Vehicle control device and vehicle control method

Abstract

In one aspect of a vehicle control device and a vehicle control method according to the present invention: a reference trajectory is generated on the basis of a travelable range in front of a vehicle based on information on the surroundings of the vehicle and a predetermined constraint condition when the vehicle travels in the travelable range; a target vehicle control amount for bringing the travel trajectory of the vehicle closer to the reference trajectory is obtained; a signal for changing, on the basis of the target vehicle control amount, an output amount of an actuator unit relative to a change amount in physical quantity related to a driving operation by a driver is obtained; and the actuator unit is controlled on the basis of the signal. Thus, in manual driving, it is possible to suppress the occurrence of a sense of incongruity by securing the linkage between the driving operation of the driver and the vehicle behavior while supporting traveling along an ideal trajectory.

Description

Vehicle control device and vehicle control method

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

[0002] The vehicle travel control device of Patent Document 1 includes an ideal trajectory generation means for generating an ideal trajectory of the vehicle, and a travel trajectory control means for controlling the travel trajectory of the vehicle based on the ideal trajectory and the driver's operation. The travel trajectory control means includes a lateral direction control means for controlling an actuator that adjusts the lateral position of the vehicle with respect to the ideal trajectory, and a longitudinal direction control means for controlling an actuator that adjusts the longitudinal position of the vehicle with respect to the ideal trajectory. The control amount given to the actuator in the lateral direction and the control amount given to the actuator in the longitudinal direction are determined independently of each other.

[0003] Japanese Unexamined Patent Application Publication No. 2009-262837

[0004] By the way, in autonomous driving, stable vehicle travel on an ideal trajectory (route and vehicle speed) can be realized. However, in manual driving, depending on the skill level of the driver, it may be impossible to take an appropriate course on a mountain road with continuous curves, resulting in a large lateral acceleration due to a sharp turn, or it may be difficult to maintain the stability of the lane, making it difficult to travel along an ideal trajectory. Here, it is conceivable to perform driving support based on an ideal trajectory during manual driving. However, in this case, there is a concern that the driver may feel discomfort due to the breakdown of the linkage between the driver's driving operation and the vehicle behavior.

[0005] Therefore, an object of the present invention is to provide a vehicle control device and a vehicle control method that can support traveling along an ideal trajectory in manual driving while ensuring the linkage between the driver's driving operation and the vehicle behavior and suppressing the occurrence of discomfort.

[0006] Therefore, according to one embodiment of the present invention, the vehicle control device comprises: a driving operation acquisition unit that acquires physical quantities related to the driving operation of a vehicle by a driver; a trajectory generation unit that generates a reference trajectory based on the drivable range in front of the vehicle and predetermined constraint conditions when the vehicle travels within the drivable range; a vehicle control unit that determines a target vehicle control amount to bring the vehicle's trajectory closer to the reference trajectory based on the reference trajectory; a control signal calculation unit that determines a signal to change the output amount of an actuator unit in response to the change in the physical quantities related to the driving operation based on the target vehicle control amount; and an actuator control unit that controls the actuator unit based on the signal.

[0007] Furthermore, according to the vehicle control method of the present invention, in one embodiment, information about the surroundings of the vehicle is acquired, physical quantities related to the driving operations performed by the driver of the vehicle are acquired, a reference trajectory is generated based on the drivable range in front of the vehicle based on the information about the surroundings of the vehicle and predetermined constraints when the vehicle travels within the drivable range, a target vehicle control quantity is determined to bring the vehicle's trajectory closer to the reference trajectory, a signal is obtained to change the output quantity of the actuator unit in response to the change in the physical quantities related to the driving operations based on the target vehicle control quantity, and the actuator unit is controlled based on the signal.

[0008] According to the present invention, in manual driving, it is possible to support driving along an ideal trajectory while ensuring coordination between the driver's operation and the vehicle's behavior, thereby suppressing the occurrence of unnatural sensations.

[0009] This is a block diagram of a vehicle control system. This is a block diagram of the driver assistance functions of a vehicle control device. This is a diagram showing the forward gaze point and closest approach point. This is a block diagram of the functions of the control signal calculation unit. This is a block diagram of the reference trajectory generation function and the assistance functions for each actuator. This is a diagram showing the trajectory in a scene where the trajectory control amount is on the same side as the change direction of the left-right driving operation. This is a diagram showing the trajectory in a scene where the trajectory control amount is on a different side from the change direction of the left-right driving operation. This is a diagram showing the trajectory in a scene where the left-right driving operation by the driver is constant. This is a diagram illustrating the reference trajectory, driving trajectory, and assistance amount when driving on a curve. This is a diagram illustrating the difference in actual steering angle with and without driver assistance. This is a diagram showing assistance control when acceleration is performed when the vehicle speed is lower than the reference vehicle speed. This is a diagram showing assistance control when deceleration is performed when the vehicle speed is lower than the reference vehicle speed. This is a diagram showing the vehicle state when the forward and backward driving operation is constant. This is a diagram illustrating the first setting pattern of the control ratio. This is a diagram illustrating the second setting pattern of the control ratio. This is a diagram illustrating the third setting pattern of the control ratio. This is a diagram illustrating the fourth setting pattern of the control ratio. This is a diagram illustrating the fifth setting pattern of the control ratio. This figure illustrates the sixth setting pattern for the control ratio. This figure illustrates the seventh setting pattern for the control ratio. This block diagram shows a function for switching the differential value according to the direction of change in the driving operation. This figure shows how the control ratio is switched according to the direction of change in the steering operation. This block diagram shows a driving support function with an added driver target generation unit. This block diagram shows a driving support function having a driver target generation unit and an additional control unit. This figure shows reaction force control when the trajectory control amount is on the opposite side to the direction of change in the driving operation in the left and right directions. This figure shows reaction force control when the trajectory control amount is on the same side as the direction of change in the driving operation in the left and right directions. This figure shows reaction force control when deceleration is performed when the actual vehicle speed is lower than the reference vehicle speed. This figure shows reaction force control when acceleration is performed when the actual vehicle speed is lower than the reference vehicle speed. This figure illustrates the correlation between the target vehicle control amount and the additional reaction force. This figure illustrates the correlation between the control ratio and the additional reaction force. This figure illustrates the correlation between the control ratio and the additional reaction force. This figure shows reaction force control when the driving operation by the driver is constant.This is a block diagram showing a steering angle control function with an added steering angle limiter. This diagram shows the change in the actuator control amount due to limiter processing by the steering angle limiter. This diagram shows the correlation between the steering operation angle and the actuator control amount when limiter processing by the steering angle limiter is not performed. This diagram shows the correlation between the steering operation angle and the actuator control amount when limiter processing is performed. This is a block diagram showing a driving assistance function in which the target vehicle control amount is calculated from the reference trajectory and the predicted trajectory.

[0010] Hereinafter, embodiments of the vehicle control device and the vehicle control method executed by the vehicle control device according to the present invention will be described with reference to the drawings. Figure 1 is a block diagram showing a vehicle driving system 100 mounted on a vehicle 10. The vehicle 10 is a four-wheeled automobile equipped with a pair of left and right front wheels 11, 12 and a pair of left and right rear wheels 13, 14.

[0011] The vehicle driving system 100 includes an external environment recognition unit 200, a vehicle state detection unit 300, a driving operation detection unit 400, a vehicle control device 500, and an actuator unit 600. Here, the vehicle driving system 100 is a system that has a function to support driving operations by the driver in manual driving.

[0012] The external environment recognition unit 200 recognizes external information, which is information about the area around the vehicle 10; in other words, it is a device for detecting the surrounding conditions of the vehicle 10. The external environment recognition unit 200 includes, for example, a GPS (Global Positioning System) receiver 210, a map database 220, a vehicle-to-infrastructure communication device 230, a camera 240, a radar 250, and a LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) 260. The GPS receiver 210 and the map database 220 constitute a car navigation system.

[0013] The vehicle state detection unit 300 is a device for detecting physical quantities related to the driving state of the vehicle 10, and includes a wheel speed sensor 310, an inertia sensor 320, a hydraulic pressure sensor 330, a torque sensor 340, a steering angle sensor 350, and the like. The wheel speed sensor 310 is a sensor that detects the rotational speed of each of the wheels 11-14 of the vehicle 10, and the detection result of the wheel speed sensor 310 is used to estimate the speed of the vehicle 10 (hereinafter referred to as vehicle speed).

[0014] The inertial sensor 320 detects the roll rate, pitch rate, and yaw rate, which are angular velocities around the three axes of the vehicle 10, as well as the longitudinal acceleration, lateral acceleration, and vertical acceleration, which are accelerations in the three axes. The hydraulic sensor 330 detects the brake fluid pressure in the braking system 630, which will be described later (in other words, the force that presses the brake pads against the brake rotor, or the braking force).

[0015] The torque sensor 340 detects the driving torque of the vehicle 10 generated by the drive unit 620, which will be described later. The steering angle sensor 350 detects the steering angle of the front wheels 11 and 12, which is variable by the steering device 610, which will be described later, in other words, the tire angle of the steered wheels.

[0016] The driving operation detection unit 400 is a device that detects physical quantities related to the driving operations of the vehicle 10 performed by the driver, in other words, the amount of operation of the operation input members that receive driving operations from the driver. Specifically, the driving operation detection unit 400 includes an accelerator pedal sensor 410 that detects the amount of accelerator operation, which is the amount of operation of the accelerator pedal (not shown), a brake pedal sensor 420 that detects the amount of brake operation, which is the amount of operation of the brake pedal (not shown), and a steering operation sensor 430 that detects the amount of operation of the steering wheel (not shown).

