Vehicle control system and vehicle control method

Abstract

This vehicle control system controls a vehicle provided with a steering actuator in which a steering device of a driver and a tire steering mechanism are mechanically separated, and the tire steering mechanism is controlled to follow a command steering angle, the vehicle control system provided with: a normative vehicle state calculation unit that calculates a normative vehicle state, which is targeted by the vehicle, by using external information surrounding the vehicle and the current state of the vehicle; a driving support unit that calculates a change amount of the command steering angle such that a future vehicle state, which is predicted on the basis of a steering amount of the steering device, approaches the normative vehicle state; and a command steering angle determination unit that determines the command steering angle on the basis of the steering amount and the change amount.

Description

Vehicle control system, vehicle control method

[0001] The present invention relates to a vehicle control system and a vehicle control method.

[0002] Devices that support driving of a vehicle by a driver are known. Patent Document 1 discloses a steering mechanism that is mechanically disconnected from a steering wheel and steers steered wheels by a first actuator, a second actuator that rotates the steering wheel via a steering shaft, a steering angle sensor that detects a steering angle of the steering wheel, a steering torque sensor that detects steering torque acting on the steering shaft, and a steering control device that controls a steering angle according to a steering angle command value given to the first actuator, wherein the steering control device performs: processing of receiving a first target steering angle for driving support from the outside of the steering control device; processing of driving the second actuator according to a steering angle command value which is a conversion of the first target steering angle into a steering angle; processing of calculating a second target steering angle which is a conversion of an actual steering angle detected by the steering angle sensor into a steering angle; processing of reflecting only the first target steering angle to a final target steering angle when a magnitude of an actual steering torque detected by the steering torque sensor is equal to or less than a threshold, and reflecting at least the second target steering angle to the final target steering angle when the magnitude of the actual steering torque exceeds the threshold; processing of determining the steering angle command value based on the final target steering angle; and processing of changing a magnitude of the threshold according to the acceleration or deceleration of a steering operation by the driving support.

[0003] Japanese Patent Laid-Open No. 2022-111970

[0004] In the invention described in Patent Document 1, a torque sensor is indispensable for implementation.

[0005] A vehicle control system according to a first aspect of the present invention is a vehicle control system for controlling a vehicle in which a driver's steering device and a tire steering mechanism are mechanically separated, and a steering actuator is controlled to follow a command steering angle, comprising: a reference vehicle state calculation unit that calculates a reference vehicle state which is a target vehicle state for the vehicle using external information around the vehicle and the current state of the vehicle; a driving support unit that calculates an amount of change to the command steering angle so that a future vehicle state which is a future vehicle state predicted based on the steering amount of the steering device approaches the reference vehicle state; and a command steering angle determination unit that determines the command steering angle based on the steering amount and the amount of change. A second aspect of the present invention relates to a vehicle control method performed by one or more computers that control a vehicle in which a driver's steering device and a tire steering mechanism are mechanically separated, and a steering actuator is controlled to follow a command steering angle, the method comprising: calculating a reference vehicle state which is a target vehicle state for the vehicle using external information around the vehicle and the current state of the vehicle; calculating an amount of change to the command steering angle so that a future vehicle state which is a future vehicle state predicted based on the steering amount of the steering device approaches the reference vehicle state; and determining the command steering angle based on the steering amount and the amount of change.

[0006] According to the present invention, a vehicle can be controlled to approach a standard vehicle state without using a torque sensor.

[0007] Overall vehicle configuration diagram Functional configuration diagram of the vehicle control system Detailed configuration diagram of the driver support unit and command steering angle determination unit Diagram illustrating the status of an example of operation Conceptual diagram showing the operation of the driver support unit Diagram showing an example of operation of the driver support unit Hardware configuration diagram of the vehicle control system Functional configuration diagram of the vehicle control system in modified example 1 Diagram showing an example of operation of the driver support unit in modified example 1 Functional configuration diagram of the driver support unit in modified example 2 Diagram showing an example of operation of the driver support unit in modified example 2 Configuration diagram of the vehicle control system in modified example 3 Configuration diagram of the vehicle control system in modified example 4 Diagram showing the output of the conversion unit in modified example 6 Functional configuration diagram of the vehicle control system in the second embodiment Diagram showing an example of driver data Diagram showing an example of threshold change based on driver characteristics Functional configuration diagram of the vehicle control system in the third embodiment Diagram showing an example of operation of the driver support unit in the third embodiment Diagram showing another example of operation of the driver support unit in the third embodiment Configuration diagram of the vehicle control system in the fourth embodiment

[0008] —First Embodiment— The first embodiment of a vehicle control system and a vehicle control method will be described below with reference to Figures 1 to 7.

[0009] Figure 1 is a plan view showing the overall configuration of vehicle 1 (sometimes referred to as the vehicle itself) in the first embodiment. Vehicle 1 comprises a vehicle control system 100, an external control device 3, a combine sensor 4, wheels 11, a motor 12, a brake mechanism 13, a steering mechanism 14, a suspension 15, an accelerator pedal 16, a brake pedal 17, and a steering device 61. In the figure, FL is a reference numeral indicating the left front, FR is a reference numeral indicating the right front, RL is a reference numeral indicating the left rear, and RR is a reference numeral indicating the right rear. For example, in the wheel 11, 11FL, 11FR, 11RL, and 11RR represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively. Also, F is a reference numeral indicating the front side, and R is a reference numeral indicating the rear side.

[0010] In the following, we define the front-to-back direction of vehicle 1 as the x-axis (forward direction is positive), the left-to-right direction as the y-axis (left direction is positive), and the up-to-down direction as the z-axis (up direction is positive), and then we will explain the details of each component in order. In the following, the person operating vehicle 1 will be referred to as the driver.

[0011] The vehicle control system 100 is a control device that integrates and controls various actuators such as the motor 12, brake mechanism 13, steering mechanism 14, and suspension 15 in response to driver operations, external commands from the external control device 3, and detection signals from the combine sensor 4. The detection signals from the combine sensor 4 are detection signals related to the six control axes, totaling six degrees of freedom, including acceleration in the longitudinal, lateral, and vertical directions, and roll, pitch, and yaw rates.

[0012] The external control unit 3 is a higher-level controller that performs driver assistance control and autonomous driving control via the vehicle control system 100. The external control unit 3 performs various calculations based on external information acquired by external sensors 19 (camera, radar, LiDAR, etc.) and outputs them to the vehicle control system 100 as external commands. For example, the external control unit 3 calculates speed command values ​​and acceleration command values ​​to realize adaptive cruise control (ACC) that follows the preceding vehicle. For example, the external control unit 3 calculates yaw command values, etc., to realize lane keeping control (LKC) that maintains driving within the lane. In Figure 1, the vehicle control system 100 and the external control unit 3 are shown as separate units, but both may be realized in a single ECU.

