Vehicle control system and vehicle control method

Abstract

To inform a driver of a vehicle turning direction by driving support control, in a steer-by-wire system vehicle.SOLUTION: A vehicle control system, which controls a steer-by-wire system vehicle, executes driving support control of supporting driving of the vehicle. Further the vehicle control system executes interlocking reaction-force control by which steering reaction-force constituents are applied to a steering wheel in interlock with turning of the vehicle by the driving support control. A driving support direction is a turning direction of the vehicle by the driving support control. The interlocking reaction-force control includes feed-forward reaction-force control by which the steering wheel is moved in the same direction as the driving support direction, without depending on a steering angle of the steering wheel.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a technique for controlling a steer-by-wire vehicle, and more particularly, to a technique for controlling a steer-by-wire vehicle having a driving assistance control function for assisting driving of the vehicle. [Background technology]

[0002] Patent Document 1 discloses a steering control device for a steer-by-wire type vehicle. The steering control device calculates a steering reaction force based on a feedback axial force and a feedforward axial force, and applies the steering reaction force to a steering wheel. The feedback axial force corresponds to a road reaction force, and is calculated based on a steering current of a steering actuator that performs steering according to an operation amount of the steering wheel. On the other hand, the feedforward axial force corresponds to a damping component, etc., and is calculated based on the steering angle of the steering wheel. During operation of a lane keeping assist that prevents the vehicle from deviating from its lane, the steering reaction force is calculated based on the feedforward axial force without using the feedback axial force. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5994868 Summary of the Invention [Problem to be solved by the invention]

[0004] Consider a case where a steer-by-wire vehicle also has a driving assistance control function that assists the driver in driving the vehicle. For example, the driving assistance control automatically steers the vehicle without the driver's steering operation. In that case, the driver may feel uncomfortable with unintended vehicle behavior.

[0005] One object of the present disclosure is to provide a technique capable of transmitting the vehicle steering direction under driving assistance control to a driver in a steer-by-wire vehicle. [Means for solving the problem]

[0006] The first aspect relates to a vehicle control system that controls a steer-by-wire vehicle. The vehicle control system includes one or more processors. The one or more processors A driving assistance control that assists driving of a vehicle; A reaction force control that applies a steering reaction force component to the steering wheel in conjunction with the steering of the vehicle by the driving assistance control. The apparatus is configured to execute the following steps: The driving assistance direction is the direction in which the vehicle is steered under driving assistance control. The interlocking reaction force control includes a feedforward reaction force control that moves the steering wheel in the same direction as the driving assistance direction, regardless of the steering angle of the steering wheel.

[0007] The second aspect relates to a vehicle control method for controlling a steer-by-wire vehicle. The vehicle control method includes: A driving assistance control that assists driving of a vehicle; A reaction force control that applies a steering reaction force component to the steering wheel in conjunction with the steering of the vehicle by the driving assistance control. Includes. The driving assistance direction is the direction in which the vehicle is steered under driving assistance control. The interlocking reaction force control includes a feedforward reaction force control that moves the steering wheel in the same direction as the driving assistance direction, regardless of the steering angle of the steering wheel. Effect of the Invention

