustrated in FIG. 3B.

  The subtraction unit 311 subtracts the current steering angular velocity STRV from the target steering angular velocity TSTRV, and outputs the subtraction result (steering angular velocity deviation) to the amplification unit 313. The amplifying unit 313 performs processing for multiplying the steering angular velocity deviation obtained by the subtracting unit 311 by a predetermined gain PCON, and outputs the steering angular velocity deviation after the multiplication processing to the limiting unit 315. Limiting section 315 performs a limiting process of discarding predetermined minimum and maximum values from the output value of amplification section 313, and outputs the output value after the limiting process as second target torque TT2OUT.

The first and second target torque calculation units 209A and 209B are functional members used when calculating the weighted target torque based on the target steering angular speed TSTRV.
The weighted target torque is a target torque calculated based on the target steering angular speed TSTRV in order to reduce the steering force and the steering amount in order to respond to the flick steering request from the driver. The first target torque TT1OUT and the second target torque TT2OUT correspond to the “weighted target torque” of the present invention.
The target torque calculation unit 209 is at least one of the first target torque calculation unit 209A and the second target torque calculation unit 209B as a functional member used when calculating the weighted target torque based on the target steering angular speed TSTRV. As long as it has.

For example, when the configuration including only the first target torque calculation unit 209A is adopted as the configuration of the target torque calculation unit 209, the target torque calculation unit 209 may adopt the first target torque TT1OUT as the target torque.
When the configuration including only the second target torque calculation unit 209B is employed as the configuration of the target torque calculation unit 209, the target torque calculation unit 209 may employ the second target torque TT2OUT as the target torque.
Further, when the configuration including both the first target torque calculation unit 209A and the second target torque calculation unit 209B is adopted as the configuration of the target torque calculation unit 209, the target torque calculation unit 209 includes the first target torque TT1OUT and the second target torque calculation unit 209B. A value obtained by dividing the two target torques TT2OUT by an appropriate ratio may be adopted as the target torque.

  The target torque calculation unit 209 includes a third target torque calculation unit 209C as a functional member used when calculating the standard target torque based on the steering torque TRQ. The standard target torque is a target torque set as a standard based on the steering torque TRQ in order to respond to a normal steering request (excluding a flick steering request) by the driver. The third target torque TT3OUT corresponds to the “standard target torque” of the present invention.

  As shown in FIG. 3C, the third target torque calculation unit 209C includes an absolute value processing unit 321, a third target torque conversion unit 323, a code acquisition unit 325, and a multiplication unit 327.

  The absolute value processing unit 321 performs absolute value processing on the steering torque TRQ, and outputs the steering torque TRQ after the absolute value processing to the third target torque conversion unit 323.

  The third target torque conversion unit 323 converts the steering torque TRQ after the absolute value processing into the third target torque TT3OUT using a conversion table (preliminarily set as appropriate) of the third target torque TT3OUT with respect to the change in the steering torque TRQ. Then, the converted third target torque TT3OUT is output to the multiplier 327.

  The sign acquisition unit 325 acquires a sign (plus or minus) related to the directing direction of the steering torque TRQ, and outputs the obtained sign to the multiplication unit 327.

  The multiplying unit 327 multiplies the third target torque TT3OUT converted by the third target torque converting unit 323 by the sign of the steering torque TRQ acquired by the code acquiring unit 325, and the multiplication result is set as the third target torque TT3OUT. Output.

[Summary of Vehicle Steering Device 11]
The vehicle steering device 11 according to (1) includes a steering torque sensor (steering torque detector) 25 that detects a steering torque TRQ generated in a steering system including a steering wheel (steering member) 13 of the vehicle, and an auxiliary torque in the steering system. The steering assist motor (electric motor) 27 for applying the steering torque, the integration processing unit 203 for integrating the steering torque TRQ, the target steering angular velocity TSTRV based on the integrated value of the steering torque TRQ obtained by the integration processing, and the target A target torque calculation unit 209 that calculates a weighted target torque (first target torque TT1OUT and second target torque TT2OUT) based on the steering angular speed TSTRV, and a weighted target current value corresponding to the weighted target torque, is used for the steering assist motor 27. EPS control device (control part) 51 which performs drive control.

In the vehicle steering apparatus 11 according to (1), the target steering angular velocity TSTRV is calculated based on the integral value of the steering torque TRQ, the weighted target torque is calculated based on the target steering angular velocity TSTRV, and the calculated weighted target torque is calculated. The drive control of the steering assist motor 27 is performed using the corresponding target current value.
According to the vehicle steering apparatus 11 according to (1), it is possible to ensure the comfort of the steering feeling given to the driver by reducing the steering force and the steering amount of the driver.