[0017] Here, the accelerator pedal, brake pedal, and steering wheel are input components that receive the driver's driving operations. Furthermore, the operation of the accelerator pedal and brake pedal are driving operations that control the vehicle in the forward and backward directions, and the operation of the steering wheel is a driving operation that controls the vehicle in the left and right directions. In this application, driving operations that control the vehicle in the forward and backward directions are referred to as forward and backward driving operations or accelerator operations and brake operations, and driving operations that control the vehicle in the left and right directions are referred to as left and right driving operations or steering operations.

[0018] The actuator unit 600 includes a steering device 610, a drive device 620, and a braking device 630 for driving the vehicle 10. Here, the steering device 610, the drive device 620, and the braking device 630 are all electronically controlled in response to signals from the driver's driving operations.

[0019] The steering device 610 is a steer-by-wire system (SBW system) that steers the steering wheels (front wheels 11, 12) of the vehicle 10, which are mechanically disconnected from the steering wheel. The steering device 610, being a steer-by-wire system, includes a road wheel actuator that applies steering force to the steering wheels and a steering reaction force actuator that applies steering reaction force to the steering wheel operated by the driver. The road wheel actuator is electronically controlled in response to a signal of the steering wheel's operation amount (operation angle) to control the steering angle of the front wheels 11, 12.

[0020] The steering device 610 is not limited to a steer-by-wire system. For example, the steering device 610 may be an electric power steering system that mechanically connects the steering wheel to the steering wheels of the vehicle 10 (specifically, the front wheels 11 and 12) and includes an electric motor that generates a steering assist force to assist the movement of a rack bar or pinion gear connected to the steering wheel. Furthermore, the operating input member of the steering device 610 is not limited to a steering wheel, but may be a lever, joystick, rotary knob, or the like.

[0021] The drive unit 620 includes an internal combustion engine and a motor, and the drive torque applied to at least one of the front wheels 11, 12 and the rear wheels 13, 14 is electronically controlled in accordance with the driver's accelerator operation signal (specifically, an accelerator operation input member such as an accelerator pedal). The braking unit 630 includes a hydraulic brake capable of increasing or decreasing the supplied hydraulic pressure, an electric caliper, a regenerative motor, and the braking force applied to the wheels 11-14 is electronically controlled in accordance with the driver's brake operation signal (specifically, a brake operation input member such as a brake pedal).

[0022] Furthermore, the accelerator and brake operation input members are not limited to pedals. For example, instead of operation input members operated by the driver's foot, such as accelerator pedals and brake pedals, operation input members operated by the driver's hand, such as levers, joysticks, and rotary knobs, can be used as accelerator and brake operation input members. In addition, the vehicle 10 may have a so-called one-pedal system where acceleration and deceleration (driving operations in the forward and backward directions of the vehicle 10) are performed with a single pedal, and this system may also have an operation input member that accepts forward and backward driving operations.

[0023] The vehicle control device 500 is equipped with a computer that performs calculations based on acquired information and outputs the calculation results, and functions as a driver assistance controller that supports the driver's operation of the vehicle 10. As will be described in detail later, in driver assistance, the vehicle control device 500 determines a target vehicle control amount to bring the vehicle 10's trajectory closer to a reference trajectory (in other words, an ideal trajectory or target trajectory), determines a signal to change the output amount of the actuator unit 600 in response to changes in physical quantities related to driving operations, including left-right driving operations and forward-reverse driving operations (steering operations, accelerator operations, brake operations), based on the target vehicle control amount, and controls the actuator unit 600 based on the signal.

[0024] In this application, the reference track includes a reference path which is the target travel path of the vehicle 10, and a reference vehicle speed which is the target vehicle speed at each point on the reference path. The control to bring the vehicle 10's travel path closer to the reference track includes track control (path control) for controlling the path and vehicle speed control for controlling the vehicle speed. The reference track is generated based on the drivable range in front of the vehicle 10 and predetermined constraints when the vehicle 10 travels within the drivable range, and is the track that the vehicle control device 500 refers to when assisting the driver's operation of the vehicle 10.

[0025] Here, the drivable range is set, for example, as the area in front of vehicle 10 in the lane in which vehicle 10 is traveling, based on recognition results such as lane markers. Then, the route, speed, and vehicle behavior of vehicle 10 during its travel within the drivable range, as well as the road surface conditions within the drivable range and the trajectory of the preceding vehicle, are used as constraints, and a reference trajectory that passes through the drivable range is generated taking these constraints into consideration.

[0026] The following describes in detail the process of generating a reference trajectory performed by the vehicle control device 500. The vehicle control device 500 sets the drivable range in front of the vehicle 10 based on the external information of the vehicle 10 recognized by the external recognition unit 200. For example, the vehicle control device 500 sets the drivable range as the area between the left and right lane markers on the road, or between the left and right edges of the road.

[0027] Furthermore, if there is an object within the lane in which the vehicle 10 is traveling, the vehicle control device 500 can set the drivable range to exclude that object. The above-mentioned objects include, for example, parked vehicles, preceding vehicles, oncoming vehicles, fallen objects, installed objects, trees, utility poles, pedestrians, signs, etc.

[0028] The vehicle control device 500 then generates a reference track, for example, a track that passes through the drivable range and in which the absolute values ​​of the lateral acceleration and / or lateral jerk of the vehicle 10 are minimized as much as possible. In other words, the vehicle control device 500 can generate a reference track based on constraints such as minimizing the absolute value of the lateral acceleration within the drivable range (in other words, suppressing the occurrence of lateral acceleration as much as possible) and minimizing the absolute value of the lateral jerk within the drivable range (in other words, suppressing the occurrence of lateral jerk as much as possible).

[0029] Furthermore, the vehicle control device 500 can generate a reference trajectory that does not deviate from constraints such as the maximum speed, minimum speed, maximum absolute value of lateral acceleration, and maximum absolute value of lateral jerk at predetermined points. For example, the maximum speed is the legal maximum speed, and the minimum speed is the legal minimum speed or a predetermined minimum speed that does not disrupt the flow of traffic. Also, for example, the maximum absolute value of lateral acceleration is a value set based on the ride comfort of the vehicle 10 and the lateral acceleration allowed in autonomous driving, and the maximum absolute value of the lateral jerk of the vehicle 10 is a value set based on the ride comfort of the vehicle 10, etc.

[0030] Furthermore, if there are objects such as other vehicles, pedestrians, obstacles, fallen objects, or signs within the drivable area, the vehicle control device 500 can generate a reference trajectory using these objects as constraints. In other words, the vehicle control device 500 can define a reference trajectory that the vehicle 10 travels while avoiding objects, and can also generate a reference trajectory that minimizes the absolute values ​​of lateral acceleration and / or lateral jerk while avoiding objects.

[0031] Furthermore, the vehicle control device 500 can acquire road surface information such as the road surface friction coefficient μ, road surface cant, road surface inclination, road surface undulation, road surface unevenness, speed bumps, and potholes as constraints, and can set a reference trajectory using these constraints. Specifically, the vehicle control device 500 can set a reference trajectory that avoids areas with a low road surface friction coefficient μ and areas with uneven road surfaces. Also, if the vehicle control device 500 adopts a trajectory that passes through areas with a low road surface friction coefficient μ or areas with uneven road surfaces, it can set the vehicle speed on the reference trajectory so that the vehicle 10 slows down when passing through these areas with a low road surface friction coefficient μ or areas with uneven road surfaces.

[0032] As described above, the vehicle control device 500 generates a reference trajectory, which is an ideal trajectory that takes into account safety, stability, and ride comfort, based on the drivable range in front of the vehicle 10 and predetermined constraints when the vehicle 10 travels within that range. The vehicle control device 500 then changes the output amount of the actuator unit 600 in response to the amount of change in the driving operation so that the vehicle 10's trajectory approaches the reference trajectory.

[0033] Figure 2 is a block diagram schematically showing the driving assistance functions of the vehicle control device 500. The drivable range creation unit 510 acquires the recognition results from the external environment recognition unit 200 and generates the drivable range in front of the vehicle 10 as described above. The trajectory generation unit 520 generates a reference trajectory as described above, based on the drivable range generated by the drivable range creation unit 510 and various constraint conditions. The vehicle control unit 530 acquires information on the reference trajectory and determines the target vehicle control amount (trajectory control amount and vehicle speed control amount) to bring the vehicle 10's trajectory closer to the reference trajectory.

[0034] Here, the trajectory control amount may be any of the following: a target vehicle control amount to bring the vehicle 10 closer to the reference path, a target vehicle control amount to bring the vehicle 10's travel path closer to the reference path, a target vehicle control amount to bring the shape of the vehicle 10's travel path closer to the shape of the reference path, a target vehicle control amount to bring the vehicle 10's predicted path closer to the reference path, or a target vehicle control amount to bring the shape of the vehicle 10's predicted path closer to the shape of the reference path. Note that the predicted trajectory of the vehicle 10 is the trajectory that the vehicle 10 is predicted to travel in the future, and can be rephrased as future trajectory or self-predicted trajectory.

[0035] Furthermore, the trajectory control quantity includes the momentum of the vehicle 10 in the yaw angle direction or the lateral direction, and is expressed, for example, as a target lateral acceleration, target yaw rate, target moment, target lateral force, target steering angle, target curvature, etc. In addition, the vehicle speed control quantity is a target vehicle control quantity for bringing the vehicle speed of the vehicle 10 closer to the reference vehicle speed (target vehicle speed, vehicle speed command) included in the reference trajectory, and includes the momentum or acceleration / deceleration of the vehicle 10 in the longitudinal direction, and is expressed, for example, as a target longitudinal acceleration, target longitudinal force, target braking force, target braking torque, etc.