[0008] According to the present disclosure, an interlocking reaction force control is performed that applies a steering reaction force component to the steering wheel in conjunction with the steering of the vehicle by the driving assist control. The interlocking reaction force control includes feedforward reaction force control that moves the steering wheel in the same direction as the driving assist direction (the vehicle steering direction by the driving assist control) without depending on the steering angle of the steering wheel. This feedforward reaction force control makes it possible to effectively convey the driving assist direction to the driver. This reduces the discomfort felt by the driver. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a configuration example of a vehicle and a vehicle control system according to an embodiment; [Diagram 2] 2 is a block diagram showing a functional configuration of a control device of the vehicle control system according to the embodiment; FIG. [Diagram 3] FIG. 2 is a conceptual diagram for explaining risk avoidance control, which is an example of driving assistance control. [Figure 4] FIG. 11 is a conceptual diagram for explaining lane keeping assist control, which is another example of driving assist control. [Diagram 5] FIG. 11 is a conceptual diagram for explaining lane departure suppression control, which is yet another example of driving assistance control. [Figure 6] FIG. 4 is a block diagram for explaining an example of interlocking reaction force control according to the embodiment. [Figure 7] FIG. 11 is a block diagram for explaining another example of the interlocking reaction force control according to the embodiment. [Figure 8] 4 is a block diagram showing a first example of a driving assistance direction acquisition unit according to an embodiment. FIG. [Figure 9] 6 is a timing chart for explaining an example of feedforward reaction force control of the interlocking reaction force control according to the embodiment. [Figure 10] 11 is a block diagram showing a second example of a driving assistance direction acquisition unit according to an embodiment. FIG. [Figure 11] FIG. 13 is a conceptual diagram for explaining a modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0011] 1. Vehicle Control System 1 is a schematic diagram showing an example of the configuration of a vehicle 1 and a vehicle control system 10 according to this embodiment. The vehicle 1 is equipped with wheels 2 and a handle (steering wheel) 3. The handle 3 is an operating member used by a driver of the vehicle 1 to perform steering operations. A steering shaft 4 is connected to the handle 3 and rotates together with the handle 3. The vehicle 1 is a steer-by-wire type vehicle, and the wheels 2 and the handle 3 (steering shaft 4) are mechanically separated.

[0012] The vehicle control system 10 controls a steer-by-wire vehicle 1. The vehicle control system 10 includes a steering device 20, a reaction force device 30, a driving environment information acquisition device 40, and a control device 100.

[0013] The steering device 20 steers the wheels 2. The steering device 20 includes a steering actuator 21 for steering the wheels 2. For example, the steering actuator 21 is a steering motor. A rotor of the steering motor is connected to a steering shaft 23 via a reducer 22. The steering shaft 23 is connected to the wheels 2. When the steering motor rotates, the rotational motion is converted into linear motion of the steering shaft 23, thereby steering the wheels 2. That is, the wheels 2 can be steered by operating the steering motor. The operation of the steering actuator 21 is controlled by the control device 100.

[0014] The reaction force device 30 applies a steering reaction force (reaction torque) to the steering wheel 3. The reaction force device 30 includes a reaction force actuator 31 for applying a steering reaction force to the steering wheel 3. For example, the reaction force actuator 31 is a reaction force motor. A rotor of the reaction force motor is connected to the steering shaft 4 via a reducer 32. By operating the reaction force motor, a steering reaction force can be applied to the steering shaft 4 and ultimately to the steering wheel 3. The operation of the reaction force actuator 31 is controlled by the control device 100.

[0015] The driving environment information acquisition device 40 acquires driving environment information ENV indicating the driving environment of the vehicle 1. The driving environment information acquisition device 40 includes a vehicle state sensor 50, a recognition sensor 60, and the like.

[0016] Vehicle state sensor 50 detects the state of vehicle 1. Vehicle state sensor 50 includes steering angle sensor 51, steering torque sensor 52, rotation angle sensor 53, rotation angle sensor 54, steering current sensor 55, vehicle speed sensor 56, etc. Steering angle sensor 51 detects steering angle θs (steering wheel angle) of steering wheel 3. Steering torque sensor 52 detects steering torque Ts applied to steering shaft 4. Rotation angle sensor 53 detects rotation angle Φ of reaction force actuator 31 (reaction force motor). Rotation angle sensor 54 detects the rotation angle of steering actuator 21 (steering motor). The rotation angle of the steering motor corresponds to the steering angle (actual steering angle δa) of wheels 2. Therefore, it can be said that rotation angle sensor 54 detects actual steering angle δa of wheels 2. Steering current sensor 55 detects steering current Im that drives steering actuator 21. Vehicle speed sensor 56 detects vehicle speed V that is the speed of vehicle 1. Additionally, the vehicle state sensor 50 may include a yaw rate sensor and an acceleration sensor.

[0017] The recognition sensor 60 recognizes (detects) the situation around the vehicle 1. Examples of the recognition sensor 60 include a camera, a LIDAR (Laser Imaging Detection and Ranging), a radar, and the like.