  Further, the vehicle steering device 11 according to (2) is a steering angle sensor (steering angle detection unit) that detects the steering angle STR based on the midpoint of the steering system in the vehicle steering device 11 according to (1). 26, the EPS control device (control unit) 51 has a target current value when the directivity direction related to the steering angle STR and the directivity direction related to the target rudder angular velocity TSTRV are different from each other when the directivity directions are the same. Control to decrease compared with the target current value is performed.

  The directivity direction related to the steering angle STR reflects the current steering position, while the directivity direction related to the target steering angular speed TSTRV reflects the steering position intended by the driver. In short, when the directivity direction related to the steering angle STR and the directivity direction related to the target rudder angular velocity TSTRV are different, the current steering position and the steering position intended by the driver are different from each other with reference to the midpoint. Means the case exists. Further, the case where the two directivity directions are the same means that the current steering position and the steering position intended by the driver are in the same directivity direction with reference to the midpoint.

In the vehicle steering apparatus 11 according to (2), the target current value when the directivity direction related to the steering angle STR and the directivity direction related to the target steering angular speed TSTRV are different from the target current value when both directivity directions are the same. Since the current steering position and the steering position intended by the driver exist in different directivity directions with the midpoint as a reference, the target current value when the current steering position and the driver intend The steering position acts so as to be reduced compared to the target current value when the steering position is in the same directivity direction with the midpoint as a reference.
The operation of the vehicle steering device 11 according to (2) is realized mainly by the cooperation of the integration processing unit 203 and the adjustment gain calculation unit 207.

  According to the vehicle steering device 11 according to (2), the driving force of the steering assist motor 27 when the current steering position and the steering position intended by the driver are in different directivity directions with the midpoint as a reference. In order to reduce the current steering position and the steering position intended by the driver in comparison with the driving force of the steering assist motor 27 when the middle point is in the same direction, the steering angle across the middle point A situation in which the behavior of the vehicle is disturbed when the STR largely fluctuates can be suppressed.

  Further, in the vehicle steering device 11 according to (3), the EPS control device (control unit) 51 in the vehicle steering device 11 according to (2) is a degree of decrease in the target current value when the two directivity directions are different. Is increased as the rudder angle STR approaches the middle point.

In the vehicle steering device 11 according to (3), the EPS control device (control unit) 51 performs control to increase the degree of decrease in the target current value when the two directivity directions are different as the steering angle STR approaches the midpoint. Therefore, the driving force of the steering assist motor 27 when the current steering position and the steering position intended by the driver are in different directivity directions with the midpoint as a reference, as the steering angle STR approaches the midpoint. It can be gradually reduced.
The operation of the vehicle steering apparatus 11 according to (3) is realized mainly by the cooperation of the integration processing unit 203 and the adjustment gain calculation unit 207.

  According to the vehicle steering apparatus 11 according to (3), when the current steering position and the steering position intended by the driver are in different directivity directions with the midpoint as a reference, the steering assist motor near the midpoint Since the vehicle 27 is decelerated (including a temporary stop), a situation in which the behavior of the vehicle is disturbed when the steering angle STR fluctuates greatly across the middle point can be accurately suppressed.

  The vehicle steering apparatus 11 according to (4) includes a steering torque sensor (steering torque detector) 25 for detecting a steering torque TRQ generated in a steering system including a steering wheel (steering member) 13 of the vehicle, and a steering system. A steering assist motor (electric motor) 27 for applying an assist torque, an integration processing unit 203 for performing an integration process of the steering torque TRQ, and a standard target torque based on a detected value of the steering torque TRQ, are obtained by an integration process. A target torque calculation unit 209 that calculates a target steering angular velocity TSTRV based on an integral value of the steering torque TRQ and calculates a weighted target torque (first target torque TT1OUT and second target torque TT2OUT) based on the target steering angular velocity TSTRV; Of the standard target current value corresponding to the standard target torque and the weighted target current value corresponding to the weighted target torque. And it is used either provided with EPS control device (controller) 51 for controlling the driving of the steering assist motor 27.

  According to the vehicle steering apparatus 11 according to (4), while calculating the standard target torque based on the detected value of the steering torque TRQ, the target steering angular speed TSTRV is calculated based on the integrated value of the steering torque TRQ, and the target The weighted target torque is calculated based on the steering angular speed TSTRV, and the steering assist motor 27 is operated using at least one of the standard target current value corresponding to the standard target torque and the weighted target current value corresponding to the weighted target torque. Since the drive control is performed, similarly to the vehicle steering apparatus 11 according to (1), it is possible to ensure the comfort of the steering feeling given to the driver by reducing the steering force and the steering amount of the driver.