[0036] Furthermore, the trajectory control and vehicle speed control quantities included in the target vehicle control quantity are generally obtained by multiplying the trajectory deviation and vehicle speed deviation by a gain to convert them into acceleration and force. However, the control quantities for acceleration and force can be determined by considering the derivative and integral values ​​of the deviation quantity. In particular, in the case of trajectory control, the control quantities for acceleration and force can be determined by considering the derivative and integral values ​​of angular deviation, trajectory curvature, position deviation at the forward gaze point, angular deviation, curvature, etc.

[0037] Figure 3 shows the forward gaze point, which is a point located a distance from the vehicle 10 equal to the forward gaze distance, and the closest point on the reference path, which is the point closest to the vehicle 10. In one embodiment shown in Figure 3, the angular deviation at the forward gaze point, the positional deviation at the forward gaze point, the curvature at the forward gaze point, the distance from the vehicle 10 to the forward gaze point, the angular deviation at the closest point, the positional deviation at the closest point, and the curvature at the closest point can be determined.

[0038] The orbital control quantity can then be calculated, for example, according to the following formula: Orbital control quantity = (K1 × angular deviation at the forward gaze point + K2 × positional deviation at the forward gaze point + K3 × curvature at the forward gaze point) × F (distance to the forward gaze point) + (K4 × angular deviation at the point of closest approach + K5 × positional deviation at the point of closest approach + K6 × curvature at the point of closest approach)

[0039] Furthermore, the vehicle speed control amount can be determined, for example, according to the following formula: Target vehicle control amount = K7 × (Target speed at the forward gaze point - Vehicle speed). Note that the forward gaze distance can be a fixed value, and can be set to a longer distance as the vehicle speed increases, based on the vehicle speed and the forward gaze time, which is given as a constant value.

[0040] The driving operation acquisition unit 560 acquires the output of the driving operation detection unit 400 and acquires physical quantities related to the driver's left-right driving operations and the driver's forward-backward driving operations. The control signal calculation unit 540, as will be explained in detail later, acquires the signals of the physical quantities related to the driver's driving operations acquired by the driving operation acquisition unit 560, and the signals of the target vehicle control quantities (track control quantities and vehicle speed control quantities) output by the vehicle control unit 530, and calculates a signal to change the output amount of the actuator unit 600 in response to the change in the physical quantities related to the driving operations, based on the target vehicle control quantities. The actuator control unit 550 controls the actuator unit 600 based on the signals output by the control signal calculation unit 540.

[0041] Figure 4 is a block diagram showing the configuration of the control signal calculation unit 540. The control ratio calculation unit 541 calculates and outputs the control ratio (control ratio ≥ 0) for track control and vehicle speed control, respectively, based on the target vehicle control amount (track control amount and vehicle speed control amount) obtained by the vehicle control unit 530. The above control ratio is a parameter that changes the gain of the output amount of the actuator unit 600 in response to the driver's driving operation, based on the target vehicle control amount.

[0042] Here, the control ratio is a value that controls the driving support amount, which is the difference between the actuator control amount when driving support is off and the actuator control amount when driving support is on, and the control ratio can also be regarded as the driving support amount. Note that the actuator control based on the control ratio can include the control of the reaction force applied to the operation input member, as will be described later, along with the control of the steering angle (tire angle), braking and driving force, etc.

[0043] The calculation of the control ratio by the control ratio calculation unit 541 is generally performed as follows. When it is determined that the target vehicle control amount is zero and the traveling trajectory of the vehicle 10 substantially follows the reference trajectory, the control ratio is set to 1.0, and the gain of the output force of the actuator unit 600 with respect to the driving operation of the driver is set as the standard gain, that is, the gain when driving support is not implemented. On the other hand, when it is determined that the target vehicle control amount is not zero and the traveling trajectory of the vehicle 10 deviates from the reference trajectory, the control ratio is changed from 1.0, and the output force of the actuator unit 600 with respect to the driving operation of the driver is increased or decreased (in other words, the gain of the output force of the actuator unit 600 with respect to the driving operation of the driver is increased or decreased) to bring the traveling trajectory of the vehicle 10 closer to the reference trajectory.

[0044] That is, when the target vehicle control amount is on the side different from the change direction of the driving operation, for example, when the change direction of the steering wheel operation is the direction of changing the steering angle to the left direction, and the target vehicle control amount is the direction of turning the vehicle 10 clockwise, the control ratio is made smaller than 1.0 to be in a low gain state. Thereby, for example, the change in the actual steering angle with respect to the steering wheel operation is suppressed, and the traveling trajectory of the vehicle 10 leaving the reference trajectory is suppressed. In the reaction force control in the above scene, for example, by increasing the reaction force with respect to the steering wheel operation, the driving operation itself in the direction in which the traveling trajectory of the vehicle 10 leaves the reference trajectory can be directly suppressed.

[0045] Further, when the target vehicle control amount is on the same side as the changing direction of the driving operation, for example, when the changing direction of the steering wheel operation is a direction to change the steering angle to the left direction, and the target vehicle control amount is also in the direction to turn the vehicle 10 counterclockwise, the control ratio is made larger than 1.0 to be in a high gain state. Thereby, for example, the change in the actual steering angle with respect to the steering wheel operation is increased, and assistance is provided so that the traveling trajectory of the vehicle 10 approaches the reference trajectory. In the reaction force control in the above scene, for example, by reducing the reaction force with respect to the steering wheel operation, the driving operation itself in the direction in which the traveling trajectory of the vehicle 10 approaches the reference trajectory can be directly promoted. The calculation process of the control ratio will be described in detail later.

[0046] The differentiator 542 obtains the time differential value of the driving operation amount such as the operation angle of the steering wheel and the stroke amount of each pedal, that is, the change amount per unit time (in other words, the change amount of the physical quantity related to the driving operation). In the present application, in the driving operation amount and the target vehicle control amount, the left - right direction is distinguished as plus and minus. For example, the counterclockwise or left side of the vehicle 10 is represented as plus, and the clockwise or right side of the vehicle 10 is represented as minus.

[0047] The multiplier 543 acquires the control ratio obtained by the control ratio calculation unit 541 and the time differential value of the driving operation amount obtained by the differentiator 542, and outputs the result of multiplying the time differential value of the driving operation amount by the control ratio. Here, since the control ratio is variably set within the range of 0 or more, the absolute value of the time differential value of the driving operation amount is increased or decreased and corrected according to the control ratio.

[0048] The integrator 544 integrates the time differential value of the driving operation amount, which is the output of the multiplier 543, that is, the time differential value after correction by the control ratio, to obtain the driving operation amount used for actuator control. The converter 545 converts the driving operation amount obtained by the integrator 544 into the target actuator control amount based on the conversion coefficient, and outputs the target actuator control amount to the actuator control unit 550. The conversion coefficient is a coefficient for the steering gear ratio, physical specifications, unit conversion, and the like.

[0049] As described above, the vehicle control device 500 is configured to change the gain of the output amount of the actuator unit 600 in response to the amount of change in driving operation according to a control ratio based on the target vehicle control amount, and driving assistance is performed to bring the travel trajectory of the vehicle 10 closer to the reference trajectory through such change in gain. Figure 5 is a block diagram that shows in detail the reference trajectory generation function of the vehicle control device 500 and the support function for each actuator.

[0050] The surrounding environment recognition unit 561 acquires external environment recognition information from the external environment recognition unit 200 and recognizes the situation around the vehicle. The situation around the vehicle recognized by the surrounding environment recognition unit 561 includes information such as road curvature, road surface cant, road surface gradient, road surface friction coefficient μ, positions of left and right lane markers, positions of left and right road edges, moving objects, and stationary objects. The vehicle state recognition unit 562 acquires vehicle state signals detected by the vehicle state detection unit 300, recognizes the state of the vehicle 10, and estimates the vehicle speed from the wheel speed.

[0051] The action planning unit 563 acquires the surrounding conditions recognized by the surrounding conditions recognition unit 561 and the vehicle condition recognized by the vehicle condition recognition unit 562, and creates an action plan for the vehicle 10, including the selection of a driving lane and the selection of the direction of travel at intersections and junctions. The reference trajectory generation unit 564 acquires the surrounding conditions recognized by the surrounding conditions recognition unit 561, the vehicle condition recognized by the vehicle condition recognition unit 562, and the action planned by the action planning unit 563.

[0052] The reference trajectory generation unit 564 then generates the reference trajectory based on the drivable range in front of the vehicle 10 and predetermined constraints when the vehicle 10 travels within that range, as described above. The drivable range creation unit 510 and the trajectory generation unit 520 are composed of the surrounding situation recognition unit 561, the vehicle state recognition unit 562, the action planning unit 563, and the reference trajectory generation unit 564.

[0053] The track control unit 565 calculates track control amounts such as lateral acceleration based on the reference track, its own position, etc. The vehicle speed control unit 566 calculates vehicle speed control amounts such as longitudinal acceleration based on the reference vehicle speed, actual vehicle speed, etc. The track control unit 565 and the vehicle speed control unit 566 together constitute the vehicle control unit 530.

