JP4517902B2 - Steering control device - Google Patents

Steering control device Download PDF

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Publication number
JP4517902B2
JP4517902B2 JP2005075667A JP2005075667A JP4517902B2 JP 4517902 B2 JP4517902 B2 JP 4517902B2 JP 2005075667 A JP2005075667 A JP 2005075667A JP 2005075667 A JP2005075667 A JP 2005075667A JP 4517902 B2 JP4517902 B2 JP 4517902B2
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steering
control
torque
reaction force
value
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JP2006256453A (en
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範規 久保川
直孝 千野
孝彰 江口
拓 鈴木
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日産自動車株式会社
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  The present invention relates to a steer-by-wire system in which a steering unit having a steering wheel and a steering reaction force actuator, and a steering unit having a steered wheel and a steering actuator can be mechanically separated and connected via backup means. It belongs to the technical field of steering control devices.

In recent years, a so-called steer-by-wire (hereinafter abbreviated as “SBW”) system in which a mechanical connection between a steering wheel and a steered wheel is released and a part of a steering system is configured by an electrical path is mounted. A vehicle steering control device has been proposed. In this type of SBW system, for example, it is important to take a fail-safe measure against when an abnormality occurs in the steering reaction force actuator. Therefore, at the time of abnormality, system check, failure diagnosis, or turning to the vicinity of the maximum turning angle, control by the reaction force control unit is stopped and the steering member and the steered wheels are mechanically connected. The mechanical backup mechanism is activated, the steering control unit is switched to control for assisting steering, the steering actuator is controlled, and the function as a normal electric power steering (hereinafter abbreviated as “EPS”) device is achieved. The structure to implement | achieve is proposed (for example, refer patent document 1).
Japanese Patent Application Laid-Open No. 2004-090783

  However, in the conventional steering control device, after the transition from SBW control to EPS control, when a predetermined condition (end of system check, failure diagnosis, switch back from the vicinity of the maximum turning angle, etc.) is established Although EPS control is restored to SBW control, when the mechanical backup mechanism is disconnected, it takes time from the output of the separation command to the completion of separation, and the steering torque of SBW control is not instantaneously changed. There is a problem that the assist torque by the driver at the time of control is reduced when returning to SBW control, the steering torque is insufficient after separation is completed, and the steered wheel is not cut more than intended by the driver .

  The present invention has been made paying attention to the above-mentioned problem, and at the time of return from steering assist control to steer-by-wire control, the steered wheel unintended by the driver is suppressed by suppressing reduction in steering torque after completion of separation of the backup means. An object of the present invention is to provide a steering control device that can prevent a lack of cutting.

In order to achieve the above object, in the present invention,
A steering part having a steering wheel and a steering reaction force actuator and a steering part having a steered wheel and a steering actuator can be mechanically separated and connected via backup means,
Steer-by-wire control is performed by controlling the steering actuator that separates the backup means and sets the steering angle according to the steering state and the steering reaction force actuator that applies the steering reaction force according to the steering state. Steer-by-wire control means to perform,
Steering assist control means for connecting the backup means and performing steering assist control using at least one of the steering reaction force actuator and the steering actuator as an assist means;
Control switching means for returning to the steer-by-wire control by the steer-by-wire control means when a predetermined condition is satisfied during the steering assist control by the steering-assist control means;
In a steering control device with
The control switching means is a transition from steering assist control to steer-by-wire control, and during the period from the separation command to the backup means until the separation is completed, the reduction of the steering torque that acts on the steered wheels after the separation is completed. The amount of correction is used as a correction amount, and the turning torque in the steering assist control is increased and corrected.

  Therefore, in the steering control device of the present invention, the control switching means is operated when returning from the steering assist control to the steer-by-wire control, from the separation command to the backup means until the completion of separation, and after the separation is completed. The amount corresponding to the decrease in the turning torque acting on the facing wheel is used as a correction amount, and the turning torque in the steering assist control is corrected to increase. That is, the increase in the turning torque in the transition period of control transition from the separation command to the backup means to the completion of separation suppresses the decrease in the turning torque acting on the steered wheels after the separation is completed, and the operation at the time of the separation command is suppressed. The torque difference between the steering torque that acts on the steering wheel and the steering torque that acts on the steering wheel when separation is completed can be reduced. As a result, when returning from the steering assist control to the steer-by-wire control, it is possible to suppress a decrease in the steering torque after the completion of the separation of the backup means, and to prevent the steering wheel from being insufficiently cut not intended by the driver.

  Hereinafter, the best mode for carrying out a steering control device of the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall configuration diagram showing a steer-by-wire system (hereinafter referred to as “SBW system”) to which the steering control device of the first embodiment is applied, and FIG. 2 shows an example of a backup clutch in the steering control device of the first embodiment. FIG. 3 is a control block diagram showing the entire system of the steering control device of the first embodiment. The steering control device according to the first embodiment includes (1) a reaction force device (steering unit), (2) a backup device (backup means), (3) a steering device (steering unit), and (4) a control controller. ing. Hereinafter, each configuration will be described in detail.

(1) Reaction force device The reaction force device includes a steering angle sensor 1, 1, an encoder 2, torque sensors 3, 3 (steering torque detecting means), a Hall IC 4, and a reaction force motor 5 (steering reaction force actuator). And is configured.

  The steering angle sensors 1 and 1 are means for detecting an operation angle of the handle 6 and are provided on a column shaft 8 that couples a cable column 7 and a handle 6 to be described later. The two torque sensors are configured in a double system. That is, the rudder angle sensors 1 and 1 are installed between the handle 6 and the torque sensors 3 and 3 so that the steering angle can be detected without being affected by the angle change caused by the twist of the torque sensors 3 and 3. It has become. The rudder angle sensors 1 and 1 use an absolute resolver or the like.

  The torque sensors 3 and 3 are installed between the rudder angle sensor 1 and the reaction force motor 5, and are configured in a double system by two torque sensors of the torque sensor 1 and the torque sensor 2. . The torque sensors 3, 3 are connected to, for example, an axially extending torsion bar, one end of the torsion bar, a first shaft that is coaxial with the torsion bar, and the other end of the torsion bar, A second axis coaxial with the torsion bar and the first axis; a first magnetic body fixed to the first axis; a second magnetic body fixed to the second axis; the first magnetic body; The coil includes a coil facing the second magnetic body, and a third magnetic body that surrounds the coil and forms a magnetic circuit together with the first magnetic body and the second magnetic body. Then, the inductance of the coil changes corresponding to the relative displacement between the first magnetic body and the second magnetic body based on the twist acting on the torsion bar, and the torque is detected by the output signal based on the inductance.

  The reaction force motor 5 is a steering reaction force actuator that applies a reaction force to the handle 6. The reaction force motor 5 includes a 1-rotor 1-stator electric motor having the column shaft 8 as a rotation axis, and its casing is provided at an appropriate position of the vehicle body. It is fixed to. As this reaction force motor 5, a brushless motor is used, and an encoder 2 and a Hall IC 4 are added as the brushless motor is used. In that case, motor drive that generates motor torque is possible with only the Hall IC 4, but minute torque fluctuations occur and the feeling of steering reaction force is poor. Therefore, in order to perform more delicate and smooth reaction force control, the encoder 2 is mounted on the column shaft 8 and motor control is performed, so that minute torque fluctuations are reduced and the steering reaction force feeling is improved. To do. A resolver may be used instead of the encoder 2.

(2) The backup device that can mechanically separate and connect the backup device reaction force device (1) and the steering device (3) includes a cable column 7 and a backup clutch 9.

  While the cable column 7 is in the backup mode in which the backup clutch 9 is engaged, the torque of the cable column 7 is reduced while avoiding interference with a member interposed between the reaction device (1) and the steering device (3). It is a mechanical backup mechanism that demonstrates the function of a column shaft that transmits power. The cable column 7 winds two inner cables whose ends are fixed to the two reels in opposite directions, and fixes both ends of the outer tube in which the two inner cables are inserted into the two reel cases. It is constituted by.

