WO2026047858A1 - Vehicle control device and vehicle control method - Google Patents

Abstract

This vehicle control device and this vehicle control method are configured to acquire vehicle momentum, such as lateral acceleration, generated in a vehicle and to control, when a steering device is automatically steered, the operation amount of a steering input member of the steering device on the basis of the vehicle momentum, such control being independent of the tire angle of the vehicle. As a result, during automatic steering, the operation amount of the steering input member can be safely and automatically controlled while information on the direction into which the vehicle turns is presented to a driver via a change in the operation amount of the steering input member.

Description

Vehicle control device and vehicle control method

The present invention relates to a vehicle control device and a vehicle control method.

The driving assistance system disclosed in Patent Document 1 is configured to change the steering characteristics in response to a change in the vehicle speed during the period from when autonomous driving begins, between when the driver's steering stops and when the driver's steering resumes. The change in steering characteristics includes reducing the steering angle of the vehicle's tires relative to the steering torque input by the driver in response to an increase in the vehicle speed during the period, and increasing the steering angle relative to the steering torque in response to a decrease in the vehicle speed during the period.

JP 2023-144726 A

For example, in the case of a steer-by-wire steering device in which a steering input member such as a steering wheel is mechanically separated from the steered wheels, during automatic steering that automatically controls the tire angle of the steered wheels (in other words, during automatic driving), it is possible to automatically control the operation amount of the steering input member (in other words, the operation position, steering angle, etc.) independently of the tire angle by utilizing the output of the steering reaction force actuator.
Here, if the steering input member moves quickly in response to a sudden change in tire angle during automatic steering, there is a possibility that the driver will be shocked.
On the other hand, if the driver cannot obtain indications of future vehicle behavior, such as which direction the vehicle will turn, through changes in the amount of operation of the steering input member, the driver may feel uneasy or distrustful of automatic steering.

The object of the present invention is to provide a vehicle control device and vehicle control method that can safely automatically control the amount of steering input member operation while presenting future vehicle behavior to the driver through changes in the amount of steering input member operation during automatic steering.

In one aspect, the vehicle control device according to the present invention is provided in a vehicle equipped with a steering device including a steering input member that accepts steering operations by a driver, and includes a vehicle momentum acquisition unit that acquires the vehicle momentum generated in the vehicle, and a target operation amount calculation unit that, when the steering device is automatically steered, calculates a target operation amount for the steering input member based on the vehicle momentum, independent of the tire angle of the vehicle, and outputs a signal of the target operation amount to the steering device.

In one aspect, the vehicle control method of the present invention is executed by a control unit provided in a vehicle equipped with a steer-by-wire steering device that includes a steering input member that accepts steering operations from the driver, and when the steering device is automatically steered, the amount of operation of the steering input member is controlled based on the lateral acceleration generated in the vehicle, independently of the tire angle of the vehicle.

According to the present invention, during automatic steering, the amount of steering input member operation can be safely and automatically controlled while providing the driver with information about the direction in which the vehicle will turn via changes in the amount of steering input member operation.

FIG. 1 is a block diagram showing a vehicle control system. FIG. 2 is a block diagram showing in detail the control function of the steer-by-wire system. FIG. 2 is a block diagram showing an example of a functional unit that calculates a target operation amount from a lateral acceleration. FIG. 10 is a diagram showing an example of a conversion table for calculating a target operation amount from a lateral acceleration. FIG. 10 is a diagram showing another example of a conversion table for obtaining a target operation amount from a lateral acceleration. FIG. 10 is a diagram showing an example of a conversion table for calculating a target operation amount from a lateral acceleration and a vehicle speed. 10 is a time chart illustrating an example of the correlation between tire angle, vehicle speed, lateral acceleration, and target operation amount in autonomous driving. 10A and 10B are diagrams illustrating a state in which the operation amount of a steering input member is changed in accordance with lateral acceleration. 10 is a time chart illustrating a change in the correlation between the tire angle and the operation amount due to switching between manual driving and automatic driving. FIG. 10 is a diagram showing an example of a conversion table for determining a target operation amount from a combination of a vehicle momentum amount such as a lateral acceleration and a lateral jerk or a roll rate. FIG. 10 is a diagram showing look-ahead points for predicting vehicle momentum. 10 is a time chart showing setting of a target operation amount based on a predicted vehicle momentum amount. 10A and 10B are diagrams illustrating a state in which the operation amount of the steering input member is changed in accordance with the predicted lateral acceleration. 10 is a time chart illustrating an example of a change in the correlation between a tire angle and an operation amount in control based on predicted vehicle momentum. 10 is a flowchart showing a flow of operation amount control based on vehicle momentum. FIG. 4 is a functional block diagram of a process for determining a target operation amount based on a predicted vehicle momentum amount. FIG. 10 is a diagram illustrating a process for setting a target manipulated variable based on a plurality of look-ahead points. FIG. 10 is a diagram illustrating a process of setting all points on a target trajectory as look-ahead points. FIG. 10 is a diagram illustrating a process for calculating a target manipulated variable by definite integration. FIG. 10 is a diagram illustrating an example of a function of a weighting coefficient with a look-ahead distance as a variable. FIG. 10 is a diagram illustrating an example of a function of a weighting coefficient with a look-ahead distance as a variable. FIG. 10 is a diagram illustrating an example of a function of a weighting coefficient with a look-ahead distance as a variable. 10A and 10B are diagrams illustrating examples of correlations between the curvature of a target trajectory, the differential value of the curvature, and the look-ahead time. FIG. 10 is a diagram illustrating an example of the correlation between lane width and look-ahead time. FIG. 10 is a diagram showing the setting characteristics of the look-ahead time when the curvature of the target trajectory is small and the road width is wide. 10A and 10B are diagrams illustrating examples of look-ahead points on a continuous curve with a large curvature; FIG. 10 is a diagram illustrating an example of the correlation between driving complexity and look-ahead time. FIG. 10 is a diagram illustrating how look-ahead points are set when the vehicle is made to follow a preceding vehicle. FIG. 10 is a diagram illustrating how look-ahead points are set when the vehicle is made to follow a preceding vehicle. FIG. 10 is a diagram illustrating how to set look-ahead points when the vehicle is not allowed to follow the preceding vehicle. FIG. 10 is a diagram illustrating how to set look-ahead points when the vehicle is not allowed to follow the preceding vehicle. FIG. 10 is a diagram showing look-ahead points on a target trajectory that avoids an obstacle. FIG. 10 is a diagram showing look-ahead points when a target trajectory for avoiding an obstacle is not set. FIG. 10 is a diagram showing look-ahead points on a target trajectory during emergency driving. FIG. 10 is a diagram showing the setting characteristics of the target manipulated variable during emergency operation. 10 is a time chart showing changes in tire angle and operation amount accompanying switching between manual driving and automatic driving. 10 is a flowchart showing the adjustment process when switching from manual driving to automatic driving. FIG. 10 is a functional block diagram showing a process for calculating a target manipulated variable after adjustment. 4 is a time chart showing a change in a target operation amount when switching from manual driving to automatic driving. 10 is a flowchart showing the adjustment process when switching from automatic driving to manual driving. FIG. 4 is a functional block diagram showing a process for calculating a target tire angle after adjustment. 10 is a time chart showing changes in tire angle and operation amount when switching from automatic driving to manual driving.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a vehicle control device and a vehicle control method according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a block diagram showing one embodiment of a vehicle control system 200 that is mounted on a vehicle 100 such as a four-wheeled automobile and controls the movement of the vehicle 100 .
The vehicle control system 200 is a system that enables automatic driving (automatic steering) of the vehicle 100 to travel along a target trajectory, and includes an external environment recognition unit 300, a vehicle momentum detection unit 400, a vehicle control device 500, and a travel actuator unit 600.

The external environment recognition unit 300 includes various sensor devices for acquiring external environment information of the vehicle 100 .
The external environment recognition unit 300 includes, for example, a GPS (Global Positioning System) receiving unit 310, a map database 320, a road-to-vehicle communication device 330, a camera 340, a radar 350, a LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) 360, and other sensor devices.

The GPS receiver 310 receives signals from GPS satellites to measure the latitude and longitude of the vehicle 100 .
The map database 320 is formed in a storage device mounted on the vehicle 100, and the map information in the map database 320 includes information such as road locations, road shapes, and intersection locations.