[0013] The external sensor 19 is, for example, a fisheye camera with a 180° field of view. By installing this fisheye camera on the front, left and right sides, and rear of the vehicle 1, the relative distance and relative speed of objects such as other vehicles, bicycles, pedestrians, and obstacles in the vicinity of the vehicle 1 can be detected. In Figure 1, 19F, 19SL, 19SR, and 19R show the fisheye cameras positioned on the front, left side, right side, and rear of the vehicle 1. Note that the fisheye camera is merely one example of a sensor configuration; ultrasonic sensors, stereo cameras, infrared cameras, laser radars, etc., may be used, or a combination of these may be used. In addition, a laser radar capable of sensing a 360° surrounding area may be mounted on the roof of the vehicle 1. Hereinafter, the signal output by the external sensor 19 will be referred to as the "sensor signal". The sensor signal is input to the vehicle control system 100 and the external control device 3.

[0014] The drivetrain of vehicle 1 is as follows. Vehicle 1 is equipped with a torque generating device that provides driving force to each wheel 11 as a key component of its drivetrain. One example of this torque generating device is an engine or motor that transmits driving force to a pair of left and right wheels 11 via a differential gear and a drive shaft. Another example of a torque generating device is an in-wheel motor type motor 12 that independently drives each wheel 11. The following describes the details of the configuration based on the vehicle structure shown in Figure 1, in which an in-wheel motor type motor 12 is mounted on each wheel 11.

[0015] When the driver wants to move vehicle 1 forward or backward, the driver sets the shift lever to the desired position and then operates the accelerator pedal 16. At this time, the stroke sensor 16a detects the amount the accelerator pedal 16 is pressed, and the acceleration control device 16b outputs an accelerator command converted from the amount pressed to the vehicle control system 100. The vehicle control system 100 supplies power corresponding to the input accelerator command from a battery (not shown) to the motors 12 of each wheel and controls the torque of each motor. As a result, vehicle 1 can be accelerated or decelerated in response to the operation of the accelerator pedal 16.

[0016] Furthermore, when driving assistance or automated driving is performed in response to an external command from the external control device 3, the vehicle control system 100 controls the torque of each motor by supplying the desired power to the motors 12 of each wheel in accordance with the input external command. As a result, the vehicle 1 is accelerated or decelerated, and the desired driving assistance or automated driving is performed.

[0017] The braking system of vehicle 1 is configured as follows. Vehicle 1 is equipped with a wheel cylinder 13a as the main part of the braking system, which applies braking force to each wheel 11. The wheel cylinder 13a is composed of, for example, a cylinder, piston, pads, disc rotor, etc. In the wheel cylinder 13a, the piston is propelled by the working fluid supplied from the master cylinder. The pad connected to the piston is pressed against the disc rotor, which rotates with the wheel 11, and the brake torque acting on the disc rotor becomes the braking force acting between the wheel 11 and the road surface.

[0018] When the driver wants to brake vehicle 1, the driver operates the brake pedal 17. At this time, the force applied by the driver to the brake pedal 17 is increased by a brake booster (not shown), and the master cylinder generates hydraulic pressure approximately proportional to that force. The generated hydraulic pressure is supplied to the wheel cylinders 13aFL, 13aFR, 13aRL, and 13aRR of each wheel via the brake mechanism 13. Therefore, in response to the driver's brake pedal operation, the pistons of the wheel cylinders 13a of each wheel are pressed against the disc rotor, generating braking force on each wheel. In vehicle 1 equipped with the vehicle control system 100, the brake booster and master cylinder may be omitted. In that case, the brake pedal 17 and the brake mechanism 13 may be directly connected, and the brake mechanism 13 may operate directly when the driver presses the brake pedal 17.

[0019] Furthermore, when driving assistance or automated driving is performed in response to an external command from the external control device 3, the vehicle control system 100 controls the brake mechanism 13 and the wheel cylinders 13a of each wheel via the brake control device 13b in response to the input external command. As a result, the vehicle 1 is braked, and the desired driving assistance or automated driving is performed. The brake control device 13b also has the function of converting the steering amount of the brake pedal 17 by the driver into a brake command and outputting it to the vehicle control system 100 as an external command.

[0020] The steering system of vehicle 1 is configured as follows. Vehicle 1 is equipped with a steering mechanism 14 that provides steering force to each wheel 11 as the main part of the steering system. Figure 1 shows a front steering mechanism 14F that steers the front wheels 11F (left front wheel 11FL, right front wheel 11FR) and a rear steering mechanism 14R that steers the rear wheels 11R (left rear wheel 11RL, right rear wheel 11RR). However, vehicle 1 is not required to be equipped with both the front steering mechanism 14F and the rear steering mechanism 14R; for example, the rear steering mechanism 14R may be omitted.

[0021] The driver changes the direction of travel of the vehicle 1 by operating the steering device 61. At this time, the "steering torque" and "steering angle" input by the driver via the steering device 61 are detected by the steering torque detection device 18a and the steering angle detection device 18b. The steering angle detected by the steering angle detection device 18b is input to the vehicle control system 100 as the steering amount 51, which will be described later. The steering control devices 14aF and 14aR receive the command steering angle from the vehicle control system 100, as will be described later. Note that the vehicle 1 does not necessarily have to be equipped with the steering torque detection device 18a.

[0022] The suspension system of vehicle 1 is configured as follows. Vehicle 1 is equipped with a suspension 15 as a key part of its suspension system, which absorbs vibrations and shocks generated in each wheel 11 and improves the stability of the vehicle body and ride comfort. This suspension 15 is, for example, a semi-active suspension or a fully active suspension. The semi-active suspension is a combination of a damper with adjustable viscosity and a coil spring. The fully active suspension is a combination of an actuator with adjustable length, a damper and a coil spring, which can arbitrarily change the relative distance between the vehicle body and the wheels 11. The vehicle control system 100 not only improves ride comfort and the like by controlling the viscosity of the semi-active suspension and the length of the fully active suspension, but also appropriately controls the attitude of vehicle 1 according to the environment.

[0023] Figure 2 is a functional configuration diagram of the vehicle control system 100. The vehicle control system 100 includes a reference vehicle state calculation unit 110, a driving support unit 120, and a command steering angle determination unit 130. The steering amount 51, vehicle state 52, and external conditions 53 are input to the vehicle control system 100 from the steering device 61, vehicle state acquisition unit 62, and external conditions acquisition unit 63, respectively. The steering device 61, vehicle state acquisition unit 62, and external conditions acquisition unit 63 will be described first, and then the configuration of the vehicle control system 100 will be described. The steering device 61 is operated by the driver and outputs the steering amount 51 to the vehicle control system 100. The steering device 61 is at least one of the steering control device 14aF and the steering control device 14aR in Figure 1.

[0024] The vehicle state acquisition unit 62 acquires vehicle states such as translational and rotational speed and acceleration occurring in the vehicle 1 and outputs them as vehicle state 52. The vehicle state acquisition unit 62 may acquire detected values ​​of longitudinal, lateral, and vertical accelerations, as well as roll, pitch, and yaw rates from the combine sensor 4, or it may calculate them from the steering amounts of actuators such as the motor 12, brake mechanism 13, and steering mechanism 14. The vehicle state acquisition unit 62 may also acquire detected values ​​of roll and pitch angles from the information of the stroke sensors 16a of the suspension 15 attached to each wheel, and its own position acquired by GNSS.