[0018] The driving environment information acquisition device 40 may include a position sensor that acquires the position of the vehicle 1. An example of the position sensor is a GPS (Global Positioning System) sensor. The driving environment information acquisition device 40 may acquire map information.

[0019] The driving environment information ENV includes vehicle state information and surrounding situation information. The vehicle state information indicates the vehicle state detected by the vehicle state sensor 50. The surrounding situation information indicates the recognition result by the recognition sensor 60. For example, the surrounding situation information includes an image captured by a camera. The surrounding situation information may include object information related to objects around the vehicle 1. Examples of objects around the vehicle 1 include pedestrians, other vehicles (preceding vehicles, parked vehicles, etc.), signs, white lines, roadside structures, etc. The object information indicates the relative position and relative speed of the object with respect to the vehicle 1. The driving environment information ENV may further include position information of the vehicle 1, map information, etc.

[0020] The control device 100 controls the vehicle 1. The control device 100 includes one or more processors 110 (hereinafter simply referred to as processor 110) and one or more storage devices 120 (hereinafter simply referred to as storage devices 120). The processor 110 executes various processes. For example, the processor 110 includes a CPU (Central Processing Unit). The storage device 120 stores various information required for processing by the processor 110. Examples of the storage device 120 include a volatile memory, a non-volatile memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), and the like. The control device 100 may include one or more ECUs (Electronic Control Units).

[0021] The processor 110 executes a control program, which is a computer program, to realize various processes by the control device 100. The control program is stored in the storage device 120. Alternatively, the control program may be recorded in a computer-readable recording medium.

[0022] The control device 100 (processor 110) acquires the driving environment information ENV from the driving environment information acquisition device 40. The driving environment information ENV is stored in the storage device 120.

[0023] Fig. 2 is a block diagram showing the functional configuration of control device 100. Control device 100 includes, as functional blocks, steering control section 200, reaction force control section 300, and driving assistance control section 400. These functional blocks are realized by cooperation between processor 110, which executes a control program, and storage device 120. Note that steering control section 200, reaction force control section 300, and driving assistance control section 400 may each be realized by a separate control device. In that case, the respective control devices are connected to each other so as to be able to communicate with each other, and exchange necessary information with each other.

[0024] The steering control unit 200, the reaction force control unit 300 and the driving assistance control unit 400 will each be described in detail below.

[0025] 2.Steering control The steering control section 200 performs “steering control” for steering the wheels 2. More specifically, the steering control section 200 controls the steering actuator 21 of the steering device 20 to steer the wheels 2.

[0026] Steering control section 200 performs steering control in response to steering operation of steering wheel 3 by the driver. For example, steering control section 200 calculates target steering angle δt based on steering angle θs and vehicle speed V. Steering angle θs is detected by steering angle sensor 51. Alternatively, steering angle θs may be calculated from rotation angle Φ detected by rotation angle sensor 53. Vehicle speed V is detected by vehicle speed sensor 56. Steering control section 200 steers wheels 2 in accordance with target steering angle δt. Actual steering angle δa of wheels 2 is detected by rotation angle sensor 54. Steering control section 200 controls steering actuator 21 so that actual steering angle δa follows target steering angle δt. More specifically, steering control section 200 generates a control signal for driving steering actuator 21 based on the deviation between target steering angle δt and actual steering angle δa of wheels 2. The steering actuator 21 is driven in accordance with the control signal, thereby steering the wheels 2. Note that the current that drives the steering actuator 21 at this time is the steering current Im.

[0027] Furthermore, the steering control section 200 performs steering control in accordance with a request from the driving assistance control section 400, which will be described later. In this case, the steering control section 200 acquires a target control amount from the driving assistance control section 400, and performs steering control in accordance with the target control amount.

[0028] 3.Reaction Force Control The reaction force control unit 300 performs "reaction force control" to apply a steering reaction force (reaction force torque) to the steering wheel 3. More specifically, the reaction force control unit 300 applies the steering reaction force to the steering wheel 3 by controlling the reaction force actuator 31 of the reaction force device 30.