The road-to-vehicle communication device 330 is a device that communicates with roadside devices, transmits information about the vehicle 100 to the roadside devices, and receives road traffic information such as curves and intersections from the roadside devices.
The external environment recognition unit 300 may include an inter-vehicle communication device that communicates with other vehicles to acquire road traffic information, behavior information of other companies, and the like from the other vehicles.

The camera 340 is a stereo camera, a monocular camera, a 360-degree camera, or the like, and captures images of the surroundings of the vehicle 100 to obtain image information of the surroundings of the vehicle 100 .
The radar 350 and the LiDAR 360 detect objects around the vehicle 100 and output information about the detected objects.

The vehicle momentum detection unit 400 includes a wheel speed sensor 410, an inertial measurement unit 420, and the like.
The wheel speed sensor 410 is a sensor that detects the rotation speed of each wheel of the vehicle 100 , and the detection result of the wheel speed sensor 410 is used in the calculation of an estimated speed of the vehicle 100 .

In addition, the inertial measurement unit 420 detects the acceleration of the vehicle 100 in three directions: front-to-back, left-to-right, and up-to-down (front-to-back acceleration, lateral acceleration, and up-to-down acceleration), and also detects the angular velocity of the vehicle 100 in three directions: pitch, roll, and yaw (pitch rate, roll rate, and yaw rate).
Instead of the inertial measurement unit 420, an acceleration sensor and an angular velocity sensor may be separately provided in the vehicle 100. Also, instead of the inertial measurement unit 420, only an acceleration sensor may be provided in the vehicle 100.

The vehicle control device 500 is an electronic control device equipped with a microcomputer 510 that performs calculations based on input information and outputs the calculation results. The microcomputer 510 is equipped with an MPU (Microprocessor Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., which are not shown in the figure.
The microcomputer 510 of the vehicle control device 500 acquires external environment recognition signals such as position information, road shape information, road surface information, and object information of the vehicle 100 from the external environment recognition unit 300, and also acquires vehicle momentum signals including wheel speed, acceleration and angular velocity applied to the vehicle 100 from the vehicle momentum detection unit 400.

Then, the microcomputer 510 of the vehicle control device 500 calculates a target command for automatic driving based on the acquired various information, and outputs the calculated target command to the traveling actuator unit 600.
The microcomputer 510 of the vehicle control device 500 includes, as software, functional units for autonomous driving, namely, a surrounding situation recognition unit 511, an action planning unit 512, a target trajectory generation unit 513, and a trajectory tracking control unit 514.

The surrounding situation recognition unit 511 recognizes the situation around the vehicle (in other words, the surrounding environment of the vehicle) based on the external environment recognition signal from the external environment recognition unit 300 and the vehicle momentum signal from the vehicle momentum detection unit 400.
The situation around the vehicle recognized by the surrounding situation recognition unit 511 includes, for example, information about the road on which the vehicle 100 is traveling, such as the curvature of the road, the road surface cant, the road surface gradient, the friction coefficient μ of the road surface, the positions of the left and right lane markers, and the positions of the left and right road edges, as well as object information such as moving objects and stationary objects around the vehicle 100.

The behavior planning unit 512 acquires the recognition results of the situation around the vehicle from the surrounding situation recognition unit 511, and creates a behavior plan for the vehicle 100 based on the acquired recognition results, including the selection of a driving lane and the selection of the direction of travel at intersections and branching points.
Then, the target trajectory generation unit 513 generates a target trajectory including trajectory and vehicle speed commands for when the vehicle 100 is driven automatically, based on the situation around the vehicle recognized by the surrounding situation recognition unit 511 and the behavior plan for the vehicle 100 created by the behavior planning unit 512.
The trajectory tracking control unit 514 calculates control commands for causing the vehicle 100 to follow the target trajectory generated by the target trajectory generation unit 513, more specifically, steering angle commands and acceleration or deceleration commands which are control commands for controlling the traveling actuator unit 600, and outputs the calculated control commands.

The traveling actuator unit 600 includes a traveling motor 610 as a power source that generates driving force for the vehicle 100, a braking device 620 that applies braking force to the vehicle 100, a steering device 630 that changes the direction of travel of the vehicle 100 by changing the tire angle of the front wheels 101, 102 that are the steered wheels of the vehicle 100, and an electronically controlled suspension 640 that can adjust the damping force and vehicle height.
The traveling actuator unit 600 can operate the traveling motor 610 as a generator to apply a braking force (in other words, a regenerative braking force) to the vehicle 100 .

The steering device 630 is of a steer-by-wire type and has a steering unit 630A and a turning unit 630B.
The steering unit 630A has a steering input member 630A1 that accepts steering operations by the driver of the vehicle 100, a steering reaction force actuator 630A2 that applies a steering reaction force to the steering input member 630A1, and an operation amount sensor 630A3 that detects the operation amount (in other words, the steering angle) of the steering input member 630A1.

The steering input member 630A1 may be a steering wheel, a dial type, a stick type, or the like.
For example, when a steering wheel is used as the steering input member 630A1, the operation amount sensor 630A3 detects the rotation angle of the steering shaft as the operation amount (steering angle) of the steering input member 630A1.
Furthermore, steering reaction force actuator 630A2 is, for example, a steering reaction force motor, and when a steering wheel is used as steering input member 630A1, the output of the steering reaction force motor is transmitted to the steering shaft via a reduction mechanism.

The steering unit 630B includes a steering actuator 630B1 that applies a steering force to the front wheels 101, 102, which are the steered wheels of the vehicle 100, a steering mechanism 630B2 that transmits the steering force generated by the steering actuator 630B1 to the steered wheels, and a tire angle sensor 630B3 that detects the tire angle (in other words, the steering angle) of the front wheels 101, 102, which are the steered wheels.
For example, when a steering motor is used as the steering actuator 630B1, the steering mechanism 630B2 converts the rotational motion of the steering motor into linear motion of the rack shaft 630B4 using a rack and pinion system, thereby changing the tire angle of the front wheels 101, 102 connected to the rack shaft 630B4.
Here, steering unit 630A and steering unit 630B (in other words, steering input member 630A1 and front wheels 101, 102, which are steered wheels) are mechanically separated.

The microcomputer 510 of the vehicle control device 500 has a steer-by-wire control unit 515 which is a functional unit that controls the steering device 630, more specifically, the steering reaction force actuator 630A2 and the turning actuator 630B1.
Steer-by-wire control unit 515 has a function of controlling steering actuator 630B1 based on a target tire angle (target steering angle) when vehicle 100 is being driven automatically (during automatic steering) and when vehicle 100 is being driven manually (during manual steering).

Here, during automatic driving (automatic steering), the tire angle for driving the vehicle 100 along the target trajectory is set as the target tire angle, and during manual driving (manual steering), the target tire angle is set according to the amount of operation of the steering input member 630A1 by the driver.
In other words, during manual driving, the steering actuator 630B1 is controlled based on an electrical signal indicating the amount of driving operation, which is the amount of operation of the steering input member 630A1 by the driver, and the tire angle of the front wheels 101, 102 is changed in accordance with the steering operation of the driver.

Furthermore, during automatic driving (automatic steering) of the vehicle 100, the steer-by-wire control unit 515 determines a target operation amount (target steering angle), which is a target value in the automatic control of the operation amount of the steering input member 630A1 (for example, the rotation angle of the steering wheel), based on the vehicle momentum, independently of the tire angle of the front wheels 101, 102.
During autonomous driving, steer-by-wire control unit 515 has the function of automatically controlling the operation amount, by controlling steering reaction force actuator 630A2 in accordance with the determined target operation amount, so that the operation amount of steering input member 630A1 becomes the target operation amount.

In other words, the steering reaction force actuator 630A2 is used as an actuator for automatically varying the amount of operation of the steering input member 630A1 while the vehicle 100 is being automatically driven (during automatic steering).
As will be explained in detail later, the vehicle momentum used to set the target operation amount during autonomous driving is, for example, lateral acceleration, and the target operation amount of the steering input member 630A1 is determined based on the lateral acceleration that occurs during driving in autonomous driving.
Therefore, during automatic driving, the amount of operation of the steering input member 630A1 is automatically controlled to a value according to the vehicle momentum such as lateral acceleration that occurs during automatic driving.

This allows the driver to recognize in which direction the vehicle 100 will turn due to automatic driving, based on changes in the amount of operation of the steering input member 630A1 (such as the rotation angle of the steering wheel).
This prevents the driver of the vehicle 100 from feeling uneasy or distrustful of the automatic steering.
Furthermore, if the target operation amount is set according to vehicle momentum such as lateral acceleration, sudden changes in the operation amount of the steering input member 630A1 are prevented more than when the operation amount is controlled to be proportional to the tire angle, and shock to the driver is prevented.