  The backup clutch 9 is provided on the steered device (3) side, and an electromagnetic clutch is used in the first embodiment. FIG. 2 shows a schematic diagram of the backup clutch 9. The backup clutch 9 has both an electromagnetic clutch and a mechanical clutch. When the clutch is engaged, the initial sliding by turning on the electromagnet is applied to the friction plate, and the cam of the mechanical fastening portion is moved by the friction plate. Fastening with reasonable strength. When releasing the fastening, it can be released by turning off the electromagnet and moving the cam of the machine fastening part to either input or output. By fastening the backup clutch 9, both the torque from the reaction force device (1) and the torque from the steering device (3) can be transmitted via the cable column 7 and the backup clutch 9.

(3) Steering device The steering device includes encoders 10, 10, rudder angle sensors 11, 11, torque sensors 12, 12, Hall IC 13, steered motors 14, 14 (steering actuator), steering mechanism 15, steering It has a ring 16, 16.

  The steering angle sensors 11 and 11 and the torque sensors 12 and 12 are provided on an axis of a pinion shaft 17 in which the backup clutch 9 is attached to one end and a pinion gear is formed at the other end. As the rudder angle sensors 11 and 11, an absolute resolver or the like that forms a double system and detects the rotational speed of the shaft is used in the same manner as the rudder angle sensors 1 and 1. Further, as the torque sensors 12, 12, a sensor that forms a double system like the torque sensors 3, 3 and detects torque by a change in inductance is used. The steering angle sensors 11 and 11 are arranged on the downstream side via the pinion gear, and the torque sensors 12 and 12 are arranged on the upstream side, whereby the torque sensors 12 and 12 are detected when the steering angle sensors 11 and 11 detect the turning angle. It is made not to be affected by the angle change due to the twisting of the.

  The steering motors 14 and 14 are provided with pinion gears on the motor shaft that mesh with worm gears provided at intermediate positions between the backup clutch 9 and the torque sensors 12 and 12 on the pinion shaft 17, so that the pinion shaft 17 is driven when the motor is driven. It is comprised so that steering torque may be provided to. The steered motors 14 and 14 form a double system and are brushless motors that constitute the first steered motor 14 and the second steered motor 14. Similarly to the reaction force motor 5, the encoders 10 and 10 and the Hall IC 13 are added as the brushless motor is used.

  The steering mechanism 15 is a steering mechanism that steers the left and right steered wheels 16 and 16 by the rotation of the pinion shaft 17, and a rack gear that is inserted into the rack tube 15 a and meshes with the pinion gear of the pinion shaft 17. The formed rack shaft 15b, tie rods 15c and 15c coupled to both ends of the rack shaft 15b extending in the vehicle left-right direction, one end coupled to the tie rods 15c and 15c, and the other end of the steered wheels 16 and 16 And knuckle arms 15d and 15d coupled to each other.

(4) Control Controller The control controller has a dual system composed of two control controllers 19 and 19 that perform processing calculations and the like by the power supply 18.

  As shown in FIG. 3, the controller 19 includes a steering angle sensor 1, 1 of the reaction force device (1), an encoder 2, torque sensors 3, 3, a Hall IC 4 and an encoder 10, a steering device (3). 10, detection values from the steering angle sensors 11 and 11, the torque sensors 12 and 12, and the Hall IC 13 are input.

  The controller 19 includes a failure diagnosis unit 19a. In the failure diagnosis unit 19a, each failure diagnosis of steering control and reaction force control in steer-by-wire control (hereinafter referred to as “SBW control”) by clutch release is performed. Then, failure diagnosis in electric power steering control (hereinafter referred to as “EPS control”), which is assist torque control by clutch connection, and transition control from “SBW control” to “EPS control” at the time of failure diagnosis are diagnosed.

  In addition to the failure diagnosis unit 19a, the controller 19 includes a reaction force command value calculation unit 19b, a reaction force motor drive unit 19c, a reaction force device current sensor 19d, a turning command value calculation unit 19e, a turning motor drive unit 19f, Steering device current sensors 19g and 19g, and a controller diagnosis unit 19h are included. The two controllers 19 and 19 are connected to each other via a bidirectional communication line 20 so as to exchange information.

  The two controllers 19, 19 include a yaw rate / lateral G sensor 20 (vehicle behavior amount detecting means), a vehicle speed sensor 21 for detecting the vehicle speed, a reaction force motor temperature sensor 22 for detecting the temperature of the reaction force motor 5, and the like. Sensor information from is input.

  FIGS. 4 and 5 are a block diagram of the steering control during the “SBW control” by the control controllers 19 and 19 of the steering control device of the first embodiment, and a block diagram of the steering servo control during the “SBW control”. Rudder torque control). Hereinafter, based on FIG. 4 and FIG. 5, the steering control at the time of “SBW control” in the first embodiment and the steering torque correction control at the time of transition from “SBW control” to “EPS control” will be described.

  As shown in FIG. 4, the steering control during the “SBW control” includes a target steering angle θt obtained by multiplying the actual steering angle θh of the handle 6 by a gear ratio G set according to the vehicle speed and the like, and a steering motor. The deviation from the actual turning angle θp obtained from the rotation angle of 14 is converted into a turning torque, and a limiter process is performed to obtain a motor control command value. Then, as shown in FIG. 5, a command current is obtained from the motor control command value by the steering servo control by feedforward control + feedback control + robust compensation, and the steering motor 14 is driven.

Then, the turning torque correction control at the time of transition from “SBW control” to “EPS control” is turned ON during the clutch operation time (time from the engagement command to the completion of engagement) in the steering control block diagram of FIG. This is done by subtracting the turning torque correction value ΔT with the first switch SW1.
Here, the “steering torque correction value ΔT” is obtained by multiplying the steering torque correction reference value ΔTO by the steering angular velocity gain Gdθ, the axial force change gain GdF, and the vehicle behavior amount gain GdY (FIGS. 11 to 11). (See FIG. 14).

  6 and 7 are a reaction force control block diagram during "SBW control" by the control controllers 19 and 19 of the steering control device of the first embodiment, and a reaction force servo control block diagram during "SBW control" (steering during SBW control). Reaction force control). Hereinafter, based on FIGS. 6 and 7, the reaction force control at the time of “SBW control” in the first embodiment, the reaction force control at the time of transition from “SBW control” to “EPS control”, and from “EPS control” to “SBW” The reaction force control at the time of “control” return will be described.

  As shown in FIG. 6, the reaction force control during the “SBW control” includes a value obtained by multiplying the actual steering angle θh of the handle 6 by the gain Ka and a value obtained by multiplying the actual steering angular velocity dθh / dt by the gain Ks. In addition, a steering reaction force torque corresponding to the steered state of the steered wheels 16 and 16 is set, and a limiter process is performed to obtain a motor control command value. Then, as shown in FIG. 7, the reaction force servo control by feedforward control + feedback control + robust compensation is used to obtain a command current from the motor control command value, and the reaction force motor 5 is driven.

  Then, the reaction force control at the time of transition from “SBW control” to “EPS control” is performed at the time of “EPS control” by the first switch SW1 which is turned ON when the clutch is confirmed in the reaction force control block diagram of FIG. The reaction force torque value (zero or torque in the same direction as the steering torque direction) is used.

The reaction force control when returning from “EPS control” to “SBW control” is the second switch that is turned on during the clutch OFF operation time (time from the release command to the completion of release) in the reaction force control block diagram of FIG. This is done by adding the steering reaction torque correction value ΔT ′ at SW2.
Here, the “steering reaction force torque correction value ΔT ′” is obtained by multiplying the steering reaction force torque correction reference value ΔT1 by the steering angular velocity gain Gdθ, the axial force change gain GdF, and the vehicle behavior amount gain GdY ( 19 to 22).

