JP2022041538A - Vehicular steering controller - Google Patents

Abstract

To provide a steering controller improved so that a driver can grasp a relation between a steering angle and a rudder angle of a turning wheel correctly in a transition from an automatic steering to a manual steering in a vehicle having a steer-by-wire type steering device.SOLUTION: A control unit controlling a steer-by-wire type steering device is a vehicular steering controller for setting a steering gear ratio Rst as a steering gear ratio Rsta in an automatic steering smaller than a standard steering gear ratio Rstn in a manual steering mode in an automatic steering mode so as to control a rudder angle of a turning wheel to be a target rudder angle. The control unit sets the steering gear ratio as a steering gear ratio Rstt between the steering gear ratio Rsta in the automatic steering mode and the standard steering gear ratio Rstn to control the rudder angle of the turning wheel when it is determined that a prescribed condition that the degree to which an operation of the steering wheel by a driver is reflected on the control of the steering angle of the turning wheel preferably becomes high is established.SELECTED DRAWING: Figure 2

Description

The present invention relates to a steering control device for a vehicle such as an automobile.

As steering control of a vehicle, automatic steering in which the steering wheels are automatically steered, such as automatic driving, is known. In automatic steering, the target steering angle of the steering wheel is calculated, and the steering device is controlled so that the steering angle of the steering wheel becomes the target steering angle.

In particular, when the steering device is a steer-by-wire type steering device including a steering input device and a steering device that are not mechanically connected to each other, the steering device does not rotate the steering wheel of the steering input device. The steering wheel can be steered by. Therefore, during automatic steering, the steering gear ratio is higher than the steering gear ratio during automatic steering, that is, 0 or the standard steering gear ratio during manual steering so that the driver does not feel annoyed due to the rotation of the steering wheel. Set to a much smaller value.

For example, in Patent Document 1 below, the steering device is a steer-by-wire type steering device, and in a vehicle equipped with an automatic driving system, the steering gear ratio can be changed when the automatic driving system is operating. The configured steering device is described.

Japanese Unexamined Patent Publication No. 2004-224238

[Problems to be solved by the invention]
In a situation where automatic steering is performed such as automatic driving, when an abnormality that cannot be continued automatically occurs, it is necessary to shift from automatic steering to steering by the driver, that is, manual steering. However, during automatic steering, the rotation angle of the steering wheel, that is, the relationship between the steering angle and the steering angle of the steering wheel is different from the relationship during manual steering. Therefore, at the start of manual steering, the driver cannot accurately grasp the rotation angle of the steering wheel, that is, the relationship between the steering angle and the steering angle of the steering wheel, and steering tends to be excessive or under-steering. .. In addition, the steering gear ratio suddenly changes from the steering gear ratio during automatic steering to the standard steering gear ratio, and the relationship between the steering angle and the steering angle of the steering wheel also changes rapidly, so the driver tends to feel uncomfortable. ..

A major subject of the present invention is to compare the relationship between the steering angle and the steering angle of the steering wheel when the driver shifts from automatic steering to manual steering in a vehicle equipped with a steer-by-wire steering device. It is to provide an improved steering control device so that it can be grasped accurately.

[Means for Solving Problems and Effects of Invention]
According to the present invention, a steering wheel (20), a steering angle detecting device (22) that detects the rotation angle of the steering wheel as a steering angle, and a reaction force actuator (24) that applies steering reaction force torque to the steering wheel. , A steering mechanism (30) configured to steer the steering wheels (28FL, 28FR) in response to steering torque, a steering actuator (32) that applies steering torque to the steering mechanism, and a steering wheel. A steering angle detection device (34) for detecting the steering angle of the rudder, and a steer-by-wire type steering device (14) including the steering angle detection device (14).
A control unit (16) that controls a reaction force actuator and a steering actuator, and when the steering mode is the manual steering mode, the steering gear ratio (Rst) is set to a preset standard steering gear ratio (Rstn). Then, the steering angle (δ) of the steering wheel is controlled based on the steering angle (θ) detected by the steering angle detecting device, and when the steering mode is the automatic steering mode, the target steering angle (δt) of the steering wheel is set. With a control unit configured to calculate and set the steering gear ratio to the steering gear ratio (Rsta) during automatic steering, which is smaller than the standard steering gear ratio, and control the steering angle of the steering wheel to the target steering angle. ,
A vehicle steering control device (10) including the above is provided.

In the situation where the steering mode is the automatic steering mode, the control unit (16) satisfies a predetermined condition that it is preferable that the operation of the steering wheel by the driver is reflected in the control of the steering angle of the steering wheel to a high degree. When it is determined that the steering gear ratio (Rst) is set to the transient steering gear ratio between the steering gear ratio (Rsta) at the time of automatic steering and the standard steering gear ratio (Rstn) until the steering mode is changed to the manual steering mode. It is configured to be set to (Rstt) to control the steering angle of the steering wheel so as to be the target steering angle.

According to the above configuration, in a situation where the steering mode is the automatic steering mode, when it is determined that a predetermined condition is satisfied, the steering gear ratio is set to the automatic steering mode until the steering mode becomes the manual steering mode. It is set to a transient steering gear ratio between the steering gear ratio and the standard steering gear ratio. The transient steering gear ratio is closer to the standard steering gear ratio than the steering gear ratio during automatic steering. Therefore, the driver accurately grasps the relationship between the steering angle and the steering angle of the steering wheel as compared with the case where the steering gear ratio when the steering operation is started by the driver is the steering gear ratio at the time of automatic steering. can do. Therefore, it is possible to reduce the risk of excessive or under-steering when shifting from automatic steering to manual steering.

[Aspects of the invention]
In one aspect of the invention, the control unit (16) is configured to change the transient steering gear ratio so that the transient steering gear ratio (Rstt) gradually approaches the standard steering gear ratio.

According to the above aspect, the transient steering gear ratio is gradually changed to approach the standard steering gear ratio. Therefore, the relationship between the steering angle and the steering angle of the steering wheel changes sharply compared to the case where the steering gear ratio suddenly changes to the standard steering gear ratio when shifting from automatic steering to manual steering. As a result, it is possible to reduce the risk that the driver feels uncomfortable.

Note that "the transient steering gear ratio gradually approaches the standard steering gear ratio" means that the change is gentler than when the transient steering gear ratio momentarily changes to the standard steering gear ratio. ..
Is.

In another aspect of the invention, the control unit (16) is such that the transient steering gear ratio (Rstt) gradually approaches the standard steering gear ratio (Rstn) from the steering gear ratio (Rsta) during automatic steering to the standard. It is configured to change the transient steering gear ratio so as to have the steering gear ratio of.

According to the above aspect, the transient steering gear ratio is changed from the steering gear ratio at the time of automatic steering to the standard steering gear ratio gradually approaching the standard steering gear ratio. Therefore, it is possible to more effectively reduce the risk that the driver feels uncomfortable due to the sudden change in the relationship between the steering angle and the steering angle of the steering wheel when shifting from automatic steering to manual steering. ..

In the conventional steering control device, the steering angle of the steering wheel determined by the steering angle and the standard steering gear ratio when the steering operation is started by the driver is smaller than the steering angle of the steering wheel by automatic steering. Sometimes. In that case, the steering wheel is steered in the direction opposite to the direction in which the driver tries to steer the steering wheel by operating the steering wheel, so that the driver may feel a sense of discomfort.