[0054] The left-right control ratio calculation unit 567 calculates the control ratio used for trajectory control based on the trajectory control amount as the target vehicle control amount. The front-rear control ratio calculation unit 568 calculates the control ratio used for vehicle speed control based on the vehicle speed control amount as the target vehicle control amount. The left-right control ratio control unit 569 outputs a steering angle command and a target reaction force as the target actuator control amount, based on the steering wheel operation angle (steering operation amount) signal obtained from the steering operation amount sensor 430 and the control ratio calculated by the left-right control ratio calculation unit 567.

[0055] The longitudinal acceleration control unit 570 calculates the longitudinal acceleration (acceleration / deceleration) during driving operation from the accelerator operation amount (accelerator pedal stroke amount) obtained from the accelerator pedal sensor 410 and the brake operation amount (brake pedal stroke amount) obtained from the brake pedal sensor 420. The longitudinal control ratio calculation unit 571 calculates a longitudinal acceleration command as a target actuator control amount from the longitudinal acceleration calculated by the longitudinal acceleration control unit 570 and the control ratio calculated by the longitudinal control ratio calculation unit 568.

[0056] The distribution control unit 572 calculates the target brake fluid pressure and target drive torque as target actuator control amounts based on the front-rear acceleration command obtained by the front-rear control ratio calculation unit 571. The control signal calculation unit 540 is composed of the left-right control ratio calculation unit 567, front-rear control ratio calculation unit 568, left-right control ratio control unit 569, front-rear acceleration control unit 570, front-rear control ratio calculation unit 571, and distribution control unit 572.

[0057] The reaction force control unit 573 controls the steering reaction force actuator (FBA) of the steering device 610 based on the target reaction force determined by the left / right control ratio control unit 569, thereby setting the reaction force applied to the steering wheel to the target reaction force. Note that the control of the reaction force is not limited to the control of the reaction force applied to steering operation input members such as the steering wheel, but can also include the control of the reaction force applied to acceleration / deceleration operation input members such as pedals that operate the acceleration and deceleration of the vehicle 10.

[0058] The steering angle control unit 574 controls the steering angle of the front wheels 11 and 12 to the steering angle command (target steering angle) obtained by the left / right control ratio control unit 569 by controlling the road wheel actuators (RWA) of the steering device 610. The brake control unit 575 controls the brake fluid pressure in the braking device 630 based on the target brake fluid pressure obtained by the distribution control unit 572.

[0059] The drive control unit 576 controls the output torque of the drive device 620 based on the target drive torque determined by the distribution control unit 572. The actuator control unit 550 is composed of the reaction force control unit 573, steering angle control unit 574, brake control unit 575, and drive control unit 576.

[0060] The following describes in detail the control ratio calculation process in the control signal calculation unit 540 (left-right control ratio calculation unit 567, front-rear control ratio calculation unit 568). The left-right control ratio calculation unit 567 sets the control ratio to 1.0 when the vehicle 10 is traveling approximately along the reference path and the trajectory control amount (for example, target left-right acceleration) is calculated to be zero.

[0061] When the control ratio is 1.0, the time derivative of the left-right driving operation amount, such as the steering wheel operating angle, is not increased or decreased by the control ratio, and the target actuator control amount (steering angle command) is determined by the default gain (standard gain). On the other hand, when the vehicle 10's travel trajectory deviates from the reference trajectory, and the trajectory control amount is on the same side as the change in the left-right driving operation, the left-right control ratio calculation unit 567 sets the control ratio to a value greater than 1.0, thereby increasing the gain of the output amount of the steering device 610 in response to the driver's steering operation compared to the standard.

[0062] Here, the case where the track control amount is on the same side as the direction of change of the left-right driving operation means that when the direction of change of the left-right driving operation is the direction in which the steering angle is changed to the right (left), the track control amount is also a control amount that causes the vehicle 10 to turn clockwise (counterclockwise). In other words, the driver is steering the vehicle 10 in a direction that brings the vehicle's trajectory closer to the reference trajectory, but there is an insufficient amount of steering operation at this time, and the track control amount is generated in the same direction as the steering operation, which corresponds to the case where the track control amount is on the same side as the direction of change of the left-right driving operation.

[0063] At this time, the left-right control ratio calculation unit 567 increases the control ratio to a value greater than 1.0 so that the actual steering angle for left-right driving operations is larger, or the momentum of the vehicle 10 in the yaw angle direction or left-right direction for left-right driving operations is larger, compared to when the control ratio is 1.0 (in other words, when the target vehicle control amount is zero). For example, as shown in Figure 6, when the driver operates the steering wheel to the left, which is the direction in which the vehicle 10's travel path approaches the reference path, the left-right control ratio calculation unit 567 increases the control ratio to a value greater than 1.0 so that the change in the actual steering angle for left-right driving operations to the left is greater, thereby realizing driving assistance that brings the vehicle 10's trajectory closer to the reference path.

[0064] On the other hand, the left / right control ratio calculation unit 567 sets the control ratio to a value less than 1.0 if the track control amount is on the opposite side to the direction of change of the left / right driving operation. Here, the case where the track control amount is on the opposite side to the direction of change of the left / right driving operation means that when the direction of change of the left / right driving operation is the direction that changes the steering angle to the right (left), the track control amount is the control amount that makes the vehicle 10 turn counterclockwise (clockwise).

[0065] In other words, when the driver is steering the vehicle 10 so that its travel path deviates from the reference path, and the trajectory control amount is generated in the opposite direction to the steering operation, this corresponds to the case where the trajectory control amount is on the opposite side to the direction of change of the left-right driving operation. At this time, the left-right control ratio calculation unit 567 makes the control ratio less than 1.0 so that the actual steering angle for the left-right driving operation is smaller, or the momentum of the vehicle 10 in the yaw angle direction or left-right direction for the left-right driving operation is smaller, compared to when the control ratio is 1.0 (in other words, when the target vehicle control amount is zero).

[0066] For example, as shown in Figure 7, when the driver operates the steering wheel to the left, which is the direction in which the vehicle 10's trajectory deviates from the reference trajectory, the left / right control ratio calculation unit 567 reduces the control ratio to less than 1.0, thereby reducing the change in the actual steering angle to the left in response to the left / right driving operation and preventing the vehicle 10's trajectory from deviating from the reference trajectory. Here, even if the left / right control ratio calculation unit 567 reduces the control ratio to less than 1.0, the state in which left / right acceleration occurs in the direction of the driver's steering operation is maintained, so the occurrence of vehicle behavior different from the driver's driving operation and causing discomfort to the driver is prevented.

[0067] Furthermore, if the driver's left-right driving operation is constant, for example, if the steering wheel is held in a constant position, the time derivative of the driving operation amount becomes zero. Therefore, when the left-right driving operation is constant, the output of the multiplier unit 504 becomes zero regardless of the control ratio (trajectory deviation), and the output of the integral unit 505 does not change, so the target actuator control amount is kept constant. In other words, when the left-right driving operation is constant, the control is performed so that the actual steering angle with respect to the left-right driving operation is constant, or the momentum of the vehicle 10 in the yaw angle direction or left-right direction with respect to the left-right driving operation is constant.

[0068] As shown in Figure 8, even if there is a deviation between the vehicle 10's travel trajectory and the reference trajectory, the vehicle will be maintained in a steady-state circular turn as long as the driver's lateral driving input remains constant. Therefore, even if the driver's lateral driving input remains constant, changes in the actual steering angle or the momentum of the vehicle 10 in the yaw angle or lateral direction will prevent changes in vehicle behavior that may cause discomfort to the driver.

[0069] In this way, while suppressing the occurrence of vehicle behavior that differs from the driver's driving operations, assistance can be provided to bring the vehicle's driving path closer to the reference path, ensuring natural drivability and guiding the vehicle to travel along a path that is as close to the reference path as possible. Figure 9 illustrates the reference trajectory, driving trajectory, and amount of assistance in a scene where the vehicle 10 is traveling on a curve. Without driver assistance control, the driver may perform driving operations that cause the vehicle 10 to drift outwards on the curve, whereas with driver assistance, an amount of assistance is provided to bring the driving trajectory closer to the reference trajectory that traces the center of the lane, enabling safe and stable curve driving.

[0070] Figure 10 illustrates the difference in actual steering angle with and without driver assistance. At point p1, the driver begins operating the steering wheel to change the steering angle to the right. However, since this steering operation causes the vehicle 10's travel path to deviate from the reference path, the control ratio is set to a predetermined value less than 1.0.

[0071] As a result, the change in the actual steering angle (actual tire angle) in response to the driver's steering input is kept smaller than in the case without support control, and the vehicle 10's travel path is prevented from deviating from the reference path. Furthermore, when the driver maintains a constant steering wheel angle at point p2, the actual steering angle remains constant regardless of the deviation of the vehicle 10's travel path from the reference path, thus avoiding the situation where the vehicle's behavior changes and causes discomfort to the driver even though the driver maintains a constant steering wheel angle.

[0072] Then, at point p3, when the driver resumes steering wheel operation in a direction away from the reference path, the control ratio is set to a predetermined value less than 1.0, preventing the vehicle 10 from deviating from the reference path. Subsequently, at point p4, when the driver changes the steering wheel operation direction towards the reference path, the control ratio is set to a predetermined value greater than 1.0, resulting in a larger change in the actual steering angle (actual tire angle) in response to the driver's steering wheel operation than in the case without support control, thus assisting the vehicle 10 to move closer to the reference path.

[0073] With the assistance control for left-right driving operations, if the driver makes an incorrect operation, the system can assist in returning to the reference path. Also, if the driver is about to collide with a wall or other obstacle due to a perception or judgment error, the system can guide the vehicle away from the wall. Furthermore, if there is an obstacle in the path of the vehicle 10, the system can guide the vehicle to travel along a path that avoids the obstacle.