FIG. 2 is a block diagram showing the control functions of the steer-by-wire control unit 515 in detail.
Steer-by-wire control unit 515 has a vehicle momentum acquisition unit 521 , a target tire angle calculation unit 522 , a driving operation amount acquisition unit 523 , a target operation amount calculation unit 524 , and an adjustment unit 525 .
The vehicle momentum acquisition unit 521 is a functional unit that acquires vehicle momentum such as lateral acceleration used to determine a target operation amount, and includes a vehicle momentum acquisition unit 521A and/or a future vehicle momentum estimation unit 521B.

The vehicle momentum acquisition unit 521A acquires information on the vehicle momentum actually occurring in the vehicle 100 in an autonomous driving state from the detection signal of the vehicle momentum detection unit 400.
The vehicle momentum acquisition unit 521A can acquire the vehicle momentum directly detected by the vehicle momentum detection unit 400 as the vehicle momentum used to determine the target operation amount, and may also be configured to calculate the vehicle momentum used to determine the target operation amount from the vehicle momentum directly detected by the vehicle momentum detection unit 400, external environment recognition information, etc.

In addition, the future vehicle momentum estimation unit 521B calculates the vehicle momentum that is estimated to occur in the vehicle 100 at a future point in time that is a predetermined time from the present time, based on the target trajectory for autonomous driving, specifically, the curvature of the target trajectory, the target vehicle speed at each point on the target trajectory, etc.
Here, the vehicle momentum used to set the target operation amount includes the above-mentioned lateral acceleration (left and right acceleration), as well as lateral jerk, roll angle, roll rate, yaw rate, vehicle body sideslip angle, etc., and the vehicle momentum acquisition unit 521 acquires at least one of these vehicle momentum amounts.

During automatic driving in which the steering device 630 is automatically steered, the target operation amount calculation unit 524 calculates the target operation amount of the steering input member 630A1 based on the vehicle momentum such as lateral acceleration acquired by the vehicle momentum acquisition unit 521, independently of the tire angles of the front wheels 101, 102 (steered wheels), and outputs a signal of the calculated target operation amount.
The target operation amount calculation unit 524 sets the target operation amount to a value in the operation direction corresponding to the turning direction of the vehicle 100, and increases the absolute value of the target operation amount as the absolute value of the vehicle momentum increases.

On the other hand, the driving operation amount obtaining unit 523 obtains the amount of operation of the steering input member 630A1 by the driver from the output of the operation amount sensor 630A3.
Then, the target tire angle calculation unit 522 calculates a target tire angle for driving the vehicle 100 along the target trajectory from the target trajectory in autonomous driving, and also calculates a target tire angle corresponding to the driver's driving operation amount from the driver's operation amount (driving operation amount) of the steering input member 630A1 and the steering gear ratio.
The steering gear ratio is set variably based on the vehicle speed, etc.

The adjustment unit 525 acquires information on the target operation amount calculated by the target operation amount calculation unit 524 and the target tire angle calculated by the target tire angle calculation unit 522 .
Then, when switching from manual driving to automatic driving, and when switching from automatic driving to manual driving, the adjustment unit 525 adjusts the target operation amount or target tire angle to adjust the deviation amount between the operation amount of the steering input member 630A1 and the tire angle of the front wheels 101, 102 (steered wheels), and outputs the adjusted target value to the steering device 630.

Here, steering reaction force actuator 630A2 is controlled so that the amount of operation of steering input member 630A1 becomes the target amount of operation output by adjustment unit 525.
Further, steering actuator 630B1 is controlled so that the tire angle of front wheels 101, 102 (steered wheels) becomes the target tire angle output by adjustment unit 525.
In addition, in the automatic control of the operation amount of the steering input member 630A1 and the automatic control of the tire angle of the front wheels 101, 102 (steered wheels), feedback control is implemented in which a control operation signal is obtained based on the deviation between a target value and an actual value (sensor detection value).

3 to 6 are diagrams illustrating examples of the calculation process of the target operation amount based on lateral acceleration when the target operation amount calculation unit 524 sets the target operation amount according to the lateral acceleration that actually occurs during autonomous driving.
FIG. 3 shows the calculation process in which the target operation amount calculation unit 524 obtains the target operation amount from the lateral acceleration by multiplying the lateral acceleration by a fixed ratio constant.

FIG. 4 also shows the calculation process in which the target operation amount calculation unit 524 has a conversion table with a characteristic of increasing the absolute value of the target operation amount at a constant rate with respect to an increase in the absolute value of the lateral acceleration, and the target operation amount calculation unit 524 determines the target operation amount from the lateral acceleration by referring to the conversion table.
In FIG. 4, the plus and minus signs of the lateral acceleration and the target operation amount indicate the direction in which the lateral acceleration occurs (in other words, the turning direction of the vehicle 100) and the operation direction (left and right steering direction) of the steering input member 630A1 from the neutral position.

FIG. 5 also shows a calculation process for determining a target manipulated variable from the lateral acceleration using a conversion table, similar to the calculation process shown in FIG. 4 . However, in the case of the calculation process shown in FIG. 5 , the calculation process determines a target manipulated variable from the lateral acceleration using a non-linear table in which the target manipulated variable does not exceed a predetermined maximum value (upper limit value) as the lateral acceleration increases; in other words, the target manipulated variable changes according to the lateral acceleration within a predetermined variable range including the neutral position.
For example, even if automatic steering is performed to avoid danger (avoid a collision) of the vehicle 100 and the lateral acceleration acting on the vehicle 100 increases, the target operation amount is limited to within a predetermined maximum limit value (maximum operation amount) according to the calculation process of the target operation amount shown in FIG.

In other words, according to the calculation process of the target operation amount shown in Figure 5, even if the lateral acceleration acting on the vehicle 100 increases, the operation amount of the steering input member 630A1 is prevented from being automatically controlled to an amount greater than necessary.
For example, even in a situation where a lateral acceleration of about 0.2 G occurs due to danger avoidance (collision avoidance), it is possible to set the rotation angle of the steering wheel as the steering input member 630A1 to be limited to 90 degrees or less.

FIG. 6 shows a calculation process for determining a target operation amount from lateral acceleration using a nonlinear table that limits the increase in the target operation amount, similar to the calculation process shown in FIG. 5, but is configured so that the characteristics for determining the target operation amount from lateral acceleration are changed depending on the vehicle speed at that time.
Specifically, even if the lateral acceleration is the same, the characteristic (gain) for calculating the target operation amount from the lateral acceleration is changed according to the vehicle speed so that the target operation amount is set to a larger value the higher the vehicle speed of the vehicle 100.

According to this calculation processing, even in driving situations where lateral acceleration is unlikely to occur, such as when the vehicle 100 is traveling at high speed, the driver can be made aware of the direction in which the vehicle 100 will move through automatic driving (automatic steering) by changes in the amount of operation of the steering input member 630A1 (such as the rotation angle of the steering wheel).
Incidentally, even in the calculation process for determining the target operation amount from the lateral acceleration with a linear characteristic, as in the calculation process shown in FIG. 3 or 4, the ratio constant and gain can be increased in accordance with an increase in vehicle speed.

Figure 7 is a time chart showing changes in tire angle, vehicle speed, lateral acceleration, and target operation amount when the operation amount of steering input member 630A1 is automatically controlled to a target operation amount corresponding to the lateral acceleration occurring in vehicle 100 during automatic driving of vehicle 100.
In this case, lateral acceleration is generated in accordance with the automatically controlled tire angle and vehicle speed, and the target operation amount of the steering input member 630A1 is determined in accordance with the generated lateral acceleration using the characteristics exemplified in Figures 3 to 6, and the steering reaction force actuator 630A2 is controlled so that the operation amount of the steering input member 630A1 becomes the target operation amount.

In other words, as shown in Figure 8, automatic steering causes the tire angle of the front wheels 101, 102 (steered wheels) to turn left from the neutral position, generating leftward lateral acceleration, and as a result of this leftward lateral acceleration being generated, the amount of operation of the steering input member 630A1 (the rotation angle of the steering wheel) is automatically controlled in the left turning direction from the neutral position.
Similarly, when automatic steering causes the tire angle of the front wheels 101, 102 to turn to the right from the neutral position, a rightward lateral acceleration is generated, and as a result of this rightward lateral acceleration being generated, the amount of operation of the steering input member 630A1 is automatically controlled in the right-turn direction from the neutral position.
Then, when the tire angle of the front wheels 101, 102 returns to the neutral position due to automatic steering and lateral acceleration no longer occurs, the operation amount of the steering input member 630A1 is also automatically returned to the neutral position.