  FIGS. 8 and 9 are a block diagram of turning control at the time of “EPS control” and a block diagram of turning servo control at the time of “EPS control” (assist at the time of EPS control) by the control controllers 19 and 19 of the steering control device of the first embodiment. Torque control). Hereinafter, based on FIG. 8 and FIG. 9, steering control at the time of “EPS control” and steering control at the time of returning from “EPS control” to “SBW control” in the first embodiment will be described.

  In the steering control at the time of “EPS control”, as shown in FIG. 8, the steering assist torque Ta is set by the steering torque Th and the gain map input to the handle 6, the limiter process is performed, and the motor control command value and To do. Then, as shown in FIG. 9, the steering motor 14 is driven by obtaining the command current from the motor control command value by the steering servo control by feedforward control + feedback control + robust compensation.

The steering control when returning from the “EPS control” to the “SBW control” is performed by the first switch SW1 that is turned on during the clutch OFF operation time (time from the release command to the completion of release) in the steering control block diagram of FIG. Thus, the steering torque correction value ΔT is added.
Here, the “steering reaction force torque correction value ΔT” is obtained by multiplying the steering reaction force torque correction reference value ΔT1 by the steering angular velocity gain Gdθ, the axial force change gain GdF, and the vehicle behavior amount gain GdY (FIG. 15 to 18).

  Next, the operation will be described.

[Switch control processing]
FIG. 10 is a flowchart showing the flow of the switching control process executed by the control controllers 19 and 19 according to the first embodiment. Each step will be described below. This process is executed at a predetermined control cycle (for example, 10 msec) (switching control means).

  In step S1, the control state of the steer-by-wire system is confirmed, and the process proceeds to step S2.

In step S2, following the system status check in step S1, it is determined whether or not the steer-by-wire system is abnormal. If the system is normal, the process proceeds to step S3, at which level “EPS control” can be maintained. When the system is abnormal, at the time of system check, at the time of failure diagnosis, at the time of turning to the maximum turning angle, etc., the process proceeds to step S5. When the system failure cannot maintain “EPS control”, the process proceeds to step S18. To do.
That is, in this step S2, the “SBW control” state is confirmed, and a determination for performing state transition is made. The determination is a determination for performing a system check and a determination for performing a fail diagnosis. Normally, the system operates as “SBW control” after the system is started, and the status transition to “EPS control” is necessary when the backup mechanism check is performed. Otherwise, in case of system failure during “SBW control”, transition from “SBW control” to “EPS control” as redundant system when avoiding sudden system down from “SBW control” to manual steer (control stop) You will need it.

  In step S3, following the determination that the system is normal in step S2, it is determined whether or not it is time to return from “EPS control” to “SBW control”. If YES, the process proceeds to step S13. If NO, Moves to step S4.

  In step S4, following the determination of “SBW control” by clutch OFF in step S3, normal “SBW control” by turning torque control and steering reaction force control is executed, and the process proceeds to step S20.

In step S5, following the determination that the predetermined conditions for shifting to EPS control in step S2 (system abnormality, system check, failure diagnosis, near the maximum turning angle, etc.) are satisfied, “SBW control” to “EPS It is determined whether or not the control shifts to “control”. If YES, the process proceeds to step S6. If NO, the process proceeds to step S12.
When the process proceeds to step S5, first, an engagement command is output to the backup clutch 9, and "SBW control" by the steering torque correction control by steps S6 to S10 and the steering reaction force control by step S11. Transition transition control from “EPS control” to “EPS control” is passed and “EPS control” is entered.

  In step S6, following the determination that the control shifts from “SBW control” to “EPS control” in step S5, steering torque, steering angular velocity, rack shaft, which are input information for turning torque correction, are provided. Force change, yaw rate, and lateral G are read, and the process proceeds to step S7.

In step S7, following the reading of input information for turning torque correction in step S6, a turning torque correction value ΔT is calculated, and the process proceeds to step S8.
Here, the steering torque correction value ΔT is obtained by multiplying the steering torque correction reference value ΔTO by the steering angular velocity gain Gdθ, the axial force change gain GdF, and the vehicle behavior amount gain GdY.
ΔT = ΔTO × Gdθ × GdF × GdY
It is calculated by the following formula. The calculation of each value will be described.

・ Turning torque correction reference value ΔTO (Fig. 11)
The turning torque correction reference value ΔTO of the turning torque correction value ΔT subtracted during the transitional transition period of the backup clutch 9 is obtained by comparing the steering torque Th with the turning torque correction value map shown in FIG. The steered torque correction value map is set as a characteristic that increases as the steering torque Th increases to the right or left side. That is, as the steering torque Th input by the driver via the handle 6 is larger, the turning torque correction reference value ΔTO is given a larger value.

-Rudder angular velocity gain Gdθ (Fig. 12)
As shown in FIG. 12, the steering angular velocity gain Gdθ for adjusting the steering torque correction reference value ΔTO is given as a value of 1 in the region where the steering angular velocity dθh / dt is equal to or smaller than the set value, and the steering angular velocity dθh / dt is set to the set value. If it exceeds, the smaller the steering angular velocity dθh / dt is, the smaller the value is given.

・ Axial force change gain GdF (Fig. 13)
As shown in FIG. 13, the axial force change gain GdF for adjusting the turning torque correction reference value ΔTO increases when the axial force direction of the rack axial force change dF / dt is in the + direction (increase). When the axial force direction of the rack axial force change dF / dt is in the negative direction (decrease), the value is greater than 1 as the value decreases.

-Vehicle behavior amount gain GdY (Fig. 14)
As shown in FIG. 14, the vehicle behavior amount gain GdY for adjusting the turning torque correction reference value ΔTO is given as a value of 1 when the yaw rate or the lateral G is equal to or less than the set value, and the yaw rate or the lateral G exceeds the set value. As the yaw rate or lateral G increases, a value greater than 1 is given.

In step S8, following the calculation of the turning torque correction value ΔT in step S7, the calculated turning torque correction value ΔT is output, and the process proceeds to step S9.
Here, the output of the turning torque correction value ΔT means to subtract the turning torque correction value ΔT from the turning torque command value in the “SBW control” as shown in FIG. The value ΔT can be rephrased as the “SBW control” turning torque decrease correction value.

  In step S9, following the output of the steering torque correction value ΔT in step S8, it is confirmed whether or not the backup clutch 9 is completely engaged. If YES, the process proceeds to step S10. If NO, step S8 is performed. Return to.

In step S10, following the complete engagement confirmation of the backup clutch 9 in step S9, the turning torque correction value ΔT is rewritten to zero, and the process proceeds to step S11.
Here, after the backup clutch 9 is completely engaged, the turning torque correction value ΔT is rewritten to zero, as shown in FIG. 8, the turning torque during “EPS control” using the turning motor 14 as assist means ( It means to shift to (steering assist torque).

In step S11, following the zero rewriting of the turning torque correction value ΔT in step S10, the reaction torque value at the time of “EPS control” is output, and the process proceeds to step S12.
Here, to output the reaction force torque value at the time of “EPS control”, as shown in FIG. 6, the steering reaction force torque is set to zero with the aim of shifting to “EPS control” after the backup clutch 9 is completely engaged. (Normal steering reaction force control stop) or applying torque in the steering assist direction opposite to the reaction force application direction (reaction force motor 5 and steered motor 14 are used as assist means). Say.

In step S12, following the reaction force torque value output during EPS control in step S11, the backup clutch 9 is engaged, and at least one of the reaction force motor 5 and the steering motor 14 is steering assist control. Execute “EPS control”.
In this EPS control, whether the steering assist torque Ta obtained by the control block shown in FIG. 8 is borne by only the steering motor 14, or is shared by the steering motor 14 and the reaction force motor 5, or When the steered motor 14 is in the failure mode, the burden is borne by only the reaction force motor 5.

  In step S13, following the determination that “EPS control” is returned to “SBW control” in step S3, the steering torque, which is input information for correcting the steering torque and the steering reaction torque, The steering angular velocity, rack axial force change, yaw rate, and lateral G are read, and the process proceeds to step S14. When the process proceeds from step S3 to step S13, an engagement / disengagement command for the backup clutch 9 is output in step S3.