[0029] The reaction force control unit 300 performs reaction force control in response to the steering operation of the steering wheel 3 by the driver. For example, the reaction force control unit 300 calculates a target steering reaction force (spring component) equivalent to a self-aligning torque applied to the wheels 2 based on the steering angle θs and the vehicle speed V. The target steering reaction force may further include a damping component according to the steering speed (dθs / dt). Then, the reaction force control unit 300 controls the reaction force actuator 31 so as to generate the target steering reaction force. More specifically, the reaction force control unit 300 generates a control signal for driving the reaction force actuator 31 based on the target steering reaction force. The reaction force actuator 31 is driven according to the control signal, thereby generating a steering reaction force.

[0030] The reaction force control unit 300 may also perform reaction force control in accordance with a request from a driving assistance control unit 400, which will be described later. Furthermore, the reaction force control unit 300 may perform reaction force control in conjunction (cooperation) with driving assistance control by the driving assistance control unit 400. The reaction force control in conjunction with driving assistance control will be described in detail later.

[0031] 4. Driving Assistance Control The driving assistance control unit 400 performs "driving assistance control" that assists in driving the vehicle 1. The driving assistance control automatically controls the running of the vehicle 1, regardless of the driving operation by the driver. In this embodiment, in particular, driving assistance control related to steering is considered. Examples of such driving assistance control include automatic driving control, risk avoidance control, lane keeping assistance control (LTA: Lane Tracing Assist), lane departure prevention control (LDA: Lane Departure Alert), and the like.

[0032] The automatic driving control controls the automatic driving of the vehicle 1. Specifically, the driving assistance control unit 400 generates a driving plan for the vehicle 1 based on the driving environment information ENV. Examples of the driving plan include maintaining the current driving lane, changing lanes, turning right or left, and avoiding obstacles. Furthermore, the driving assistance control unit 400 generates a target trajectory TRJ required for the vehicle 1 to drive according to the driving plan based on the driving environment information ENV. The target trajectory TRJ includes a target position and a target speed. Then, the driving assistance control unit 400 performs vehicle driving control so that the vehicle 1 follows the target trajectory TRJ.

[0033] More specifically, the driving assistance control unit 400 calculates the deviation (lateral deviation, yaw angle deviation, speed deviation) between the vehicle 1 and the target trajectory TRJ, and calculates a target control amount required to reduce the deviation. Examples of the target control amount include a target steering angle, a target yaw rate, a target speed, a target acceleration, a target deceleration, and a target current. The driving assistance control unit 400 performs vehicle running control in accordance with the target control amount. The vehicle running control includes steering control, acceleration control, and deceleration control. The steering control is performed via the above-mentioned steering control unit 200. The acceleration control and deceleration control are performed by controlling the drive device and the brake device (not shown) of the vehicle 1.

[0034] FIG. 3 is a conceptual diagram for explaining risk avoidance control. The risk avoidance control is a driving assistance control for reducing the risk of collision with an object in front of the vehicle 1. Examples of objects to be avoided include pedestrians, bicycles, two-wheeled vehicles, animals, other vehicles, and the like. The driving assistance control unit 400 recognizes an object in front of the vehicle 1 based on surrounding situation information (object information) included in the driving environment information ENV. For example, when the risk of collision with the recognized object exceeds a threshold, the driving assistance control unit 400 performs risk avoidance control. Specifically, the driving assistance control unit 400 generates a target trajectory TRJ that moves in a direction away from the object in order to secure a lateral distance from the object. Then, the driving assistance control unit 400 performs vehicle running control so that the vehicle 1 follows the target trajectory TRJ. The vehicle running control here includes at least one of steering control and deceleration control. The steering control is performed via the above-mentioned steering control unit 200.

[0035] FIG. 4 is a conceptual diagram for explaining lane keeping assist control. Lane keeping assist control is driving assist control that assists the vehicle 1 to travel along the lane center LC. A lane is a range between left and right lane boundaries LB. Examples of the lane boundary LB include a white line (dividing line), a curb, and the like. The lane center LC is the center line of the lane. The driving assist control unit 400 recognizes the lane boundary LB and the lane center LC based on the surrounding situation information included in the driving environment information ENV. When the vehicle 1 deviates from the lane center LC, the driving assist control unit 400 performs lane keeping assist control. Specifically, the driving assist control unit 400 performs steering control so that the vehicle 1 returns to the lane center LC. The steering control is performed via the above-mentioned steering control unit 200.