Figure 9 is a time chart illustrating the changes in the tire angle and the operation amount of the steering input member 630A1 when the vehicle is configured to set the target operation amount of the steering input member 630A1 based on the lateral acceleration occurring in the vehicle 100 during automatic driving, in a scene where the vehicle goes from manual driving to automatic driving and then back to manual driving.
In manual driving, the tire angle is changed according to the amount of operation of the steering input member 630A1, and the amount of operation of the steering input member 630A1 and the tire angle are linked while maintaining a predetermined steering gear ratio.

On the other hand, in autonomous driving, the amount of operation of the steering input member 630A1 is changed in accordance with the lateral acceleration occurring in the vehicle 100, independent of the tire angle.
This makes it possible to prevent sudden or large changes in the amount of operation of the steering input member 630A1 even when the vehicle 100 is avoiding danger (avoiding a collision), and at approximately the same time that the driver of the vehicle 100 feels the centrifugal force, the steering input member 630A1 will automatically turn in the direction of turning of the vehicle 100.
This makes it possible to achieve automated driving (automatic steering) that is less uncomfortable for the driver and prevents them from feeling anxious or distrustful.

In addition, the acquisition of the lateral acceleration occurring in the vehicle 100 by the vehicle momentum acquisition unit 521A is not limited to acquiring the detection value (output value of the acceleration sensor) by the inertial measurement unit 420 of the vehicle momentum detection unit 400, but can also acquire an estimated value of the lateral acceleration.
For example, the vehicle momentum acquisition unit 521A can acquire the lateral acceleration estimated from the tire angle δ and the vehicle speed V according to Equation 1. In Equation 1, A is the stability factor, and l (lowercase l) is the wheelbase.

Furthermore, the vehicle momentum acquisition unit 521A can acquire the lateral acceleration estimated from the detection result of the vehicle position by the GPS, and the lateral acceleration estimated from the image of the camera 340.

Furthermore, the control is not limited to determining the target operation amount from the lateral acceleration, and the vehicle momentum acquisition unit 521A can acquire at least one of lateral acceleration, lateral jerk, roll angle, roll rate, yaw rate, vehicle body sideslip angle, etc., and the target operation amount calculation unit 524 can calculate the target operation amount based on these.
Here, when the vehicle momentum acquisition unit 521A acquires any one of the lateral acceleration, roll angle, yaw rate, and vehicle body sideslip angle as the vehicle momentum, the target operation amount calculation unit 524 can calculate the target operation amount with the characteristics shown in FIGS. 3 to 5 described above.

That is, the "lateral acceleration" in FIGS. 3 to 5 can be interpreted as any one of the "roll angle,""yawrate," and "vehicle body sideslip angle."
When the target operation amount is calculated according to the roll angle, the driver can grasp the stability of the vehicle 100 when cornering or making a sudden change of direction through the operation amount of the steering input member 630A1.

Furthermore, when the target operation amount is calculated according to the yaw rate, the driver can grasp the possibility of slipping or sliding of the vehicle 100 through the operation amount of the steering input member 630A1.
Furthermore, when the target operation amount is calculated according to the vehicle body sideslip angle, the driver can grasp the stable driving state of the vehicle 100 while maintaining an appropriate vehicle body sideslip angle through the operation amount of the steering input member 630A1.

Also, the control process may be such that the target operation amount is calculated from a combination of any one of lateral acceleration, roll angle, yaw rate, and vehicle body sideslip angle with the lateral jerk or roll rate.
FIG. 10 is a diagram illustrating an example of characteristics for calculating a target operation amount from a combination of any one of lateral acceleration, roll angle, yaw rate, and vehicle body sideslip angle with lateral jerk or roll rate.

Here, the larger the absolute values of the lateral acceleration, roll angle, yaw rate, and vehicle body sideslip angle, the larger the absolute value of the target operation amount. On the other hand, even if the absolute values of the lateral acceleration, roll angle, yaw rate, and vehicle body sideslip angle are the same, the smaller the absolute value of the lateral jerk or roll rate, the larger the absolute value of the target operation amount.
If the target operation amount is changed in accordance with the lateral jerk, the driver can grasp the sudden direction changes and ride comfort of the vehicle 100 through the operation amount of the steering input member 630A1.
Furthermore, if the target operation amount is changed according to the roll rate, the driver can understand the effect that sharp cornering or sudden changes in direction of the vehicle 100 have on the vehicle 100 through the operation amount of the steering input member 630A1.

Incidentally, the vehicle momentum such as lateral acceleration used in calculating the target operation amount is not limited to the vehicle momentum occurring in the vehicle 100 at the present time (in other words, the vehicle momentum in the driving state of the vehicle 100 due to automatic steering), but can also include the vehicle momentum at a future time estimated from the target trajectory.
In other words, when the vehicle 100 is driven along the target trajectory, the future vehicle momentum estimation unit 521B can estimate (predict) the vehicle momentum at a point on the target trajectory that will be reached in the future (hereinafter also referred to as a look-ahead point) shown in Figure 11 from the curvature of the target trajectory and the target vehicle speed at the look-ahead point.

Then, the target operation amount calculation unit 524 can calculate the target operation amount of the steering input member 630A1 with the characteristics shown in Figures 3 to 6 or 10 based on the future vehicle momentum acquired by the future vehicle momentum estimation unit 521B.
The look-ahead point is a point a predetermined distance ahead of the current position of the vehicle 100, or a point that will be reached a predetermined time from the current time.

Here, the distance and arrival time from the current position to the look-ahead point can be fixed values, or can be variable based on the vehicle momentum such as the vehicle speed, and preferably, the higher the vehicle speed, the farther the point from the current position will be.
Furthermore, it is also possible to obtain future vehicle momentum at each of a plurality of different look-ahead points, and to obtain the final target operation amount from the plurality of future vehicle momentums obtained at each look-ahead point.
The variable control of the look-ahead point and the control for determining the final target operation amount from a plurality of future vehicle motion amounts determined at a plurality of look-ahead points will be described in detail later.

FIG. 12 is a time chart showing the characteristics of the future lateral acceleration and the target operation amount when the future vehicle momentum estimating unit 521B acquires the future lateral acceleration as the future vehicle momentum.
The future lateral acceleration is the phase of the lateral acceleration actually occurring in vehicle 100 that has been advanced, and the target operation amount based on the future lateral acceleration is a value whose phase is advanced relative to the target operation amount based on the lateral acceleration actually occurring in vehicle 100.

That is, the driver can sense a change in the vehicle momentum, such as lateral acceleration, through a change in the amount of operation of the steering input member 630A1, before the vehicle momentum actually changes.
In this way, with a configuration in which the target operation amount is calculated based on future lateral acceleration, the future vehicle behavior is presented to the driver through changes in the operation amount of the steering input member 630A1, so the driver can know in advance how the vehicle 100 will next be controlled by automatic driving (automatic steering), thereby reducing the driver's anxiety.

FIG. 13 illustrates an example of a change in the operation amount of the steering input member 630A1 relative to the curvature of the target trajectory at the look-ahead point.
In other words, if the look-ahead point is a left curve, the amount of operation of the steering input member 630A1 (the rotation angle of the steering wheel) is automatically controlled in advance from the neutral position in the left turning direction.
Similarly, if the predicted point is a right curve, the operation amount of the steering input member 630A1 (the rotation angle of the steering wheel) is automatically controlled in advance from the neutral position in the right turning direction.
Then, when the look-ahead point returns to a straight road, the operation amount of the steering input member 630A1 is automatically returned to the neutral position.

Figure 14 is a time chart illustrating changes in the tire angle and the operation amount of the steering input member 630A1 in a scene where the vehicle goes from manual driving to automatic driving and then back to manual driving, in a case where the target operation amount of the steering input member 630A1 is set based on vehicle momentum such as lateral acceleration that is estimated to occur at the look-ahead point during automatic driving.
In manual driving, the tire angle is changed according to the amount of operation of the steering input member 630A1, and the amount of operation of the steering input member 630A1 and the tire angle are linked while maintaining a predetermined steering gear ratio.

On the other hand, in automatic driving, the amount of operation of the steering input member 630A1 is changed in accordance with the amount of vehicle momentum estimated to occur at the look-ahead point, independent of the tire angle.
That is, before the vehicle momentum changes due to a change in the tire angle, the amount of operation of the steering input member 630A1 is changed, and the upcoming vehicle behavior is presented to the driver in advance.