[0074] Furthermore, when the driver deviates from the reference trajectory planned for the ideal route and speed, the system can guide them back to follow the reference trajectory, enabling driving similar to that of a relatively skilled driver, even if the driver's skill level is low. In addition, it avoids the unnatural feeling caused by changes in the vehicle's lateral behavior that do not correspond to the driver's lateral steering inputs.

[0075] Next, the process of setting the control ratio used for driving assistance to bring the actual vehicle speed of the vehicle 10 closer to the reference vehicle speed, which is performed by the front-rear control ratio calculation unit 568, will be described below. The front-rear control ratio calculation unit 568 sets the control ratio to 1.0 when the vehicle speed of the vehicle 10 is approximately equal to the reference vehicle speed and the vehicle speed control amount is calculated to be zero. When the control ratio is 1.0, the time derivative value of the driving operation amount in the front-rear direction by the driver is not increased or decreased by the control ratio, and the target actuator control amount, such as the target front-rear acceleration, is determined with the default gain (standard gain) for the driving operation in the front-rear direction by the driver.

[0076] On the other hand, the front-to-rear control ratio calculation unit 568 sets the control ratio to a value greater than 1.0 if the vehicle speed of the vehicle 10 deviates from the reference vehicle speed and the vehicle speed control amount is on the same side as the direction of change of the driving operation in the front-to-rear direction. Here, the case where the vehicle speed control amount is on the same side as the direction of change of the driving operation in the front-to-rear direction means that the direction of change of the driving operation in the front-to-rear direction is the direction that accelerates (decelerates) the vehicle 10, and the vehicle speed control amount is also a control amount that accelerates (decelerates) the vehicle 10.

[0077] At this time, the front-to-rear control ratio calculation unit 568 sets the control ratio to a value greater than 1.0 so that the forward-to-rear momentum or acceleration / deceleration of the vehicle 10 in response to the forward-to-rear driving operation is greater than when the control ratio is 1.0. As shown in Figure 11, for example, when the vehicle speed is lower than the reference vehicle speed and the driver is performing a forward-to-rear driving operation to accelerate the vehicle 10 (for example, by pressing the accelerator pedal), the front-to-rear control ratio calculation unit 568 sets the control ratio to a value greater than 1.0 so that the change in the forward-to-rear momentum or acceleration / deceleration of the vehicle 10 in response to the forward-to-rear driving operation is greater, thereby realizing driving assistance that brings the vehicle speed of the vehicle 10 closer to the reference vehicle speed.

[0078] On the other hand, the front-to-rear control ratio calculation unit 568 sets the control ratio to a value less than 1.0 if the vehicle speed control amount is on the opposite side to the direction of change of the driving operation in the front-to-rear direction. Here, the case where the vehicle speed control amount is on the opposite side to the direction of change of the driving operation in the front-to-rear direction means that the direction of change of the driving operation in the front-to-rear direction is the direction that accelerates (decelerates) the vehicle 10, while the vehicle speed control amount is the control amount that decelerates (accelerates) the vehicle 10.

[0079] At this time, the front-rear control ratio calculation unit 568 reduces the control ratio to less than 1.0 so that the forward-rear momentum or acceleration / deceleration of the vehicle 10 in response to the forward-rear driving operation is smaller compared to when the control ratio is 1.0. As shown in Figure 12, for example, when the vehicle speed is lower than the reference vehicle speed and the driver is performing a forward-rear driving operation to decelerate the vehicle 10 (for example, reducing the amount the accelerator pedal is pressed), the front-rear control ratio calculation unit 568 sets the control ratio to a value smaller than 1.0 so that the change in the forward-rear momentum or acceleration / deceleration of the vehicle 10 in response to the forward-rear driving operation is small, thereby preventing the vehicle speed of the vehicle 10 from deviating from the reference vehicle speed.

[0080] Furthermore, even if the driver's forward or backward driving operation causes the vehicle speed to deviate from the reference vehicle speed, the actuator control amount (acceleration / deceleration) is not changed in the opposite direction to the driver's operation. This prevents the vehicle from behaving differently from the driver's operation and causing discomfort to the driver. Also, if the driver's forward or backward driving operation is constant, for example, if the depression position of each pedal is constant, the time derivative of the driving operation amount will be zero.

[0081] Therefore, if the longitudinal driving operation is constant, the output of the multiplier unit 504 becomes zero regardless of the control ratio (vehicle speed deviation), and the output of the integral unit 505 does not change, so the target actuator control amount is kept constant. In other words, if the longitudinal driving operation is constant, the vehicle 10 is controlled to maintain a constant longitudinal momentum or acceleration / deceleration. As shown in Figure 13, for example, even if the vehicle speed is lower than the reference vehicle speed, if the driver's longitudinal driving operation is constant, the acceleration / deceleration does not change by not intervening with the driver assistance system, thus preventing the driver from feeling uncomfortable.

[0082] This support control for forward and backward driving operations helps maintain an ideal vehicle speed even when driving uphill, where it is difficult to drive at an ideal speed. Furthermore, it enables appropriate and safe deceleration when approaching a preceding vehicle, such as at the entrance to a curve or before a stop line. It also enables appropriate and safe acceleration at the exit of a curve or when merging onto a highway. Additionally, it avoids situations where the vehicle's forward and backward behavior changes in a way that does not correspond to the driver's forward and backward driving operations, thus preventing the driver from feeling uneasy.

[0083] By the way, in one embodiment shown in Figure 10, the control ratio can be switched to one of three values: a first value of 1.0, a second value less than 1.0, or a third value greater than 1.0. However, the control ratio setting patterns are not limited to these patterns. Several control ratio setting patterns are given below as examples.

[0084] In the control ratio setting patterns shown in Figures 14-20 described below, the control direction based on the target vehicle control quantity is distinguished as positive or negative, and further, the direction of change in driving operation is also distinguished as positive or negative. The control ratio setting patterns shown in Figures 14-20 represent the control ratio to be applied when the control direction based on the target vehicle control quantity is positive (negative) and the direction of change in driving operation is positive (negative), and the control ratio to be applied when the control direction based on the target vehicle control quantity is negative (positive) and the direction of change in driving operation is positive (negative).

[0085] In the control ratio setting pattern shown in Figure 14, the control ratio is set to 1.0 when the actual track closely matches the reference track (in other words, the deviation is approximately zero) and the target vehicle control amount becomes zero. When the control direction due to the target vehicle control amount is positive (negative) and the direction of change of the driving operation is positive (negative), that is, when the target vehicle control amount is on the same side as the direction of change of the driving operation, the control ratio is increased from 1.0 in proportion to the increase in the absolute value of the target vehicle control amount, in other words, the greater the deviation of the actual track from the reference track.

[0086] On the other hand, in the control ratio setting pattern shown in Figure 14, when the control direction due to the target vehicle control amount is positive (negative) and the direction of the driving operation is negative (positive), that is, when the target vehicle control amount is on the opposite side to the direction of change of the driver's driving operation, the larger the absolute value of the target vehicle control amount, in other words, the larger the deviation of the actual track from the reference track, the more the control ratio is reduced from 1.0. Here, the product of the control ratio when the target vehicle control amount is on the same side as the direction of change of the driver's driving operation and the control ratio when the target vehicle control amount is on the opposite side to the direction of change of the driver's driving operation is set to 1.0.

[0087] In the control ratio setting pattern shown in Figure 14, the control ratio changes continuously in response to changes in the target vehicle control quantity. However, as shown in Figure 15 or Figure 16, the control ratio can be made discontinuous depending on the direction of the deviation. In the control ratio setting pattern shown in Figure 15, when the target vehicle control quantity is on the same side as the direction of change in the driver's driving operation, the control ratio increases from 1.0 in proportion to the increase in the absolute value of the target vehicle control quantity, similar to the setting pattern shown in Figure 14.

[0088] On the other hand, in the setting pattern shown in Figure 15, when the target vehicle control amount is on the opposite side to the direction of change of the driver's operation, the initial value of the control ratio is set to a value smaller than 1.0, and the control ratio is gradually decreased in accordance with the increase in the target vehicle control amount. In other words, in the setting pattern shown in Figure 15, when the direction of change of the operation is constant, the control ratio changes discontinuously, or in other words, in steps, as the sign of the target vehicle control amount reverses. According to this setting pattern, when the target vehicle control amount is on the opposite side to the direction of change of the driver's operation, the control ratio (the gain of the output amount of the actuator unit 600 in relation to the operation) can be made sufficiently small from a state where the trajectory deviation is small, and the deviation of the vehicle 10's trajectory from the reference trajectory can be suppressed more effectively.

[0089] The control ratio setting pattern shown in Figure 16 is a pattern that discontinuously changes the control ratio, similar to Figure 15, but differs in that it has a region in which the control ratio remains constant in response to changes in the target vehicle control quantity. In the control ratio setting pattern shown in Figure 16, when the target vehicle control quantity is on the same side as the direction of change of the driver's driving operation, the control ratio is increased proportionally as the absolute value of the target vehicle control quantity increases from zero, and after the absolute value of the target vehicle control quantity reaches a predetermined value, the control ratio is kept constant. Also, in the control ratio setting pattern shown in Figure 16, when the target vehicle control quantity is on the opposite side of the direction of change of the driver's driving operation, the control ratio is kept at a constant value less than 1.0.