[0025] The external environment information acquisition unit 63 calculates and outputs the external environment information 53 using the sensor signals output by the external environment sensor 19. The external environment information 53 includes, for example, the position, size, and speed of objects (obstacles, etc.) around the vehicle 1. The external environment information 53 may also include the position and type of road signs, road markings, traffic lights, etc. The external environment information 53 may further include data on traffic rules in the area in front of the vehicle 1, available parking spaces in the parking lot, and the presence or absence of obstacles. If the external environment sensor 19 includes a camera, the captured images obtained by the camera are used as processing targets, and external environment information can be acquired by simultaneously identifying the type of multiple objects. In particular, a stereo camera using two cameras is superior because it can also calculate the relative distance and relative speed of moving objects and obstacles.

[0026] The external environment information acquisition unit 63 may have a map information acquisition unit (not shown) that pre-stores or acquires map information, such as the shape of the road on which the vehicle 1 travels and the location of road markings, through communication or other means. In this case, the vehicle status acquisition unit 62 can correct its own position by comparing the road markings and other information in the external environment information acquired by the external environment information acquisition unit 22 with the map information, thereby calculating a more accurate self-position. Furthermore, the external environment information acquisition unit 22 can acquire more accurate traffic rules from the aforementioned map information.

[0027] The vehicle control system 100 includes a normative vehicle state calculation unit 110, a driving support unit 120, and a command steering angle determination unit 130. The normative vehicle state calculation unit 110 calculates and outputs a normative vehicle state 55, which is the state that vehicle 1 should be in the future. For example, the normative vehicle state calculation unit 110 recognizes a parking area that exists around vehicle 1 and calculates the state of vehicle 1 parked in that parking area as the normative vehicle state 55. The normative vehicle state 55 includes the position, orientation, steering angle, etc., of vehicle 1.

[0028] The driver assistance unit 120 calculates the change amount 56 using a method described later and outputs it to the command steering angle determination unit 130. The driver assistance unit 120 receives the steering amount 51, vehicle state 52, and reference vehicle state 55 as input. The command steering angle determination unit 130 calculates the command steering angle 57 using a method described later and outputs it to the steering actuator 64. The command steering angle determination unit 130 receives the steering amount 51 and the change amount 56 as input.

[0029] Figure 3 is a detailed configuration diagram of the driver support unit 120 and the command steering angle determination unit 130. The driver support unit 120 includes a future vehicle state prediction unit 121, a driver support difference calculation unit 122, a conversion unit 123, and a selection unit 124.

[0030] The future vehicle state prediction unit 121 uses the steering input 51 and the vehicle state 52 to calculate the future vehicle state 58, which is the state of vehicle 1 in the future if the steering input 51, which is the driver's input, is directly reflected in the operation of vehicle 1. For example, the future vehicle state prediction unit 121 calculates the state of vehicle 1 after a predetermined time, for example 5 seconds, starting from the current position of vehicle 1, while maintaining the current speed of vehicle 1 and reflecting the steering input 51. The driving support difference calculation unit 122 calculates the deviation 59, which is the difference between the reference vehicle state 55 and the future vehicle state 58, and outputs it to the conversion unit 123.

[0031] The conversion unit 123 outputs High if the absolute value of the deviation 59 is less than or equal to threshold D, and outputs Low if the deviation 59 is greater than a predetermined absolute value. This threshold D is a fixed value that is predetermined. The selection unit 124 outputs either the deviation 59 or zero depending on the output of the conversion unit 123. If the output of the conversion unit 123 is High, the selection unit 124 outputs the deviation 59 as the change amount 56, and if the output of the conversion unit 123 is Low, it outputs zero as the change amount 56.

[0032] The command steering angle determination unit 130 includes a first steering angle conversion unit 131, a second steering angle conversion unit 132, and a target steering angle sum calculation unit 133. The first steering angle conversion unit 131 converts the steering amount 51 into a steering angle 51A and outputs it. The second steering angle conversion unit 132 converts the change amount 56 into an assist angle 56A and outputs it. The conversion of steering angles in the first steering angle conversion unit 131 and the second steering angle conversion unit 132 may be achieved by referring to a pre-created conversion table or by using a pre-created conversion formula. The target steering angle sum calculation unit 133 calculates the sum of the output of the first steering angle conversion unit 131 and the output of the second steering angle conversion unit 132 and outputs it to the steering actuator 64 as a command steering angle 57.

[0033] The operation example will be explained with reference to Figures 4 to 6. Figure 4 is a diagram illustrating the situation in the operation example. The rectangle shown by the solid line at the top of the diagram is the current position of vehicle 1, and the parking area is located at the bottom of the diagram. Vehicle 1 reverses into the parking area to park. That is, in this diagram, at the current position of vehicle 1, the front of vehicle 1 is facing to the upper right.

[0034] The rectangle shown by the dashed line at the bottom of the figure represents the standard vehicle state 55, the solid line represents the driver's intended trajectory L1, and the dashed line represents the standard trajectory L2 calculated by the standard vehicle state calculation unit 110. However, the driver's trajectory L1 is shown for the sake of explanation and is not actually known in advance. The driver operates the steering device 61 so that the vehicle 1 follows the driver's trajectory L1. Because the amount of steering by the driver of the steering device 61 is small, the driver's trajectory L1 is a so-called wide-turn trajectory that bulges to the left in the figure. If the driver's trajectory L1 is adopted, the vehicle 1 will overlap with the lane marking on the left. The driving support unit 120 generates a change amount 56 so that the vehicle 1 follows the standard trajectory L2.

[0035] In the following, the vehicle state will be described in terms of the steering angle. That is, the reference vehicle state 55 is embodied in the reference steering state 55, and the future vehicle state 58 is embodied in the future steering state 58. However, the reference vehicle state calculation unit 110 may output not only the reference vehicle state 55 but also reference position and orientation to the driving support unit 120.

[0036] Figure 5 is a conceptual diagram illustrating the operation of the driver assistance unit 120, showing the time-series change of the steering angle. In this figure, the X-axis represents time, with time progressing from left to right. The Y-axis represents the steering angle, with straight-ahead driving defined as zero degrees, left as positive, and right as negative. The solid line represents the steering angle 51A by the driver, the dashed line represents the reference steering angle 55A, and the dashed-dot line represents the commanded steering angle 57.

[0037] The reference steering angle 55A is generally calculated based on at least one of the following: the lateral deviation between the current position of the vehicle 1 and the reference trajectory L2, and the deviation (angle deviation) between the tangential direction of the reference trajectory L2 near the vehicle and the direction of travel of the vehicle 1. A known method is the "forward gaze model," which takes the deviation between a specific point on the reference trajectory that is an extension of the direction of travel of the vehicle 1 and the nearest point on the reference trajectory. In the configuration diagram shown in Figure 2, the reference vehicle state calculation unit 110 calculates the reference vehicle state 55, which is a different dimension from the steering angle. However, for the sake of explanation, Figure 5 shows the reference steering angle 55A obtained by converting the reference vehicle state 55 to the dimension of the steering angle. The conversion between the reference vehicle state 55 and the reference steering angle 55A can be achieved by known configurations such as the first steering angle conversion unit 131 and the second steering angle conversion unit 132.