Generally, the steering operation by the driver is started when a certain amount of time has elapsed after the predetermined condition is satisfied. Therefore, according to the above aspect, when the steering operation by the driver is started, the steering gear ratio t. Is the standard steering gear ratio or a value close to it. Therefore, the driver can accurately grasp the relationship between the rotation operation amount of the steering wheel and the steering angle of the steering wheel and perform the steering operation accurately, and at the same time, the direction opposite to the direction in which the steering wheel is to be steered is opposite. It is possible to reduce the risk that the driver feels uncomfortable due to the steering wheel being steered in the direction.

Further, in another aspect of the present invention, the control unit (16) is configured to generate an alarm when the steering gear ratio (Rst) is set to the transient steering gear ratio (Rstt).

According to the above aspect, an alarm is generated when the steering gear ratio is set to the transient steering gear ratio. Therefore, the driver can recognize that the steering gear ratio is set to the transient steering gear ratio by the generation of the alarm and changes.

Further, in another aspect of the present invention, the control unit (16) sets a target steering angle (δt) of the steering wheel for controlling automatic driving when the automatic driving switch (48) is on. Along with the calculation, it is determined that the steering mode is the automatic steering mode, and if it is determined that an abnormality occurs in the control of automatic driving and the steering mode needs to shift to the manual steering mode, it is determined that the predetermined conditions are satisfied. It is configured to do.

According to the above aspect, when it is determined that an abnormality occurs in the control of automatic driving and the steering mode needs to shift to the manual steering mode when the automatic driving switch is on, a predetermined condition is satisfied. Is determined. Therefore, when it is determined that an abnormality occurs in the control of automatic operation and the steering mode needs to shift to the manual steering mode, the steering gear ratio is set between the steering gear ratio at the time of automatic steering and the standard steering gear ratio. It can be set to the transient steering gear ratio.

Further, in another aspect of the present invention, the control unit (16) sets a target steering angle (δt) of the steering wheel for controlling driving assistance when the driving assistance switch (68) is on. It is configured to calculate and determine that the steering mode is the automatic steering mode, and if it is determined that the driver may perform corrective steering, it is determined that a predetermined condition is satisfied.

According to the above aspect, when it is determined that the driver may perform corrective steering when the driving support switch is on, it is determined that a predetermined condition is satisfied. Therefore, when it is determined that there is a possibility that the driver corrects the steering, the steering gear ratio may be set to the transient steering gear ratio between the steering gear ratio at the time of automatic steering and the standard steering gear ratio. can.

Further, in another aspect of the present invention, the control unit (16) is for controlling remote driving performed by a standby driver boarding a vehicle when receiving a remote driving command. It is configured to calculate the target steering angle (δt) of the steering wheel, determine that the steering mode is the automatic steering mode, and determine that the predetermined conditions are satisfied when it is determined that the remote driving control is abnormal. Will be done.

According to the above aspect, when it is determined that the control of remote control is abnormal while receiving a command for remote control, it is determined that a predetermined condition is satisfied. Therefore, when it is determined that the control of remote control is abnormal when receiving a command for remote control, the steering gear ratio is set to transient steering between the steering gear ratio at the time of automatic steering and the standard steering gear ratio. It can be set to the gear ratio.

In the above description, in order to help the understanding of the present invention, the reference numerals used in the embodiments are added in parentheses to the configurations of the invention corresponding to the embodiments described later. However, each component of the present invention is not limited to the component of the embodiment corresponding to the reference numeral attached in parentheses. Other objects, other features and accompanying advantages of the invention will be readily understood from the description of embodiments of the invention described with reference to the following drawings.

It is a schematic block diagram which shows the 1st Embodiment of the steering control device for a vehicle by this invention applied to the vehicle which controls the automatic driving as the automatic steering control. It is a flowchart which shows the steering control routine in 1st Embodiment. It is a time chart which shows the specific example of operation of 1st Embodiment. It is a schematic block diagram which shows the 2nd Embodiment of the steering control device for a vehicle by this invention applied to the vehicle which controls the driving support as automatic steering control. It is a flowchart which shows the steering control routine in 2nd Embodiment. It is a time chart which shows the specific example of the operation of the 2nd Embodiment. It is a schematic block diagram which shows the 3rd Embodiment of the steering control device for a vehicle by this invention applied to the vehicle which controls the remote control as an automatic steering control. It is a flowchart which shows the steering control routine in 3rd Embodiment. It is a map which shows the relationship between a vehicle speed V and a standard steering gear ratio Rstn. It is a graph which shows various changes of a transient steering gear ratio Rst t.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying figures.

[First Embodiment]
The vehicle steering control device 10 according to the first embodiment is applied to a vehicle 12 in which automatic driving is controlled as automatic steering control. As shown in FIG. 1, the steering control device 10 includes a steer-by-wire type steering device 14 and a control unit 16 for controlling the steering device 14.

The steering device 14 includes a steering input device 17 and a steering device 18 that are not mechanically connected to each other. The steering input device 17 includes a steering wheel 20, a steering angle detecting device 22 that detects the rotation angle of the steering wheel as a steering angle θ, and a reaction force actuator 24 that applies a steering reaction force torque Tre to the steering wheel. There is.

The steering wheel 20 is a steering input member operated by a driver (not shown), and may be in the form of a steering wheel. The reaction force actuator 24 includes an electric motor, and the rotating shaft 26 of the electric motor is integrally connected to the steering wheel 20. The steering angle detecting device 22 may be a rotary encoder built in the electric motor.

The steering device 18 includes a steering mechanism 30 configured to steer the left and right front wheels 28FL and 28FR, which are steering wheels, in response to the steering torque Tst, and a steering actuator that applies steering torque to the steering mechanism. 32 and a steering angle detecting device 34 for detecting the steering angle δ of the steering wheel are included. In FIG. 1, reference numerals 28RL and 28RR indicate left and right rear wheels which are non-steering wheels. Further, the drive wheels may be any or all of the front wheels and the rear wheels. In other words, the vehicle 12 may be any of a front-wheel drive vehicle, a rear-wheel drive vehicle, and a four-wheel drive vehicle.

In the illustrated embodiment, the steering mechanism 30 includes a rack and pinion device 40 having a rack bar 36 and a pinion shaft 38. Although not shown in the figure, the pinion shaft 38 has a pinion that meshes with the rack teeth of the rack bar 36, and the rotational motion of the pinion shaft 38 is converted into the reciprocating motion of the rack bar 36 to reciprocate the rack bar 36. The motion is converted into the reciprocating motion of the pinion shaft 38. The steering mechanism may have any structure known in the art.

Further, the steering mechanism 30 includes the tie rods 42L and 42R, and the inner ends of the tie rods 42L and 42R are pivotally attached to the left and right tips of the rack bar 36, respectively. The outer ends of the tie rods 42L and 42R are pivotally attached to the knuckle arms of the front wheels 28FL and 28FR, although not shown in the figure. The steering actuator 32 includes an electric motor, and the rotation shaft of the electric motor is integrally connected to the pinion shaft 38.

Therefore, the steering mechanism 30 is configured to receive steering torque from the steering actuator 32 at the pinion shaft 38 to steer the front wheels 28FL and 28FR. There is a certain relationship between the rotation angle φ of the pinion shaft 38 and the steering angles δ of the front wheels 28FL and 28FR. Therefore, in the illustrated embodiment, the steering angle detecting device 34 detects the steering angles δ of the front wheels 28FL and 28FR by detecting the rotation angle φ of the rotation shaft of the motor of the pinion shaft 38 or the steering actuator 32.