[0090] Furthermore, the driver assistance can be implemented in either the case where the target vehicle control amount is on the same side as the direction of change of the driver's driving operation, or the case where the target vehicle control amount is on the opposite side of the direction of change of the driver's driving operation. In the case of the latter, the control ratio setting pattern is as shown in Figure 17 or Figure 18, for example. In the control ratio setting pattern shown in Figure 17, when the target vehicle control amount is on the opposite side of the direction of change of the driver's driving operation, in order to reduce the amount of actuator output relative to the amount of change of the driving operation, the control ratio is reduced from 1.0 as the absolute value of the target vehicle control amount increases, or in other words, as the deviation of the actual trajectory from the reference trajectory increases.

[0091] On the other hand, in the control ratio setting pattern shown in Figure 17, if the target vehicle control amount is on the same side as the direction of change of the driver's driving operation, the control ratio is kept at 1.0 and no driving assistance is provided. In other words, in the control ratio setting pattern shown in Figure 17, the control ratio is set so that no driving assistance is provided when the target vehicle control amount is on the same side as the direction of change of the driver's driving operation, and driving assistance is provided only when the target vehicle control amount is on a different side from the direction of change of the driver's driving operation.

[0092] Furthermore, in the control ratio setting pattern shown in Figure 18, when the target vehicle control amount is on the same side as the direction of change of the driver's driving operation, the control ratio increases proportionally as the absolute value of the target vehicle control amount increases from zero. On the other hand, in the control ratio setting pattern shown in Figure 18, when the target vehicle control amount is on a different side from the direction of change of the driver's driving operation, the control ratio is maintained at 1.0 and no driving assistance is provided. In other words, in the control ratio setting pattern shown in Figure 18, the control ratio is set so that no driving assistance is provided when the target vehicle control amount is on a different side from the direction of change of the driver's driving operation, and driving assistance is provided only when the target vehicle control amount is on the same side as the direction of change of the driver's driving operation.

[0093] Furthermore, to further improve driving safety when the target vehicle control amount is on the opposite side to the direction of change in the driver's driving operation, the control ratio setting pattern can be changed according to the risk. In other words, when the target vehicle control amount is on the opposite side to the direction of change in the driver's driving operation, and the vehicle is approaching an obstacle or lane boundary line beyond a predetermined distance in the direction of change in the driver's driving operation (in other words, when the risk is high), the control ratio can be made smaller than usual in order to further reduce the amount of actuator output in relation to the amount of change in driving operation.

[0094] The control ratio setting patterns shown in Figures 19 and 20 represent patterns in which the control ratio is varied based on proximity information to obstacles or lane boundaries when the target vehicle control amount is on the opposite side to the direction of change of the driver's driving operation. Figure 19 shows the setting pattern when the vehicle 10 is on the right side and approaching an obstacle or boundary, and Figure 20 shows the setting pattern when the vehicle 10 is on the left side and approaching an obstacle or boundary.

[0095] The control ratio setting patterns shown in Figures 19 and 20 have the same basic characteristics as those in Figure 18, but the control ratio is reduced to less than the basic value of 1.0 when the target vehicle control amount is on the opposite side of the direction of change of the driver's operation, and when there is a possibility of contact with an obstacle on one side of the vehicle 10 or a possibility of deviating from one side of the boundary line. This further suppresses the change in the actuator output when the vehicle is operated in a direction that is contrary to the reference trajectory and approaches an obstacle or boundary line, and effectively prevents the vehicle 10 from approaching the obstacle or boundary line.

[0096] Furthermore, the control ratio can be reduced as the distance from the vehicle 10 to the obstacle or lane boundary decreases. In addition, in an emergency where the distance from the vehicle 10 to the obstacle or lane boundary reaches the minimum value, the control ratio can be set to zero, preventing changes in the output amount of actuators such as the actual steering angle even if the driver performs driving operations in the direction of approaching the obstacle or lane boundary.

[0097] As shown in Figures 14-20, the control ratio is switched according to the direction of change in the driving operation. Therefore, the multiplication unit 543 shown in Figure 4, more specifically as shown in the block diagram of Figure 21, multiplies the time derivative of the driving operation amount by the control ratio for each direction of change in the driving operation, and selects one of the multiplication results according to the direction of change in the driving operation. In Figure 21, the multiplication unit 543 includes a first multiplication unit 543A that multiplies the time derivative of the driving operation amount by the control ratio when the direction of change in the driving operation is positive, a second multiplication unit 543B that multiplies the time derivative of the driving operation amount by the control ratio when the direction of change in the driving operation is negative, a positive / negative determination unit 543C that determines whether the time derivative of the driving operation amount is positive or negative, and a selector unit 543D that outputs either the multiplication result of the first multiplication unit 543A or the multiplication result of the second multiplication unit 543B based on the positive / negative determination unit 543C.

[0098] Figure 22 illustrates how the control ratio is switched depending on the direction of change in steering input, and the characteristics of the change in actual steering angle due to the control ratio. In Figure 22, from time t1 to time t2, the direction of change in steering input is positive, and the control ratio for a positive direction of change in steering input (>1.0) is applied, resulting in a high gain change in the actual steering angle in response to the steering input.

[0099] From time t2 to time t3, the steering input remains constant, and the actual steering angle also remains constant. From time t3 to time t4, the direction of change of the steering input is positive, and the control ratio for a positive steering input change (>1.0) is applied, resulting in a high-gain change in the actual steering angle relative to the steering input. From time T4 to time t5, the direction of change of the steering input remains positive, but since the steering input is in the direction of moving away from the reference trajectory, the control ratio for a positive steering input change is changed to less than 1.0, resulting in a low-gain change in the actual steering angle relative to the steering input.

[0100] From time t5 to time t6, the steering input remains constant, and the actual rudder angle also remains constant. From time t6 to time t7, the direction of change of the steering input is negative, and the control ratio for a negative steering input (>1.0) is applied, resulting in a high gain change in the actual rudder angle in response to the steering input. From time t7 to time t8, the direction of change of the steering input remains negative, but since the steering input is in the direction of moving away from the reference trajectory, the control ratio for a negative steering input is changed to less than 1.0, resulting in a low gain change in the actual rudder angle in response to the steering input.

[0101] From time t8 to time t9, the steering input remains constant, and the actual steering angle also remains constant. From time t9, the direction of change of the steering input changes to positive, and from time t9 to time t10, a control ratio (>1.0) with a positive direction of change of steering input is applied, and the actual steering angle changes with high gain in response to the steering input. From time t10 onward, the steering input remains constant, and the actual steering angle also remains constant.

[0102] By the way, although the differential unit 503 shown in the block diagram of Figure 4 is shown to calculate the time derivative of a physical quantity related to the driver's driving operation, the differential unit 503 may also calculate the time derivative of a control target value (driver target value) obtained from the physical quantity related to the driver's driving operation. Figure 23 is a block diagram showing a driving support function that, in addition to the functional units shown in Figure 4, further includes a driver target generation unit 507.

[0103] The driver target generation unit 507 acquires signals of physical quantities related to the driver's driving operations, calculates driver target values ​​from the driving operation quantities, and outputs the driver target values ​​to the differentiation unit 503. For example, if the physical quantity related to the driver's driving operations is the steering wheel angle, the driver target generation unit 507 calculates the target steering angle, target rack stroke amount, etc., as the driver target value.

[0104] Furthermore, if the physical quantity related to the driver's operation is the amount the brake pedal is pressed, the driver target generation unit 507 determines the target braking force, target brake fluid pressure, etc., as the driver target value. Also, if the physical quantity related to the driver's operation is the amount the accelerator pedal is pressed, the driver target generation unit 507 determines the target driving force, target driving torque, etc., as the driver target value.

[0105] Figure 24 is a block diagram showing a driver assistance function configured with an additional control unit 508 that performs additional control on the driver's driving operations, in addition to the driver target generation unit 507. Here, additional control refers to, for example, control that makes the steering gear ratio of the steering device 610 variable, or brake assist control that further assists the force applied to the brake pedal to increase the braking force.

[0106] The additional control unit 508 converts the driver target values ​​generated by the driver target generation unit 507 into driver target values ​​corresponding to the operation of the additional control. For example, if the additional control is variable steering gear ratio control, the additional control unit 508 outputs the target steering angle at the changed steering gear ratio as the driver target value. Also, if the additional control is brake assist control, the additional control unit 508 outputs the target braking force after assist as the driver target value.

[0107] Next, the control of reaction forces in driver assistance will be explained in detail. A reaction force is a force or torque that acts in a direction opposite to the direction of change in the driving operation. In the control function shown in Figure 5, only the control of reaction forces applied to the steering wheel is performed, but if the accelerator pedal, brake pedal, etc. are equipped with reaction force actuators, reaction force control for driving operations in the forward and backward directions can also be included. Furthermore, the input members to which reaction force control is applied are not limited to the steering wheel or pedals, but may also be joysticks, rotary knobs, levers, etc., equipped with reaction force actuators.

[0108] In detail, the vehicle control device 500 (control signal calculation unit 540) reduces the reaction force to the driving operation when the target vehicle control amount is on the same side as the direction of change of the driving operation, compared to when the target vehicle control amount is zero, and increases the reaction force to the driving operation when the target vehicle control amount is on a different side from the direction of change of the driving operation, compared to when the target vehicle control amount is zero. For example, as shown in Figure 25, when the steering wheel is operated to the left, but the control direction of the track control amount is to the right, that is, when the track control amount is on a different side from the direction of change of the driving operation in the left-right direction, the reaction force to the driving operation in the left-right direction is increased compared to when the track control amount is zero, thereby hindering driving operations that cause the vehicle 10's travel path to deviate from the reference path.

