JP7400912B1 - automatic driving device - Google Patents

Abstract

An object of the present invention is to improve safety when avoiding obstacles in front of a vehicle. [Solution] An automatic driving device 1 that determines the driving behavior of a vehicle V based on a potential field includes an obstacle detection unit 121 that detects obstacles around the vehicle V, and an obstacle detection unit 121 that detects obstacles around the vehicle V. An avoidance position that is a predetermined minimum obstacle avoidance distance in the width direction of the travel lane of the host vehicle V from the outer edge of a stationary obstacle that is stationary in front of the host vehicle in the travel direction is located in the width direction based on the width of the travel lane. An avoidance trajectory that generates an obstacle avoidance trajectory in which the distance between the stationary obstacle and the own vehicle in the width direction is greater than or equal to the minimum obstacle avoidance distance when the own vehicle is closer to the center of the driving lane than the maximum movable position. It includes a generation unit 122 and a potential generation unit 124 that generates a vehicle speed potential indicating the degree of recommendation of the vehicle speed at which the host vehicle travels along the obstacle avoidance trajectory and a lane potential indicating the degree of recommendation of the traveling position. [Selection diagram] Figure 1

Description

The present invention relates to an automatic driving device that determines the driving behavior of its own vehicle.

Techniques for avoiding obstacles in front of one's own vehicle are known. Patent Document 1 discloses a technique in which, when an obstacle is detected in front of the own vehicle, the vehicle runs out of the travel lane of the own vehicle to avoid the obstacle.

JP 2022-60073 Publication

However, if the own vehicle protrudes too far from the driving lane in order to avoid an obstacle, there is a risk of collision with another vehicle traveling in an adjacent lane or an oncoming vehicle traveling in the opposite lane.

The present invention has been made in view of these points, and an object of the present invention is to improve safety when avoiding obstacles in front of the own vehicle.

In an aspect of the present invention, there is provided an automatic driving device that determines the driving behavior of its own vehicle based on a potential field, wherein the obstacle detection section detects obstacles around the own vehicle; An avoidance position that is a predetermined minimum obstacle avoidance distance in the width direction of the travel lane of the host vehicle from the outer edge of the detected stationary obstacle that is stationary in front of the travel direction of the host vehicle is within the width of the travel lane. When the distance between the stationary obstacle and the own vehicle in the width direction is closer to the center position of the driving lane than the maximum movable position of the own vehicle in the width direction based on the width direction, the distance between the stationary obstacle and the own vehicle in the width direction is equal to or greater than the minimum obstacle avoidance distance. an avoidance trajectory generation unit that generates an obstacle avoidance trajectory, and a vehicle speed potential that indicates a recommended degree of a vehicle speed for driving the host vehicle along the obstacle avoidance trajectory, and a lane potential that indicates a recommended degree of a driving position. An automatic driving device having a potential generating section is provided.

The avoidance trajectory generation unit does not generate the obstacle avoidance trajectory if the avoidance position is further from the center position than the maximum movement position, and does not generate the obstacle avoidance trajectory if the avoidance position is closer to the center position than the maximum movement position. One or more of the obstacle avoidance trajectories that are greater than or equal to the minimum obstacle avoidance distance may be generated.

If the obstacle avoidance cost when traveling on the obstacle avoidance track is lower than the maintenance cost when the host vehicle continues to travel on the current travel track, an obstacle avoidance mode in which the own vehicle runs on the obstacle avoidance track is selected. The vehicle may further include a driving mode determining unit that determines the driving mode of the host vehicle.

The driving mode determining unit determines that the orientation of the own vehicle is within a predetermined determination angle range based on the tangential direction of the route point of the travel trajectory, and the orientation of the own vehicle at the end point of the obstacle avoidance trajectory. is within the determination angle range based on the tangential direction of the end point of the obstacle avoidance trajectory, the avoidance risk when traveling on the obstacle avoidance trajectory is less than the risk threshold, and the above maintenance cost is lower than the maintenance cost. If the state in which the obstacle avoidance cost is low continues for a predetermined determination duration or longer, the obstacle avoidance mode may be determined as the driving mode of the host vehicle.

The avoidance trajectory generation unit generates a plurality of obstacle avoidance trajectories that differ in at least one of the distance between the stationary obstacle and the own vehicle and the target speed of the own vehicle, and the driving mode determination unit , an obstacle avoidance mode in which the host vehicle travels on an obstacle avoidance track with the lowest obstacle avoidance cost among the plurality of obstacle avoidance tracks may be determined as the drive mode of the host vehicle.

The avoidance trajectory generation section generates a return trajectory in which the host vehicle travels at the center position in the width direction of the travel lane after the host vehicle passes the stationary obstacle; The orientation of the vehicle is within the determination angle range based on the tangential direction of the route point of the obstacle avoidance trajectory on which the vehicle is traveling, and the orientation of the vehicle at the end point of the return travel trajectory is The vehicle is within the determination angle range based on the tangential direction of the end point of the return trajectory, the return risk when traveling on the return trajectory is less than the risk threshold, and the vehicle continues to travel on the obstacle avoidance trajectory. If a state in which the return trajectory cost when traveling on the return trajectory is lower than the return trajectory cost when traveling on the return trajectory continues for the determination duration time or more, the driving mode for traveling on the return trajectory is determined to be the driving mode of the own vehicle. You may.

The driving mode determining unit may lengthen the determination continuation time as the position of the stationary obstacle is closer to the center position.

When the distance between the position of the stationary obstacle and the center position is less than a predetermined threshold, the driving mode determining unit does not determine the obstacle avoidance mode as the driving mode of the own vehicle, and If the distance between the position and the center position is greater than or equal to the threshold value, the obstacle avoidance mode may be determined as the driving mode of the host vehicle.

The driving mode determining unit shortens the determination duration time when it is determined that the stationary obstacle continues to remain stationary, and lengthens the determination duration time when it is determined that the stationary obstacle starts moving. Good too.