  The vehicle steering device 11 according to (5) further includes a vehicle speed sensor (vehicle speed detection unit) 53 for detecting the vehicle speed V in the vehicle steering device 11 according to (4), and an EPS control device (control unit). 51 sets and sets a target current value used when drive control of the steering assist motor 27 is performed based on the vehicle speed V and at least one of the standard target current value and the weighted target current value. The drive control of the steering assist motor 27 is performed using the target current value.

Here, the control mode of the steering assist motor 27 included in the EPS control device 51 will be described with reference to FIG. FIG. 4 is a diagram for explaining the control mode switching operation of the EPS control device 51.
As shown in FIG. 4, the EPS control device (control unit) 51 controls the steering assist motor 27 using a standard target current value corresponding to the steering torque TRQ as a control mode of the steering assist motor 27. Torque control and weighted target torque control for performing drive control of the steering assist motor 27 using a weighted target current value corresponding to the weighted target torque.

The standard target torque control (normal control) is a control mode suitable for responding to a steering request (excluding a flick steering request) during normal driving.
On the other hand, the weighted target torque control (flick control) is a control mode suitable for responding to frequent turn-back requests of the steering wheel 13 when traveling at a low speed or traveling backward as a traveling scene where a flick steering request occurs. .

Based on the characteristics of the control modes, in the vehicle steering device 11 according to (5), the EPS control device (control unit) 51 sets the vehicle speed V to a predetermined vehicle speed threshold value Vth (see FIG. 4: appropriately set in advance). When the vehicle speed is less than a low speed that can be changed as appropriate (for example, 10 km / h), the control mode is switched from the standard target torque control to the weighted target torque control (the weighted target current value is set as the target current value). Drive control of the steering assist motor 27 is performed using a weighted target current value suitable for the vehicle speed V.
Further, the EPS control device (control unit) 51 switches the control mode from the weighted target torque control to the standard target torque control when the vehicle speed V exceeds a predetermined vehicle speed threshold Vth (see FIG. 4) (as the target current value). By setting a standard target current value), drive control of the steering assist motor 27 is performed using a standard target current value suitable for the current vehicle speed V.
In addition, when switching the control mode, a configuration in which the magnitude of the target current value is gradually changed (increased or decreased) may be employed so as not to give the driver an uncomfortable feeling related to steering.

  According to the vehicle steering device 11 according to (5), the steering assist motor 27 is driven using a target current value that is appropriately set according to the vehicle speed V (which can reduce the steering force and the steering amount for the driver). Control can be performed.

  Note that the case where the vehicle speed V is less than the predetermined threshold Vth means that the period in which the vehicle speed V is less than the predetermined threshold Vth is a predetermined time (preliminary time) (in advance). It includes the case where the time length that can be changed as appropriate is exceeded. Similarly, the case where the vehicle speed V is equal to or higher than the predetermined threshold value Vth refers to a period when the vehicle speed V is equal to or higher than the predetermined threshold value Vth in addition to the case where the vehicle speed V simply exceeds the predetermined threshold value Vth. This includes the case where a predetermined time length that can be changed as appropriate is exceeded.

  Further, the vehicle steering device 11 according to (6) includes a reverse position sensor (reverse position detection unit) that detects whether or not the select lever of the vehicle is in the reverse position in the vehicle steering device 11 according to (4). 55 (see FIG. 1), and the EPS control device (control unit) 51 performs drive control of the steering assist motor 27 using the weighted target current value when it is detected that the select lever is in the retracted position. Do.

  According to the vehicle steering device 11 according to (6), the EPS control device (control unit) 51 uses the weighted target current value to detect the steering assist motor 27 when it is detected that the select lever is in the reverse position. Therefore, it is possible to perform the drive control of the steering assist motor 27 using a weighted target current value (which can reduce the steering force and the steering amount for the driver) suitable for the reverse of the vehicle.

  The vehicle steering device 11 according to (7) is a select switch (selection) used when the vehicle steering device 11 according to (4) selects either the standard target current value or the weighted target current value. Part) 57 (see FIG. 1), and the EPS control device (control part) 51 performs drive control of the steering assist motor 27 using the target current value selected by the select switch 57.

  According to the vehicle steering device 11 according to (7), the EPS control device (control unit) 51 uses the target current value selected by the select switch 57 among the standard target current value or the weighted target current value. In order to perform drive control of the steering assist motor 27, drive control of the steering assist motor 27 is performed using the target current value selected by the select switch 57 (for example, the steering force and the steering amount of the driver can be reduced). It can be carried out.