In step S14, following the reading of input information for turning torque correction and steering reaction force torque correction in step S13, a turning torque correction value ΔT and a steering reaction force torque correction value ΔT ′ are calculated, and the process proceeds to step S15. Transition (steering torque correction unit, steering reaction force torque correction unit).
Here, the steering torque correction value ΔT is obtained by multiplying the steering torque correction reference value ΔTO by the steering angular velocity gain Gdθ, the axial force change gain GdF, and the vehicle behavior amount gain GdY.
ΔT = ΔTO × Gdθ × GdF × GdY
It is calculated by the following formula. The calculation of each value will be described.

・ Turning torque correction reference value ΔTO (Fig. 15)
The turning torque correction reference value ΔTO of the turning torque correction value ΔT that is added during the opening transition period of the backup clutch 9 is obtained by comparing the steering torque Th with the turning torque correction value map shown in FIG. The steered torque correction value map is set as a characteristic that increases as the steering torque Th increases to the right or left side. That is, as the steering torque Th input by the driver via the handle 6 is larger, the turning torque correction reference value ΔTO is given a larger value.

-Rudder angular velocity gain Gdθ (Fig. 16)
As shown in FIG. 16, the steering angular velocity gain Gdθ for adjusting the steering torque correction reference value ΔTO is given as a value of 1 in the region where the steering angular velocity dθh / dt is equal to or smaller than the set value, and the steering angular velocity dθh / dt is set to the set value. If it exceeds, the larger the steering angular velocity dθh / dt, the larger the value is given.

・ Axial force change gain GdF (Fig. 17)
As shown in FIG. 17, the axial force change gain GdF for adjusting the turning torque correction reference value ΔTO increases when the axial force direction of the rack axial force change dF / dt is in the + direction (increase). If the axial force direction of the rack axial force change dF / dt is in the negative direction (decrease), the value is smaller than 1 as the value decreases.

-Vehicle behavior amount gain GdY (Fig. 18)
As shown in FIG. 18, the vehicle behavior amount gain GdY for adjusting the turning torque correction reference value ΔTO is given as a value of 1 when the yaw rate or lateral G is equal to or less than the set value, and the yaw rate or lateral G exceeds the set value. As the yaw rate or lateral G increases, a value smaller than 1 is given.

The steering reaction force torque correction value ΔT ′ is obtained by multiplying the steering reaction force torque correction reference value ΔT1 by the steering angular velocity gain G1dθ, the axial force change gain G1dF, and the vehicle behavior amount gain G1dY.
ΔT '= ΔT1 × G1dθ × G1dF × G1dY
It is calculated by the following formula. The calculation of each value will be described.

Steering reaction force torque correction reference value ΔT1 (FIG. 19)
The steering reaction force torque correction reference value ΔT1 of the steering reaction force torque correction value ΔT ′ added during the release transition period of the backup clutch 9 is obtained by comparing the steering torque Th with the steering reaction force torque correction value map shown in FIG. Desired. This steering reaction force torque correction value map is set as a characteristic that increases as the steering torque Th increases to the right or left side. That is, the steering reaction force torque correction reference value ΔT1 is given a larger value as the steering torque Th input by the driver via the handle 6 is larger. Note that the steering reaction force correction value map of FIG. 19 may be the same as the steering torque correction value map of FIG.

-Rudder angular velocity gain G1dθ (Fig. 20)
As shown in FIG. 20, the steering angular velocity gain G1dθ for adjusting the steering reaction force torque correction reference value ΔT1 is given as a value of 1 in the region where the steering angular velocity dθh / dt is equal to or less than the set value, and the steering angular velocity dθh / dt is the set value. If the steering angle speed d is exceeded, the smaller the steering angular velocity dθh / dt is, the smaller the value is given.

・ Axial force change gain G1dF (Fig. 21)
As shown in FIG. 21, the axial force change gain G1dF for adjusting the steering reaction force torque correction reference value ΔT1 increases when the axial force direction of the rack axial force change dF / dt is in the + direction (increase). The smaller the value is, the smaller the value is. When the axial force direction of the rack axial force change dF / dt is in the negative direction (decrease), the value is greater than 1 as the value decreases.

-Vehicle behavior amount gain G1dY (Fig. 22)
As shown in FIG. 22, the vehicle behavior amount gain G1dY for adjusting the steering reaction torque correction reference value ΔT1 is given as 1 when the yaw rate or the lateral G is equal to or less than the set value, and the yaw rate or the lateral G has the set value. When it exceeds, the larger the yaw rate or lateral G is, the larger the value is given.

In step S15, following the calculation of the steering torque correction value ΔT and the steering reaction force torque correction value ΔT ′ in step S14, the calculated steering torque correction value ΔT and the steering reaction force torque correction value ΔT ′ are output, Control goes to step S16.
Here, the output of the turning torque correction value ΔT is to add the turning torque correction value ΔT to the turning torque command value in “EPS control” as shown in FIG. The value ΔT can be restated as a turning torque increase correction value when returning from “EPS control” to “SBW control”.
Further, outputting the steering reaction force torque correction value ΔT ′ is to add the steering reaction force torque correction value ΔT ′ to the steering reaction force torque command value in “EPS control” as shown in FIG. The steering reaction torque correction value ΔT ′ can be rephrased as a steering reaction force torque increase correction value when returning from “EPS control” to “SBW control”.

  In step S16, following the output of the steering torque correction value ΔT and the steering reaction force torque correction value ΔT ′ in step S15, it is confirmed whether or not the backup clutch 9 has been completely released. If YES, the process proceeds to step S17. If NO, the process returns to step S15.

In step S17, following the confirmation of complete release of the backup clutch 9 in step S16, the turning torque correction value ΔT and the steering reaction torque correction value ΔT ′ are rewritten to zero, and the process proceeds to step S4.
Here, after the backup clutch 9 is completely disengaged, the steering torque correction value ΔT and the steering reaction force torque correction value ΔT ′ are rewritten to zero from “EPS control” using the steering motor 14 as an assist means. This means that the steering torque is applied to the wheels 16 and 16 according to the steering state and the steering wheel 6 is shifted to “SBW control” that applies the steering reaction torque according to the steering state.

  In step S18, both “SBW control” and “EPS control” are stopped based on the determination of the system failure or the like in step S2, and the process proceeds to step S19.

In step S19, following the control stop in step S18, a command for fastening the backup clutch 9 is output.
The backup clutch 9 is a clutch that is released when the power is turned on and is engaged when the power is turned off. Even when the power is turned off due to disconnection or the like, the backup clutch 9 is also engaged and there is no steering assist, Manual steering is performed to perform steering only by operating force.

  In step S20, following step S4, step S12, or step S19, it is determined whether the steer-by-wire system is OFF (eg, ignition OFF). If NO, the process returns to step S1, and if YES, the process proceeds to the end.

[Control transfer action]
When the system is normal, the process proceeds from step S1 to step S2 to step S3 to step S4 in the flowchart of FIG. 10, and in step S3, the reaction force device (1) and the steering device (3) by engaging and releasing the backup clutch 9 In step S4, a control command for applying a steering torque to the steering device (3) according to the steering state of the steering wheel 6 is issued in step S4. Steering torque control that outputs to the reaction force motor 5, and a steering reaction force control that outputs to the reaction force motor 5 a control command for applying a steering reaction torque by the reaction force device (1) according to the steered state of the steered wheels 16 and 16. “SBW control” is performed.

  If a system abnormality or the like is diagnosed during the “SBW control”, the process proceeds to step S1, step S2, step S5, step S6, step S7, step S8, step S9 in step S5 in the flowchart of FIG. Equivalent to an increase in the steering torque that acts on the steered wheels 16 and 16 after the completion of the engagement until the completion of the engagement of the backup clutch 9 is confirmed in step S9 after the output of the engagement command to the backup clutch 9 is started. The turning torque correction control for reducing and reducing the turning torque in the “SBW control” is executed with the minute as the correction amount.