According to the present invention, it is possible to improve safety when avoiding obstacles in front of the vehicle.

FIG. 2 is a diagram for explaining the configuration of an automatic driving device. FIG. 3 is a diagram for explaining an obstacle avoidance trajectory. FIG. 2 is a schematic diagram of an obstacle avoidance state machine. FIG. 4 is a diagram for explaining processing for determining whether the vehicle is in a stable running state. 12 is a flowchart illustrating an example of a process for determining whether to enter the obstacle avoidance mode. 12 is a flowchart illustrating an example of a process for determining whether to return to the center position of the driving lane.

FIG. 1 is a diagram for explaining the configuration of an automatic driving device 1. As shown in FIG. The automatic driving device 1 is mounted on a self-driving vehicle V, which is an automatic driving vehicle. In addition to the automatic driving device 1, the own vehicle V is equipped with a sensor group 2 and an ECU (Electronic Control Unit) 3.

The sensor group 2 is a sensor that detects the state of the host vehicle V and the surrounding environment. The sensor group 2 includes, for example, a vehicle speed sensor that detects vehicle speed and an acceleration sensor that detects acceleration as the state of the host vehicle V, and detects the vehicle speed and acceleration of the host vehicle V. The sensor group 2 includes a GPS (Global Positioning System) receiver for detecting the position of the vehicle, and detects the position of the own vehicle V. Further, the sensor group 2 includes a sensor that detects the yaw rate as the state of the own vehicle V, and detects the yaw rate. The sensor group 2 detects the direction in which the host vehicle V is traveling. The traveling direction of the host vehicle V is, for example, the azimuth of the host vehicle V with respect to north. The sensor group 2 includes external sensors such as a camera, radar, and LIDAR as sensors for detecting the surrounding environment. The sensor group 2 outputs the output value of the external sensor to the automatic driving device 1.

ECU3 is an ECU that controls own vehicle V. The ECU 3 controls the acceleration and yaw rate of the own vehicle V according to the driving behavior determined by the automatic driving device 1. For example, the ECU 3 controls the throttle opening of the engine connected to the drive wheels of the host vehicle V or the amount of electric power supplied to the motor so that the acceleration determined by the automatic driving device 1 is achieved. Further, the ECU 3 controls the angle of the steered wheels of the own vehicle V so that the yaw rate determined by the automatic driving device 1 is achieved.

The automatic driving device 1 includes a storage section 11 and a control section 12. The storage unit 11 is a storage medium including a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk, and the like. The storage unit 11 stores programs executed by the control unit 12.

The control unit 12 is a calculation resource including a processor such as a CPU (Central Processing Unit). By executing the program stored in the storage unit 11, the control unit 12 operates as an obstacle detection unit 121, an avoidance trajectory generation unit 122, a basic driving mode determination unit 123, a potential generation unit 124, and a driving behavior determination unit 125. Achieve functionality.

The obstacle detection unit 121 detects obstacles around the own vehicle V based on the output values of the sensor group 2. For example, the obstacle detection unit 121 detects a moving obstacle (eg, another vehicle, a bicycle, a pedestrian, etc.). Further, the obstacle detection unit 121 detects a stationary obstacle in front of the own vehicle V in the traveling direction. The stationary obstacle is, for example, another vehicle stopped in front of the vehicle V in the traveling direction of the vehicle V. Further, the stationary obstacle may be a fence, a guardrail, a sign, a signboard, or the like.

The obstacle detection unit 121 identifies the state of another vehicle detected as an obstacle based on the captured image captured by the camera included in the sensor group 2. For example, the obstacle detection unit 121 identifies the lighting states of the other vehicle's brake lights, emergency flashing indicator lights, and direction indicators by analyzing the captured image. Specifically, the obstacle detection unit 121 identifies whether the brake lamp is on, whether the emergency blinking indicator light is blinking, and whether the direction indicator is blinking.

Further, the obstacle detection unit 121 may detect the position, width, etc. of the lane in which the host vehicle V travels based on the output values of the sensor group 2. Specifically, the obstacle detection unit 121 detects the outer road line and the lane boundary line of the lane in which the own vehicle V is traveling by analyzing the captured image taken by the camera, and detects the outer road line and the lane boundary line of the lane in which the own vehicle V is traveling. The distance is detected as the width of the driving lane. The obstacle detection unit 121 detects the left and right lane boundaries of the lane in which the host vehicle V is traveling, and detects the distance between the left and right lane boundaries as the width of the traveling lane.

The avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory that avoids the stationary obstacle detected by the obstacle detection unit 121. The obstacle avoidance trajectory includes, for example, information indicating the target speed, target position, and target time of reaching the target position of the host vehicle V at each time from the current moment until after a predetermined predicted time. FIG. 2 is a diagram for explaining the obstacle avoidance trajectory T. The other vehicle B is a stationary obstacle that is stopped in front of the host vehicle V in the traveling direction X, straddling the outer road line G.

First, the avoidance trajectory generation unit 122 specifies an avoidance position A that is separated by the minimum obstacle avoidance distance K from the position E of the outer edge of the other vehicle B in the width direction Y of the driving lane. The position E of the outer edge is, for example, the right end or left end of the other vehicle B in the width direction Y. Specifically, the outer edge position E is the one of the right end and left end of the other vehicle B that is closer to the center position C of the driving lane. If the stationary obstacle is another vehicle, the avoidance trajectory generation unit 122 makes the minimum obstacle avoidance distance K longer than the reference distance. The avoidance trajectory generation unit 122 makes the minimum obstacle avoidance distance K shorter than the reference distance if the stationary obstacle is a wall, guardrail, sign, signboard, etc. The reference distance is, for example, a distance obtained by adding a predetermined length to half the width of the own vehicle V. The predetermined length is, for example, one meter, but is not limited to this. For example, if half the width of the own vehicle V is 1 meter, the reference distance is 2 meters.