The control unit 16 of the first embodiment includes a steering control electronic control device 44 that controls a steering input device 17 and a steering device 18, and an automatic driving electronic control device 46 that controls automatic driving. The electronic control device 46 for automatic operation does not operate when the automatic operation switch (denoted as “automatic operation SW” in the figure) 48 is off, and operates when the automatic operation switch 48 is on. .. Hereinafter, the "electronic control unit" will be referred to as an "ECU".

Although not shown in detail in FIG. 1, the ECUs 44 and 46 and the control driving force control ECU 56 described later include a microcomputer and a drive circuit, and exchange necessary information with each other. Each microcomputer has a CPU, ROM, RAM, and an input / output port device, which have a general configuration in which they are connected to each other by a bidirectional common bus.

A signal indicating the steering angle θ detected by the steering angle detecting device 22 is input to the steering control ECU 44, and a signal indicating the steering angles δ of the front wheels 28FL and 28FR detected by the steering angle detecting device 34 is input. .. A signal indicating whether or not the automatic driving switch (denoted as "automatic driving SW" in the figure) 48 is turned on is input to the automatic driving ECU 46, and the vehicle speed V detected by the vehicle speed sensor 50 is input. The indicated signal is input. Further, a signal indicating information around the vehicle 12 acquired by the surrounding information acquisition device 52 such as a CCD camera and radar is input to the automatic driving ECU 46, and the navigation device 54 to the current location and the destination of the vehicle 12 are input. Information such as the target route is input.

When the automatic operation switch 48 is off, the steering control ECU 44 determines that the steering mode is the manual steering mode, sets the steering gear ratio Rst to the standard steering gear ratio Rstn, and detects it by the steering angle detecting device 22. The steering actuator 32 is controlled based on the steering angle θ. Therefore, the steering angles δ of the front wheels 28FL and 28FR are controlled to be θ / Rstn. The steering angle θ and the steering angle δ become 0 when the vehicle 12 is in a straight-ahead state. Further, the standard steering gear ratio Rstn is a positive value preset so as to increase as the vehicle speed V increases.

Further, the steering control ECU 44 controls the electric motor of the reaction force actuator 24 based on the steering angle θ, the differential value of the steering angle θ, and the second-order differential value of the steering angle θ when the automatic operation switch 48 is off. , The steering reaction force torque Tre is applied to the steering wheel 20. The steering reaction force torque Tre is variably set according to the vehicle speed so that it increases as the vehicle speed V increases. The steering reaction force torque Tre applied to the steering wheel 20 may be controlled by any method known in the art.

When the automatic operation switch 48 is on, the steering control ECU 44 determines that the steering mode is the automatic steering mode, and sets the steering gear ratio to the steering gear ratio Rsta during automatic steering, which is smaller than the standard steering gear ratio Rstn. do. In the first embodiment and other embodiments described later, the steering gear ratio Rsta at the time of automatic steering is 0, so that the steering wheel 20 does not rotate at all even if the front wheels 28FL and 28FR are steered by automatic driving. For example, it may be a positive value close to 0. When the target route is not set by the navigation device 54, the automatic driving switch 48 is not turned on even if it is operated by a vehicle occupant.

Further, the steering control ECU 44 calculates the target rotation angle φt of the rotation shaft of the motor of the steering actuator 32 based on the target steering angles δt of the front wheels 28FL and 28FR input from the automatic driving ECU 46. Further, the steering control ECU 44 controls the motor of the steering actuator 32 so that the rotation angle φ of the rotation shaft of the motor becomes the target rotation angle φt. Therefore, the steering angles δ of the front wheels 28FL and 28FR are controlled to be the target steering angle δ, whereby the vehicle 12 is automatically driven so as to travel along the target route set by the navigation device 54.

The automatic driving ECU 46 sets the vehicle as a target route based on the information around the vehicle 12 input from the surrounding information acquisition device 52 and the information of the target route to the current location and the destination of the vehicle 12 input from the navigation device 54. The target steering angle δt of the front wheels 28FL and 28FR for traveling along the above is calculated. The signal indicating the target steering angle δt is input to the steering control ECU 44. Further, the automatic driving ECU 46 calculates the target acceleration / deceleration speed Gx of the vehicle based on the vehicle speed V, the information around the vehicle 12 and the information of the target route to the current location and the destination of the vehicle, and indicates the target acceleration / deceleration speed Gxt. The signal is output to the control driving force control ECU 56.

Although not shown in the figure, the control driving force control ECU 56 controls a driving force generator such as an engine when the target acceleration / deceleration speed Gxt of the vehicle is the target acceleration, and the target acceleration / deceleration speed Gxt of the vehicle is the target deceleration. When it is at speed, it controls a braking force generating device such as a braking device. Therefore, the vehicle speed is controlled by controlling the control driving force of the vehicle so that the acceleration / deceleration speed Gx of the vehicle 12 becomes the target acceleration / deceleration speed Gxt.

The target steering angle δt for automatic operation may be calculated by any method known in the art. Similarly, the control of the controlling driving force of the vehicle for autonomous driving may be calculated by any method known in the art.

Further, the automatic driving ECU 46 determines by self-diagnosis whether or not the surrounding information acquisition device 52, the navigation device 54, and the communication with them are normal, and the automatic driving control is normally executed. When the automatic operation ECU 46 determines that an abnormality has occurred in the surrounding information acquisition device 52 or the like and the automatic operation control cannot be normally executed, the alarm device 58 is activated to indicate that the automatic operation control is not normal. It issues an alarm and urges the driver to end automatic driving and drive.

When it is determined that the steering control ECU 44 cannot normally execute the automatic driving control by the automatic driving ECU 46, the operation of the steering wheel 20 by the driver is reflected in the control of the steering angles of the front wheels 28FL and 28FR. It is determined that a predetermined condition in which a higher degree is preferable is satisfied. Further, the steering control ECU 44 sets the steering gear ratio Rst to the transient steering gear ratio Rstt between the steering gear ratio Rsta at the time of automatic steering and the standard steering gear ratio Rstn, and sets the steering angles δ of the front wheels 28FL and 28FR. Control so that the target rudder angle is δt. In this case, the steering control ECU 44 controls the reaction force actuator 24 so that the steering angle θ becomes Rstt · δt, so that the steering wheel 20 is rotationally driven by the reaction force actuator 24.

In the embodiment, the steering control ECU 44 has a transient steering gear until the steering gear ratio Rst changes from the steering gear ratio Rsta during automatic steering to the standard steering gear ratio Rstn, as shown by the solid line in FIG. The ratio Rstt is gradually increased. Further, the steering control ECU 44 maintains the standard steering gear ratio when the steering gear ratio Rst becomes the standard steering gear ratio Rstn. Further, in the steering control ECU 44, while the steering gear ratio is set to the transient steering gear ratio Rstt, the steering wheel 20 causes the driver to change the steering gear ratio Rst by operating the alarm device 60. Generates an alarm to notify that it is rotating.

The alarm generated by the alarm devices 58 and 60 may be an auditory alarm such as an alarm sound or voice, a visual alarm such as lighting or blinking of an alarm lamp or a display, or a sensory alarm such as vibration. good. This also applies to the alarm device of other embodiments described later. Further, it is preferable that the alarm generated by the alarm device 58 and the alarm generated by the alarm device 60 are clearly distinguishable from each other.