The target operation amount calculation unit 524 can calculate the target operation amount using both the vehicle momentum currently occurring in the vehicle 100 acquired by the vehicle momentum acquisition unit 521A and the future vehicle momentum (predicted vehicle momentum at the pre-read point) acquired by the future vehicle momentum estimation unit 521B.
The flowchart in FIG. 15 illustrates an example of a calculation process for calculating a target operation amount based on both the vehicle momentum acquired by the vehicle momentum acquisition unit 521A and the future vehicle momentum acquired by the vehicle momentum estimation unit 521B.

In step S801, the microcomputer 510 of the vehicle control device 500 generates a target trajectory for the automatic driving of the vehicle 100.
Next, in step S802, the microcomputer 510 calculates a look-ahead time for specifying a look-ahead point for estimating future vehicle momentum.

The look-ahead time may be a fixed value, or, as will be described later, may be variable depending on various vehicle information (track curvature, lane width, complexity of the driving environment, traffic signals, obstacles, preceding vehicles).
Then, the microcomputer 510 calculates the look-ahead distance from the look-ahead time and the vehicle speed at that time.

The look-ahead distance is a value that determines how far in the future the vehicle momentum is to be estimated, and a point that is the look-ahead distance away from the current position of the vehicle 100 is set as the look-ahead point for estimating the vehicle momentum.
Therefore, the higher the vehicle speed, the farther the look-ahead point is set forward from the current position of the vehicle 100 .

In step S803 (future vehicle momentum estimation unit 521B), microcomputer 510 estimates vehicle momentum such as lateral acceleration at the look-ahead point identified by the look-ahead distance, that is, vehicle momentum that will occur at a point the look-ahead distance ahead.
Then, in step S804 (target operation amount calculation unit 524), microcomputer 510 calculates a first target operation amount (a target operation amount based on the future vehicle momentum) from the future vehicle momentum (for example, future lateral acceleration) calculated in step S803.

Meanwhile, in step S805 (target tire angle calculation unit 522), the microcomputer 510 calculates a target tire angle for causing the vehicle 100 to travel along the target track.
Then, in step S806, microcomputer 510 controls the steering force generated by steering actuator 630B1 so that the actual tire angles of front wheels 101, 102 become the target tire angles.

Furthermore, in step S807 (vehicle momentum acquisition unit 521A, target operation amount calculation unit 524), microcomputer 510 acquires the vehicle momentum, such as the lateral acceleration, currently being generated by vehicle 100, as a sensor detection value or an estimated value based on tire angle, vehicle speed, etc., and calculates a second target operation amount (a target operation amount based on the current vehicle momentum) from the acquired vehicle momentum.
Then, in step S808, the microcomputer 510 calculates a final target operation amount by weighting, for example, the first target operation amount (the target operation amount based on the future vehicle momentum) and the second target operation amount (the target operation amount based on the current vehicle momentum).

Here, the weighting for each of the first target operation amount and the second target operation amount may be fixed, or may be variable based on a comparison of the magnitude between the first target operation amount and the second target operation amount.
For example, the larger of the first target manipulated variable and the second target manipulated variable can be set as the final target manipulated variable.
In addition, either the processing of steps S802 to S804 or the processing of step S807 can be omitted, and either the first target operation amount or the second target operation amount can be used as the final target operation amount.

After setting the final target operation amount, in step S809, the microcomputer 510 controls the operation force of the steering input member 630A1 generated by the steering reaction force actuator 630A2 so that the actual operation amount of the steering input member 630A1 becomes the target operation amount.
That is, during automatic driving, microcomputer 510 automatically controls the amount of operation of steering input member 630A1 to a value according to the amount of vehicle momentum, independently of the tire angle.

The block diagram of FIG. 16 shows in detail the process of estimating the lateral acceleration at a look-ahead point specified by the look-ahead distance and calculating a target operation amount from the estimated lateral acceleration (future vehicle momentum), i.e., the functions of the future vehicle momentum estimation unit 521B and the target operation amount calculation unit 524.
The future vehicle momentum estimation unit 521B includes a look-ahead distance calculation unit 521B1, a look-ahead point extraction unit 521B2, and a lateral acceleration estimation unit 521B3.

The look-ahead distance calculation unit 521B1 acquires signals of a fixed look-ahead time and the vehicle speed of the vehicle 100, and calculates the distance traveled at the current vehicle speed for the look-ahead time as the look-ahead distance, which is the travel distance to the look-ahead point where lateral acceleration is estimated.
In other words, the higher the vehicle speed, the farther the look-ahead point is set from the current position.

The look-ahead point extraction unit 521B2 obtains information on the curvature of the target trajectory and the target vehicle speed for each travel distance from the current position of the vehicle 100 from the target trajectory generation unit 513, and also obtains information on the look-ahead distance from the look-ahead distance calculation unit 521B1.
Then, the look-ahead point extraction unit 521B2 uses linear interpolation to find the curvature and vehicle speed (look-ahead curvature, look-ahead vehicle speed) at the look-ahead point where the travel distance from the current position of the vehicle 100 is the look-ahead distance.

The lateral acceleration estimation unit 521B3 acquires information on the curvature and vehicle speed at the look-ahead points from the look-ahead point extraction unit 521B2.
Then, the lateral acceleration estimation unit 521B3 estimates the lateral acceleration that will occur in the vehicle 100 at the look-ahead point (in other words, future lateral acceleration) based on the information on the curvature and vehicle speed at the look-ahead point.

Here, the lateral acceleration estimation unit 521B3 can calculate the lateral acceleration α _c (tilde) at the look-ahead point according to Equation 2, where K (tilde) is the curvature at the look-ahead point and v (tilde) is the vehicle speed at the look-ahead point.

The target operation amount calculation unit 524 acquires the signal of the lateral acceleration α _c (tilde) at the look-ahead point from the lateral acceleration estimation unit 521B3, and converts it into a signal of the target operation amount, for example, by multiplying the lateral acceleration α _c (tilde) by a set constant γ.

Incidentally, the estimation of future vehicle momentum in the future vehicle momentum estimation unit 521B is not limited to the process of estimating vehicle momentum occurring at one look-ahead point, but can estimate future vehicle momentum at each of multiple different points on the target trajectory.
Then, the target operation amount calculation unit 524 can calculate the target operation amount based on a plurality of future vehicle motion amounts.

FIG. 17 is a diagram illustrating a processing function for calculating a target operation amount based on the future vehicle motion amount estimated at each of a plurality of look-ahead points.
In the example shown in Figure 17, future vehicle momentum g(x1) and g(x2), such as future lateral acceleration, are calculated, which are estimated to occur at a nearby first look-ahead point with a look-ahead distance of x1 and a distant second look-ahead point with a look-ahead distance of x2 (x1 < x2).

Then, as shown in Equation 3, the microcomputer 510 weights the future vehicle momentum g(x1) and g(x2) with weighting coefficients c1 and c2 given as fixed values to determine the target operation amount θ.

Here, the microcomputer 510 can vary the weighting of the future vehicle momentum g(x1), g(x2) estimated to occur at each look-ahead point depending on the look-ahead distances x1, x2.
That is, the microcomputer 510 uses weighting coefficients c1(x1) and c2(x2) corresponding to the look-ahead distances x1 and x2 to determine the target manipulated variable θ according to Equation 4.

FIG. 18 shows a process for determining the target operation amount θ by setting all points on the target trajectory as look-ahead points, calculating the future vehicle momentum estimated to occur at each look-ahead point, and weighting each estimated future vehicle momentum according to the look-ahead point.
Here, the target operation amount θ is calculated according to Equation 5, where c(k) is the weighting coefficient at each look-ahead point and gk is the future vehicle momentum estimated at each look-ahead point.

FIG. 19 shows a process for determining the target operation amount θ by performing definite integration on the future vehicle momentum g estimated at the look-ahead point, weighted in accordance with the distance from the current position of the vehicle 100 to the look-ahead point, and integrating the weighted value over the range from the current position of the vehicle 100 to the length D of the target trajectory.
Here, the target manipulated variable θ is calculated according to Equation 6.

When weighting of the future vehicle momentum estimated at the look-ahead point is made variable depending on the distance from the current position of the vehicle 100 to the look-ahead point, the weighting of the look-ahead point close to the current position of the vehicle 100 is made larger than the weighting of the look-ahead point far from the current position of the vehicle 100.
That is, the longer the distance (look-ahead distance) from the current position of the vehicle 100 to the look-ahead point, the smaller the weighting of the look-ahead point.