[Other Embodiments]
The embodiments described above show examples of realization of the present invention. Therefore, the technical scope of the present invention should not be limitedly interpreted by these. This is because the present invention can be implemented in various forms without departing from the gist or main features thereof.

  For example, in the description according to the embodiment of the present invention, the magnetostrictive (non-contact detection) steering torque sensor 25 has been described as an example of the “steering torque detection unit” according to the present invention. It is not limited. A contact detection type steering torque sensor 25 that detects steering torque by directly detecting torsion of the torsion bar unit 20 may be adopted as the “steering torque detection unit”.

  In the description of the embodiment of the present invention, the example in which the steering angle sensor 26 is provided on the steering shaft 19 has been described. However, the present invention is not limited to this example. A configuration in which rotational position information of the steering assist motor 27 (detected by a resolver built in the steering assist motor 27) is converted into a steering angle STR of the handle 13 may be employed.

  Further, in the description according to the embodiment of the present invention, the configuration in which the assist force of the steering assist motor 27 is applied to the steering shaft 19 is described as an example, but the present invention is not limited to this example. For example, a configuration in which the assist force of the steering assist motor 27 is applied to the pinion shaft 35 or a configuration in which the assist force of the steering assist motor 27 is applied to the rack shaft 47 may be employed.

  In the description according to the embodiment of the present invention, the example in which the vehicle steering device 11 is applied to the electric power steering device has been described. However, the present invention is not limited to this example. For example, a configuration in which the vehicle steering device 11 is applied to a steer-by-wire steering device may be employed. In this case, the wording “the electric motor that applies the assist torque to the steering system” described in the claims may be replaced with “the electric motor that applies the reaction torque to the steering system”.

11 Vehicle Steering Device 13 Handle (Steering Member)
25 Steering torque sensor (steering torque detector)
26 Rudder angle sensor (steering angle detector)
27 Steering assist motor (electric motor)
51 EPS control device (control unit)
55 Reverse position detector (reverse position sensor)
203 Integration processing unit 209 Target torque calculation unit

Claims (7)

A steering torque detector for detecting a steering torque generated in a steering system including a steering member of the vehicle;
An electric motor for applying auxiliary torque to the steering system;
An integration processing unit for integrating the steering torque;
A target torque calculation unit that calculates a target rudder angular velocity based on an integral value of the steering torque obtained by the integration process, and calculates a weighted target torque based on the target rudder angular velocity;
A control unit that performs drive control of the electric motor using a target current value corresponding to the weighted target torque;
A vehicle steering apparatus comprising: The vehicle steering apparatus according to claim 1,
A steering angle detection unit for detecting a steering angle based on a midpoint of the steering system;
The control unit decreases the target current value when the directivity direction related to the steering angle and the directivity direction related to the target rudder angular speed are different from the target current value when both directivity directions are the same. A vehicle steering apparatus characterized by performing control. The vehicle steering apparatus according to claim 2,
The control unit performs control to increase a decrease degree of the target current value when the two directivity directions are different as the steering angle approaches the midpoint. A steering torque detector for detecting a steering torque generated in a steering system including a steering member of the vehicle;
An electric motor for applying auxiliary torque to the steering system;
An integration processing unit for integrating the steering torque;
While calculating the standard target torque based on the detected value of the steering torque, the target steering angular speed is calculated based on the integrated value of the steering torque obtained by the integration process, and the weighted target torque is calculated based on the target steering angular speed. A target torque calculation unit for calculating
A control unit that performs drive control of the electric motor using at least one of a standard target current value corresponding to the standard target torque and a weighted target current value corresponding to the weighted target torque;
A vehicle steering apparatus comprising: The vehicle steering device according to claim 4,
A vehicle speed detector for detecting the vehicle speed;
The control unit sets a target current value used when performing drive control of the electric motor based on the vehicle speed and at least one of the standard target current value and the weighted target current value, and A vehicle steering apparatus, wherein drive control of the electric motor is performed using a set target current value. The vehicle steering device according to claim 4,
The vehicle further comprises a reverse position detector that detects whether or not the select lever of the vehicle is in the reverse position,
The vehicle steering apparatus according to claim 1, wherein the control unit performs drive control of the electric motor using the weighted target current value when it is detected that the select lever is in a reverse position. The vehicle steering device according to claim 4,
A selection unit used when selecting either the standard target current value or the weighted target current value;
The vehicle steering apparatus, wherein the control unit performs drive control of the electric motor using a target current value selected by the selection unit.

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