Next, the avoidance trajectory generation unit 122 identifies a maximum movement position M in which the own vehicle V can move in the width direction Y based on the width of the driving lane. The maximum movable position M is, for example, a position that is a movable distance W away from the center position C of the driving lane. For example, the avoidance trajectory generation unit 122 sets the movable distance W to half the width of the driving lane, and moves the maximum movable distance M to a position on the lane boundary line H that is away from the center position C by the movable distance W. Specify as. Further, if an obstacle is detected around the host vehicle V, the avoidance trajectory generating unit 122 sets the movable distance W to a length shorter than half the width of the driving lane. Specifically, if another vehicle traveling on the opposite side of the own vehicle V across the lane boundary line H is detected, the avoidance trajectory generation unit 122 sets the movable distance W to less than half the width of the traveling lane. also set to a short length. For example, if the width of the driving lane is 3 meters, the avoidance trajectory generation unit 122 sets the movable distance W to 1 meter.

Then, if the avoidance position A is closer to the center position C than the maximum movement position M, the avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory in which the distance between the host vehicle V and the other vehicle B is equal to or greater than the minimum obstacle avoidance distance K. Generate T. Specifically, the avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory T that includes a target speed, a target position, and a target arrival time at each of a plurality of route points. In addition, the avoidance trajectory generation unit 122 generates a plurality of obstacle avoidance trajectories T that travel between the avoidance position A and the maximum movement position M in the width direction Y and have different distances between the host vehicle V and the other vehicle B. You may. Specifically, the avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory T that travels through the maximum movement position M and a second obstacle avoidance trajectory that travels through the avoidance position A. Thereby, the avoidance trajectory generation unit 122 can generate an obstacle avoidance trajectory T in which the own vehicle V does not deviate from the driving lane too much and is as far away from the other vehicle B as possible.

The avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory T in accordance with the driving behavior of the own vehicle V determined using a potential field obtained by adding, for example, a basic driving potential and an actual risk potential. Specifically, the avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory T in a long-term prediction time that is longer than the short-term prediction time, based on driving behavior within a short-term prediction time determined using a potential field. Note that the method by which the avoidance trajectory generation unit 122 generates the obstacle avoidance trajectory T is not limited to this.

The avoidance trajectory generation unit 122 generates a plurality of obstacle avoidance trajectories T having different target speeds. For example, the avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory with a target speed that is the same as the current speed of the host vehicle V, an obstacle avoidance trajectory with a target speed that is faster than the current speed, and an obstacle avoidance trajectory that has a target speed that is slower than the current speed. Generate an obstacle avoidance trajectory. Specifically, the avoidance trajectory generation unit 122 generates obstacle avoidance trajectories for each of a plurality of target speeds, with the upper limit being the speed limit of the road on which the host vehicle V travels and the lower limit being 0. To give a specific example, if the speed limit is 80 km/h and the speed of the host vehicle V is 70 km/h, the avoidance trajectory generation unit 122 generates multiple target speeds of 80, 75, 70, 60, and 50. Generate an obstacle avoidance trajectory.

Note that the avoidance trajectory generation unit 122 generates as many obstacle avoidance trajectories as can be generated within a predetermined calculation time. The calculation time is, for example, 50 milliseconds, but is not limited to this. For example, when it takes 10 milliseconds to generate one obstacle avoidance trajectory, the avoidance trajectory generation unit 122 generates five obstacles that differ in at least one of the target speed and the distance between the host vehicle V and the other vehicle B. Generate an avoidance trajectory.

The avoidance trajectory generation unit 122 does not generate the obstacle avoidance trajectory T if the avoidance position A is farther from the center position C than the maximum movement position M. Thereby, the avoidance trajectory generation unit 122 can suppress the generation of an obstacle avoidance trajectory T that would cause the vehicle to deviate from the driving lane too much or pass close to another vehicle B.

The basic driving mode determining unit 123 determines the basic driving mode of the own vehicle V to be the lane keeping mode if no stationary obstacle is detected in front of the own vehicle V in the traveling direction X. When the basic driving mode determination unit 123 determines the basic driving mode to be the lane keeping mode, it generates a driving trajectory in which the host vehicle V travels in the center position C in the width direction Y of the driving lane in which the vehicle V is traveling. The travel trajectory includes, for example, information indicating the target speed of the host vehicle at each time from the current moment until after a predetermined predicted time, the target position, and the target time at which the vehicle reaches the target position.

When a stationary obstacle is detected in front of the vehicle V in the traveling direction Decide on mode. FIG. 3 is a schematic diagram of the obstacle avoidance state machine SM1. The lane keeping mode SM11 is a driving mode in which the vehicle continues to travel on the current traveling trajectory without avoiding obstacles. The right obstacle avoidance acceleration mode SM12 is a driving mode in which the vehicle accelerates and passes on the right side of a stationary obstacle. Obstacle right avoidance vehicle speed maintenance mode SM13 is a driving mode in which the vehicle passes on the right side of a stationary obstacle while maintaining the vehicle speed. Obstacle right avoidance deceleration mode SM14 is a driving mode in which the vehicle decelerates and passes on the right side of a stationary obstacle. Obstacle left avoidance acceleration mode SM15 is a driving mode in which the vehicle accelerates to pass the left side of a stationary obstacle. Obstacle left avoidance vehicle speed maintenance mode SM16 is a driving mode in which the vehicle passes on the left side of a stationary obstacle while maintaining the vehicle speed. The left obstacle avoidance deceleration mode SM17 is a driving mode in which the left side of a stationary obstacle is decelerated and avoided.