  When the completion of the engagement of the backup clutch 9 is confirmed in step S9, the process proceeds from step S9 to step S10 → step S11 → step S12 in the flowchart of FIG. 10, and the steering torque correction control in step S10 is performed. After the stop and the steering reaction force control in “EPS control” in step S11 have elapsed, in step S12, “SBW control” is switched to “EPS control” using the steered motor 14 as an assisting means. Thereafter, the flow from step S12 to step S20 → step S1 → step S2 → step S5 → step S12 is repeated, and “EPS control” is maintained.

  On the other hand, when conditions such as system check end, failure diagnosis end, and switchback from near the maximum turning angle are satisfied, in the flowchart of FIG. 10, step S1, step S2, step S3, step S13, step S14, step S15, and so on. The process proceeds to step S16, and after the disengagement completion of the backup clutch 9 is confirmed in step S16 after the output of the engagement / disengagement command to the backup clutch 9 is started in step S3, the steering wheel 16 is completed after the disengagement is completed. , 16 is used as a correction amount, and a steering torque correction control and a steering reaction torque correction control for increasing the steering torque and the steering reaction torque in the “EPS control” are executed. The

  When the completion of disengagement of the backup clutch 9 is confirmed in step S16, the process proceeds from step S16 to step S17 to step S4 in the flowchart of FIG. 10, and the steering torque correction control and steering reaction force in step S17 are performed. After stopping the torque correction control, in step S4, the control returns from “EPS control” to “SBW control”. Thereafter, the flow from step S4 to step S20 → step S1 → step S2 → step S3 → step S4 is repeated, and “SBW control” is maintained.

  Further, if a system failure or the like occurs during “SBW control” or “EPS control”, the process proceeds from step S1 to step S2 → step S18 → step S19 in the flowchart of FIG. The “SBW control” and “EPS control” are stopped, and in step S19, the backup clutch 9 is engaged and switched to manual steering. If a system failure or the like occurs during the “SBW control”, the “EPS control” may be passed, and the backup clutch 9 may be first engaged to shift to manual steering.

[Operation of turning torque correction when “SBW control” → “EPS control”]
Conventionally, when shifting from “SBW control” to “EPS control” and connecting a mechanical backup mechanism, it takes time from the connection command output time to the completion of connection. That is, when a backup clutch is used as a mechanical backup mechanism, it has a mechanical and electrical specific time constant before the input / output shaft is fastened, and a predetermined time determined by the natural time constant is required from the fastening instruction to the completion of the fastening. .

  Thus, at the time of transition from “SBW control” to “EPS control”, the turning torque of “EPS control” is not instantaneously changed, and as shown in FIG. 23, “SBW control” is changed to “EPS control”. At the time of transition, the torque directions of the reaction force portion and the steered portion are opposite to the steering operation direction and the rack rotation direction. Conventionally, the steering torque during the “SBW control” is maintained as it is from the engagement instruction of the backup clutch to the completion of the engagement.

  For this reason, as shown in the steering torque characteristic (thin line characteristic) acting on the conventional tire in FIG. 24, the steering torque is adjusted to the steering torque in the “SBW control” after the completion of the engagement by the backup clutch. Therefore, after the mechanical connection is completed, the steering torque becomes excessive, and the steered wheels are cut more than intended by the driver.

  On the other hand, in the steering control device according to the first embodiment, when shifting from “SBW control” to “EPS control”, the steering torque control side starts to output the engagement command to the backup clutch 9 as described above. Until the completion of engagement is confirmed until the completion of engagement, the amount equivalent to the increase in steering torque (steering torque, etc.) acting on the steered wheels 16 and 16 after completion of engagement is used as the correction amount, and the “SBW control” When the steering torque correction control for reducing the steering torque is executed and the engagement of the backup clutch 9 is completed, the steering assist torque Ta in the “EPS control” is thereafter applied.

  For this reason, in the first embodiment of the present invention, as shown in the steering torque command value characteristic (dotted line characteristic) in FIG. As shown in the steering torque characteristic (thick solid line) acting on the tire of the present invention in FIG. 24, the steering torque at the time of mechanical connection is the steering assist torque Ta in “EPS control”. The increase in torque is reduced, the steering torque in the “SBW control” acting on the steered wheels 16 and 16 at the time of the instruction to shift to “EPS control”, and the steered wheels 16 and 16 at the mechanical connection time. The torque difference between the steering torque acting on the motor and the steering torque can be kept small.

  Therefore, at the time of transition from “SBW control” to “EPS control”, the increase of the steering torque after the completion of the connection of the backup clutch 9 is reduced, and the steering wheels 16 and 16 unintended by the driver are prevented from being steered. Can do.

  Then, the steering torque correction value ΔT is given as a steering torque correction reference value ΔTO with respect to the steering torque Th, so that the amount of increase in the steering torque is offset and the steering that acts on the steered wheels 16 and 16 is performed. The torque is ensured to be substantially the same at the time of instruction to shift to “EPS control” and the time of mechanical connection. The steering angular velocity gain Gdθ, the axial force change gain GdF, and the vehicle behavior amount gain GdY are shifted to “EPS control” and then the ease of turning by the driver based on the turning torque correction reference value ΔTO (reduction of turning torque). It is used to adjust the correction amount (small correction amount) and the difficulty of cutting (turning torque reduction correction amount large).

[Reaction torque control action during "SBW control" → "EPS control"]
On the other hand, with regard to the reaction force torque, when shifting from “SBW control” to “EPS control”, the reaction force control is conventionally stopped from the point of the fastening instruction (reverse torque of the reaction force motor). As shown in the reaction force characteristic (thin line characteristic) generated in the conventional handle in FIG. 17, the reaction torque decreases after the connection by the backup clutch, and the driver feels that the reaction force is lost. Will give.

  On the other hand, in the steering control device of the first embodiment, when the reaction force control side confirms the completion of the engagement with the backup clutch 9 at the time of transition from “SBW control” to “EPS control”, The reaction torque is zero or the torque of the reaction motor is reversed and applied with a small torque in the steering torque direction.

  For this reason, in Example 1 of the present invention, as shown in the reaction force characteristic (thick solid line characteristic) generated in the handle in the present invention in FIG. 25, the reaction force torque characteristic shows a characteristic that smoothly connects before and after the mechanical connection, It is possible to prevent the reaction force from being lost by reversing the reaction torque early, and the occurrence of a reaction force shock due to the reaction force torque being reversed when the reaction force torque is delayed from the mechanical connection.

[Operation of turning torque correction when “EPS control” → “SBW control”]
Conventionally, when the mechanical backup mechanism is separated from the “EPS control” to the “SBW control”, it takes time from the output of the separation command to the completion of the separation. That is, when a backup clutch is used as a mechanical backup mechanism, it has a mechanical and electrical specific time constant until the input / output shaft is separated, and a predetermined time determined by the specific time constant is required from the release instruction to the completion of the release. .

  As described above, when returning from “EPS control” to “SBW control”, the steering torque of “SBW control” is not changed instantaneously, and when shifting from “EPS control” to “SBW control”, The torque directions of the force unit and the steering unit are opposite to the steering operation direction and the rack rotation direction. Conventionally, the steering torque (assist torque) during the “EPS control” is maintained as it is from the instruction to release the backup clutch to the completion of the release.

  For this reason, as shown in the steering torque characteristic (thin line characteristic) acting on the conventional tire in FIG. 26, the steering torque is only the steering torque during “EPS control” after mechanical separation by the backup clutch, The steering torque by the driver is removed, and after the mechanical separation is completed, the steering torque acting on the tire is reduced by the steering torque, and the steered wheels are not cut more than intended by the driver.