[0038] Both the steering angle 51A and the system-referenced steering angle 55A take negative values ​​in all time periods, but their magnitudes differ. The steering angle 51A has a small absolute value, while the system-referenced steering angle 55A has a large absolute value. As shown in the example in Figure 4, adopting the steering angle 51A results in a deviation from the ideal position, so the driving support unit 120 generates a change amount 56 to bring the steering angle 51A closer to the system-referenced steering angle 55A. This change amount 56 is converted by the second steering angle conversion unit 132 to match the dimensions of the steering angle to become an assist angle 56A, and the sum of this with the steering angle 51A becomes the command steering angle 57.

[0039] Figure 6 shows an example of the operation of the driving support unit 120. Figure 6 shows the time-series changes of the steering angle 51A and the assist angle 56A from time t0 to time t3. The time shown on the horizontal axis in the two graphs is synchronized. The correspondence between the line type and data in the steering angle graph is the same as in Figure 5, and the time-series changes of the steering angle 51A and the reference steering angle 55A are also the same as in Figure 5. The time-series change of the command steering angle 57 is as follows. That is, from time t0 to time t1 and from time t2 to time t3, the command steering angle 57 matches the reference steering angle 55A, as in the example in Figure 5. However, from time t1 to time t2, the command steering angle 57 matches the steering angle 51A, not the reference steering angle 55A. The reason for this is as follows.

[0040] Up until time t1, the absolute value of the deviation 59 is less than the threshold D, so the selection unit 124 outputs the deviation 59 as the change amount 56. However, from time t1 to time t2, the absolute value of the deviation 59 becomes greater than or equal to the threshold D, so the selection unit 124 outputs zero as the change amount 56. Therefore, during the period from time t1 to time t2, the assist angle 56A is also zero, and the steering angle 51A obtained by converting the steering amount 51 is output as is as the command steering angle 57.

[0041] Figure 7 is a hardware configuration diagram of the vehicle control system 100. The vehicle control system 100 includes a CPU 41 which is a central processing unit, a ROM 42 which is a read-only storage device, a RAM 43 which is a read-write storage device, a fixed disk 44, and a communication device 45. The CPU 41 performs the various calculations mentioned above by loading the program stored in the ROM 42 into the RAM 43 and executing it.

[0042] The vehicle control system 100 may be implemented using a rewritable logic circuit such as an FPGA (Field Programmable Gate Array) or an application-specific integrated circuit such as an ASIC (Application Specific Integrated Circuit) instead of the combination of CPU 41, ROM 42, and RAM 43. Alternatively, the vehicle control system 100 may be implemented using a different configuration, such as a combination of CPU 41, ROM 42, RAM 43 and FPGA, instead of the combination of CPU 41, ROM 42, and RAM 43.

[0043] The fixed disk 44 is a non-volatile storage device, such as a hard disk drive. The communication device 45 is a communication module capable of at least one of wireless and wired communication, and enables communication with other components mounted on the vehicle 1, namely the steering device 61 and the steering actuator 64.

[0044] For convenience in FIG. 7, although the vehicle control system 100 is illustrated as being configured by one hardware device, the vehicle control system 100 may be configured by a plurality of hardware devices. In this case, the hardware devices may be installed adjacent to each other, or may be connected via a local area network or the like.

[0045] According to the first embodiment described above, the following operational effects can be obtained. (1) The vehicle control system 100 includes a steering actuator 64 in which a driver's steering device 61 and a tire steering mechanism are mechanically disconnected, and the tire steering mechanism is controlled to follow a commanded steering angle 57. The vehicle control system 100 includes: a reference vehicle state calculation unit 110 that calculates a reference vehicle state 55, which is a target state of the vehicle 1, using external world information around the vehicle and a current vehicle state 52 of the vehicle 1; a driving support unit 120 that calculates a change amount 56 of the commanded steering angle 57 such that a future vehicle state 58, which is a future state of the vehicle 1 predicted based on a steering amount 51 of the steering device 61, approaches the reference vehicle state 55; and a commanded steering angle determination unit 130 that determines the commanded steering angle 57 based on the steering amount 51 and the change amount 56. Therefore, the vehicle 1 can be controlled to approach the reference vehicle state 55 without measuring the torque of the steering device 61.

[0046] (2) The driving support unit 120 calculates the change amount when a deviation between the future vehicle state 58 and the reference vehicle state 55 is within a threshold value. Therefore, when the driver performs steering by their own intention, the driver's intention can be reflected in the commanded steering angle 57.

[0047] (3) The vehicle state is a steering angle.

[0048] (Modified Example 1) FIG. 8 is a functional configuration diagram of a vehicle control system 100 according to Modified Example 1. The vehicle control system 100 according to the present modified example further includes a steering maintaining unit 66. An output of a conversion unit 123 and the commanded steering angle 57 are output to the steering maintaining unit 66. The commanded steering angle determination unit 130 according to the present modified example outputs the commanded steering angle 57 to the steering maintaining unit 66 instead of the steering actuator 64. The conversion unit 123 according to the present modified example outputs the same value to a selection unit 124 and the steering maintaining unit 66.

[0049] The steering maintenance unit 66 performs the following processing according to the output of the conversion unit 123. Specifically, if the output of the conversion unit 123 is High, the steering maintenance unit 66 records the value of the command steering angle 57 as the recorded value 57R and outputs that value as the processed command steering angle 57K. If the output of the conversion unit 123 is High, the recorded value 57R is overwritten and only the latest value remains. If the output of the conversion unit 123 is Low, the steering maintenance unit 66 compares the recorded value 57R and the command steering angle 57 in absolute value, and outputs the command steering angle 57 as the processed command steering angle 57K only if the command steering angle 57 has a larger absolute value; otherwise, it outputs the recorded value 57R as the processed command steering angle 57K. In this modified example, the steering actuator 64 operates based on the processed command steering angle 57K input from the outside.

[0050] Figure 9 shows an example of the operation of the driving support unit 120 in modified example 1. This figure corresponds to Figure 6 in the first embodiment. The difference between Figure 7 and Figure 6 is that the recorded value 57R and the command steering angle 57 are shown at the bottom. From time t0 to time t1, the output of the conversion unit 123 is High, so the value of the recorded value 57R is updated. At time t1, the assist angle 56A becomes zero, but since the absolute value of the recorded value 57R is larger than the command steering angle 57, the steering maintenance unit 66 maintains the recorded value 57R, which is the output at time t1. From time t11 to time t12, although the assist angle 56A is zero, the steering angle 51A has increased, so the absolute value of the command steering angle 57 exceeds the absolute value of the recorded value 57R, and the command steering angle 57 is output as the processed command steering angle 57K.