If a plurality of obstacle avoidance trajectories have been generated, the basic driving mode determination unit 123 determines whether the obstacle is to be traveled on the obstacle avoidance trajectory with the lowest cost function value among the driving modes corresponding to each obstacle eschar. Identify avoidance modes. For example, the basic driving mode determining unit 123 determines that the function value of the obstacle-right avoidance vehicle speed maintenance mode SM13, in which the vehicle travels on the obstacle avoidance trajectory T in which the vehicle maintains the vehicle speed and passes on the right side of a stationary obstacle, is If it is smaller than the function value of the mode, the obstacle right avoidance vehicle speed maintenance mode SM13 is specified as the driving mode with the lowest function value.

If the obstacle avoidance cost of the obstacle avoidance mode with the lowest function value is lower than the maintenance cost when the host vehicle V continues to travel on the current travel trajectory, the basic travel mode determination unit 123 determines that the obstacle avoidance The vehicle speed maintenance mode SM13 is determined as the driving mode of the own vehicle V. To give a specific example, if the function value of the obstacle avoidance trajectory cost function of the obstacle right avoidance vehicle speed maintenance mode SM13 is smaller than the function value of the maintenance cost function, the basic driving mode determination unit 123 determines the obstacle right avoidance vehicle speed. The maintenance mode SM13 is determined as the driving mode of the own vehicle V. If the maintenance cost is equal to or greater than the obstacle avoidance cost, the basic driving mode determining unit 123 does not decide the driving mode of the host vehicle V to be the obstacle avoidance mode, and continues running on the travel trajectory on which the host vehicle V is currently running. The lane keeping mode SM11 is determined. The following description will be made assuming that the obstacle avoidance mode with the lowest function value among the plurality of obstacle avoidance modes is "obstacle right avoidance vehicle speed maintenance mode SM13".

The basic driving mode determination unit 123 determines whether the vehicle V running on the running track is in a stable running state and when the own vehicle V is in a stable running state when traveling on the obstacle avoidance track T. The avoidance vehicle speed maintenance mode SM13 is determined as the driving mode of the own vehicle V. FIG. 4 is a diagram for explaining the process of determining whether the vehicle is in a stable running state. The black circles in FIG. 4 indicate route points on the travel trajectory on which the own vehicle V is traveling. The white circles in FIG. 4 indicate the route points of the obstacle avoidance trajectory T.

The basic running mode determination unit 123 determines that the own vehicle V is in a stable running state if the traveling direction F1 of the own vehicle V is within the first determination angle range H1. The first determination angle range H1 is an angle range based on the tangential direction of the closest route point SP closest to the current position of the own vehicle V. The first determination angle range H1 is, for example, an acute angle, and is from -15 degrees to plus 15 degrees centered on a direction D1 from the nearest route point SP of the travel trajectory to the next route point NP in the tangential direction. degree. If the direction of the own vehicle V is outside the first determination angle range H1, the basic driving mode determining unit 123 determines that the own vehicle V is in an unstable driving state, and determines the driving mode of the own vehicle V to be the lane keeping mode. do.

If the traveling direction F2 of the own vehicle V at the end point EP of the obstacle avoidance trajectory T is within the second determination angle range H2, the basic driving mode determining unit 123 determines that when traveling on the obstacle avoidance trajectory T, It is determined that the host vehicle V is in a stable running state. The second determination angle range H2 is an angle range based on the tangential direction of the end point EP of the obstacle avoidance trajectory T. The second determination angle range H2 is, for example, an acute angle, and ranges from -15 degrees to plus 15 degrees centered on the direction from the route point BP immediately before the end point EP to the end point EP in the tangential direction at the end point EP. If the direction of the own vehicle V at the end point EP is outside the second determination angle range H2, the basic driving mode determination unit 123 determines that the own vehicle V will be in an unstable running state if it travels on the obstacle avoidance trajectory T, and The driving mode of vehicle V is determined to be lane keeping mode.

When it is determined that the vehicle V can safely travel on the obstacle avoidance trajectory T, the basic driving mode determining unit 123 determines the obstacle right avoidance vehicle speed maintenance mode SM13 as the driving mode of the own vehicle V. The basic driving mode determination unit 123 determines that the vehicle can safely travel on the obstacle avoidance trajectory T if the avoidance risk when traveling on the obstacle avoidance trajectory T is less than the risk threshold. The avoidance risk is the magnitude of the risk that the own vehicle V will come into contact with obstacles around the own vehicle V when traveling on the obstacle avoidance trajectory T. The risk threshold is a threshold for determining whether it is necessary to urgently avoid obstacles around the vehicle V. The risk threshold is a value lower than the standard risk at which an average driver determines that it is necessary to make an emergency avoidance when driving a vehicle. If the avoidance risk is equal to or greater than the risk threshold, the basic driving mode determining unit 123 determines that the vehicle cannot safely travel on the obstacle avoidance trajectory T, and determines the driving mode of the own vehicle V to be the lane keeping mode.

The basic driving mode determination unit 123 determines that the own vehicle V is in a stable driving state, and that the own vehicle V is in a stable driving state when traveling on the obstacle avoidance trajectory T, and that the own vehicle V can safely travel on the obstacle avoidance trajectory T. When it is determined that the obstacle avoidance cost is smaller than the maintenance cost and continues for the determination duration time or more, the obstacle right avoidance vehicle speed maintenance mode SM13 is determined as the basic driving mode. The determination duration time is the time expected for the determination result to become stable, and the reference value for the determination duration time is, for example, 1 second, but is not limited to this.

In this manner, the basic driving mode determination unit 123 determines the obstacle right avoidance vehicle speed maintenance mode SM13 as the basic driving mode after the determination result becomes a stable state that continues for the determination duration time or longer. As a result, the basic driving mode determination unit 123 does not change the obstacle right avoidance vehicle speed maintenance mode SM13 to the basic driving mode, for example, if any of the conditions is no longer satisfied in the determination immediately after the conditions are satisfied. Thus, the driving mode of the own vehicle V can be continued to be determined as the lane keeping mode. In other words, the basic driving mode determination unit 123 can suppress frequent switching of driving modes due to frequent changes in determination results.