[0109] Conversely, as shown in Figure 26, when the steering wheel is operated to the left and the control direction of the track control amount is to the left, that is, when the track control amount is on the same side as the direction of change of the left-right driving operation, the reaction force to the left-right driving operation is made smaller than when the track control amount is zero, thereby promoting driving operations that bring the track of the vehicle 10 closer to the reference track. With this configuration, the driver's left-right driving operations can be guided so that the track of the vehicle 10 approaches the reference track, and the driver can be informed that it is an undesirable driving operation or, conversely, that it is the right time to operate through an increase in the reaction force.

[0110] Figures 27 and 28 illustrate reaction force control in the drive unit 620 and braking unit 630, where the operating input member is a pedal. Figure 27 shows a situation where the actual vehicle speed is lower than the reference vehicle speed, but the driver is performing a pedal operation to decelerate the vehicle 10 (for example, pressing the brake pedal), that is, the target vehicle control amount (vehicle speed control amount) is on the opposite side to the direction of change of the driving operation in the longitudinal direction.

[0111] In this case, compared to when the target vehicle control amount (vehicle speed control amount) is zero, the reaction force to driving operations in the longitudinal direction, specifically deceleration operations (pressure on the brake pedal), is increased. This reaction force control suppresses deceleration operations by the driver, preventing the actual vehicle speed from falling below the reference vehicle speed.

[0112] Figure 28 shows the case where the actual vehicle speed is lower than the reference vehicle speed, and the driver is performing a pedal operation to accelerate the vehicle 10 (for example, pressing the accelerator pedal), that is, the target vehicle control amount (vehicle speed control amount) is on the same side as the direction of change of the longitudinal driving operation. In this case, the reaction force to the longitudinal driving operation, specifically the acceleration operation (pressing the accelerator pedal), is reduced compared to the case where the target vehicle control amount (vehicle speed control amount) is zero. This reaction force control promotes the driver's acceleration operation, bringing the actual vehicle speed closer to the reference vehicle speed. Note that the control for increasing or decreasing the reaction force can be configured to perform only one of either a control that increases the reaction force or a control that decreases the reaction force.

[0113] Figure 29 shows an example of the correlation between the target vehicle control amount and the additional reaction force added to the basic reaction force. According to the additional reaction force characteristics shown in Figure 29, when the target vehicle control amount is on the opposite side to the direction of change of the driving operation, as the absolute value of the target vehicle control amount increases, the additional reaction force as an increase correction increases, and driving operations that cause the vehicle 10's trajectory to deviate from the reference trajectory are hindered. On the other hand, as the absolute value of the target vehicle control amount decreases, the additional reaction force, that is, the reaction force after correction by the additional reaction force, decreases and approaches the basic reaction force, making it easier to operate.

[0114] Furthermore, an additional reaction force can be set relative to the control ratio. Figures 30 and 31 show an example of the correlation between the control ratio and the additional reaction force. Figure 30 shows the characteristics of the additional reaction force applied when the steering is performed to the right, and Figure 31 shows the characteristics of the additional reaction force applied when the steering is performed to the left. Note that the characteristics of the additional reaction force applied when the steering is performed to the right and the characteristics of the additional reaction force applied when the steering is performed to the left are basically the same, although the direction in which the reaction force acts is different.

[0115] When the target vehicle control variable is on the opposite side to the direction of change in the driving operation, and the control ratio is 1.0 or less, the additional reaction force (reaction force increase correction) is increased as the control ratio decreases below 1.0, making it more difficult to perform driving operations (steering operations) in the direction away from the reference track. Conversely, when the target vehicle control variable is on the same side as the direction of change in the driving operation, and the control ratio is 1.0 or greater, the additional reaction force (reaction force reduction correction) which is reduced from the basic reaction force is set so that the reduction increases as the control ratio increases, making it easier to perform driving operations in the direction closer to the reference track. Note that, as shown by the dotted lines in Figures 30 and 31, when the control ratio is 1.0 or greater, the additional reaction force can be kept at zero, so that the reaction force does not become smaller than the basic reaction force even when the target vehicle control variable is on the same side as the direction of change in the driving operation. In other words, only the reaction force increase correction can be implemented.

[0116] Furthermore, the vehicle control device 500 can, as a reaction force control, reduce the reaction force to the driving operation when the driver's driving operation is constant, if the target vehicle control amount increases in the same direction as the change in the driving operation or decreases in the opposite direction, and increase the reaction force to the driving operation when the target vehicle control amount increases in the opposite direction to the change in the driving operation or decreases in the same direction. Figure 32 shows one embodiment of reaction force control when the driver's driving operation is constant.

[0117] Point p11 in Figure 32 represents a state where the driver is holding the steering wheel to the right of the neutral position, and an obstacle is present to the right of the vehicle 10. In this case, if the reference path is shifted to the left to avoid the obstacle on the right, resulting in an increase in the trajectory control amount in the counterclockwise direction or a decrease in the clockwise direction, the reaction force to the lateral driving operation, that is, the reaction force acting to return the steering wheel, which is being operated to the right, to the neutral position, will be increased compared to when there is no change in the trajectory control amount. This increase in reaction force guides the steering wheel's operating angle to the left, which is the direction to avoid the obstacle, thereby enabling obstacle avoidance driving assistance.

[0118] Point p12 in Figure 32 is the opposite of point p11 in terms of steering wheel operation direction and obstacle position. In this case, if the reference path is shifted to the right, resulting in an increase in the clockwise direction or a decrease in the counterclockwise direction of the trajectory control amount, the reaction force to the leftward driving operation, that is, the reaction force acting to return the steering wheel that is being operated to the left to the neutral position, will be larger than when there is no change in the trajectory control amount.

[0119] Conversely, if an obstacle is located on the opposite side of the steering wheel's direction of operation, control is implemented to reduce the reaction force. For example, if the driver holds the steering wheel to the right of the neutral position, and an obstacle is located to the left of the vehicle 10, and the reference path is shifted to the right, resulting in an increase in the clockwise direction or a decrease in the counterclockwise direction of the trajectory control amount, the reaction force acting to return the steering wheel, which is being operated to the right, to the neutral position is reduced compared to when there is no change in the trajectory control amount. This reduction in reaction force guides the steering wheel's angle of operation to the right, which is the direction to avoid the obstacle, thereby enabling obstacle avoidance driving assistance.

[0120] By the way, when the aforementioned driver assistance control is implemented, which changes the output amount of the actuator unit 600 in response to the change in a physical quantity related to driving operations based on the target vehicle control amount, there is a possibility that the actuator control amount will not return to zero even when the driving operation amount returns to zero. As a countermeasure, a system can be implemented that applies limiter processing to the target actuator control amount. Figure 33 is a functional block diagram in which a steering angle limiter unit 577 that performs limiter processing on the steering angle command is added.

[0121] The steering angle limiter unit 577 acquires the steering angle command (target actuator control amount) output by the left / right control ratio control unit 569 and performs limiter processing on the steering angle command so that when the steering operation angle returns to zero (neutral position), the steering angle command also returns to zero (straight position). Then, the steering angle limiter unit 577 outputs the steering angle command after limiter processing to the steering angle control unit 574.

[0122] Figure 34 illustrates a scenario in which the steering angle command (target actuator control amount) does not return to zero even when the driver returns the steering angle to zero. In states (1) and (2) of Figure 34, the trajectory control amount is on the same side as the direction of change of the left-right driving operation, and by making the control ratio greater than 1.0, the change in the actual steering angle with respect to the left-right driving operation is increased. Subsequently, in state (3), the driver returns the left-right driving operation to zero, then operates it in the opposite direction, and then returns the left-right driving operation to zero again in state (3). However, due to the effect of increasing the change in the actual steering angle with respect to the left-right driving operation, the steering angle command does not return to zero in states (3) and (4).

[0123] Figure 35 shows the correlation between the steering angle and the actuator control amount when limiter processing is not performed in the scene shown in Figure 34, and indicates that in state (4), the steering angle is zero but the actuator control amount has not returned to zero. In contrast, Figure 36 shows the correlation between the steering angle and the actuator control amount when limiter processing is performed by the steering angle limiter unit 577.

[0124] The steering angle limiter unit 577 limits the actuator control amount relative to the steering angle so that it does not exceed the limiter (upper limiter and lower limiter) based on the limiter (upper limiter and lower limiter) of the actuator control amount relative to the steering angle. In other words, the steering angle limiter unit 577 allows changes in the actuator control amount relative to the steering angle only within the range enclosed by the upper limiter and the lower limiter. The upper limiter and lower limiter are expressed as a linear function with a zero intercept (actuator control amount = a × steering angle).

[0125] As a result of the limiter processing by the steering angle limiter unit 577, when the actuator control amount reaches the upper limit limit in state (3), the actuator control amount then decreases in accordance with the decrease in the steering angle, and when the steering angle returns to zero, the actuator control amount (steering angle) also returns to zero. Therefore, even when driver assistance control is implemented that changes the output amount of the actuator unit 600 in response to the change in a physical quantity related to driving operation based on the target vehicle control amount, the actuator control amount can be returned to zero when the driving operation amount returns to zero, thereby realizing vehicle behavior corresponding to the driving operation.

[0126] Incidentally, the vehicle control unit 530 can determine the target vehicle control amount from the difference between the reference track and the predicted track on which the vehicle 10 is expected to travel in the future. Figure 37 is a functional block diagram of the vehicle control device 500 configured to determine the target vehicle control amount from the difference between the reference track and the predicted track. In Figure 37, the same reference numerals are used for functional parts that are the same as those shown in Figure 5, and detailed explanations are omitted.