[0036] FIG. 5 is a conceptual diagram for explaining lane departure suppression control. The lane departure suppression control is a driving support control for suppressing the vehicle 1 from deviating from the driving lane. The driving support control unit 400 recognizes the lane boundary LB based on the surrounding situation information included in the driving environment information ENV. When the distance between the vehicle 1 and the lane boundary LB becomes less than a predetermined threshold, the driving support control unit 400 performs lane departure suppression control. Specifically, the driving support control unit 400 notifies the driver of the possibility of lane departure. For example, the driving support control unit 400 controls a steering wheel vibration mechanism (not shown) to vibrate the steering wheel 3. The driving support control unit 400 may output a warning through a display and / or a sound. The driving support control unit 400 may also perform a steering control so that the vehicle 1 moves toward the lane center LC. The steering control is performed via the above-mentioned steering control unit 200.

[0037] 5. Coordination of driving assistance control and reaction force control Next, let us consider the cooperation between the driving assistance control and the reaction force control. For example, let us consider the case where the reaction force control is performed in conjunction (linked) with the steering of the vehicle 1 by the driving assistance control. Hereinafter, the reaction force control performed in conjunction with the steering of the vehicle 1 by the driving assistance control will be referred to as "linked reaction force control."

[0038] The interlocking reaction force control is intended to move the steering wheel 3 in conjunction with the steering of the vehicle 1 (wheels 2) by the driving assist control when the driving assist control is operating. To this end, the interlocking reaction force control imparts a steering reaction force component to the steering wheel 3 to make the steering wheel 3 follow the steering of the vehicle 1 by the driving assist control. By rotating the steering wheel 3, the driver can know the steering direction targeted by the driving assist control. In other words, the interlocking reaction force control makes it possible to communicate (notify) the driver of the steering direction of the vehicle 1 by the driving assist control.

[0039] The interlocking reaction force control according to this embodiment will be described in more detail below.

[0040] 5-1. Feedback reaction force control 6 is a block diagram for explaining an example of interlocking reaction force control according to this embodiment. Reaction force control section 300 includes interlocking reaction force control section 310. Interlocking reaction force control section 310 calculates a target control amount CON_C for generating a steering reaction force component for interlocking reaction force control.

[0041] 6, interlocking reaction force control unit 310 includes a feedback reaction force control unit 310_FB. Feedback reaction force control unit 310_FB includes a driver turning angle acquisition unit 320, a difference calculation unit 330, and a control amount calculation unit 340.

[0042] The driver turning angle acquisition unit 320 acquires the steering angle θs (steering wheel angle) of the steering wheel 3 included in the vehicle state information. Furthermore, the driver turning angle acquisition unit 320 calculates a target turning angle δt corresponding to the steering angle θs of the steering wheel 3 based on a variable gear ratio, etc. The calculation of this target turning angle δt is similar to that by the above-mentioned turning control unit 200. For convenience, the target turning angle δt corresponding to the steering angle θs of the steering wheel 3 is hereinafter referred to as the "driver turning angle δx".

[0043] On the other hand, the "system steering angle δy" is a target steering angle δt required by the driving assistance control. As described above, the system steering angle δy is determined by the driving assistance control unit 400. The interlocking reaction force control unit 310 acquires the system steering angle δy determined by the driving assistance control unit 400.

[0044] The difference calculation unit 330 calculates the difference (deviation) between the driver turning angle δx and the system turning angle δy.

[0045] The control amount calculation unit 340 calculates the target control amount CON_C for generating a steering reaction force component in a direction that reduces the difference between the driver turning angle δx and the system turning angle δy. For example, the control amount calculation unit 340 calculates the target control amount CON_C so that the steering reaction force component increases as the difference increases.