  On the other hand, in the steering control device of the first embodiment, when returning from “EPS control” to “SBW control”, the steering torque control side starts to output the release command to the backup clutch 9 as described above. Until the completion of opening is confirmed, the amount equivalent to the reduction in steering torque (steering torque, etc.) that acts on the steered wheels 16, 16 after completion of opening is used as the correction amount, and the "EPS control" When the steering torque correction control for increasing the steering torque is executed and the release of the backup clutch 9 is completed, the steering torque is connected to the steering torque in the “SBW control” thereafter.

  For this reason, in the first embodiment of the present invention, as shown in the steering torque command value characteristic (dotted line characteristic) in FIG. 26, the command value starts increasing from the time point when the instruction to shift to “SBW control” is given, and from the mechanical separation time point. As shown in the steering torque characteristics (thick solid line) acting on the tire of the present invention in FIG. 26, the steering torque at the time of mechanical separation is the steering torque. The steering torque in the “EPS control” acting on the steered wheels 16 and 16 at the time of the instruction to shift to “SBW control” and the steered wheels 16 and 16 at the time of mechanical separation are suppressed. The torque difference between the steering torque that acts and the torque can be kept small.

  Therefore, when returning from “EPS control” to “SBW control”, the reduction of the steering torque after the completion of disengagement of the backup clutch 9 is suppressed, and the steering torque shortage of the steered wheels 16 and 16 unintended by the driver is prevented. can do.

  The steering torque correction value ΔT is given as the steering torque correction reference value ΔTO with respect to the steering torque Th, so that the amount of decrease of the steering torque is offset and the steering that acts on the steered wheels 16 and 16 is performed. The torque is ensured to be substantially the same at the time of instruction to shift to “SBW control” and at the time of mechanical separation. After the steering angular velocity gain Gdθ, the axial force change gain GdF, and the vehicle behavior amount gain GdY are shifted to “SBW control”, the ease of turning by the driver (increasing the turning torque) based on the turning torque correction reference value ΔTO. It is used to adjust the correction amount (large) and the difficulty of cutting (turning torque increase correction amount small).

[Reaction torque control action during "EPS control" → "SBW control"]
On the other hand, with regard to reaction force torque, when returning from “EPS control” to “SBW control”, the steering reaction force control (zero) in “EPS control” is maintained until the release is completed. As shown in the reaction force characteristic (thin line characteristic) generated in the conventional handle in FIG. 27, the reaction torque decreases after the completion of mechanical separation by the backup clutch, and the reaction force is lost. Is given to the driver.

  On the other hand, in the steering control device according to the first embodiment, when returning from “EPS control” to “SBW control”, the steering reaction force torque control side outputs the release command to the backup clutch 9 as described above. From the start until the completion of opening is confirmed, the amount corresponding to the decrease in the steering reaction torque acting on the handle 6 after the opening is completed (steering torque, etc.) is used as the correction amount, and the steering reaction force in “EPS control” When the steering reaction force torque correction control for increasing the torque is executed and the release of the backup clutch 9 is completed, the steering reaction force torque in the “SBW control” is connected thereafter.

  For this reason, in the first embodiment of the present invention, as shown in the reaction force torque command value characteristic (dotted line characteristic) in FIG. As shown in the reaction torque characteristic (thick solid line) acting on the tire of the present invention in FIG. 27, the steering reaction torque at the time of mechanical separation is the steering torque. Reduction in torque is suppressed, steering reaction force torque in “EPS control” acting on the handle 6 at the time of instruction to shift to “SBW control”, and steering reaction force torque acting on the handle 6 at the time of mechanical separation Thus, the torque drop can be kept small.

  Therefore, at the time of returning from “EPS control” to “SBW control”, it is possible to suppress a decrease in the steering reaction torque after the completion of disengagement of the backup clutch 9, and to prevent the driver from feeling a reaction force slip.

  This steering reaction force torque correction value ΔT ′ is given as a torque in the direction opposite to the steering torque correction value ΔT, so that the steering reaction force torque acting on the handle 6 becomes the time point when the instruction to shift to “SBW control” is given. It is ensured to be almost the same as when the mechanism is separated. After the steering angular velocity gain Gdθ, the axial force change gain GdF, and the vehicle behavior amount gain GdY are returned to the “SBW control”, the driver's ease of turning (steering reaction force) based on the steering reaction force torque correction reference value ΔT1. The torque increase correction amount is small) and the difficulty of cutting (steering reaction force torque increase correction amount is large) is used for adjustment.

Next, the effect will be described.
In the steering control device of the first embodiment, the effects listed below can be obtained.

  (1) The steering part having the handle 6 and the reaction force motor 5 and the steering part having the steered wheels 16 and 16 and the steering motor 14 can be mechanically separated and connected via the backup clutch 9. And the control of the steering motor 14 that disengages the backup clutch 9 and sets the turning angle according to the steering state, and the control of the reaction force motor 5 that applies the steering reaction force according to the steering state. SBW control means for performing “SBW control”, EPS control means for connecting the backup clutch 9 and performing “EPS control” using at least one of the reaction force motor 5 and the steered motor 14 as assist means, When a predetermined condition is satisfied during `` EPS control '', the control switching means includes a control switching means that returns to `` SBW control '', wherein the control switching means switches from `` EPS control '' to `` SBW control '' At the time of return, Between the separation command for the backup clutch 9 and the completion of separation, the amount equivalent to the decrease in the turning torque that acts on the steered wheels 16 and 16 after the completion of separation is used as the correction amount, and the turning torque in the “SBW control” is increased. In order to compensate, when returning from “EPS control” to “SBW control”, the reduction of the steering torque after the completion of the separation of the backup clutch 9 is suppressed, and the steering wheels 16 and 16 are not cut unintentionally by the driver. can do.

  (2) The reaction device torque sensor 3 for detecting the steering torque Th input to the steering unit is provided, and the control switching means sets the turning torque increase correction value to be larger as the steering torque Th is larger. Since the torque correction unit is included, the steering torque reduction amount corresponding to the steering torque after completion of the separation of the backup clutch 9 is suppressed, and the steering torque acting on the steered wheels 16 and 16 at the time of completion of separation of the backup clutch 9 is Optimal turning torque increase correction that substantially matches the turning torque at the time when the backup clutch 9 is released can be performed.

  (3) A steering angular velocity detection means for detecting the steering angular velocity dθh / dt of the steering unit is provided, and the steering torque correction unit increases the steering torque increase correction value as the steering angular velocity dθh / dt increases. When the steering speed is fast, it is possible to facilitate steering in response to a driver's steering response request.

  (4) A rack axial force change detecting means for detecting a rack axial force change dF / dt of the steered portion is provided, and the steered torque correcting unit rotates as the rack axial force change dF / dt increases. As the steering torque increase correction value is increased and the rack axial force change dF / dt is in the decreasing direction, the steering torque increase correction value is reduced, so that it is easier to steer on the increase side of the steering torque due to disturbance. The unintended turning of the driver can be prevented on the side of reduction of the turning torque due to disturbance.

  (5) Vehicle behavior amount detection means for detecting a vehicle behavior amount (yaw rate or lateral G) is provided, and the turning torque correction unit decreases the turning torque increase correction value as the vehicle behavior amount detection value increases. Therefore, when the yaw rate or the lateral G is large, the steering beyond the driver's intention is prevented, and the stability of the vehicle behavior can be ensured.

  (6) The control switching means is a steering that acts on the handle 6 after the completion of the separation from the separation command to the backup clutch 9 until the separation is completed when returning from the “EPS control” to the “SBW control”. The amount corresponding to the decrease in the reaction torque is used as the correction amount, and the steering reaction torque in SBW control is increased and corrected. Therefore, when returning from EPS control to SBW control, the reaction during the turning torque increase correction is in progress. It is possible to reduce the force loss and prevent the reaction force from being lost after the separation of the backup clutch 9 is completed.