The automatic driving ECU 46 stops the alarm device 58 (and 60) when the steering angle θ is different from the reference value or more from Rstt · δt and the driver operates the steering wheel 20 to determine that the automatic driving is completed. At the same time, the automatic operation switch 48 is switched off. Therefore, the steering control ECU 44 determines that the steering mode is the manual steering mode, and sets the steering gear ratio Rst to the standard steering gear ratio Rstn. Even if the automatic operation switch 48 is turned off by the driver before the steering gear ratio Rst becomes the standard steering gear ratio Rstn, the steering control ECU 44 determines that the steering mode is the manual steering mode. Then, the steering gear ratio Rst is set to the standard steering gear ratio Rstn.

<Steering control routine of the first embodiment>
Next, the steering control routine of the first embodiment will be described. Unless otherwise specified, the CPU of the steering control ECU 44 (hereinafter, “CPU” refers to the CPU of the steering control ECU 44) performs the steering control routine shown in the flowchart of FIG. 2 every time a predetermined time elapses. Execute.

At a predetermined timing, the CPU starts processing from step 200 in FIG. 2, executes steps 205 to 285, and then proceeds to step 290 to temporarily end this routine. The control program corresponding to the flowchart of FIG. 2 is stored in the ROM of the steering control ECU 44.

First, in step 205, the CPU determines whether or not the automatic operation switch 48 is on. When the affirmative determination is made, the steering control proceeds to step 215, and when the negative determination is made, the steering control proceeds to step 210.

In step 210, the CPU controls the electric motor of the reaction force actuator 24 based on the steering angle θ, the differential value of the steering angle, the second derivative value of the steering angle, and the vehicle speed V, so that the steering reaction force torque is applied to the steering wheel 20. Give Tre. When step 210 is completed, steering control proceeds to step 275.

In step 215, the CPU determines whether or not the automatic operation control is normally performed based on the result of the self-diagnosis by the automatic operation ECU 46. When the affirmative determination is made, the CPU sets the steering gear ratio Rst to the steering gear ratio Rsta (= 0) at the time of automatic steering in step 220. When the negative determination is made, the steering control proceeds to step 225.

In step 225, the CPU activates the alarm device 58 to generate an alarm notifying that the steering wheel 20 rotates with a change in the steering gear ratio Rst. When the alarm device 58 is already stopped in step 250 described later, the alarm device 58 is not activated.

In step 230, the CPU determines whether or not the steering operation has been performed by the driver. When the affirmative determination is made, the steering control proceeds to step 270, and when the negative determination is made, the steering control proceeds to step 235.

In step 235, the CPU sets Rstf as the previous value of the steering gear ratio Rst, ΔRstt as the gradual increase of the steering gear ratio Rst, and the steering gear ratio Rst as the transient steering gear ratio Rstt of Rstf + ΔRstt. The gradual increase amount ΔRstt may be a positive constant, but for example, the absolute value of the target steering angle δt or the vehicle speed V increases as the absolute value of the target steering angle δt for automatic operation decreases and increases as the vehicle speed V increases. It may be variably set according to the above. Further, the gradual increase amount ΔRstt is set so that the change speed of the steering gear ratio Rst is lower than the change speed when the automatic operation switch 48 is switched from on to off.

In step 240, the CPU calculates a standard steering gear ratio Rstn by referring to the map shown in FIG. 9 based on the vehicle speed V. As shown in FIG. 9, the standard steering gear ratio Rstn is calculated so as to increase as the vehicle speed increases, except that the minimum value Rstnmin and the maximum value Rstnmax become constant values in the very low speed range and the high speed range, respectively. Will be done.

In step 245, the CPU determines whether or not the steering gear ratio Rst calculated in step 235 is equal to or greater than the standard steering gear ratio Rstn. When a negative determination is made, the steering control proceeds to step 260, and when an affirmative determination is made, the CPU stops the alarm device 58 in step 250, and in step 255, the steering gear ratio Rst is changed to the standard steering gear ratio Rstn. Set.

In step 260, the CPU inputs the target steering angle δt by reading a signal indicating the target steering angle δt of the front wheels 28FL and 28FR calculated by the automatic driving ECU 46.

In step 265, the CPU controls the steering actuator 32 so that the steering angles δ of the front wheels 28FL and 28FR become the target steering angle δt. Further, the CPU controls the reaction force actuator 24 so that the steering gear ratio becomes the Rst set in step 220, 235 or 255. When the steering gear ratio is Rst set in step 235 or 255, the steering wheel 20 is rotationally driven by the reaction force actuator 24, but when the steering gear ratio is Rst set in step 220, the steering wheel 20 Is not driven to rotate.

In step 270, the CPU stops the alarm device 58 when it is in operation. Further, the CPU switches the automatic operation switch 48 to off.

In step 275, as in step 240, the CPU calculates the standard steering gear ratio Rstn by referring to the map shown in FIG. 9 based on the vehicle speed V, and calculates the steering gear ratio Rst. The steering gear ratio is set to Rstn.

In step 280, the CPU calculates the target steering angles δt of the front wheels 28FL and 28FR as θ / Rstn based on the steering angle θ detected by the steering angle detecting device 22 and the standard steering gear ratio Rstn.

In step 285, the CPU controls the steering actuator 32 so that the steering angles δ of the front wheels 28FL and 28FR become the target steering angle δt.

<Operation of the first embodiment>
Next, various cases of the operation of the first embodiment will be described.

A. During automatic driving (during automatic steering mode)
A-1. When the control of automatic driving is normal, a positive determination is made in steps 205 and 215, and the steering gear ratio Rst is set to the steering gear ratio Rsta at the time of automatic steering in step 220. Since the steering gear ratio Rsta at the time of automatic steering is 0, the steering wheel 20 does not rotate at all. Further, in step 260, a signal indicating the target steering angles δt of the front wheels 28FL and 28FR calculated by the automatic operation ECU 46 is read, and in step 265, the steering angles δ of the front wheels 28FL and 28FR are changed so as to be the target steering angle δt. The rudder actuator 32 is controlled.

A-2. When the control of automatic driving becomes abnormal, a positive determination is made in step 205, but a negative determination is made in step 215. Therefore, when the alarm device 58 is activated in step 225, an alarm indicating that the automatic operation control is not normal is generated, and when the alarm device 60 is activated, the steering wheel 20 is changed according to the change in the steering gear ratio Rst. An alarm is generated to inform that the wheel is rotating.

A-2-1. When the steering operation is not performed by the driver A negative determination is made in step 230, and the steering gear is determined in steps 235 and 240 until it is determined in step 245 that the steering gear ratio Rst is equal to or greater than the standard steering gear ratio Rstn. The ratio Rst is gradually increased. Further, in steps 260 and 265, the steering actuator 32 is controlled so that the steering angles δ of the front wheels 28FL and 28FR become the target steering angle δt. Therefore, the rotation angle of the steering wheel 20 gradually increases with the change of the steering angle δ of the front wheels 28FL and 28FR.

When the steering gear ratio Rst becomes equal to or higher than the standard steering gear ratio Rstn, a positive determination is made in step 245, and the alarm device 60 is stopped in step 250. Further, in step 255, the steering gear ratio Rst is set to the standard steering gear ratio Rstn, and in steps 260 and 265, the steering actuator 32 is controlled so that the steering angles δ of the front wheels 28FL and 28FR become the target steering angle δt. .. Therefore, the steering wheel 20 rotates at the same standard steering gear ratio Rstn as in the manual steering mode as the steering angles δ of the front wheels 28FL and 28FR change.