As a function of the weighting coefficient c(x) with the look-ahead distance x as a variable, c(x) = -cx + b, c(x) = 1/x, c(x) = e- ^x, etc. can be applied, as shown in Figures 20 to 22.
Here, when the weighting coefficient c(x) is determined in accordance with the function "c(x) = -cx + b" shown in FIG. 20, the formula for calculating the target operation amount when determining the target operation amount from a nearby first look-ahead point with a look-ahead distance of x1 and a distant second look-ahead point with a look-ahead distance of x2 (x1 < x2) (see FIG. 17) is Equation 7.

Furthermore, when the weighting coefficient c(x) is determined in accordance with the function "c(x)=1/x" shown in FIG. 21, the formula for calculating the target operation amount when determining the target operation amount from a nearby first look-ahead point with a look-ahead distance of x1 and a distant second look-ahead point with a look-ahead distance of x2 (x1<x2) (see FIG. 17) is Equation 8.

Furthermore, when the weighting coefficient c(x) is determined in accordance with the function "c(x)=e- ^x " shown in FIG. 22, the formula for calculating the target manipulated variable when determining the target manipulated variable from a nearby first look-ahead point with a look-ahead distance of x1 and a distant second look-ahead point with a look-ahead distance of x2 (x1<x2) (see FIG. 17) is Equation 9.

The following describes in detail the process of variably setting the look-ahead time in accordance with the vehicle information in step S802 of the flowchart in FIG.
FIG. 23 illustrates the correlation between the curvature of the target trajectory, the differential value of the curvature, and the look-ahead time.
Here, the microcomputer 510 shortens the look-ahead time as the curvature of the target trajectory increases and the target trajectory curves sharply.

In other words, the microcomputer 510 shortens the look-ahead distance as the curvature of the target trajectory increases, and by determining the target operation amount based on the estimated vehicle momentum at a point close to the vehicle 100, information about the vehicle behavior at a point close to the vehicle 100 is presented to the driver via changes in the operation amount of the steering input member 630A1.
Furthermore, the microcomputer 510 shortens the look-ahead time as the differential value of the curvature of the target trajectory increases and the curvature change increases.

In other words, when traveling on a road with a series of curves, such as a mountain road, the change in curvature becomes larger, and information about the vehicle behavior at points close to the vehicle 100 is presented to the driver through changes in the amount of operation of the steering input member 630A1.
In this way, by setting the look-ahead time based on the curvature or curvature differential of the target trajectory, when the vehicle 100 is traveling around a curve, the driver can be appropriately given hints about the vehicle behavior via the amount of operation of the steering input member 630A1.

FIG. 24 illustrates an example of the correlation between the lane width (road width) of the road on which the vehicle 100 is traveling and the look-ahead time.
Here, the narrower the lane width, the shorter the microcomputer 510 sets the look-ahead time.
In other words, the narrower the lane width, the closer points to the vehicle 100 should be taken into consideration, so the narrower the lane width, the closer the look-ahead points are to be placed from the vehicle 100 .

Figure 25 shows how the look-ahead time is set long (the look-ahead point is set far away) when the vehicle 100 is traveling on a road with a small curvature of the target trajectory and a wide road width, such as when the vehicle 100 is traveling on a highway.
In contrast, FIG. 26 shows how, when the vehicle 100 is traveling on a series of curves with large curvatures, the look-ahead time is set short and the look-ahead point is set just before the vehicle 100.

FIG. 27 illustrates the correlation between the complexity of the driving environment and the look-ahead time.
Here, the more complicated the driving environment, the more attention should be paid to points closer to the vehicle 100. Therefore, the more complicated the driving environment, the shorter the look-ahead time the microcomputer 510 sets.
The microcomputer 510 determines the complexity of the driving environment based on the external environment recognized by the camera 340, map information, and the like.

A complex driving environment refers to a situation where there is a high possibility of repeated small steering turns or sudden steering turns.
Specifically, factors that can increase the complexity of the driving environment include continuous curves, narrow roads, heavy traffic, many obstacles such as parked vehicles, steep road gradients, and rain and snow.

Therefore, if the road on which vehicle 100 is traveling is a narrow road with no sidewalk, with many pedestrians walking on the shoulders of the road and with many oncoming vehicles, the complexity of the driving environment is determined to be at a high level.
Conversely, when the vehicle 100 is traveling on an uncongested highway, the complexity of the driving environment is determined to be low.
In this way, by variably setting the look-ahead time according to the complexity of the driving environment, when the driving environment is complex, it is possible to suggest to the driver, via the amount of operation of the steering input member 630A1, vehicle behavior in the short distance that requires attention.

Here, in relation to the complexity of the driving environment, it is preferable to shorten the look-ahead time on mixed roads.
This makes it possible to suggest to the driver on a congested road, via the amount of operation of the steering input member 630A1, vehicle behavior in the short distance that requires caution.

In addition, when the traffic light ahead of vehicle 100 is a stop light (red light), it is preferable to modify the look-ahead time (look-ahead distance) so that the look-ahead point is not a point beyond the traffic light (stop line), but a position just before the traffic light (stop line).
This prevents the steering input member 630A1 from being moved from the neutral position due to the influence of the estimated vehicle momentum at a point beyond the stop line when it is estimated that the vehicle 100 will stop at the stop line ahead because the traffic light ahead is a stop signal (red light).

Furthermore, the microcomputer 510 can variably set the look-ahead time based on information about a preceding vehicle traveling ahead of the vehicle 100 .
28 and 29 show how to set the look-ahead time (look-ahead point) when there is a preceding vehicle that the vehicle 100 is to follow.
When vehicle 100 is driven to follow a preceding vehicle, microcomputer 510 can set a look-ahead time in which the look-ahead point is the driving position of the preceding vehicle to be followed, instead of a look-ahead point based on the look-ahead time and a look-ahead distance corresponding to the vehicle speed.

In this case, as shown in FIG. 28, if the preceding vehicle is traveling straight, the vehicle momentum at the look-ahead point indicates a straight traveling state, and the steering input member 630A1 of the vehicle 100 is held in the neutral position.
On the other hand, when the preceding vehicle turns right as shown in Figure 29, the operation amount in the right turn direction is set as the target operation amount, and the driver can be informed via the operation amount of the steering input member 630A1 that the vehicle 100 will turn right to follow the preceding vehicle.

On the other hand, Figures 30 and 31 show examples of the setting of the look-ahead point and the operation amount of the steering input member 630A1 when a leading vehicle is present but the vehicle 100 is not made to follow the leading vehicle.
At this time, if the look-ahead time is made variable according to the curvature of the target trajectory, for example, without being restricted by the driving position of the preceding vehicle, when the target trajectory for lane change to the right lane is set and the curvature of the target trajectory increases, as shown in Figure 30, the look-ahead time is shortened and the look-ahead point is set to be just before vehicle 100.

Then, based on the target trajectory of the right turn for lane change, the target operation amount of the steering input member 630A1 is set in the right turn direction.
This notifies the driver that a lane change will be made even if the vehicle 100 approaches a leading vehicle ahead, giving the driver a sense of security.

On the other hand, as shown in FIG. 31, when the vehicle 100 travels straight while the preceding vehicle turns right at a branch road, the target operation amount is set based on the target trajectory of the vehicle 100 traveling straight, which is different from the trajectory of the preceding vehicle.
As a result, the target operation amount of the steering input member 630A1 is maintained in the neutral position, and the driver can be informed via the operation amount of the steering input member 630A1 that the vehicle is traveling in a state where it is not following the preceding vehicle.

Furthermore, the microcomputer 510 can variably set the look-ahead time based on the recognition information of an obstacle present ahead of the vehicle 100 .
When an obstacle is present ahead of the vehicle 100, the microcomputer 510 can set the look-ahead time (look-ahead distance) so that a point in front of the obstacle becomes the look-ahead point.

In this case, if a target trajectory for avoiding the obstacle is set as shown in Figure 32, the target operation amount of the steering input member 630A1 is set corresponding to the path for avoiding the obstacle (a right-turn path in the case of Figure 32) based on the target trajectory.
Therefore, the driver can predict that automatic driving to avoid an obstacle ahead will be performed through a change in the amount of operation of the steering input member 630A1.