  (7) A reaction force device torque sensor 3 for detecting a steering torque Th input to the steering unit is provided, and the control switching means sets the steering reaction force torque increase correction value to a larger value as the steering torque Th increases. Since the reaction force torque correction unit is provided, the steering reaction force torque decrease amount after the completion of the separation of the backup clutch 9 is suppressed, and the steering reaction force torque acting on the handle 6 at the time of completion of the separation of the backup clutch 9 is applied to the backup clutch 9. Optimal steering reaction torque increase correction that substantially matches the steering reaction torque at the time of release command can be performed.

  (8) The control switching means is configured to increase the turning torque after the separation is completed from the separation command to the backup clutch 9 until the separation is completed when returning from “EPS control” to “SBW control”. In order to increase the steering reaction torque in “SBW control” according to the correction amount, when returning from “EPS control” to “SBW control”, reduction of reaction force during turning torque increase correction is reduced and backup is performed. Occurrence of a feeling of reaction force loss after completion of separation of the clutch 9 can be prevented.

  (9) A steering angular velocity detecting means for detecting a steering angular velocity dθh / dt of the steering unit is provided, and the steering reaction force torque correction unit decreases the steering reaction force torque increase correction value as the steering angular velocity dθh / dt increases. Therefore, when the steering speed is high, steering of the steering wheel can be facilitated according to the driver's steering response request.

  (10) A rack axial force change detecting means for detecting a rack axial force change dF / dt of the steered portion is provided, and the steering reaction force torque correcting unit increases the rack axial force change dF / dt in an increasing direction. The steering torque increase correction value is decreased and the steering reaction force torque increase correction value is increased as the rack axial force change dF / dt decreases. Therefore, the steering wheel can be steered more easily on the increase side of the steering torque due to disturbance. Thus, steering of the steering wheel unintended by the driver can be prevented on the side where the steering torque is reduced due to disturbance.

  (11) Vehicle behavior amount detection means for detecting a vehicle behavior amount (yaw rate or lateral G) is provided, and the steering reaction force torque correction unit increases the steering reaction force torque increase correction value as the vehicle behavior amount detection value increases. Therefore, when the yaw rate or the lateral G is large, the steering of the steering wheel beyond the driver's intention is prevented, so that the stability of the vehicle behavior can be ensured.

  The steering control device of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and the gist of the invention according to each claim of the claims. As long as they do not deviate, design changes and additions are permitted.

  In the first embodiment, the control switching means is “EPS control” when the steering torque is larger during the return from “EPS control” to “SBW control” and from the separation command to the completion of separation for the backup clutch. An example in which the steering torque is corrected to increase is shown. However, for example, the steering torque, steering angular velocity, road surface friction coefficient, etc. are used to estimate the amount equivalent to the reduction in steering torque that acts on the steered wheels after completion of separation, and this is used as the correction amount for turning torque in EPS control. An increase correction may be performed. In short, at the time of return from “EPS control” to “SBW control”, the amount equivalent to the decrease in the steering torque that acts on the steered wheels after the completion of separation is corrected from the separation command to the backup means until the completion of separation. It is included in the present invention as long as the steering torque in the “EPS control” is increased and corrected.

  In the first embodiment, the control switching means is “EPS control” when the steering torque is larger during the return from “EPS control” to “SBW control” and from the separation command to the completion of separation for the backup clutch. An example in which the steering reaction torque is corrected to increase is shown. However, for example, the amount corresponding to the decrease in the steering reaction torque acting on the steering wheel after the completion of the separation is estimated by the steering angle, the steering angular velocity, the road surface friction coefficient, etc., and this is used as a correction amount to calculate the steering reaction force torque in the “EPS control”. An increase correction may be performed. In short, during the return from “EPS control” to “SBW control”, the amount corresponding to the decrease in the steering reaction torque acting on the steering wheel after the completion of the separation from the separation command to the backup means until the separation is completed is the correction amount. In the present invention, any correction for increasing the steering reaction torque in “EPS control” is included.

  In the first embodiment, an example in which the turning torque increase correction value and the steering reaction force torque increase correction value are determined by adjusting the steering angular velocity, the rack axial force change, and the vehicle behavior amount is shown. The steering torque increase correction value and the steering reaction force torque increase correction value may be determined based on the state quantity, and a characteristic determined in advance with respect to the steering torque without performing gain adjustment or the like. The steering torque increase correction value and the steering reaction force torque increase correction value may be uniquely given only in accordance with (FIGS. 15 and 19). Further, the steering reaction force torque increase correction value may be obtained by multiplying the turning torque increase correction value by a gain (for example, 0.8).

  In the first embodiment, an example of a steering control device applied to a steer-by-wire system using a cable column and a backup clutch as backup means has been shown. However, the steering section and the steering section can be mechanically separated and connected. Any system provided with backup means can be applied to steer-by-wire systems other than the first embodiment.

1 is an overall configuration diagram illustrating a steer-by-wire system to which a steering control device according to a first embodiment is applied. It is a schematic diagram which shows the example of a position of the backup clutch used with the steer-by-wire system to which the steering control apparatus of Example 1 is applied. It is a control block diagram which shows the control structure used for SBW control in the steering control apparatus of Example 1. FIG. It is a steering control block diagram at the time of "SBW control" by the control controller of the steering control apparatus of Example 1. It is a turning servo control block diagram at the time of "SBW control" by the control controller of the steering control apparatus of Embodiment 1. FIG. 3 is a reaction force control block diagram during “SBW control” by the control controller of the steering control device according to the first embodiment. FIG. 5 is a reaction force servo control block diagram during “SBW control” by the control controller of the steering control device according to the first embodiment. It is a steering control block diagram at the time of "EPS control" by the control controller of the steering control apparatus of Example 1. FIG. It is a turning servo control block diagram at the time of "EPS control" by the control controller of the steering control apparatus of Example 1. 3 is a flowchart illustrating a flow of switching control processing executed by the control controller according to the first embodiment. FIG. 7 is a characteristic diagram showing a steering torque correction value map for steering torque used in the steering torque correction control in the transitional transition period from “SBW control” to “EPS control” in the first embodiment. FIG. 6 is a steering angular velocity gain characteristic graph with respect to a steering angular velocity used in the turning torque correction control in the transitional transition period from “SBW control” to “EPS control” in the first embodiment. FIG. 6 is an axial force change gain characteristic diagram with respect to a change in rack axial force used in the turning torque correction control during the transitional transition from “SBW control” to “EPS control” in the first embodiment. FIG. 6 is a vehicle behavior amount gain characteristic diagram with respect to a vehicle behavior amount used in the turning torque correction control in the transitional transition period from “SBW control” to “EPS control” in the first embodiment. FIG. 6 is a characteristic diagram illustrating a steering torque correction value map for steering torque used in the steering torque correction control in the transitional transition period from “EPS control” to “SBW control” according to the first embodiment. FIG. 6 is a steering angular velocity gain characteristic graph with respect to a steering angular velocity used in a turning torque correction control in a return transition period from “EPS control” to “SBW control” in the first embodiment. FIG. 6 is an axial force change gain characteristic diagram with respect to a change in rack axial force used in a turning torque correction control in a return transition period from “EPS control” to “SBW control” in the first embodiment. FIG. 6 is a vehicle behavior amount gain characteristic diagram with respect to a vehicle behavior amount used in the turning torque correction control in the transitional transition period from “EPS control” to “SBW control” in the first embodiment. FIG. 7 is a characteristic diagram showing a steering reaction force torque correction value map for steering torque used in steering reaction force torque correction control in a return transition period from “EPS control” to “SBW control” in the first embodiment. FIG. 6 is a steering angular velocity gain characteristic graph with respect to a steering angular velocity used in steering reaction force torque correction control in a transitional transition period from “EPS control” to “SBW control” in the first embodiment. FIG. 7 is an axial force change gain characteristic diagram with respect to a change in rack axial force used in steering reaction force torque correction control in a return transition period from “EPS control” to “SBW control” in the first embodiment. FIG. 6 is a vehicle behavior amount gain characteristic diagram with respect to a vehicle behavior amount used in steering reaction force torque correction control in a return transition period from “EPS control” to “SBW control” in the first embodiment. FIG. 6 is an operation explanatory diagram showing the direction of torque at the time of transition from “SBW control” to “EPS control” in the first embodiment. 7 is a time chart showing a comparison between conventional turning torque control and turning torque correction control of the first embodiment when shifting from “SBW control” to “EPS control”. 5 is a time chart showing a comparison between the conventional reaction force torque control and the reaction force torque control of the first embodiment at the time of transition from “SBW control” to “EPS control”. 7 is a time chart showing a comparison between conventional turning torque control and turning torque correction control of Example 1 when returning from “EPS control” to “SBW control”. 6 is a time chart showing a comparison between the conventional reaction force torque control and the reaction force torque control of the first embodiment when returning from “EPS control” to “SBW control”.