[0046] The reaction force control unit 300 calculates a final target control amount by combining the target control amount CON_C by the interlocking reaction force control with target control amounts by other types of reaction force control. Then, the reaction force control unit 300 controls the reaction force actuator 31 of the reaction force device 30 in accordance with the final target control amount, thereby performing reaction force control.

[0047] 6 applies a steering reaction force component to the steering wheel 3 that causes the steering wheel 3 to follow the steering of the vehicle 1 caused by the driving assist control. By rotating the steering wheel 3, the driver can know the intended steering direction caused by the driving assist control.

[0048] However, even if the driving assistance control steers the vehicle 1, there may be a situation where the steering is not reflected in the rotation of the steering wheel 3. For example, consider a case where the change in the system steering angle δy required by the driving assistance control is small. When the steering wheel 3 is to be rotated, a static friction force acts on the steering shaft 4 connected to the steering wheel 3. Such a static friction force is generated, for example, by parts such as gears in the steering column. If the change in the system steering angle δy is small and the target control amount CON_C by the interlocking reaction force control is small, the steering reaction force applied to the steering wheel 3 does not exceed the static friction force, and the steering wheel 3 may not rotate. If the gain when calculating the target control amount CON_C in the control amount calculation unit 340 is set high, when the driver steers the steering wheel 3 with the intention of steering, a strong steering reaction force is applied in a direction that hinders the driver's steering. The driver feels discomfort with such steering reaction force control that hinders the driver's steering, so there is a limit to the setting of the gain. Furthermore, in a steer-by-wire vehicle 1, due to a quick gear ratio setting, the steering angle θs of the steering wheel 3 tends to be small relative to the steering angle of the wheels 2. Therefore, when the change in the system steering angle δy is minute, the steering wheel 3 may not rotate even if the actual steering angle δa of the wheels 2 changes following the system steering angle δy. When only vehicle behavior occurs without the steering wheel 3 rotating, the driver may feel uncomfortable due to the lack of a sense of unity between the steering wheel 3 and the vehicle behavior.

[0049] Therefore, the interlocking reaction force control according to this embodiment may include a "feedforward reaction force control" as described below.

[0050] 5-2. Feedforward reaction force control 7 is a block diagram for explaining another example of the interlocking reaction force control according to the present embodiment. The interlocking reaction force control unit 310 includes a feedforward reaction force control unit 310_FF and an adder 370 in addition to the above-mentioned feedback reaction force control unit 310_FB.

[0051] As described above, feedback reaction force control unit 310_FB calculates the driver turning angle δx according to the steering angle θs of the steering wheel 3, and calculates the target control amount CON_C for the interlocking reaction force control based on the difference between the driver turning angle δx and the system turning angle δy. For convenience, the target control amount CON_C calculated by feedback reaction force control unit 310_FB is referred to as the "FB target control amount CON_FB."

[0052] On the other hand, the feedforward reaction force control unit 310_FF calculates a target control amount CON_C for the interlocking reaction force control, without depending on the steering angle θs of the steering wheel 3. For convenience, the target control amount CON_C calculated by the feedforward reaction force control unit 310_FF is referred to as the "FF target control amount CON_FF."

[0053] An adder 370 calculates a target control amount CON_C for the interlock reaction force control by adding together the FB target control amount CON_FB and the FF target control amount CON_FF.

[0054] More specifically, the feedforward reaction force control unit 310_FF includes a driving assistance direction acquisition unit 350 and a control amount calculation unit 360.

[0055] The driving assist direction acquisition unit 350 performs a process of acquiring information on the driving assist direction Da. The driving assist direction Da is the steering direction of the vehicle 1 (wheels 2) by driving assist control. In other words, the driving assist direction Da is the leftward or rightward direction. The driving assist direction Da may be expressed as a numerical value. For example, Da=1 represents one of the leftward and rightward directions, and Da=-1 represents the other direction. An example of the driving assist direction acquisition process by the driving assist direction acquisition unit 350 will be described later.