[0051] According to this modified example, in addition to the effects and advantages of the first embodiment, the following effects and advantages can be obtained. (4) The vehicle control system 100 includes a steering maintenance unit 66 that records the target steering angle as a recorded value 57R when the deviation between the future vehicle state 58 and the reference vehicle state 55 is within a threshold, and outputs to the steering actuator as the target steering angle the value with the larger absolute value among the recorded target steering angle and the driver's steering angle when the deviation between the future vehicle state 58 and the reference vehicle state 55 exceeds the threshold. As a result, abrupt changes in the change amount 56 are prevented, and the driver's discomfort is reduced.

[0052] (Modification 2) Figure 10 is a functional configuration diagram of the driving support unit 120 in Modification 2. In this modification, the driving support unit 120 further includes a polarity maintenance unit 125. In this modification, the output of the selection unit 124 is input to the polarity maintenance unit 125, and the polarity maintenance unit 125 outputs a change amount 56. The polarity maintenance unit 125 fixes the polarity of the change amount 56 to either positive or negative. For example, the polarity maintenance unit 125 determines the polarity based on the first non-zero output of the selection unit 124 after the start of operation. If the polarity opposite to the determination is input to the polarity maintenance unit 125, it outputs zero as the change amount 56.

[0053] Figure 11 shows the operation of the driving support unit 120 in modified example 2. In this example, the conditions around the vehicle 1 are significantly different from those in the first embodiment, and the reference steering angle 55A repeatedly increases and decreases over time. Specifically, it takes a minimum value at time t11, a maximum value at time t13, and a minimum value at time t15. On the other hand, the steering angle 51A changes in the same way as in the first embodiment. In this modified example, the output of the conversion unit 123 is High at all time points.

[0054] The relationship between the reference steering angle 55A, shown by the dashed line, and the steering angle 51A, shown by the solid line, is as follows: At time t10, both are zero, and from time t10 to time t11, both take negative values, but the reference steering angle 55A changes more significantly. At time t11, the reference steering angle 55A begins to increase, and at time t12, the reference steering angle 55A and the steering angle 51A are the same value. After that, the reference steering angle 55A remains larger until time t14, and from time t14 to time t16, the steering angle 51A is larger. The command steering angle 57 is the same value as the reference steering angle 55A from time t10 to time t12, the same value as the steering angle 51A from time t12 to time t14, and the same value as the reference steering angle 55A from time t14 to time t16.

[0055] The time variation of the assist angle 56A shown at the bottom of Figure 11 is as follows: From time t10 to time t12, it is the difference between the steering angle 51A and the reference steering angle 55A; from time t12 to time t14, it is zero; and from time t14 to time t16, it is the difference between the steering angle 51A and the reference steering angle 55A. The reason why the assist angle 56A is zero from time t12 to time t14 is as follows: Immediately after time t10, the polarity maintenance unit 125 determines the polarity to be negative because the deviation 59 is a negative value. From time t10 to time t12, the polarity maintenance unit 125 outputs the deviation 59 as is because it is a negative value, but from time t12 to time t14, the deviation 59 is a positive value, i.e., a value different from the determined polarity, so it outputs zero.

[0056] According to this modified version, in addition to the effects and advantages of the first embodiment, the following effects and advantages can be obtained: (5) The vehicle control system 100 includes a polarity maintenance unit 125 that limits the positive and negative polarity of the change amount 56 to either positive or negative. Therefore, discomfort for the driver can be reduced.

[0057] (Modification 3) In the first embodiment described above, the threshold value D in the conversion unit 123 was a predetermined fixed value. However, the threshold value D may be a variable value.

[0058] Figure 12 is a configuration diagram of the vehicle control system 100 in modified example 3. The difference from Figure 2 is that it further includes an obstacle response threshold setting unit 140. The obstacle response threshold setting unit 140 determines a threshold D based on the conditions around the vehicle 1 and outputs it to the conversion unit 123. For example, the obstacle response threshold setting unit 140 uses the external conditions 53 to set the threshold D higher the closer the distance between the vehicle 1 and the obstacle, and lower the threshold D the further the distance between the vehicle 1 and the obstacle. Alternatively, the obstacle response threshold setting unit 140 may use the vehicle conditions 52 to set the threshold D higher the faster the speed of the vehicle 1, and lower the threshold D the slower the speed of the vehicle 1.

[0059] For example, if there are other parked vehicles near the parking position, the closer vehicle 1 gets to the parking position, the closer it gets to the obstacle, so the obstacle response threshold setting unit 140 sets the threshold D to a larger value. The obstacle response threshold setting unit 140 may also change the threshold D according to the surrounding conditions of vehicle 1 other than obstacles, such as the brightness of the surrounding environment or the slipperiness of the road surface.

[0060] This modified version provides the following effects in addition to those of the first embodiment: (6) The vehicle control system 100 includes an obstacle-response threshold setting unit 140 that changes the threshold value based on the distance between the vehicle 1 and the obstacle. Therefore, if the distance between the vehicle 1 and the obstacle is far, the threshold value D can be set to a small value to prioritize the driver's operation, and if the distance between the vehicle 1 and the obstacle is close, the threshold value D can be set to a large value for safety.

[0061] (Modification 4) Figure 13 is a diagram of the configuration of the vehicle control system 100 in Modification 4. The difference from Figure 3 is that the command steering angle determination unit 130 further includes a change detection unit 134. The change detection unit 134 is a differentiator and outputs a value obtained by multiplying the time change amount of the steering amount 51 by a predetermined coefficient. In this modification, the command steering angle 57 is the sum of the outputs of the first steering angle conversion unit 131 and the second steering angle conversion unit 132, plus the output of the change detection unit 134. Therefore, in this modification, regardless of the operation of the driving support unit 120, the high-frequency component of the steering amount 51 is added to the command steering angle 57, so that the fine movements included in the steering amount 51 are reflected in the command steering angle 57. If there is no change in the movement of the vehicle 1 even though the driver is steering, it is likely to lead to a feeling of unnaturalness, but the vehicle control system 100 in this modification can reduce this feeling of unnaturalness.

[0062] (Modification 5) The steering device 61 is not typically limited to a steering wheel, or so-called handle. The steering device 61 can be any input device that allows the driver 91 to specify the direction of travel of the vehicle 1, and may be a joystick or directional buttons. The input operation of the joystick or directional buttons by the driver 91 is output to the command steering angle determination unit 130 as a steering amount 51, as in the first embodiment, and the steering amount 51 is converted into a steering angle 51A by the first steering angle conversion unit 131. In this modification, the processing content of the first steering angle conversion unit 131 differs from that of the first embodiment, but the processing content of the first steering angle conversion unit 131 can be appropriately changed according to the hardware and signal characteristics. For example, the first steering angle conversion unit 131 converts the steering angle 51A to a larger value when the angle of tilt of the joystick is large or when the time the joystick is tilted is long.