The basic driving mode determination unit 123 may change the determination duration depending on the state of the stationary obstacle. For example, if the stationary obstacle is another vehicle stopped at a traffic light or in a traffic jam, the basic driving mode determination unit 123 makes the determination duration longer than the reference value. Specifically, the basic driving mode determining unit 123 determines that the closer the position of a stationary obstacle is to the center position C of the driving lane, the higher the probability that the stationary obstacle is another vehicle stopped at a traffic light or in a traffic jam. Make the determination duration longer than the reference value. The position of the other vehicle is, for example, the center of the other vehicle in the width direction. As a result, the basic driving mode determining unit 123 can lengthen the time it takes to determine the obstacle right avoidance vehicle speed maintenance mode SM13 in which the vehicle travels on the obstacle avoidance trajectory T. It is possible to prevent people from passing by.

Note that the basic driving mode determining unit 123 does not determine the obstacle right avoidance vehicle speed maintenance mode SM13 as the driving mode when the distance between the position of the stationary obstacle and the center position C of the driving lane is less than a predetermined threshold. . The basic driving mode determining unit 123 sets a predetermined threshold depending on the type of stationary obstacle. For example, the basic driving mode determining unit 123 sets the threshold value when the type of the stationary obstacle is a motorcycle to be larger than the threshold value when the type of the stationary obstacle is a car. Thereby, the basic driving mode determination unit 123 can prevent the vehicle from passing by the side of a temporarily stopped motorcycle. The basic driving mode determining unit 123 determines the obstacle right avoidance vehicle speed maintenance mode SM13 as the driving mode if the distance between the position of the stationary obstacle and the center position C of the driving lane is a predetermined threshold or more.

By the way, it is undesirable for the own vehicle V to pass by the side of another stopped vehicle even though the other vehicle is about to start moving. Therefore, when it is specified that another vehicle starts moving, the basic driving mode determining unit 123 makes the determination continuation time longer than the reference value. For example, the basic driving mode determining unit 123 determines that the other vehicle starts moving when the other vehicle's brake lamp goes out. Further, the basic driving mode determining unit 123 specifies that the other vehicle starts moving when the blinking emergency indicator light of the other vehicle goes out and the turn signal blinks. As a result, the basic driving mode determining unit 123 can suppress determining the driving mode to the obstacle right avoidance vehicle speed maintenance mode SM13 when the stationary obstacle is another vehicle that starts moving. It can prevent vehicles from passing by.

As mentioned above, it is undesirable to pass by the side of another stopped vehicle when it starts moving, but if you stop without avoiding another vehicle that is stationary, your vehicle V will There is a risk that the vehicle may obstruct traffic on the road on which it is traveling. Therefore, if it is determined that the other vehicle continues to stand still, the basic driving mode determination unit 123 shortens the determination duration time from the reference value. For example, if the other vehicle's emergency flashing indicator light is flashing, the basic driving mode determination unit 123 determines that the other vehicle continues to stop. Thereby, the basic driving mode determination unit 123 can easily avoid other parked vehicles.

The potential generation unit 124 generates a vehicle speed potential indicating the degree of recommendation of the vehicle speed at which the host vehicle V travels along the obstacle avoidance trajectory T, and a lane potential indicating the degree of recommendation of the traveling position. The vehicle speed potential is an attractive or repulsive force potential that is proportional to the difference between the target speed at each route point on the obstacle avoidance trajectory T and the current speed. The lane potential is a potential based on the target position of each route point on the obstacle avoidance trajectory T, and is a gravitational potential proportional to the difference between the target position and the current position of the own vehicle V.

The driving behavior determination unit 125 determines the driving behavior by determining a value that minimizes a cost function that includes the vehicle speed potential and the lane potential and uses the driving behavior of the own vehicle V as a parameter. Specifically, the driving behavior determination unit 125 determines the acceleration and yaw rate that are the driving behavior of the own vehicle V by determining the acceleration and yaw rate that minimize the cost function using the acceleration and yaw rate of the own vehicle V as parameters. and determine the yaw rate. More specifically, the driving behavior determination unit 125 determines the value that minimizes the cost function including the contact risk based on the obstacle potential generated according to the obstacles around the own vehicle V, and Determine driving behavior. By doing so, the own vehicle V can avoid a stationary obstacle in front of the own vehicle V in the traveling direction X along the obstacle avoidance trajectory T that is a certain distance away from the obstacle without deviating from the driving lane too much.

(Process of returning to the center position of the driving lane)
By the way, if the own vehicle V continues to run on the obstacle avoidance track T and deviate from the driving lane even after passing by the side of the other vehicle B, it will collide with another vehicle driving in the adjacent lane or oncoming lane adjacent to the driving lane. The risk of collision between own vehicle V increases. Therefore, when the own vehicle V passes by the side of the other vehicle B, the automatic driving device 1 returns to the center position C of the driving lane. The process of returning to the center position C of the driving lane will be described below.

The avoidance trajectory generation unit 122 generates a return trajectory that returns the vehicle V to the center position C of the driving lane when the vehicle V passes a stationary obstacle. Specifically, the avoidance trajectory generation unit 122 generates a return trajectory in which the vehicle V moves from the current position to the center position C in the width direction Y of the driving lane.

If the return trajectory cost when traveling on the return travel trajectory is smaller than the avoidance continuation cost when continuing to travel on the obstacle avoidance trajectory T, the basic travel mode determination unit 123 automatically selects the lane keeping mode in which the vehicle travels on the return travel trajectory. The driving mode of vehicle V is determined. Specifically, the basic driving mode determination unit 123 determines that the own vehicle V traveling on the obstacle avoidance trajectory T is in a stable driving state, as in the case where the driving mode is determined to be the obstacle right avoidance vehicle speed maintenance mode SM13. If the own vehicle V is in a stable running state when traveling on the return trajectory, the return risk when traveling on the return trajectory is less than the risk threshold, and the return trajectory cost is greater than or equal to the avoidance trajectory cost, the vehicle V is changed to lane mode. Decide on maintenance mode.