[0056] The control amount calculation unit 360 calculates the FF target control amount CON_FF based on the driving assist direction Da. Specifically, the control amount calculation unit 360 calculates the FF target control amount CON_FF for generating a steering reaction force component that moves the steering wheel 3 in the same direction as the driving assist direction Da. Here, the steering reaction force component (absolute value) that moves the steering wheel 3 in the same direction as the driving assist direction Da is set to a value larger than the static friction force acting on the steering shaft 4 connected to the steering wheel 3. The static friction force is grasped in advance through measurement or simulation. The steering reaction force component that is larger than the static friction force may be a constant value.

[0057] As described above, the feedforward reaction force control unit 310_FF performs feedforward reaction force control to move the steering wheel 3 in the same direction as the driving assist direction Da, regardless of the steering angle θs of the steering wheel 3. This feedforward reaction force control makes it possible to effectively communicate (notify) the driving assist direction Da to the driver. Even if the change in the system steering angle δy required by the driving assist control is small, it is easy to move the steering wheel 3 in the same direction as the driving assist direction Da. This makes it possible to reduce the discomfort felt by the driver.

[0058] 5-3. Example of driving assistance direction acquisition process 5-3-1. First example 8 is a block diagram showing a first example of the driving assistance direction acquisition unit 350. The driving assistance direction acquisition unit 350 acquires a system steering angle δy from the driving assistance control unit 400, and determines the driving assistance direction Da based on the system steering angle δy. More specifically, the driving assistance direction acquisition unit 350 includes a differentiation unit 351 and a sign conversion unit 352.

[0059] Differentiation section 351 acquires a system turning angle δy, and calculates a system turning angular velocity ωy by differentiating the system turning angle δy.

[0060] The sign conversion unit 352 outputs +1 if the system turning angular velocity ωy is a positive value, and outputs -1 if the system turning angular velocity ωy is a negative value. The output of this sign conversion unit 352 is used as the driving assistance direction Da. Da = 1 represents one of the left direction and the right direction, and Da = -1 represents the other direction.

[0061] The control amount calculation unit 360 calculates the FF target control amount CON_FF by multiplying the driving support direction Da by a predetermined gain.

[0062] FIG. 9 is a timing chart for explaining an example of feedforward reaction force control. FIG. 9 shows the time changes of the system turning angle δy, the system turning angular velocity ωy, the driving assistance direction Da (or the FF target control amount CON_FF), the steering angle θs of the steering wheel 3, and the system steering angle θy. The system steering angle θy is a value obtained by converting the system turning angle δy into a steering angle. As shown in FIG. 9, the steering angle θs also changes in the direction of the change in the system turning angle δy (system steering angle θy). That is, the steering wheel 3 moves in the same direction as the driving assistance direction Da. This allows the driver to know the driving assistance direction Da targeted by the driving assistance control.

[0063] In addition, in determining the driving assistance direction Da, a system steering angle θy obtained by converting the system steering angle δy into a steering angle may be used instead of the system steering angle δy. Even in this case, the driving assistance direction acquisition unit 350 still determines the driving assistance direction Da based on the system steering angle δy.

[0064] According to the first example, it is possible to quickly determine whether the driving assist direction Da is to be switched based on the system steering angle δy.

[0065] 5-3-2. Second example 10 is a block diagram showing a second example of the driving assistance direction acquisition unit 350. In the second example, the driving assistance direction Da is notified to the driving assistance direction acquisition unit 350 from the driving assistance control unit 400. That is, the driving assistance direction acquisition unit 350 directly acquires information on the driving assistance direction Da from the driving assistance control unit 400. The driving assistance control unit 400 can recognize the driving assistance direction Da in the near future based on a target trajectory TRJ (see FIG. 3) determined by the driving assistance control unit 400 itself.

[0066] 5-4.Modifications 11, when the driving assist direction Da is switched, the control amount calculation unit 360 may gradually change the FF target control amount CON_FF. This prevents the steering reaction force from changing suddenly when the driving assist direction Da is switched.

[0067] The interlocking reaction force control section 310 may not include the feedback reaction force control section 310_FB and may include only the feedforward reaction force control section 310_FF.