A-2-2. When the steering operation is performed by the driver, a positive determination is made in step 230, the alarm device 58 is stopped in step 270, and the automatic operation switch 48 is switched off. In step 275, the standard steering gear ratio Rstn is calculated, and the steering gear ratio Rst is set to the standard steering gear ratio Rstn. Further, in step 280, the target steering angle δt of the front wheels 28FL and 28FR is calculated as a value θ / Rstn obtained by dividing the steering angle θ by the standard steering gear ratio Rstn, and in step 285, the steering angle δ of the front wheels is the target steering angle δt. The steering actuator 32 is controlled so as to be.

B. During non-automatic operation (during manual steering mode)
Negative determination is made in step 205, and steering reaction torque Tre is applied to the steering wheel 20 in step 210. Further, as in the case of A-2-2, the standard steering gear ratio Rstn is calculated in step 275, and the steering gear ratio Rst is set to the standard steering gear ratio Rstn. Further, in step 280, the target steering angles δt of the front wheels 28FL and 28FR are calculated to θ / Rstn, and in step 285, the steering actuator 32 is controlled so that the steering angle δ of the front wheels becomes the target steering angle δt.

<Specific example of operation of the first embodiment>
Next, a specific example of the operation of the first embodiment will be described with reference to FIG. In FIG. 3 and FIG. 6 described later, the circles attached to the steering wheel 20 indicate that the steering wheel is operated by the driver's hand 62.

As shown in FIG. 3, at the time point t11 when the vehicle 12 is traveling in the manual driving mode, the automatic driving switch 48 is switched on, and at the time point t12, an abnormality occurs in the control of the automatic driving. do. It is assumed that the automatic operation switch 48 is switched off at the time point t14 and the steering operation by the driver is started. Therefore, the section from the time point t12 to the time point t14 is the transition standby time to the manual operation mode. Further, it is assumed that the steering gear ratio Rst gradually increases at the time point t12, and the steering gear ratio Rst becomes the standard steering gear ratio Rstn at the time point t13.

The steering mode changes from the manual steering mode to the automatic steering mode at the time point t11, and changes from the automatic steering mode to the manual steering mode at the time point t14. The steering gear ratio Rst switches from the standard steering gear ratio Rstn to the steering gear ratio Rsta during automatic steering at time point t11, and the steering gear ratio Rsta during automatic steering to the standard steering gear ratio in the section from time point t12 to time point t13. It is gradually increased to Rstn, and thereafter it is maintained at the standard steering gear ratio Rstn.

Therefore, in the section from the time point t11 to the time point t14, the front wheels 28FL and 28FR are steered by automatic operation, but the steering wheel 20 does not rotate in the section from the time point t11 to the time point t12. In the section from time point t12 to time point t13, the ratio of the rotation angle of the steering wheel 20 to the steering angle δ of the front wheels 28FL and 28FR gradually increases, and after the time point t13, if the vehicle speed V does not change, the ratio of the rotation angle is It does not change.

In the case of the conventional steering control device in which the steering gear ratio Rst is not gradually increased even if an abnormality occurs in the automatic operation control, the steering operation by the driver is started as shown by the two-dot chain line in FIG. At the time point t14, the steering gear ratio Rst suddenly changes from the steering gear ratio Rsta at the time of automatic steering to the standard steering gear ratio Rstn. Therefore, if the steering angle of the front wheels corresponding to the rotation angle of the steering wheel 20 at the time when the steering operation by the driver is started and the actual steering angle δ are different, the driver determines the amount of rotation operation of the steering wheel. The relationship with the steering angle δ of the front wheels cannot be accurately grasped, and there is a risk of transient excessive or under-steering.

Generally, the steering operation by the driver is started when a certain amount of time has elapsed after an abnormality occurs in the control of automatic driving. Therefore, when the steering operation by the driver is started, the steering gear ratio Rst is standard steering. The gear ratio is Rstn or a value close to it. Therefore, according to the first embodiment, the driver can accurately grasp the relationship between the rotational operation amount of the steering wheel and the steering angle δ of the front wheels and perform the steering operation accurately.

[Second embodiment]
The vehicle steering control device 10 according to the second embodiment is applied to a vehicle 12 in which driving support is controlled as automatic steering control. As shown in FIG. 4, the steering device 14 is configured similarly to the steering device of the first embodiment and includes a steering input device 17 and a steering device 18 that are not mechanically connected to each other. ..

The control unit 16 of the second embodiment includes a steering control ECU 44 that controls a steering input device 17 and a steering device 18, and a driving support ECU 66 that controls driving support. The driving support ECU 66 does not operate when the driving support switch (denoted as a driving support SW in FIG. 4) 68 is off, and operates when the driving support switch 68 is on.

Although not shown in detail in FIG. 4, the driving support ECU 66 includes a microcomputer and a drive circuit, and exchanges and exchanges necessary information with the steering control ECU 44. The microcomputer has a CPU, a ROM, a RAM, and an input / output port device, which have a general configuration in which they are connected to each other by a bidirectional common bus.

A signal indicating whether or not the driving support switch 68 is on is input to the driving support ECU 66, and a signal indicating the vehicle speed V detected by the vehicle speed sensor 50 is input. Further, a signal indicating information around the vehicle 12 acquired by the ambient information acquisition device 52 such as a CCD camera and a radar is input to the driving support ECU 66.

The driving support ECU 66 performs trajectory control (lane keeping assist control) (referred to as "LKA control" if necessary) for driving the vehicle along the lane as driving support control. The ECU 66 determines the positional relationship of the vehicle with respect to the lane based on the information around the vehicle 12 input from the surrounding information acquisition device 52, and calculates the target steering angles δt of the front wheels 28FL and 28FR based on the determination result. , A signal indicating the target steering angle δt is output to the steering control ECU 44.

Further, the driving support ECU 66 calculates the target acceleration / deceleration speed Gx of the vehicle based on the vehicle speed V, information around the vehicle 12, and outputs a signal indicating the target acceleration / deceleration speed Gxt to the control driving force control ECU 56. Further, the ECU 66 outputs a signal indicating the target steering angle δt to the steering control ECU 44, and outputs a signal indicating the target acceleration / deceleration Gxt to the control driving force control ECU 56. The LKA control as the driving support control may be executed by any method known in the art.

In particular, when an obstacle is detected in front of the vehicle 12, the driving support ECU 66 activates the alarm device 70 to generate an alarm informing the driver that there is an obstacle and avoids the obstacle. The target steering angle δt for driving and the target acceleration / deceleration speed Gx of the vehicle are calculated. The signal indicating the target steering angle δt is input to the steering control ECU 44, and the signal indicating the target acceleration / deceleration speed Gx of the vehicle is input to the control driving force control ECU 56.

The steering control ECU 44 sets the steering gear ratio Rst to the steering gear ratio Rstn during manual steering when the driving support switch 68 is off, and sets the steering gear ratio Rst to the steering gear ratio Rst when the driving support switch 68 is on. The steering gear ratio at the time is set to Rsta. When the steering control ECU 44 detects an obstacle in front of the vehicle 12 and determines that the driver may perform corrective steering, the driver operates the steering wheel 20 to steer the front wheels 28FL and 28FR. It is determined that a predetermined condition is satisfied, in which it is preferable that the degree of reflection in the angle control is high. Further, the steering control ECU 44 controls the steering gear ratio Rst and gradually increases the steering gear ratio Rs as in the case where it is determined that the automatic operation control cannot be normally executed in the first embodiment. While the alarm device 58 is activated.