The basic running mode determination unit 123 determines that the own vehicle V is in a stable running state if the direction of the own vehicle V is within the third determination angle range. The third determination angle range corresponds to the first determination angle range, and is an angle range based on the tangential direction of the route point of the obstacle avoidance trajectory T on which the host vehicle V is traveling. If the direction of the host vehicle V is outside the third determination angle range, the basic driving mode determining unit 123 determines that the host vehicle V is in an unstable driving state.

If the direction of the host vehicle V at the end point of the return travel trajectory is within the fourth determination angle range, the basic driving mode determination unit 123 determines that the host vehicle V will be in a stable travel state when traveling on the return travel trajectory. . The fourth determination angle range corresponds to the second determination angle range, and is an angle range based on the tangential direction of the end point of the return travel trajectory. If the direction of the own vehicle V at the end point of the return trajectory is outside the fourth determination angle range, the basic running mode determining unit 123 determines that the own vehicle V will be in an unstable running state if it travels on the return trajectory.

The basic driving mode determining unit 123 determines that the vehicle can safely travel on the return trajectory if the return risk when traveling on the return trajectory is less than the risk threshold. The return risk is the magnitude of the risk that the own vehicle V will come into contact with obstacles around the own vehicle V when traveling on the return travel trajectory. If the return risk is greater than or equal to the risk threshold, the basic driving mode determination unit 123 determines that the vehicle cannot safely travel on the return travel trajectory.

The basic driving mode determining unit 123 determines that the orientation of the host vehicle V is within a third determination angle range, the orientation of the host vehicle V at the end point of the return travel trajectory is within a fourth determination angle range, and the return risk is a risk threshold. If the state where the return travel trajectory cost is lower than the avoidance trajectory cost continues for the determination duration time or more, the lane keeping mode is determined as the travel mode of the own vehicle V. The basic driving mode determining unit 123 determines whether the own vehicle V traveling on the obstacle avoidance trajectory T is in an unstable traveling state and traveling on the return traveling trajectory before the above-mentioned state continues for the determination duration time or more. If it is determined that the vehicle is in an unstable running state, the return risk is equal to or higher than the risk threshold, or the return trajectory cost is equal to or greater than the avoidance trajectory cost, the vehicle V's traveling mode is determined to be the obstacle avoidance vehicle speed maintenance mode SM13. .

In this way, when the host vehicle V passes the other vehicle B and satisfies the above conditions, the basic driving mode determination unit 123 determines the lane maintenance mode in which the vehicle V returns to the center position C of the driving lane as the driving mode. Thereby, the basic driving mode determining unit 123 can prevent the own vehicle V from continuing to run on the obstacle avoidance trajectory T and deviate from the driving lane even after passing the side of the other vehicle B, and Safety can be increased.

[Processing to determine whether to enter obstacle avoidance mode]
FIG. 5 is a flowchart illustrating an example of a process for determining whether to select the obstacle avoidance mode. The flowchart in FIG. 5 is executed when a stationary obstacle is detected in front of the own vehicle V in the direction of travel.

The avoidance trajectory generation unit 122 determines whether the avoidance position A is closer to the center position C than the maximum movement position M (step S1). Specifically, the avoidance trajectory generation unit 122 generates an avoidance position A that is separated by a minimum obstacle avoidance distance K from a position E of the outer edge of another vehicle B, which is a stationary obstacle, in the width direction Y of the driving lane, and The maximum movement position M in which V can move is specified, and it is determined whether the avoidance position A is closer to the center position C than the maximum movement position M (see FIG. 2).

If the avoidance position A is closer to the center position C than the maximum movement position M (Yes in step S1), the avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory T (step S2). To give a specific example, the avoidance trajectory generation unit 122 generates an obstacle avoidance trajectory T that travels at the maximum movement position M (see FIG. 2). The avoidance trajectory generation unit 122 does not generate the obstacle avoidance trajectory T if the avoidance position A is farther from the center position than the maximum movement position M (No in step S1).

After the avoidance trajectory generation section 122 generates the obstacle avoidance trajectory T, the basic driving mode determination unit 123 determines whether the own vehicle V is in a stable driving state with respect to the driving lane (step S3). Specifically, if the traveling direction F1 of the host vehicle V is within the first determination angle range H1, the basic driving mode determining unit 123 determines that the host vehicle V is in a stable running state (see FIG. 4). ).

If the host vehicle V is in a stable travel state (Yes in step S3), the basic driving mode determination unit 123 determines whether the host vehicle V is in a stable travel state when traveling on the obstacle avoidance trajectory T. (Step S4). Specifically, the basic driving mode determining unit 123 makes a second determination that the traveling direction F2 of the own vehicle at the end point EP of the obstacle avoidance trajectory T is based on the tangential direction of the end point EP of the obstacle avoidance trajectory T. If it is within the angle range H2, it is determined that the own vehicle V will be in a stable running state when traveling on the obstacle avoidance trajectory T (see FIG. 4).

If the own vehicle V is in a stable running state when traveling on the obstacle avoidance trajectory T (Yes in step S4), the basic driving mode determination unit 123 determines that the avoidance risk when traveling on the obstacle avoidance trajectory T is a risk threshold. It is determined whether or not it is less than (step S5). If the avoidance risk is less than the risk threshold (Yes in step S5), the basic driving mode determining unit 123 determines that the obstacle avoidance cost of traveling on the obstacle avoidance trajectory T is greater than the maintenance cost of traveling in the current travel lane. It is determined whether it is small (step S6). Note that the order of the processing from steps S3 to S6 is not limited to this, and the processing may be started from any step. Furthermore, the processes from steps S3 to S6 may be executed in parallel.