[0063] (Modification 6) In the first embodiment described above, the selection unit 124 output either a deviation of 59 or zero as the change amount 56. However, the selection unit 124 may also output a continuous value with a minimum value of zero and a maximum value of a deviation of 59. For example, two threshold values, DS and DL, are set in advance in the conversion unit 123, and a value between 0 and 1 is output in relation to the deviation of 59. The selection unit 124 then outputs a value obtained by multiplying the output of the conversion unit 123 by the deviation of 59 as the change amount 56.

[0064] Figure 14 shows the output of the conversion unit 123 in the modified example 6. The conversion unit 123 outputs 1 when the deviation 59 is -Ds or greater and less than +Ds, and outputs 0 when the deviation 59 is +DL or greater and less than -DL. When the deviation 59 is +Ds or greater and less than +DL, the conversion unit 123 outputs a value proportional to the difference between these values. For example, when the deviation 59 is (Ds + DL) / 2, the conversion unit 123 outputs 0.5. When the deviation 59 is -LD or greater and less than -Ds, it outputs a value proportional to the difference between these values.

[0065] In this modified example, by increasing the difference between Ds and DL, a response similar to that of Modified Example 1 can be obtained without providing the steering maintenance unit 66 shown in Modified Example 1. That is, as the deviation 59 increases, the output of the conversion unit 123 gradually approaches zero from 1, and the output of the command steering angle 57 gradually approaches the steering angle 51A from the reference steering angle 55A.

[0066] —Second Embodiment— A second embodiment of the vehicle control system and vehicle control method will be described with reference to Figures 15 to 17. In the following description, the same reference numerals are used for components that are the same as in the first embodiment, and the differences will be mainly explained. Points that are not specifically explained are the same as in the first embodiment. This embodiment differs from the first embodiment mainly in that the threshold value D is set according to the characteristics of the driver.

[0067] Figure 15 is a functional configuration diagram of the vehicle control system 100A in the second embodiment. In addition to the configuration in the first embodiment, the vehicle 1 further includes a driver state acquisition unit 23. The driver state acquisition unit 23 outputs driver data 510 to the reference vehicle state calculation unit 110 and the driving support unit 120.

[0068] The driver status acquisition unit 23 acquires driver data 510, which is data indicating the state of the driver 91 such as head movements, gaze information, and facial expressions, through sensors and input means mounted inside the vehicle 1, and outputs it to the vehicle control system 100A. The driver-compatible threshold setting unit 150 includes a driver identification unit 151, a storage unit 152 for storing the attributes of multiple drivers, a skill discrimination unit 153, and a threshold setting unit 154.

[0069] The driver identification unit 151 identifies the driver operating vehicle 1 using the driver data 510. For example, the driver identification unit 151 identifies the driver's driver identifier by pattern matching or the like using the facial image and facial shape data included in the driver data 510. A correspondence table between facial feature quantities and driver identifiers is stored in a memory unit (not shown), and the driver identification unit 151 can identify the driver identifier by referring to this correspondence table. If the calculated feature quantity is not stored in the correspondence table, the driver identification unit 151 stores a new combination of the driver identifier and the calculated feature quantity in the correspondence table.

[0070] The memory unit 152 stores numerous combinations of driver identifiers and driver attributes. Driver attributes are, for example, either high skill or low skill. The memory unit 152 stores the determination results from the skill determination unit 153. However, data may be stored in the memory unit 152 in advance.

[0071] The skill determination unit 153 determines the driver's driving skill based on the driving history. The driving history may be the real-time driving history of vehicle 1, or it may be the past driving history of driver 91 stored in a storage device (not shown). For example, the skill determination unit 153 determines that the smoother the driving by driver 91, the higher the driving skill. The skill determination unit 153 positively evaluates the smoothness of the driving based on factors such as fewer sudden changes in acceleration, fewer reversals during parking, and less swaying. The skill determination unit 153 stores in the storage unit 152 the combination of the determined driving skill, either high skill or low skill, and the driver identifier identified by the driver identification unit 151.

[0072] The threshold setting unit 154 sets thresholds corresponding to the attributes of the driver identified by the driver identification unit 151. Specifically, the threshold setting unit 154 first reads the driver attributes corresponding to the driver identifier identified by the driver identification unit 151 from the storage unit 152. If the read driver attributes indicate high skill, the threshold setting unit 154 sets the first threshold D1 as the threshold in the conversion unit 123 of the driving support unit 120. If the read driver attributes indicate low skill, the threshold setting unit 154 sets the second threshold D2 as the threshold in the conversion unit 123 of the driving support unit 120. The second threshold D2 is a larger value than the first threshold D1. In other words, for drivers with high driving skills, the driving support unit 120 stops providing assistance when the deviation 59 is relatively small. On the other hand, for drivers with low driving skills, the driving support unit 120 continues providing assistance until the deviation 59 becomes relatively large.

[0073] Figure 16 shows an example of driver data 510. In this example, a camera 92 is installed inside the vehicle 1, near the connection point between the windshield and the ceiling, for example, near the rearview mirror. The camera 92 photographs the driver 91. The camera 92 may output the captured image itself as driver data 510. Alternatively, the camera 92 may calculate feature quantities that indicate the positional relationships between facial features and output them as driver data 510 instead of the captured image. Various known methods can be used to calculate facial feature quantities. The camera 92 may be a camera that uses infrared light in addition to visible light. Furthermore, 3D shape data measured by LiDAR or the like may be output as driver data 510 instead of the camera 92.

[0074] Figure 17 shows an example of threshold change based on driver characteristics. The situation shown in this figure is the same as in the first embodiment; specifically, the steering angle 51A shown by the solid line and the system reference steering angle 55A shown by the dashed line are the same as in Figure 6. In this figure, the dashed line shows the command steering angle 57 and assist angle 56A for a driver with high skill levels, and the dashed line shows the command steering angle 57 and assist angle 56A for a driver with low skill levels. However, in this figure, the positions of the dashed and dashed lines are intentionally offset to reduce overlap between them.

[0075] In this example, at time t21, the deviation of 59 exceeded the threshold D1, so driving assistance for the highly skilled driver ended. At time t22, the deviation of 59 exceeded the threshold D2, so driving assistance for the less skilled driver ended. The assist angle for the highly skilled driver, shown by the dashed line, is zero from time t21 to time t24. On the other hand, the assist angle for the less skilled driver, shown by the double dashed line, is zero only from time t22 to time t23.

[0076] According to the second embodiment described above, the following effects can be obtained: (7) The vehicle control system 100 includes a driver-responsive threshold setting unit 150 that changes the threshold based on the driver's characteristics. Therefore, the threshold D can be changed according to the driver's characteristics.

[0077] (8) The driver-compatible threshold setting unit 150 includes a driver identification unit 151 that identifies a driver, a storage unit 152 that stores the attributes of multiple drivers, and a threshold setting unit 154 that sets thresholds corresponding to the attributes of the drivers identified by the driver identification unit 151. Therefore, it is possible to identify a driver and set a threshold D for each driver.

[0078] (9) The driver-response threshold setting unit 150 includes a skill determination unit 153 that determines the driver's driving skills based on their driving history. The threshold setting unit 154 sets a second threshold D2 as the threshold when a driver who is determined to have low driving skills drives the vehicle 1, and sets a first threshold D1 as the threshold when a driver who is determined to have high driving skills drives the vehicle 1. The first threshold D1 is smaller than the second threshold D2. Therefore, a higher threshold D can be set to actively support drivers with low driving skills.