Further, the steering control ECU 44 controls the steering angles δ of the front wheels 28FL and 28FR to be the target steering angle δt when the driving support switch 68 is on and the driver does not perform corrective steering. On the other hand, in the steering control ECU 44, when the driving support switch 68 is on and the driver is performing the correction steering, the steering angles δ of the front wheels 28FL and 28FR correspond to the target steering angle δt and the correction steering amount. It is controlled so as to be the sum of the rudder angle correction amount Δδt.

The control driving force control ECU 56 controls the driving force of the vehicle so that the acceleration / deceleration speed Gx of the vehicle 12 becomes the target acceleration / deceleration speed Gxt, so that the driving force of the engine or the like is controlled in the same manner as in the first embodiment. Controls a braking force generator such as a generator or brake device.

<Steering control routine of the second embodiment>
Next, the steering control routine of the second embodiment will be described. The CPU of the steering control ECU 44 executes the steering control routine shown in the flowchart of FIG. 5 every time a predetermined time elapses.

At a predetermined timing, the CPU starts processing from step 500 in FIG. 5, executes steps 505 to 585, and then proceeds to step 590 to temporarily end this routine. The control program corresponding to the flowchart of FIG. 5 is stored in the ROM of the steering control ECU 44.

As can be seen from the comparison between FIG. 5 and FIG. 2, steps 505 to 585 are executed in the same manner as steps 205 to 285 of FIG. 2, except for the steps described below.

First, in step 505, the CPU determines whether or not the operation support switch 68 is on. When the affirmative determination is made, the steering control proceeds to step 515, and when the negative determination is made, the steering control proceeds to step 510.

In step 515, the CPU determines whether or not an obstacle is detected in front of the vehicle 12 by, for example, the surrounding information acquisition device 52, and the driver may perform corrective steering. When the negative determination is made, the steering control proceeds to step 520, and when the positive determination is made, the alarm device 58 is activated in step 525. It should be noted that it may be determined that the driver may perform corrective steering even in a situation where, for example, the preceding vehicle suddenly changes lanes or the following vehicle suddenly cuts in front of the vehicle. ..

In step 560, the CPU reads a signal indicating the target steering angle δt of the front wheels 28FL and 28FR calculated by the driving support ECU 66. In step 570, the CPU stops the alarm device when the alarm device 58 is activated, but does not switch the operation support switch 68 off.

As can be seen from the above description, in the second embodiment, when it is determined that the vehicle driver may perform corrective steering, "A-2. Automatic driving" of the first embodiment is performed. It operates in the same way as "when the control becomes abnormal".

However, if the driver performs a steering operation in a situation where it is determined that the driver may perform corrective steering, step 570 is executed and the driving support switch 68 cannot be switched off. .. Therefore, the LKA control as the driving support control is continued unless the driving support switch 68 is switched off by the driver.

<Specific example of operation of the second embodiment>
Next, a specific example of the operation of the second embodiment will be described with reference to FIG.

As shown in FIG. 6, at the time point t21 when the vehicle 12 is traveling in the driving support mode, an obstacle is detected in front of the vehicle 12, and the alarm device 58 is activated from the time point t21 to the time point t23. Suppose it was done. Further, in the section from the time point t21 to the time point t22, the steering gear ratio Rsta at the time of automatic steering is gradually increased to the standard steering gear ratio Rstn, and thereafter, the standard steering gear ratio Rstn is maintained.

It is assumed that the automatic braking by the driving support is operated from the time point t23 to the time point t24, and at the time point t245, the automatic steering control by the driving support for avoiding the collision with the obstacle is started. Further, it is assumed that the corrective steering is performed by the driver from the time point t25 to the time point t26.

Therefore, in the section up to the time point t21, the steering wheel 20 does not rotate even if the front wheels 28FL and 28FR are steered by driving support. In the section from time point t21 to time point t22, the ratio of the rotation angle of the steering wheel 20 to the steering angle δ of the front wheels 28FL and 28FR gradually increases, and after the time point t22, if the vehicle speed V does not change, the ratio of the rotation angle is It does not change.

In the case of the conventional steering control device in which the steering gear ratio Rst is not gradually increased even if an obstacle is detected in front of the vehicle 12, the steering operation by the driver is performed as shown by the two-dot chain line in FIG. At the start time t25, the steering gear ratio Rst suddenly changes from the steering gear ratio Rsta at the time of automatic steering to the standard steering gear ratio Rstn. Therefore, if the steering angle of the front wheels corresponding to the rotation angle of the steering wheel 20 at the time when the steering operation by the driver is started and the actual steering angle δ are different, the driver determines the amount of rotation operation of the steering wheel. The relationship with the steering angle δ of the front wheels cannot be accurately grasped, and there is a risk of transient excessive or under-steering.

In general, the driver's corrective steering operation is started when a certain amount of time has elapsed after the automatic steering of obstacle avoidance by driving assistance is started. Therefore, when the driver's steering operation is started, the steering gear is started. The ratio Rst is the standard steering gear ratio Rstn or a value close to it. Therefore, according to the second embodiment, the driver can accurately grasp the relationship between the rotational operation amount of the steering wheel and the steering angle δ of the front wheels and perform the corrective steering operation accurately.

[Third embodiment]
The vehicle steering control device 10 according to the third embodiment is applied to a vehicle 12 in which remote control is controlled as automatic steering control. The control of remote driving in the third embodiment is performed in a situation where the driver is on board the vehicle 12 and stands by in case of an emergency. As shown in FIG. 7, the control unit 16 of the steering control device 10 includes a steering control ECU 44 and a remote control ECU 80 for transmitting and receiving signals. The remote control ECU 80 wirelessly communicates with the operation command ECU 84 at a remote location via the relay station 82 or directly.

Although not shown in detail in FIG. 7, the remote control ECU 80 and the operation command ECU 84 include a microcomputer and a wireless communication device. Each microcomputer has a CPU, ROM, RAM, and an input / output port device, which have a general configuration in which they are connected to each other by a bidirectional common bus.

The steering control ECU 44 controls the steering device 14 as in the first and second embodiments. The steering device 14 includes a steering input device 17 and a steering device 18 that are not mechanically connected to each other. Although not shown in detail in FIG. 7, the steering input device 17 and the steering device 18 are configured in the same manner as the steering input device and the steering device of the first and second embodiments. Therefore, the steering input device 17 includes a steering wheel (not shown) operated as needed by the standby driver, and the steering device 18 changes the steering angles δ of the front wheels 28FL and 28FR.

The operation command ECU 84 is connected to a remote steering input device 86, a remote braking input device 88, and a remote drive input device 90 operated by a remote driver (not shown). The remote steering input device 86 includes a steering wheel 92 and a remote steering angle detecting device 94 that detects the rotation angle thereof as a remote steering angle θr. The remote braking input device 88 includes a brake pedal 96 and a pedal force detecting device 98 that detects a pedaling force Fbp with respect to the brake pedal. Further, the remote drive input device 90 includes an accelerator pedal 100 and an accelerator opening degree detecting device 102 that detects the amount of depression of the accelerator pedal as the accelerator opening degree A.

The remote control ECU 80 operates when the remote control SW 104 is on, and the operation command ECU 84 operates when the remote command SW 106 is on. The operation command ECU 84 outputs a remote control command to the remote control ECU 80 when the remote control SW104 and the remote command SW106 are on, and the remote control ECU 80 outputs the remote control command when the remote control command is received. Take control.