On the other hand, as shown in Figure 33, when a target trajectory for avoiding an obstacle ahead is not set, and a target trajectory for the vehicle 100 to move straight toward the obstacle is set, the amount of operation of the steering input member 630A1 is held in the neutral position, and no movement is shown to avoid the obstacle.
This allows the driver to sense the risk of colliding with an obstacle and perform an override (manual steering operation) to avoid the obstacle.

Furthermore, when emergency danger avoidance driving (hereinafter referred to as emergency driving) is performed during automated driving to deal with a pedestrian suddenly jumping out, as shown in Figure 34, it is preferable to limit the target operation amount for vehicle momentum such as lateral acceleration to a value smaller than that during normal driving.
That is, as shown in FIG. 35, the microcomputer 510 can change the maximum limit value of the target operation amount relative to the vehicle momentum to a smaller value during emergency driving (during emergency risk avoidance driving) than during normal driving.

In other words, during emergency driving, the microcomputer 510 can change the variable range of the target operation amount relative to the vehicle momentum to a narrower range that includes the neutral position than during normal driving, and can calculate the target operation amount so that the operation amount is closer to the neutral position than during normal driving.
This prevents the amount of operation of the steering input member 630A1 from suddenly changing significantly, even when vehicle momentum such as lateral acceleration increases rapidly due to emergency driving, thereby preventing shock to the driver.
During emergency operation, the microcomputer 510 can set a fixed target manipulated variable that is smaller than the maximum limit value of the target manipulated variable during normal operation.

The function of the adjustment unit 525 shown in the block diagram of FIG. 2 will be described in detail below.
FIG. 36 is a diagram showing changes in the tire angle and the operation amount of the steering input member 630A1 in a scene where the driving of the vehicle 100 is switched from manual driving to automatic driving and then back from automatic driving to manual driving.
The upper part of FIG. 36 shows a case where no adjustment is made by the adjustment unit 525, and the lower part of FIG. 36 shows a case where adjustment is made by the adjustment unit 525.

During automatic driving, the microcomputer 510 determines the target operation amount of the steering input member 630A1 based on the vehicle momentum, independently of the tire angle of the vehicle 100.
On the other hand, during manual driving, the tire angle and the operation amount of the steering input member 630A1 change in conjunction with each other so as to maintain a predetermined steering gear ratio.
Therefore, if no adjustment is made when switching from manual driving to automatic driving, the amount of operation of the steering input member 630A1 will be switched in a stepwise manner from a value corresponding to the tire angle to a value based on the vehicle momentum, as shown in the upper part of Figure 36.

Furthermore, if no adjustment is made when switching from automatic driving to manual driving, the tire angle will be switched in a stepwise manner from the tire angle in automatic driving to a tire angle corresponding to the amount of operation of the steering input member 630A1, as shown in the upper part of Figure 36.
In this way, if the tire angle and the amount of operation of the steering input member 630A1 are not adjusted when switching between manual and automatic driving, the amount of operation of the steering input member 630A1 and the tire angle will not change continuously, which may cause the driver to feel uncomfortable or result in unintended changes in the behavior of the vehicle 100.

Therefore, as shown in the lower part of Figure 36, when switching from manual driving to automatic driving, the adjustment unit 525 gradually adjusts the operation amount of the steering input member 630A1 from the manual driving amount to the automatic driving amount based on the vehicle momentum, which is independent of the tire angle.
Furthermore, as shown in the lower part of Figure 36, when switching from automatic driving to manual driving, the adjustment unit 525 gradually adjusts the tire angle from the automatic driving angle toward the tire angle corresponding to the amount of operation of the steering input member 630A1.

The flowchart in Figure 37 shows the adjustment process by the microcomputer 510 (adjustment unit 525) when the driving of the vehicle 100 is switched from manual driving to automatic driving.
The flowchart in FIG. 37 shows a routine that is executed as an interrupt at predetermined intervals during manual operation.

In step S821, the microcomputer 510 determines whether or not there is a command to switch from manual driving to automatic driving.
If manual driving is still instructed, microcomputer 510 proceeds to step S822 and controls the tire angle of the steered wheels in accordance with the amount of operation of steering input member 630A1 operated by the driver.

On the other hand, if a command to switch from manual driving to automatic driving (automatic steering) has been set, the microcomputer 510 proceeds to step S823, compares the target operation amount corresponding to the vehicle momentum set for automatic driving with the operation amount of the steering input member 630A1 at the time of switching, and determines whether there is a discrepancy between the two.
If there is no deviation (if the deviation amount is equal to or less than the predetermined deviation amount), the microcomputer 510 proceeds to step S824 and stores the amount of operation of the steering input member 630A1.

On the other hand, if there is a deviation (if the deviation amount exceeds a predetermined deviation amount), the microcomputer 510 proceeds to step S825 and controls the steering reaction force actuator 630A2 so that the amount of operation of the steering input member 630A1 gradually approaches the target amount of operation corresponding to the vehicle momentum set for automatic driving.
Thereafter, the microcomputer 510 proceeds from step S825 to step S826, and determines whether the amount of operation of the steering input member 630A1 matches the target amount of operation corresponding to the vehicle momentum set for automatic driving (whether the deviation amount is less than or equal to a predetermined deviation amount).
Then, when the amount of operation of the steering input member 630A1 matches the target amount of operation corresponding to the vehicle momentum set for automatic driving (when the deviation amount becomes less than a predetermined deviation amount), the microcomputer 510 proceeds to step 827 and switches to automatic driving.

The manipulated variable adjustment in step S825 is performed by, for example, determining the adjusted target manipulated variable φk according to Equation 10.
In Equation 10, θ is the target operation amount (following target value) according to the vehicle momentum set for automatic driving, δ is the actual operation amount of the steering input member 630A1, and α is the convergence speed gain.

FIG. 38 is a block diagram showing the calculation process of the adjusted target manipulated variable φk according to Equation 10.
The comparison unit 831 determines the deviation between the actual manipulated variable δk and the target manipulated variable θk.
The absolute value calculation unit 832 calculates the absolute value of the deviation between the actual manipulated variable δk and the target manipulated variable θk.

On the other hand, the change amount calculation unit 833 calculates the amount of change in the target manipulated variable θk per unit time (the rate of change in the target manipulated variable θk).
Then, the absolute value calculation unit 834 obtains the amount of change per unit time of the target manipulated variable θk calculated by the amount-of-change calculation unit 833, and calculates the absolute value of the amount of change.
The gain section 835 multiplies the absolute value of the change in the target operation amount θk calculated by the absolute value calculation section 834 by a convergence speed gain α adapted to the actual steering feel.

The comparison unit 836 subtracts the “absolute value of the change amount per unit time of the target operation amount θk” * α output by the gain unit 835 from the absolute value of the deviation amount between the actual operation amount δk and the target operation amount θk output by the absolute value calculation unit 832.
The SIGN function unit 837 determines whether the deviation between the actual manipulated variable δk and the target manipulated variable θk output by the comparison unit 831 is positive or negative.

Then, the multiplication unit 838 assigns a sign to the output of the comparison unit 836 based on the output signal of the SIGN function unit 837 .
The corrector 839 adds the output of the multiplier 838 to the target manipulated variable θk and outputs it as an adjusted target manipulated variable φk.

In addition, the delay unit 840 holds the previous value of the output of the comparison unit 836 .
The switching unit 841 acquires a flag for switching from manual driving to automatic driving, and stores the deviation amount (output of the comparison unit 836) at the start of automatic driving.
That is, as shown in FIG. 39, from the point in time when the flag for switching from manual operation to automatic operation is set, the deviation between the target operation amount θk and the adjusted target operation amount φk is gradually reduced, and the adjusted target operation amount φk is gradually converged to the target operation amount θk.

The flowchart in Figure 40 shows the adjustment process by the microcomputer 510 (adjustment unit 525) when the driving of the vehicle 100 is switched from automatic driving to manual driving.
The flowchart in FIG. 40 shows a routine that is executed as an interrupt at predetermined intervals during automatic driving.

In step S851, the microcomputer 510 determines whether or not there is a command to switch from automatic driving to manual driving.
If the automatic driving command is being continuously issued, the microcomputer 510 proceeds to step S852 and controls the operation amount of the steering input member 630A1 to become the target operation amount θk.

On the other hand, if a command to switch from automatic driving (automatic steering) to manual driving is set, the microcomputer 510 proceeds to step S853 and determines whether the amount of operation of the steering input member 630A1 has changed, in other words, whether the steering input member 630A1 is moving.
If the amount of operation of the steering input member 630A1 has not changed, the microcomputer 510 proceeds to step S854 and stores the tire angle at that time.