[0079] (Modification 1 of the second embodiment) In the second embodiment described above, the vehicle control system 100A is equipped with a threshold setting unit 154. However, the vehicle control system 100A may not be equipped with a threshold setting unit 154, and the driver-responsive threshold setting unit 150 may set the threshold using data stored in advance in the storage unit 152.

[0080] (Modification 2 of the second embodiment) In the second embodiment described above, the vehicle control system 100A is equipped with a driver identification unit 151. However, the vehicle control system 100A does not have a driver identification unit 151, and the identifier of the driver 91 may be input from an external source. For example, a configuration having the same function as the driver identification unit 151 may be provided outside the vehicle control system 100A, or the driver 91 may input its own identification data using an input device (not shown), such as a button or a touch panel.

[0081] (Modification 3 of the second embodiment) In the second embodiment described above, the threshold setting unit 154 determined two attributes: high skill and low skill. However, the threshold setting unit 154 may determine the driver's skill level of the driver 91 in three or more stages.

[0082] (Modification 4 of the second embodiment) Driver attributes are not limited to driving skills. For example, drivers may be classified in terms of the degree of discomfort with steering angle assistance. The degree of discomfort with steering angle assistance for each driver can be determined, for example, by estimating the driver's emotions using facial images included in the driver data 510, and if the emotions are negative, it can be determined that the discomfort is high.

[0083] —Third Embodiment— A third embodiment of the vehicle control system and vehicle control method will be described with reference to Figures 18 to 20. In the following description, the same reference numerals are used for components that are the same as in the first embodiment, and the differences will be mainly explained. Points that are not specifically explained are the same as in the first embodiment. This embodiment differs from the first embodiment mainly in that it also controls the reaction force actuator.

[0084] Figure 18 is a functional configuration diagram of the vehicle control system 100B in the third embodiment. In this embodiment, the vehicle 1 further includes a reaction force actuator 65. The reaction force actuator 65 generates a reaction force on the steering device 61. The configuration of the vehicle control system 100B is the same as in the first embodiment, except that the driving support unit 120 outputs a reaction force operation command 56B to the reaction force actuator 65.

[0085] The driver support unit 120 calculates the reaction force operation command 56B as follows, for example. First, the driver support unit 120 uses the reference trajectory as the target driving path of the vehicle 1 and calculates the steering angle that follows the target driving path as the reference steering angle. Next, it obtains the actual steering angle as the amount of steering input by the driver 91 and outputs a reaction force operation command 56B to generate a torque proportional to the deviation between the reference steering angle and the actual steering angle, i.e., a steering assist torque, using the steering motor 18d. When the reaction force actuator 65 outputs a steering assist torque proportional to the input reaction force operation command 56B, the driver support unit 120 can calculate the reaction force operation command 56B based on the following formula 1.

[0086] RFC = Ka(θref - θd) ... (Equation 1)

[0087] However, in Equation 1, RFC is the reaction force command 56B, Ka is the proportionality constant, θref is the reference steering angle, and θd is the actual steering angle.

[0088] Figure 19 shows an example of the operation of the driving support unit 120, illustrating the time-series changes in the steering angle 51A and the reaction torque. The time-series changes in the steering angle 51A and the reference steering angle 55A are the same as in Figure 6. In this example, since the absolute value of the deviation 59 is smaller than the threshold D in all time periods, an assist angle 56A is generated in all time periods, and the reaction torque is generated in the same way as the assist angle 56A.

[0089] Figure 20 shows another example of the operation of the driving support unit 120. The time-series changes of the steering angle 51A and the reference steering angle 55A are the same as in Figure 6, but the absolute value of the deviation 59 is greater than the threshold D between time t1 and time t2. In this example, if the absolute value of the deviation 59 exceeds the threshold D, no reaction force assist is generated, and in addition, an assist torque is generated to mitigate the self-aligning torque, which is the reaction force generated on the tires when the vehicle 1 is steered, similar to a typical steering motor. If no reaction force torque is generated between time t1 and time t2, a torque equivalent to this self-aligning torque is generated.

[0090] According to the third embodiment described above, the following effects can be obtained. (10) The vehicle control system 100B is equipped with a reaction force actuator 65 that generates a reaction force in the steering device 61 according to the amount of change calculated by the driving support unit 120. As a result, the driver 91 can experience the support effect of reaction force assist in addition to the change in steering angle, thereby realizing driving support in which the driver 91 can obtain the support effect more appropriately.

[0091] (Modification of the third embodiment) The output of the selection unit 124 may always be set to zero, and the assist angle 56A may always be set to zero. There are two possible ways to achieve this. The first method is to set the threshold value D of the conversion unit 123 to zero without changing the operation of the selection unit 124. In this case, since the output of the conversion unit 123 is always zero, the output of the selection unit 124 is always zero. The second method is to change the operation of the selection unit 124 so that the output of the selection unit 124 is always zero regardless of the output of the conversion unit 123.

[0092] —Fourth Embodiment— A fourth embodiment of the vehicle control system and vehicle control method will be described with reference to Figure 21. In the following description, the same reference numerals are used for components that are the same as in the first embodiment, and the differences will be mainly explained. Points that are not specifically described are the same as in the first embodiment. This embodiment differs from the first embodiment mainly in that the operation of the reaction force actuator is switched according to the attributes of the driver 91.

[0093] Figure 21 is a configuration diagram of the vehicle control system 100C in the fourth embodiment. In addition to the configuration of the vehicle control system 100 in the first embodiment, the vehicle control system 100C includes a driver-responsive threshold setting unit 150 and a reaction force control unit 160. Furthermore, the driving support unit 120 in this embodiment outputs a reaction force operation command 56B to the reaction force actuator 65, similar to the third embodiment.

[0094] In this embodiment, the threshold setting unit 154 reads the driver attribute corresponding to the driver identifier identified by the driver identification unit 151 from the storage unit 152 and then performs the following processing. That is, the threshold setting unit 154 not only sets the threshold, as in the second embodiment, but also outputs the attribute of the driver 91 to the reaction force control unit 160.

[0095] The reaction force control unit 160 switches the operation of the reaction force actuator 65 according to the attributes of the input driver 91. Specifically, the reaction force control unit 160 stops the reaction force actuator 65 if the driver 91 has high skill levels, and operates the reaction force actuator 65 if the driver 91 has low skill levels. Stopping the operation of the reaction force actuator 65 means that the steering device 61 does not generate a reaction force. This can be done, for example, by setting the value of the reaction force operation command 56B output by the reaction force actuator 65 to zero, by stopping the output of the reaction force operation command 56B by the reaction force actuator 65, or by stopping the operation of the reaction force actuator 65 itself.