If the obstacle avoidance cost is smaller than the maintenance cost (Yes in step S6), the basic driving mode determining unit 123 determines whether the state in which the determinations from step S3 to step S6 are Yes continues for the determination duration time or more. A determination is made (step S7). Specifically, the basic driving mode determining unit 123 determines that the own vehicle V is in a stable driving state, that the own vehicle V is in a stable driving state when traveling on the obstacle avoidance trajectory T, and that the avoidance risk is less than the risk threshold. It is determined whether or not a state where the obstacle avoidance cost is lower than the maintenance cost continues for the determination duration time or more. If the state in which the determinations from step S3 to step S6 are Yes continues for the determination duration time or longer (Yes in step S7), the basic driving mode determining unit 123 determines the obstacle avoidance mode to be the basic driving mode ( Step S8).

If the avoidance trajectory generation unit 122 does not generate the obstacle avoidance trajectory T (No in step S1) and if any of the determinations from steps S3 to S7 is No, the basic driving mode determination unit 123 determines whether the obstacle The object avoidance mode is not determined to be the basic driving mode, but the lane keeping mode is determined to be the basic driving mode (step S9). Note that the process for determining whether to set the obstacle avoidance mode is performed when the driving mode of the own vehicle V is determined to be the obstacle avoidance mode, when the own vehicle V passes a stationary obstacle, or when the own vehicle V This will be repeated until the vehicle stops in front of a stationary obstacle.

[Processing to determine whether to return to the center position of the driving lane]
FIG. 6 is a flowchart illustrating an example of a process for determining whether to return to the center position of the driving lane. The flowchart of FIG. 6 is executed when the driving mode of the own vehicle V becomes the obstacle avoidance mode.

The basic driving mode determining unit 123 determines whether the host vehicle V has passed a stationary obstacle (step S11). For example, if a stationary obstacle that was detected in front of the vehicle V in the direction of travel is detected behind the vehicle V in the direction of travel, the basic driving mode determining unit 123 determines that the vehicle V has passed the stationary obstacle. judge. When it is determined that the own vehicle V has passed a stationary obstacle (Yes in step S11), the avoidance trajectory generation unit 122 generates a return trajectory that returns to the center position of the driving lane. Specifically, the avoidance trajectory generation unit 122 moves the own vehicle V from the current traveling position in the width direction Y to the center position C in the width direction Y, and moves around the center position C in the width direction Y of the driving lane. A return traveling trajectory is generated (step S12).

The basic driving mode determining unit 123 determines whether the own vehicle V traveling on the obstacle avoidance trajectory T is in a stable driving state (step S13). For example, if the direction of the host vehicle V is within the third determination angle range, the basic driving mode determining unit 123 determines that the host vehicle V traveling on the obstacle avoidance trajectory T is in a stable driving state. If the direction of the host vehicle V is outside the third determination angle range, the basic driving mode determining unit 123 determines that the host vehicle V traveling on the obstacle avoidance trajectory T is in an unstable driving state.

If the host vehicle V traveling on the obstacle avoidance trajectory T is in a stable travel state (Yes in step S13), the basic travel mode determination unit 123 determines that the host vehicle V will be in a stable travel state when traveling on the return travel trajectory. It is determined whether or not (step S14). If the direction of the host vehicle V at the end point of the return travel trajectory is within the fourth determination angle range, the basic driving mode determination unit 123 determines that the host vehicle V is in a stable travel state, and If the direction of the host vehicle V is outside the fourth determination angle range, it is determined that the vehicle is in an unstable running state.

If the host vehicle V is in a stable running state when traveling on the return travel trajectory (Yes in step S14), the basic driving mode determining unit 123 determines whether the return risk when traveling on the return travel trajectory is less than the risk threshold value. is determined (step S15). If the return risk is less than the risk threshold (Yes in step S15), the basic driving mode determining unit 123 determines whether the return trajectory cost is smaller than the avoidance trajectory cost (step S16). Note that the order of the processing from steps S13 to S16 is not limited to this, and the processing may be started from any step. Furthermore, the processes from steps S13 to S16 may be executed in parallel.

If the return trajectory cost is smaller than the avoidance trajectory cost (Yes in step S16), the basic driving mode determining unit 123 determines whether the state in which the determinations from step S13 to step S16 are Yes continues for the determination duration time or more. is determined (step S17). Specifically, the basic driving mode determining unit 123 determines that the own vehicle V traveling on the obstacle avoidance trajectory T is in a stable traveling state, and that the own vehicle V enters the stable traveling state when traveling on the return traveling trajectory, and that the vehicle V is in a stable traveling state when traveling on the return traveling trajectory. It is determined whether the state in which the risk is less than the risk threshold and the return trajectory cost is smaller than the avoidance trajectory cost continues for a determination duration time or more. If the state in which the determination from step S13 to step S16 is Yes continues for the determination duration time or longer (Yes in step S17), the basic driving mode determination unit 123 sets the basic driving mode to the lane keeping mode in which the determination is made on the return traveling trajectory. mode is determined (step S18).

If the own vehicle V has not passed a stationary obstacle (No in step S11), and if any of the determinations in steps S13 to S17 is No, the basic driving mode determining unit 123 determines the return traveling trajectory. The lane keeping mode in which the vehicle travels is not determined to be the basic driving mode, but the obstacle avoidance mode is determined to be the basic driving mode (step S19). Note that the process of determining whether to return to the center position of the driving lane is repeatedly executed until the driving mode of the host vehicle V is determined to be the lane keeping mode.