On the other hand, if the amount of operation of steering input member 630A1 is changing, microcomputer 510 proceeds to step S855 and controls steering actuator 630B1 so as to gradually bring the tire angle closer to the target tire angle corresponding to the amount of operation of steering input member 630A1.
Thereafter, the microcomputer 510 proceeds from step S855 to step S856, and determines whether the tire angle coincides with the target tire angle corresponding to the amount of operation of the steering input member 630A1.
Then, when the tire angle coincides with the target tire angle corresponding to the amount of operation of the steering input member 630A1, the microcomputer 510 proceeds to step 857 and shifts to manual driving.

The tire angle adjustment in step S855 is performed by calculating the adjusted target tire angle δk according to Equation 11, for example.
For the sake of simplicity, the steering gear ratio is set to 1.0, and the target tire angle in manual driving is given as the operation amount of the steering input member 630A1 = the target tire angle.

FIG. 41 is a block diagram showing the calculation process of the adjusted target tire angle δk according to Equation 11.
The calculation process of the adjusted target tire angle δk is a process of gradually bringing the actual tire angle closer to the target tire angle corresponding to the operation amount of the steering input member 630A1, and although the controlled object differs from that in the block diagram of FIG. 38 and the input/output signals of each block are different, the control process is similar to the calculation process of the adjusted target operation amount φk.

The comparison unit 831A calculates the deviation between the actual tire angle δk and the operation amount θk (the target tire angle according to the operation amount θk).
The absolute value calculation section 832A calculates the absolute value of the deviation amount calculated by the comparison section 831A.
On the other hand, the change amount calculation unit 833A calculates the amount of change per unit time of the driver's operation amount θk (driving operation amount), in other words, the amount of change per unit time of the target tire angle corresponding to the operation amount θk.

Then, the absolute value calculation section 834A calculates the absolute value of the amount of change calculated by the amount of change calculation section 833A.
The gain section 835A multiplies the output of the absolute value calculation section 834A by a convergence speed gain α adapted to the actual steering feel.
The comparison section 836A subtracts the output of the gain section 835A from the output of the absolute value calculation section 832A.

The SIGN function unit 837A determines whether the output of the comparison unit 831A is positive or negative.
Then, the multiplication unit 838A assigns a sign to the output of the comparison unit 836A based on the output signal of the SIGN function unit 837A.
The correction section 839A adds the output of the multiplication section 838A to the manipulated variable θk and outputs the result as the adjusted target tire angle δk.

Furthermore, the delay unit 840A holds the previous value of the output of the comparison unit 836A.
The switching unit 841A acquires a flag for switching from automatic driving to manual driving, and stores the deviation amount (output of the comparison unit 836A) at the start of manual driving (at the time of override).
In other words, as shown in Figure 42, from the point in time when the flag for switching from automatic driving to manual driving is set, the deviation between the actual tire angle and the target tire angle corresponding to the operation amount θk is gradually reduced, and the adjusted tire angle is gradually converged to the target tire angle corresponding to the operation amount θk.

The technical ideas explained in the above embodiments can be used in appropriate combinations as long as no contradiction occurs.
Furthermore, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that a person skilled in the art can adopt various modified embodiments based on the basic technical idea and teachings of the present invention.

For example, when a target operation amount is set without predicting the vehicle momentum, the steering device is not limited to a steer-by-wire type steering device, but may be a steering device in which a steering input member such as a steering wheel is mechanically connected to steered wheels, and which is equipped with a steering actuator that assists the driver's steering operation, and a variable gear ratio mechanism that can control the change in tire angle in response to the operation amount of the steering input member.
Furthermore, in the above embodiment, one microcomputer 510 performs operations from generating the target trajectory to controlling the steer-by-wire, but a control system can be configured in which these control functions are shared and performed by a plurality of microcomputers.

100... Vehicle, 200... Vehicle control system, 300... External environment recognition unit, 400... Vehicle momentum detection unit, 500... Vehicle control device, 515... Steer-by-wire control unit, 521... Vehicle momentum acquisition unit, 522... Target tire angle calculation unit, 523... Driving operation amount acquisition unit, 524... Target operation amount calculation unit, 525... Adjustment unit, 600... Travel actuator unit

Claims (14)

A vehicle control device provided in a vehicle having a steering device including a steering input member that accepts a steering operation by a driver,
a vehicle momentum acquisition unit that acquires a vehicle momentum generated in the vehicle;
a target operation amount calculation unit that calculates a target operation amount of the steering input member based on the vehicle momentum independently of a tire angle of the vehicle when the steering device is automatically steered, and outputs a signal of the target operation amount to the steering device;
A vehicle control device comprising: The vehicle control device according to claim 1,
The target manipulated variable calculation unit
calculating the target operation amount based on the vehicle momentum in a traveling state of the vehicle due to the automatic steering;
Vehicle control device. The vehicle control device according to claim 2,
The target manipulated variable calculation unit
calculating the target operation amount based on a lateral acceleration of the vehicle among the vehicle momentum in a traveling state of the vehicle due to the automatic steering;
Vehicle control device. The vehicle control device according to claim 1,
The steering device is a steer-by-wire type.
Vehicle control device. The vehicle control device according to claim 4,
The automatic steering causes the vehicle to travel along a target trajectory,
The vehicle momentum acquisition unit
estimating the future vehicle momentum from the target trajectory;
The target manipulated variable calculation unit
calculating the target operation amount based on the future vehicle momentum;
Vehicle control device. The vehicle control device according to claim 5,
The target manipulated variable calculation unit
calculating the target operation amount based on a lateral acceleration of the vehicle included in the future vehicle momentum;
Vehicle control device. 7. The vehicle control device according to claim 6,
The vehicle momentum acquisition unit
the point on the target trajectory at which the future vehicle momentum is estimated is set farther away as the speed of the vehicle increases;
Vehicle control device. The vehicle control device according to claim 5,
The vehicle momentum acquisition unit
estimating the future vehicle momentum at each of a plurality of different points on the target trajectory;
The target manipulated variable calculation unit
determining the target operation amount based on the plurality of future vehicle motion amounts;
Vehicle control device. The vehicle control device according to claim 5,
The vehicle momentum acquisition unit
estimating the future vehicle momentum at a point on the target trajectory that is a predetermined time ahead from the present, and variably setting the predetermined time based on information on a preceding vehicle traveling ahead of the vehicle or information on an obstacle present ahead of the vehicle;
The target manipulated variable calculation unit
determining the target operation amount based on the future vehicle momentum at a point on the target trajectory that is the predetermined time ahead from the present;
Vehicle control device. The vehicle control device according to claim 1,
The target manipulated variable calculation unit
In the automatic steering for risk avoidance of the vehicle, the target operation amount is calculated so that the operation amount is closer to a neutral position than in the case of automatic steering not for risk avoidance, or so that the operation amount is fixed to a predetermined operation amount.
Vehicle control device. The vehicle control device according to claim 1,
a driving operation amount acquisition unit that acquires a driving operation amount that is information about an operation amount of the steering input member by a driver of the vehicle;
a target tire angle calculation unit that calculates a target tire angle during manual steering by the driver from information about the driving operation amount, and calculates a target tire angle during automatic steering that causes the vehicle to travel along a target trajectory from the target trajectory;
an adjustment unit that adjusts a deviation amount between the operation amount of the steering input member and the tire angle based on the target operation amount, the target tire angle, and the driving operation amount when switching between the automatic steering and the manual steering;
The vehicle control device further comprises: The vehicle control device according to claim 11,
The adjustment unit
As the adjustment of the deviation amount, when switching from the manual steering to the automatic steering, a signal of an adjusted target operation amount obtained by adjusting the target operation amount based on an amount of change per unit time of the target operation amount is output to the steering device.
Vehicle control device. The vehicle control device according to claim 11,
The adjustment unit
As the adjustment of the deviation amount, when switching from the automatic steering to the manual steering, a signal of an adjusted target tire angle obtained by adjusting the target tire angle based on a change amount per unit time of an operation amount based on the driving operation amount is output to the steering device.
Vehicle control device. A vehicle control method executed by a control unit provided in a vehicle equipped with a steer-by-wire steering device including a steering input member that accepts a steering operation by a driver, comprising:
When the steering device is automatically steered, the operation amount of the steering input member is controlled based on the lateral acceleration generated in the vehicle, independently of the tire angle of the vehicle.
Vehicle control method.