[0127] The predicted trajectory generation unit 578 acquires the results of the surrounding situation recognition unit 561 and the results of the vehicle state recognition unit 562, and estimates the predicted trajectory (predicted path and predicted vehicle speed) that the vehicle 10 is expected to travel in the future. The trajectory control unit 565 then determines trajectory control quantities such as left-right acceleration based on the reference path and the predicted path. The vehicle speed control unit 566 also determines vehicle speed control quantities such as left-right acceleration based on the reference vehicle speed and the predicted vehicle speed.

[0128] The technical ideas described in the above embodiments can be used in appropriate combinations, provided that no contradictions arise. Furthermore, although the content of the present invention has been specifically described with reference to preferred embodiments, it will be obvious to those skilled in the art that various modifications can be taken based on the basic technical ideas and teachings of the present invention.

[0129] The functions of the drivable range creation unit 510, the track generation unit 520, the vehicle control unit 530, the control signal calculation unit 540, and the actuator control unit 550 are not limited to being provided by a single control unit; multiple control units can share each function. For example, a system can be provided with a first control unit (first computer) equipped with the functions of the drivable range creation unit 510 and the track generation unit 520, a second control unit (second computer) equipped with the functions of the vehicle control unit 530 and the control signal calculation unit 540, and a third control unit (third computer) equipped with the function of the actuator control unit 550. In this case, the first control unit, the second control unit, and the third control unit constitute the vehicle control device 500.

[0130] Furthermore, as mentioned above, acceleration and deceleration operations (driving operations in the forward and backward directions) are not limited to the operation of the accelerator pedal and brake pedal, and acceleration and deceleration may be performed by operating only one pedal. In the case of such one-pedal driving, the forward and backward acceleration control unit 570 shown in Figures 5 and 37 acquires information on the amount of operation of the pedal used for acceleration and deceleration operations and determines the forward and backward acceleration.

[0131] Furthermore, a dead zone can be established so that driver assistance control is implemented only after the absolute value of the target vehicle control amount exceeds a threshold. The system can also be configured to notify the driver that driver assistance control is being implemented via voice, warning lights, etc. Additionally, the system can be configured to allow the driver to arbitrarily select whether to turn driver assistance control on or off, and the degree of assistance, i.e., the magnitude of the control ratio relative to the target vehicle control amount.

[0132] 10...Vehicle, 100...Vehicle running system, 200...External environment recognition unit, 300...Vehicle state detection unit, 400...Driving operation detection unit, 500...Vehicle control device, 510...Drivable range creation unit, 520...Trajectory generation unit, 530...Vehicle control unit, 540...Control signal calculation unit, 550...Actuator control unit, 560...Driving operation acquisition unit, 600...Actuator unit

Claims

1. A vehicle control device provided on a vehicle having an external environment recognition unit that recognizes information about the vehicle's surroundings and an actuator unit, comprising: a driving operation acquisition unit that acquires physical quantities related to the driving operations of the vehicle by the driver; a trajectory generation unit that generates a reference trajectory based on the drivable range in front of the vehicle and predetermined constraint conditions when the vehicle travels within the drivable range; a vehicle control unit that determines a target vehicle control amount to bring the vehicle's trajectory closer to the reference trajectory based on the reference trajectory; a control signal calculation unit that determines a signal to change the output amount of the actuator unit in response to the change in the physical quantities related to the driving operations based on the target vehicle control amount; and an actuator control unit that controls the actuator unit based on the signal.

2. A vehicle control device according to claim 1, wherein the reference track includes a reference path on which the vehicle travels, the target vehicle control quantity includes the momentum of the vehicle in the yaw angle direction or the left-right direction, and the control signal calculation unit determines the signal such that, when the target vehicle control quantity is on the same side as the direction of change of a driving operation that performs left-right vehicle operation, the actual steering angle for a driving operation that performs left-right vehicle operation is larger or the momentum of the vehicle in the yaw angle direction or the left-right direction for a driving operation that performs left-right vehicle operation is larger compared to when the target vehicle control quantity is zero, and when the target vehicle control quantity is on a side different from the direction of change of a driving operation that performs left-right vehicle operation, the signal determines the signal such that the actual steering angle for a driving operation that performs left-right vehicle operation is smaller or the momentum of the vehicle in the yaw angle direction or the left-right direction for a driving operation that performs left-right vehicle operation is smaller compared to when the target vehicle control quantity is zero. A vehicle control device that, when a driving operation that controls the vehicle in the left-right direction is constant, determines the signal such that the actual steering angle for a driving operation that controls the vehicle in the left-right direction is constant, or the momentum of the vehicle in the yaw angle direction or left-right direction for a driving operation that controls the vehicle in the left-right direction is constant.

3. A vehicle control device according to claim 2, wherein the vehicle control unit includes a track control unit that determines a target vehicle control amount for bringing the vehicle's travel path closer to the reference path, and the target vehicle control amount determined by the track control unit includes the vehicle's yaw rate or lateral acceleration.

4. A vehicle control device according to claim 1, wherein the reference track includes the reference vehicle speed on which the vehicle travels, the target vehicle control quantity includes the longitudinal momentum or acceleration / deceleration of the vehicle, and the control signal calculation unit determines the signal such that, when the target vehicle control quantity is on the same side as the direction of change of the driving operation that performs longitudinal vehicle operation, the longitudinal momentum or acceleration / deceleration of the vehicle for a driving operation that performs longitudinal vehicle operation is greater than when the target vehicle control quantity is zero, the signal such that, when the target vehicle control quantity is on a side different from the direction of change of the driving operation that performs longitudinal vehicle operation, the longitudinal momentum or acceleration / deceleration of the vehicle for a driving operation that performs longitudinal vehicle operation is smaller than when the target vehicle control quantity is zero, and when the driving operation that performs longitudinal vehicle operation is constant, the signal such that the longitudinal momentum or acceleration / deceleration of the vehicle is constant.

5. A vehicle control device according to claim 4, wherein the vehicle control unit includes a vehicle speed control unit that determines a target vehicle control amount for bringing the vehicle speed of the vehicle closer to the reference vehicle speed, and the target vehicle control amount determined by the vehicle speed control unit includes longitudinal acceleration, longitudinal force, or braking torque of the vehicle.

6. A vehicle control device according to claim 2 or 4, wherein the control signal calculation unit determines the signal such that, when the target vehicle control amount is on the same side as the direction of change of the driving operation that performs the vehicle operation, the reaction force to the driving operation that performs the vehicle operation is smaller than when the target vehicle control amount is zero, and when the target vehicle control amount is on a side different from the direction of change of the driving operation that performs the vehicle operation, the reaction force to the driving operation that performs the vehicle operation is larger than when the target vehicle control amount is zero.

7. A vehicle control device according to claim 2 or 4, wherein the control signal calculation unit determines the signal such that, when the driving operation for operating the vehicle is constant, the reaction force to the driving operation for operating the vehicle becomes smaller when the target vehicle control amount increases on the same side as the direction of change of the driving operation for operating the vehicle or decreases on the opposite side, and determines the signal such that the reaction force to the driving operation for operating the vehicle becomes larger when the target vehicle control amount increases on the same side as the direction of change of the driving operation for operating the vehicle or decreases on the same side.

8. A vehicle control device according to claim 6 or 7, wherein the operating input member that receives the driver's driving operation and to which a reaction force is applied is at least one of a steering wheel, a pedal, a joystick, a rotary knob, and a lever.

9. A vehicle control device according to claim 1, further comprising a predictive trajectory generation unit that determines a predicted trajectory that the vehicle is expected to travel in the future, wherein the vehicle control unit determines the target vehicle control amount from the difference between the reference trajectory and the predicted trajectory.

10. A vehicle control device provided on a vehicle, comprising an external environment recognition unit for recognizing information around the vehicle and an actuator unit, wherein the device generates a reference trajectory based on the drivable range in front of the vehicle and predetermined constraints when the vehicle travels within the drivable range, determines a target vehicle control amount to bring the vehicle's trajectory closer to the reference trajectory based on the reference trajectory, and changes the output amount of the actuator unit in response to a change in the driver's driving operation of the vehicle based on the target vehicle control amount, wherein when the target vehicle control amount is on the same side as the change in the driving operation for lateral vehicle operation, the actual steering angle for lateral vehicle operation is larger, or the momentum of the vehicle in the yaw angle direction or lateral direction is increased compared to when the target vehicle control amount is zero. A vehicle control device that, when the target vehicle control amount is on a side different from the direction of change of the driving operation that performs left-right vehicle operation, reduces the actual steering angle for the left-right vehicle operation or the momentum of the vehicle in the yaw angle direction or left-right direction for the left-right vehicle operation compared to when the target vehicle control amount is zero, and, when the driving operation that performs left-right vehicle operation is constant, keeps the actual steering angle for the left-right vehicle operation constant or keeps the momentum of the vehicle in the yaw angle direction or left-right direction for the left-right vehicle operation constant.

11. A vehicle control method performed by a vehicle control device provided on a vehicle having an external environment recognition unit that recognizes information about the vehicle's surroundings and an actuator unit, the method comprising: acquiring information about the vehicle's surroundings; acquiring physical quantities related to driving operations performed by the vehicle's driver; generating a reference trajectory based on a drivable range in front of the vehicle based on the information about the vehicle's surroundings and predetermined constraints when the vehicle travels within the drivable range; determining a target vehicle control quantity to bring the vehicle's trajectory closer to the reference trajectory; determining a signal to change the output amount of the actuator unit in response to a change in the physical quantities related to the driving operations based on the target vehicle control quantity; and controlling the actuator unit based on the signal.

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