[Effects of automatic driving device 1]
As explained above, the automatic driving device 1 determines that the avoidance position A, which is the minimum obstacle avoidance distance K in the width direction Y of the driving lane from the outer edge of a stationary obstacle in front of the vehicle V in the traveling direction, is If the center position C of the driving lane is closer than the maximum movement position M, an obstacle avoidance trajectory T is generated in which the distance between the stationary obstacle and the own vehicle V in the width direction Y is equal to or greater than the minimum obstacle avoidance distance K. Then, the automatic driving device 1 generates a vehicle speed potential and a lane potential for driving the vehicle V along the obstacle avoidance trajectory T, and determines the driving behavior of the vehicle V based on the generated potentials. By doing so, the automatic driving device 1 can move the vehicle V away from the stationary obstacle by a certain distance and avoid the stationary obstacle without causing the vehicle V to deviate from the driving lane too much. As a result, the automatic driving device 1 can reduce the risk of the own vehicle V coming into contact with another vehicle traveling in an adjacent or oncoming lane adjacent to the driving lane, and the risk of the own vehicle V coming into contact with a stationary obstacle. , it is possible to improve safety when avoiding stationary obstacles in front of the own vehicle V.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist. be. For example, all or part of the device can be functionally or physically distributed and integrated into arbitrary units. In addition, new embodiments created by arbitrary combinations of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiment resulting from the combination have the effects of the original embodiment.

1 Automatic driving device 11 Storage unit 12 Control unit 121 Obstacle detection unit 122 Avoidance trajectory generation unit 123 Basic driving mode determination unit 124 Potential generation unit 125 Driving behavior determination unit 2 Sensor group 3 ECU
V own vehicle

Claims (9)

An automatic driving device that determines driving behavior of its own vehicle,
an obstacle detection unit that detects obstacles around the own vehicle;
an avoidance position that is a predetermined minimum obstacle avoidance distance in the width direction of the travel lane of the host vehicle from an outer edge of a stationary obstacle that is stationary in front of the host vehicle in the traveling direction detected by the obstacle detection unit; When the distance between the stationary obstacle and the own vehicle in the width direction is closer to the center position of the driving lane than the maximum movement position of the own vehicle in the width direction based on the width of the driving lane, the distance between the stationary obstacle and the own vehicle in the width direction is an avoidance trajectory generation unit that generates an obstacle avoidance trajectory that is equal to or greater than the minimum obstacle avoidance distance;
A gravitational force that indicates a recommended vehicle speed for driving the own vehicle along the obstacle avoidance trajectory, and is proportional to the difference between the target speed at each route point of the obstacle avoidance trajectory and the current speed of the own vehicle. or a vehicle speed potential which is a repulsive force potential , and a running position which is an attractive potential which is proportional to the difference between the target position of the route point and the current position of the own vehicle, based on the target position of each route point on the obstacle avoidance trajectory. a potential generation unit that generates a lane potential indicating the degree of recommendation of the lane;
a driving behavior determining unit that determines, as the driving behavior, an acceleration and a yaw rate that minimize a cost function that includes the vehicle speed potential and the lane potential generated by the potential generating unit and uses the acceleration and yaw rate of the host vehicle as parameters;
An automatic driving device with The avoidance trajectory generation unit does not generate the obstacle avoidance trajectory if the avoidance position is further from the center position than the maximum movement position, and does not generate the obstacle avoidance trajectory if the avoidance position is closer to the center position than the maximum movement position. generating one or more of the obstacle avoidance trajectories that are greater than or equal to the minimum obstacle avoidance distance;
The automatic driving device according to claim 1. If the obstacle avoidance cost when traveling on the obstacle avoidance track is lower than the maintenance cost when the host vehicle continues to travel on the current travel track, an obstacle avoidance mode in which the own vehicle runs on the obstacle avoidance track is selected. further comprising a driving mode determining unit that determines the driving mode of the own vehicle;
The automatic driving device according to claim 1 or 2. The driving mode determining unit includes:
the orientation of the host vehicle is within a predetermined determination angle range based on a tangential direction of a route point of the traveling track;
the orientation of the host vehicle at the end point of the obstacle avoidance trajectory is within the determination angle range with respect to the tangential direction of the end point of the obstacle avoidance trajectory;
the avoidance risk when traveling on the obstacle avoidance trajectory is less than a risk threshold;
and if a state in which the obstacle avoidance cost is lower than the maintenance cost continues for a predetermined determination duration or more, the obstacle avoidance mode is determined to be the driving mode of the own vehicle;
The automatic driving device according to claim 3. The avoidance trajectory generation unit generates a plurality of obstacle avoidance trajectories that differ in at least one of a distance between the stationary obstacle and the own vehicle and a target speed of the own vehicle;
The driving mode determining unit determines an obstacle avoidance mode in which the host vehicle travels on an obstacle avoidance trajectory with the lowest obstacle avoidance cost among the plurality of obstacle avoidance paths as the driving mode of the host vehicle.
The automatic driving device according to claim 4. The avoidance trajectory generation unit generates a return trajectory in which the host vehicle travels at the center position in the width direction of the travel lane after passing the stationary obstacle;
The driving mode determining unit includes:
the orientation of the host vehicle is within the determination angle range based on a tangential direction of a route point of the obstacle avoidance trajectory on which the host vehicle is traveling;
the orientation of the vehicle at the end point of the return trajectory is within the determination angle range with respect to the tangential direction of the end point of the return trajectory;
The return risk when traveling on the return travel trajectory is less than the risk threshold,
And if a state in which the return trajectory cost when traveling on the return travel trajectory is lower than the return trajectory cost when continuing to travel on the obstacle avoidance trajectory continues for more than the determination duration time,
determining a driving mode for traveling on the return traveling trajectory as a driving mode for the host vehicle;
The automatic driving device according to claim 4. The driving mode determining unit increases the determination duration time as the position of the stationary obstacle is closer to the center position.
The automatic driving device according to claim 4. When the distance between the position of the stationary obstacle and the center position is less than a predetermined threshold, the driving mode determining unit does not determine the obstacle avoidance mode as the driving mode of the own vehicle, and and determining the obstacle avoidance mode as the driving mode of the own vehicle if the distance between the position of
The automatic driving device according to claim 4. The driving mode determining unit shortens the determination duration time when it is determined that the stationary obstacle continues to remain stationary, and lengthens the determination duration time when it is determined that the stationary obstacle starts moving.
The automatic driving device according to claim 4.

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