[0068] Effects As described above, according to this embodiment, the interlocking reaction force control is performed to apply a steering reaction force component to the steering wheel 3 in conjunction with the steering of the vehicle 1 by the driving assist control. The interlocking reaction force control includes a feedforward reaction force control that moves the steering wheel 3 in the same direction as the driving assist direction Da, independent of the steering angle θs of the steering wheel 3. This feedforward reaction force control makes it possible to effectively transmit (notify) the driving assist direction Da to the driver. Even if the change in the system steering angle δy required by the driving assist control is small, it is easy to move the steering wheel 3 in the same direction as the driving assist direction Da. By rotating the steering wheel 3, the driver can know the driving assist direction Da, that is, the steering direction targeted by the driving assist control. This makes it possible to reduce the discomfort felt by the driver. [Explanation of symbols]

[0069] 1 vehicle 2 wheels 3 Handle 10 Vehicle Control System 20 Steering device 30 Reaction Device 40 Driving environment information acquisition device 50 Vehicle condition sensor 60 Recognition Sensor 100 Control device 110 Processor 120 Storage device 200 Steering control unit 300 Reaction force control unit 310 Interlocking reaction force control unit 310_FB Feedback reaction force control section 310_FF Feedforward reaction force control section 320 Driver steering angle acquisition unit 330 Difference calculation part 340 Control amount calculation unit 350 Driving assistance direction acquisition unit 360 Control amount calculation unit 370 Addition section 400 Driving assistance control unit Da Driving assistance direction δx Driver's steering angle δy System steering angle

Claims

1. A vehicle control system for controlling a steer-by-wire vehicle, comprising: One or more processors; The one or more processors: A driving assistance control for assisting driving of the vehicle; an interlocking reaction force control for applying a steering reaction force component to a steering wheel in conjunction with the steering of the vehicle by the driving assist control; configured to run The system steering angle is a target steering angle required by the driving assistance control, The driving assistance direction is a steering direction of the vehicle by the driving assistance control, The interlocking reaction force control includes a feedforward reaction force control that moves the steering wheel in the same direction as the driving assistance direction, without depending on the steering angle of the steering wheel and the magnitude of the system turning angle. Vehicle control system.

2. 2. The vehicle control system according to claim 1, The feedforward reaction force control is A driving assistance direction acquisition process for acquiring information on the driving assistance direction; A process of applying a steering reaction force component to the steering wheel to move the steering wheel in the same direction as the driving assistance direction; Includes Vehicle control system.

3. 3. The vehicle control system according to claim 2, The driving assistance direction acquisition process includes: A process of acquiring a system steering angle which is a target steering angle required by the driving assistance control; A process of determining the driving assistance direction based on the system steering angle; Includes Vehicle control system.

4. 4. The vehicle control system according to claim 3, The driving assistance direction acquisition process includes a process of calculating a system turning angular velocity by differentiating the system turning angle, and determining the driving assistance direction based on the system turning angular velocity. Vehicle control system.

5. A vehicle control system according to any one of claims 1 to 4, The steering reaction force component by the feedforward reaction force control is set to a value larger than the static friction force acting on the steering shaft connected to the steering wheel. Vehicle control system.

6. A vehicle control system according to any one of claims 1 to 5, The interlocking reaction force control further includes a feedback reaction force control, The feedback reaction force control is A process of acquiring a driver's turning angle which is a target turning angle according to the steering angle of the steering wheel; A process of acquiring a system steering angle which is a target steering angle required by the driving assistance control; applying a steering reaction force component to the steering wheel in a direction that reduces a difference between the driver's turning angle and the system turning angle; Includes Vehicle control system.

7. A vehicle control method for controlling a steer-by-wire vehicle, comprising: A driving assistance control for assisting driving of the vehicle; an interlocking reaction force control for applying a steering reaction force component to a steering wheel in conjunction with the steering of the vehicle by the driving assist control; Including, The system steering angle is a target steering angle required by the driving assistance control, The driving assistance direction is a steering direction of the vehicle by the driving assistance control, The interlocking reaction force control includes a feedforward reaction force control that moves the steering wheel in the same direction as the driving assistance direction, without depending on the steering angle of the steering wheel and the magnitude of the system turning angle. A vehicle control method.

Images