The remote control ECU 80 acquires the remote steering angle θr detected by the remote steering angle detection device 94, and via the steering control ECU 44 so that the steering angles δ of the front wheels 28FL and 28FR become the steering angles corresponding to θr. It controls the steering device 14. In this case, the steering gear ratio Rst is set to the steering gear ratio Rsta during remote control. The steering gear ratio Rsta during remote control is 0, as in the other embodiments, and the steering wheel 20 does not rotate at all even if the front wheels 28FL and 28FR are steered by remote control, but is close to 0, for example. It may be a positive value.

Further, the remote control ECU 80 acquires the pedaling force Fbp detected by the pedaling force detecting device 98, and acquires the accelerator opening degree A detected by the accelerator opening degree detecting device 102. Further, the remote control ECU 80 is shown in FIG. 7 via the control drive force control ECU 56 so that the control drive force of the vehicle 12 becomes a braking force corresponding to the pedaling force Fbp or a drive force corresponding to the accelerator opening degree A. Control the uncontrolled driving force generator.

Further, when the remote control SW104 or the remote command SW106 is off, the remote control ECU 80 outputs a signal indicating that to the steering control ECU 44. The steering control ECU 44 sets the steering gear ratio Rst to the standard steering gear ratio Rstn when the remote control SW104 or the remote command SW106 is off, that is, when the vehicle 12 autonomously travels. On the other hand, the steering control ECU 44 sets the steering gear ratio Rst to the steering gear ratio Rsta during remote control when the remote control SW104 and the remote command SW106 are on.

Further, the remote control ECU 80 determines whether or not necessary information is normally acquired from the operation command ECU 84. When the necessary information cannot be obtained normally due to an abnormality in the wireless communication between the remote operation ECU 80 and the operation command ECU 84, the remote steering angle detection device 94, etc., the remote operation is abnormal. The indicated signal is output to the steering control ECU 44. Further, when the remote operation ECU 80 cannot normally acquire the necessary information, the alarm device 108 is operated to indicate that the necessary information cannot be normally acquired and the remote operation is abnormal. Generates an alarm to indicate.

When the steering control ECU 44 receives a signal indicating that the remote control is abnormal, it is preferable that the operation of the steering wheel 20 by the standby driver is reflected in the control of the steering angles of the front wheels 28FL and 28FR to a high degree. It is determined that the predetermined conditions are satisfied. Further, the steering control ECU 44 controls the steering gear ratio Rst and gradually increases the steering gear ratio Rst as in the case where it is determined that the automatic operation control cannot be normally executed in the first embodiment. While the alarm device 58 is activated.

<Steering control routine of the third embodiment>
Next, the steering control routine of the third embodiment will be described. The CPU of the steering control ECU 44 executes the steering control routine shown in the flowchart of FIG. 8 every time a predetermined time elapses.

At a predetermined timing, the CPU starts processing from step 800 in FIG. 8 to execute steps 805 to 885, and then proceeds to step 890 to temporarily end this routine. The control program corresponding to the flowchart of FIG. 8 is stored in the ROM of the steering control ECU 44.

As can be seen from the comparison between FIG. 8 and FIG. 2, steps 805 to 885 are executed in the same manner as steps 205 to 285 of FIG. 2, except for the steps described below.

First, in step 805, the CPU determines whether or not the remote operation SW104 and the remote command SW106 are on. When the affirmative determination is made, the steering control proceeds to step 815, and when the negative determination is made, that is, when it is determined that at least one of the remote control SW104 and the remote command SW106 is off, the steering control proceeds to step 810. move on.

In step 815, the CPU has not received a signal from the remote control ECU 80 indicating that the remote control is abnormal, and determines whether or not the remote control is normal. When the affirmative determination is made, the steering control proceeds to step 820, and when the negative determination is made, the alarm device 58 is activated in step 825.

In step 830, the CPU determines whether or not the steering operation has been performed by the standby driver. When the affirmative determination is made, the steering control proceeds to step 870, and when the negative determination is made, the steering control proceeds to step 835.

In step 860, the CPU calculates the target steering angles δt of the front wheels 28FL and 28FR as θr / Rst based on the remote steering angle θr. In step 870, the CPU stops the alarm device when the alarm device 58 is activated, and switches the remote operation SW104 to off.

As can be seen from the above description, in the third embodiment, when the remote control ECU 80 does not normally acquire the necessary information from the operation command ECU 84, the first embodiment except for steps 830, 860 and 870. It operates in the same manner as "A-2. When the control of automatic operation becomes abnormal" of the embodiment.

Since the specific example of the third embodiment is substantially the same as the specific example of the first embodiment, the description referring to the figure will be omitted. However, the time point t11 in the specific example of the first embodiment shown in FIG. 3 is the time point when it is determined that the remote control SW104 and the remote command SW106 are on. Further, the time point t12 is a time point when a signal indicating that the acquisition of information is abnormal is received and it is determined that a predetermined condition is satisfied. The manual operation mode and the automatic operation mode shown in FIG. 3 are an autonomous operation mode and a remote operation mode by a standby driver, respectively.

In the case of the conventional steering control device in which the steering gear ratio Rst is not gradually increased even if the necessary information cannot be acquired normally, the steering gear ratio Rst is remotely steered when the steering operation by the standby driver is started. The steering gear ratio Rsta at the time suddenly changes to the standard steering gear ratio Rstn. Therefore, if the steering angle of the front wheels corresponding to the rotation angle of the steering wheel 20 at the time when the steering operation by the driver is started and the actual steering angle δ are different, the driver determines the amount of rotation operation of the steering wheel. The relationship with the steering angle δ of the front wheels cannot be accurately grasped, and there is a risk of transient excessive or under-steering.

Generally, the steering operation by the driver is started when a certain amount of time has elapsed after an abnormality occurs in the control of remote operation. Therefore, when the steering operation by the driver is started, the steering gear ratio Rst is standard steering. The gear ratio is Rstn or a value close to it. Therefore, according to the third embodiment, the driver can accurately grasp the relationship between the rotational operation amount of the steering wheel and the steering angle δ of the front wheels and accurately perform the autonomous steering operation.

Further, according to the first to third embodiments, the steering gear ratio Rst is gradually increased to the standard steering gear ratio Rstn over a predetermined time Δt from the time when an abnormality in the control of automatic operation occurs. Therefore, the speed at which the steering wheel is rotated relative to the front wheels as the steering gear ratio changes is higher than when the steering gear ratio Rsta during automatic steering suddenly changes to the standard steering gear ratio Rstn. Since it becomes calm, it is possible to reduce the discomfort caused by the rotation of the steering wheel.

Further, in the case of the conventional steering control device in which the steering gear ratio Rst is not gradually increased even if an abnormality in the control of automatic driving occurs, it is determined by the steering angle and the standard steering gear ratio when the driver starts the steering operation. The steering angle of the front wheels may be smaller than the steering angle of the front wheels by automatic steering. In that case, the driver may feel uncomfortable because the front wheels are steered in the direction opposite to the direction in which the driver tries to steer the front wheels by operating the steering wheel.