Explanation of symbols

1 Steering angle sensor 2 Encoder 3 Torque sensor (steering torque detection means)
4 Hall IC
5 Reaction force motor (steering reaction force actuator)
6 Handle 7 Cable column (backup means)
8 Column shaft 9 Backup clutch (backup means)
10 Encoder 11 Rudder angle sensor 12 Torque sensor 13 Hall IC
14 Steering motor (steering actuator)
15 Steering mechanism 16, 16 Steering wheel 17 Pinion shaft 18 Power source 19 Control controller 20 Yaw rate / lateral G sensor (vehicle behavior amount detecting means)
21 Vehicle speed sensor 22 Reaction force motor temperature sensor

Claims (12)

  1. A steering part having a steering wheel and a steering reaction force actuator and a steering part having a steered wheel and a steering actuator can be mechanically separated and connected via backup means,
    Steer-by-wire control is performed by controlling the steering actuator that separates the backup means and sets the steering angle according to the steering state and the steering reaction force actuator that applies the steering reaction force according to the steering state. Steer-by-wire control means to perform,
    Steering assist control means for connecting the backup means and performing steering assist control using at least one of the steering reaction force actuator and the steering actuator as an assist means;
    Control switching means for returning to the steer-by-wire control by the steer-by-wire control means when a predetermined condition is satisfied during the steering assist control by the steering-assist control means;
    In a steering control device with
    The control switching means is a transition from steering assist control to steer-by-wire control, and during the period from the separation command to the backup means until the separation is completed, the reduction of the steering torque that acts on the steered wheels after the separation is completed. A steering control device characterized in that a corresponding amount is used as a correction amount to increase and correct a turning torque in steering assist control.
  2. In the steering control device according to claim 1,
    A steering torque detection means for detecting a steering torque input to the steering section;
    The steering control device according to claim 1, wherein the control switching unit includes a steering torque correction unit that sets the steering torque increase correction value to be larger as the steering torque detection value is larger.
  3. In the steering control device according to claim 2,
    A steering angular velocity detecting means for detecting a steering angular velocity of the steering section;
    The steered torque correction unit increases the steered torque increase correction value as the detected steering angular velocity value increases.
  4. In the steering control device according to claim 2 or 3,
    A rack axial force change detecting means for detecting a rack axial force change of the steered portion is provided,
    The turning torque correction unit increases the turning torque increase correction value as the rack axial force change increases, and decreases the turning torque increase correction value as the rack axial force change decreases. A steering control device characterized by:
  5. The steering control device according to any one of claims 2 to 4,
    A vehicle behavior amount detecting means for detecting the vehicle behavior amount is provided,
    The steered torque correction unit reduces the steered torque increase correction value as the vehicle behavior amount detection value is higher.
  6. The steering control device according to any one of claims 1 to 5,
    The control switching means is the time of transition from the steering assist control to the steer-by-wire control, and during the period from the separation command to the backup means until the separation is completed, the steering reaction force torque acting on the steering wheel after the separation is completed. A steering control device characterized in that an amount corresponding to a decrease is used as a correction amount, and a steering reaction torque in steering assist control is increased and corrected.
  7. In the steering control device according to claim 6,
    A steering torque detection means for detecting a steering torque input to the steering section;
    The steering control device according to claim 1, wherein the control switching unit includes a steering reaction force torque correction unit that sets a steering reaction force torque increase correction value to be larger as the steering torque detection value is larger.
  8. The steering control device according to any one of claims 1 to 5,
    The control switching means is at the time of transition from the steering assist control to the steer-by-wire control, and from the separation command to the backup means until the separation is completed, and after the separation is completed, according to the turning torque increase correction amount. And a steering reaction device for increasing the steering reaction torque in the steering assist control.
  9. In the steering control device according to claim 7 or 8,
    A steering angular velocity detecting means for detecting a steering angular velocity of the steering section;
    The steering control device, wherein the steering reaction force torque correction unit decreases the steering reaction force torque increase correction value as the steering angular velocity detection value increases.
  10. The steering control device according to any one of claims 7 to 9,
    A rack axial force change detecting means for detecting a rack axial force change of the steered portion is provided,
    The steering reaction force torque correction unit decreases the steering reaction force torque increase correction value as the rack axial force change increases, and decreases the rack axial force change as the rack axial force change decreases. A steering control device characterized by increasing a value.
  11. In the steering control device according to any one of claims 7 to 10,
    A vehicle behavior amount detecting means for detecting the vehicle behavior amount is provided,
    The steering control device, wherein the steering reaction force torque correction unit increases the steering reaction force torque increase correction value as the vehicle behavior amount detection value is higher.
  12. A steering part having a steering wheel and a steering reaction force actuator and a steering part having a steered wheel and a steering actuator can be mechanically separated and connected via backup means,
    Steer-by-wire control is performed by controlling the steering actuator that separates the backup means and sets the steering angle according to the steering state and the steering reaction force actuator that applies the steering reaction force according to the steering state. Done
    The backup means is connected, and steering assist control is performed using at least one of the steering reaction force actuator and the steering actuator as an assist means,
    In a steering control device that returns to steer-by-wire control when a predetermined condition is satisfied during steering assist control,
    During the transition from steering assist control to steer-by-wire control, between the separation command for the backup means and the completion of separation, the amount equivalent to the reduction in turning torque that acts on the steered wheels after the separation is completed is used as the correction amount. A steering control device that corrects to increase the steering torque in the steering assist control.
JP2005075667A 2005-03-16 2005-03-16 Steering control device Expired - Fee Related JP4517902B2 (en)

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Application Number Priority Date Filing Date Title
JP2005075667A JP4517902B2 (en) 2005-03-16 2005-03-16 Steering control device
US11/363,697 US7664584B2 (en) 2005-03-01 2006-02-28 Steering control system
EP20060251121 EP1698539B1 (en) 2005-03-01 2006-03-01 Steering control apparatus
DE200660017911 DE602006017911D1 (en) 2005-03-01 2006-03-01 Steering control device

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Publication number Priority date Publication date Assignee Title
JP5019104B2 (en) * 2006-12-28 2012-09-05 株式会社ジェイテクト Vehicle steering system
CN103906671B (en) * 2011-10-26 2016-04-27 日产自动车株式会社 Steering controlling device
WO2014038134A1 (en) * 2012-09-10 2014-03-13 日産自動車株式会社 Vehicle steering control device and vehicle steering control method
JP6101219B2 (en) * 2014-01-21 2017-03-22 本田技研工業株式会社 Vehicle steering system

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JP2004224158A (en) * 2003-01-22 2004-08-12 Nissan Motor Co Ltd Steering control device for vehicle
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JP2006240398A (en) * 2005-03-01 2006-09-14 Nissan Motor Co Ltd Steering controller

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JP2001088727A (en) * 1999-09-21 2001-04-03 Nissan Motor Co Ltd Steering device for vehicle
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JP2004090783A (en) * 2002-08-30 2004-03-25 Koyo Seiko Co Ltd Steering system for vehicle
JP2004224158A (en) * 2003-01-22 2004-08-12 Nissan Motor Co Ltd Steering control device for vehicle
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JP2006240398A (en) * 2005-03-01 2006-09-14 Nissan Motor Co Ltd Steering controller

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