[0096] According to the fourth embodiment described above, the following effects can be obtained: (11) The system is equipped with a reaction force control unit 160 that switches the operation of the reaction force actuator 65 based on the driving skills of the driver 91. Therefore, it is possible to switch the steering angle change and reaction force assist according to the driver, and to realize driving assistance that provides the optimal support effect for each driver.

[0097] (Modification of the fourth embodiment) The threshold D set by the threshold setting unit 154 may include zero. In this case, the assist angle 56A is always zero, as described in the modification of the third embodiment. Drivers may also be classified in terms of the degree of discomfort with steering angle assistance, and the threshold D may be set to zero for drivers who feel a great deal of discomfort with steering angle assistance. The degree of discomfort with steering angle assistance for each driver can be determined, for example, by estimating the driver's emotions using facial images included in the driver data 510, and if the emotions are negative, it can be determined that the discomfort is great.

[0098] According to this modified version, the following effects can be obtained: (12) The threshold D set by the threshold setting unit 154 includes zero. Therefore, even drivers who feel a strong sense of discomfort with steering angle assistance can drive comfortably.

[0099] In each of the embodiments and modifications described above, the threshold D and the switching of the assist method may be determined by the driver's input, such as by operating a button.

[0100] In the embodiments and modifications described above, the configuration of the functional blocks is merely an example. Several functional configurations shown as separate functional blocks may be integrated, or a configuration represented in one functional block diagram may be divided into two or more functions. Furthermore, some of the functions of each functional block may be provided by other functional blocks.

[0101] In the embodiments and modifications described above, the program is stored in the ROM 42, but the program may also be stored in the fixed disk 44. Furthermore, the vehicle control system 100 may have an input / output interface (not shown), and the program may be read from another device via the input / output interface and a medium available to the vehicle control system 100 when needed. Here, the medium refers to, for example, a storage medium detachable from the input / output interface, or a communication medium, i.e., a wired, wireless, or optical network, or a carrier wave or digital signal propagating through such a network. Also, some or all of the functions realized by the program may be realized by hardware circuits or FPGAs.

[0102] The embodiments and modifications described above may be combined in any way. Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments that can be conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0103] 1: Own vehicle 51: Steering amount 51A: Steering angle 52: Vehicle state 55: Reference vehicle state, reference steering state 55A: Reference steering angle 56: Change amount 56A: Assist angle 56B: Reaction force action command 57: Command steering angle 57K: Command steering angle after processing 57R: Recorded value 58: Future steering state, future vehicle state 59: Deviation 59R: Recorded value 61: Steering device 62: Vehicle state acquisition unit 64: Steering actuator 65: Reaction force actuator 66: Steering maintenance unit 91: Driver 100: Vehicle control system 110: Reference vehicle state calculation unit 120: Driving support unit 121: Future vehicle state prediction unit 122: Driving support difference calculation unit 123: Conversion unit 124 :Selection unit 125 :Polarity maintenance unit 130 :Command steering angle determination unit 131 :First steering angle conversion unit 132 :Second steering angle conversion unit 133 :Target steering angle sum calculation unit 134 :Change detection unit 140 :Obstacle response threshold setting unit 150 :Driver response threshold setting unit 151 :Driver identification unit 153 :Skill discrimination unit 154 :Threshold setting unit 160 :Reaction force control unit D :Threshold

Claims

1. A vehicle control system for controlling a vehicle in which the driver's steering device and the tire steering mechanism are mechanically separated, and the vehicle is equipped with a steering actuator that controls the tire steering mechanism to follow a command steering angle, comprising: a reference vehicle state calculation unit that calculates a reference vehicle state which is a target vehicle state for the vehicle using external information around the vehicle and the current state of the vehicle; a driving support unit that calculates an amount of change to the command steering angle so that the future vehicle state which is a future vehicle state predicted based on the steering amount of the steering device approaches the reference vehicle state; and a command steering angle determination unit that determines the command steering angle based on the steering amount and the amount of change.

2. A vehicle control system according to claim 1, wherein the driving support unit calculates the amount of change when the deviation between the future vehicle state and the reference vehicle state is within a threshold.

3. A vehicle control system according to claim 1, wherein the vehicle state is the steering angle.

4. A vehicle control system according to claim 2, further comprising an obstacle response threshold setting unit that changes the threshold based on the distance between the vehicle and the obstacle.

5. A vehicle control system according to claim 2, further comprising a steering maintenance unit that records the command steering angle when the deviation between the future vehicle state and the reference vehicle state is within the threshold, and outputs to the steering actuator the value with the larger absolute value among the recorded command steering angle and the driver's steering angle as the command steering angle when the deviation between the future vehicle state and the reference vehicle state exceeds the threshold.

6. A vehicle control system according to claim 2, further comprising a polarity maintenance unit that restricts the positive and negative polarity of the change amount to either positive or negative.

7. A vehicle control system according to claim 2, further comprising a driver-responsive threshold setting unit that changes the threshold based on the characteristics of the driver.

8. A vehicle control system according to claim 7, wherein the driver-corresponding threshold setting unit comprises: a driver identification unit for identifying the driver; a storage unit for storing the attributes of a plurality of the drivers; and a threshold setting unit for setting the threshold corresponding to the attribute of the driver identified by the driver identification unit.

9. A vehicle control system according to claim 8, wherein the driver-response threshold setting unit further comprises a skill determination unit that determines the driver's driving skills based on driving history, the threshold setting unit sets a first threshold as the threshold when the driver determined to have low driving skills drives the vehicle, and sets a second threshold as the threshold when the driver determined to have high driving skills drives the vehicle, and the first threshold is smaller than the second threshold.

10. A vehicle control system according to claim 1, further comprising a reaction force actuator that generates a reaction force in the steering device corresponding to the amount of change calculated by the driving support unit.

11. A vehicle control system according to claim 10, further comprising a reaction force control unit that switches the operation of the reaction force actuator based on the driving skills of the driver.

12. A vehicle control system according to claim 10, wherein the driving support unit calculates the change amount when the deviation between the future vehicle state and the reference vehicle state is within a threshold of zero, or outputs the change amount as always zero.

13. A vehicle control system according to claim 10, wherein the driving support unit further comprises a driver-responsive threshold setting unit that calculates the amount of change when the deviation between the future vehicle state and the reference vehicle state is within a threshold, and changes the threshold based on the characteristics of the driver, the driver-responsive threshold setting unit comprising a driver identification unit that identifies the driver, a storage unit that stores the attributes of a plurality of the drivers, and a threshold setting unit that sets the threshold corresponding to the attributes of the driver identified by the driver identification unit, the threshold set by the threshold setting unit includes zero.

14. A vehicle control method performed by one or more computers controlling a vehicle in which a driver's steering device and a tire steering mechanism are mechanically separated, and a steering actuator is controlled to move the tire steering mechanism to follow a command steering angle, the method comprising: calculating a reference vehicle state, which is a target vehicle state for the vehicle, using external information about the area around the vehicle and the current state of the vehicle; calculating an amount of change to the command steering angle so that a future vehicle state, which is a predicted future vehicle state based on the steering amount of the steering device, approaches the reference vehicle state; and determining the command steering angle based on the steering amount and the amount of change.

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