On the other hand, according to the first to third embodiments, when the steering operation by the driver is started as described above, the steering gear ratio Rst is at or near the standard steering gear ratio Rstn. Therefore, it is possible to reduce the possibility that the steering angle of the front wheels, which is determined by the steering angle and the standard steering gear ratio, becomes smaller than the steering angle of the front wheels by automatic steering when the driver starts the steering operation. Therefore, it is possible to reduce the risk that the driver feels uncomfortable due to the front wheels being steered in the direction opposite to the direction in which the driver tries to steer the front wheels by operating the steering wheel. ..

In the first to third embodiments, when it is determined that the predetermined conditions are satisfied, the transient steering gear ratio Rstt is the standard steering gear from the steering gear ratio Rsta (= 0) at the time of automatic steering. It is gradually increased over a predetermined time Δt until the ratio Rstn is reached. However, the transient steering gear ratio Rstt may be a constant value between the steering gear ratio Rsta during automatic steering and the standard steering gear ratio Rstn.

Even in that case, it is determined that the predetermined condition is satisfied, and the steering gear ratio Rst when the steering operation is started by the driver can be set to a value close to the standard steering gear ratio Rstn. Therefore, even if it is determined that the predetermined conditions are satisfied, the driver can operate the steering wheel rotation and the steering angle δ of the front wheels as compared with the case where the steering gear ratio Rst is not set to the transient steering gear ratio Rstt. It is possible to reduce the deviation from the steering wheel and increase the possibility that the driver can perform the steering operation accurately.

In the above, the present invention has been described in detail with respect to specific embodiments, but the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. That will be clear to those skilled in the art.

For example, in each of the above-described embodiments, the gradual increase amount ΔRstt is a positive constant. It may be variably set according to the absolute value of the angle δt or the vehicle speed V. Further, the gradual increase amount ΔRstt may be variably set by a dial operated by the driver or the like.

Further, in each of the above-described embodiments, when it is determined that the predetermined conditions are satisfied, the transient steering gear ratio Rstt is the steering gear ratio during automatic steering, as shown by the solid line in FIG. It is gradually increased over a predetermined time Δt from Rsta (= 0) to the standard steering gear ratio Rstn. However, as shown by the broken line in FIG. 10, when it is determined that the predetermined condition is satisfied, the steering gear ratio Rst gradually changes from a value larger than 0 to the standard steering gear ratio Rstn. It may be increased.

Further, as shown by the alternate long and short dash line in FIG. 10, when it is determined that a predetermined condition is satisfied, the transient steering gear ratio Rstt is from 0 to a steering gear smaller than the standard steering gear ratio Rstn. The ratio may be gradually increased until the ratio Rstn ′, and the standard steering gear ratio Rstn may be set after a predetermined time Δt has elapsed. Further, as shown by the alternate long and short dash line in FIG. 10, when it is determined that a predetermined condition is satisfied, the transient steering gear ratio Rstt starts from a value larger than 0 to the standard steering gear ratio Rstn. The steering gear ratio may be gradually increased until the steering gear ratio Rstn ′ is smaller than the standard steering gear ratio Rstn, and may be set to the standard steering gear ratio Rstn after a predetermined time Δt has elapsed. Further, although not shown in FIG. 10, the transient steering gear ratio Rstt may be non-linearly gradually increased.

Further, in the first to third embodiments described above, the control unit 16 includes a steering control ECU 44 and an automatic driving ECU 46, a steering control ECU 44 and a driving support ECU 66, a steering control ECU 44 and a remote driving ECU 80, respectively. Includes. However, the control unit 16 may be one electronic control device.

Further, in the first to third embodiments described above, the steering control device 10 is a vehicle in which automatic driving is controlled as automatic steering control, a vehicle in which driving support is controlled as automatic steering control, and an automatic vehicle. It is applied to vehicles in which remote driving is controlled as steering control.
However, at least two of the steering controls of the first to third embodiments may be implemented in combination.

10 ... Steering control device, 12 ... Vehicle, 14 ... Steering device, 16 ... Control unit, 17 ... Steering input device, 18 ... Steering device, 20 ... Steering wheel, 22 ... Steering angle detection device, 24 ... Reaction force actuator, 28FL, 28FR ... Front wheels, 30 ... Steering mechanism, 32 ... Steering actuator, 34 ... Steering angle detection device, 44 ... Steering control ECU, 46 ... Automatic operation ECU, 48 ... Automatic operation switch, 56 ... Control driving force Control ECU, 66 ... Operation support ECU, 68 ... Operation support switch, 80 ... Remote operation ECU, 84 ... Operation command ECU, 86 ... Remote steering input device, 88 ... Remote braking input device, 90 ... Remote drive input Device

Claims (7)

The steering wheel, a steering angle detecting device that detects the rotation angle of the steering wheel as a steering angle, a reaction force actuator that applies steering reaction force torque to the steering wheel, and a steering wheel that receives steering torque to steer the steering wheel. A steer-by-wire type steering device including a steering mechanism configured as described above, a steering actuator that applies steering torque to the steering mechanism, and a steering angle detection device that detects the steering angle of the steering wheel.
A control unit that controls the reaction force actuator and the steering actuator, and when the steering mode is the manual steering mode, the steering gear ratio is set to a preset standard steering gear ratio and the steering angle detection device is used. The steering angle of the steering wheel is controlled based on the steering angle detected by, and when the steering mode is the automatic steering mode, the target steering angle of the steering wheel is calculated, and the steering gear ratio is set to the standard steering. A control unit configured to control the steering angle of the steering wheel to the target steering angle by setting the steering gear ratio at the time of automatic steering smaller than the gear ratio, and
In vehicle steering control devices including
In the situation where the steering mode is the automatic steering mode, the control unit preferably satisfies a predetermined condition that the degree to which the operation of the steering wheel by the driver is reflected in the control of the steering angle of the steering wheel is high. When it is determined that the steering gear ratio is set to the transient steering gear ratio between the steering gear ratio at the time of automatic steering and the standard steering gear ratio, the steering angle of the steering wheel is set to the target steering. A steering control device for vehicles configured to control the corners. In the vehicle steering control device according to claim 1, the control unit is configured to change the transient steering gear ratio so that the transient steering gear ratio gradually approaches the standard steering gear ratio. Control device. In the vehicle steering control device according to claim 2, the control unit gradually approaches the standard steering gear ratio from the steering gear ratio at the time of automatic steering to the standard steering gear ratio. A steering control device for a vehicle configured to change the transient steering gear ratio so as to be. The vehicle steering control device according to claim 1, wherein the control unit is configured to issue an alarm when the steering gear ratio is set to the transient steering gear ratio. In the vehicle steering control device according to any one of claims 1 to 4, the control unit sets a target steering angle of the steering wheel for controlling automatic driving when the automatic driving switch is on. When it is determined that the steering mode is the automatic steering mode, an abnormality occurs in the control of the automatic operation, and it is determined that the steering mode needs to shift to the manual steering mode, the predetermined condition is satisfied. A vehicle steering control device configured to determine that it is. In the vehicle steering control device according to any one of claims 1 to 4, the control unit sets a target steering angle of the steering wheel for controlling driving support when the driving support switch is on. For vehicles configured to calculate and determine that the steering mode is an automatic steering mode, and if it is determined that there is a possibility that corrective steering may be performed by the driver, it is determined that the predetermined condition is satisfied. Steering control device. In the vehicle steering control device according to any one of claims 1 to 4, when the control unit receives a command for remote driving, the target steering angle of the steering wheel for controlling remote driving is achieved. Is calculated, and when it is determined that the steering mode is the automatic steering mode and it is determined that the remote driving control is abnormal, it is determined that the predetermined condition is satisfied. Device.

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