Vehicle control method and vehicle control device

Abstract

A controller (20): sets, in a three-dimensional space (90) including a two-dimensional plane along a travel road surface and a time axis, a planned trajectory (80) that connects a current position (901) of a host vehicle (1) to a target point (903) spaced apart from the current position (901) and that does not intersect a surrounding object (91); extracts, on a ti plane at each time (ti) in the three-dimensional space (90), a first point (94A) of interest on the surrounding object (91) that has a risk of intersecting the host vehicle (1) in a path orthogonal direction orthogonal to a path length direction along the planned trajectory (80), and a second point (94Di) of interest on the surrounding object (91) that has a risk of intersecting the host vehicle (1) in the path length direction; sets a first region limit (85A) by connecting first projection points (95A) at which the first point (94A) of interest is projected on the two-dimensional plane serving as the travel road surface; sets a second region limit (85B) by connecting second projection points (95B) at which the second point (94Di) of interest is projected on a two-dimensional curved surface (70) which is along the path length direction and perpendicular to the travel road surface; generates a steering command that corrects the planned trajectory (80) to a smooth travel trajectory (86) within the first region limit (85A); and generates an acceleration / deceleration command that moderates acceleration / deceleration of the host vehicle (1) within a region from the current position (901) of the host vehicle (1) to the second region limit (85B).

Description

Vehicle control method and vehicle control device

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

[0002] Conventionally, technologies for autonomously driving vehicles using automated driving systems are known (see, for example, Patent Document 1). The technology described in Patent Document 1 is a technology for autonomously moving an unmanned transport cart from its current position to a target position, which involves three-dimensionally depicting obstacle areas in a three-dimensional space including the time axis and setting a path that avoids obstacle areas.

[0003] Japanese Patent Publication No. 2020-4095

[0004] Incidentally, when performing autonomous driving of a vehicle traveling on a road, steering control is necessary to ensure that the vehicle's behavior is smooth. The technology described in Patent Document 1 above allows setting a path that avoids obstacle areas depicted in three-dimensional space, but when applying this technology to autonomous driving of a vehicle traveling on a road, it is necessary to modify the set path to make it smoother. In this case, the path may be modified to be closer to the obstacle than the set path.

[0005] The present invention aims to provide a vehicle control method and a vehicle control device that enable the setting of a smooth driving trajectory while suppressing excessive proximity to obstacles.

[0006] A vehicle control method according to a first aspect of this disclosure is a vehicle control method that controls the automatic driving of a vehicle using a computer, wherein the computer sets a planned trajectory in a three-dimensional space including a two-dimensional plane along the vehicle's road surface and a time axis intersecting the two-dimensional plane. This planned trajectory is a path that connects the vehicle's current position to a target point that is more than a predetermined distance away, and is a path that does not intersect the vehicle with surrounding objects. On each time plane parallel to the road surface in the three-dimensional space, the direction along the planned trajectory is defined as the path length direction, and the direction perpendicular to the planned trajectory is defined as the path orthogonal direction. The computer extracts points on surrounding objects that pose a risk of intersecting the vehicle in the path orthogonal direction as first points of interest, and extracts points on surrounding objects that pose a risk of intersecting the vehicle in the path length direction as second points of interest. First points of interest are extracted on both the left and right sides of the vehicle. Furthermore, the computer projects the first points of interest perpendicularly onto the two-dimensional plane that becomes the road surface, connects the points of the projected first points of interest, and sets the limit of the drivable area in the path orthogonal direction. Furthermore, the second point of interest is projected perpendicularly onto a two-dimensional curved surface that is along the path length and perpendicular to the road surface, and the point cloud of the projected second point of interest is connected to set the limit of the drivable area in the direction of the path length. Then, within the area from the vehicle's current position to the limit of the drivable area in the direction of the path length, an acceleration / deceleration command is generated that sets the vehicle's acceleration / deceleration to be below a predetermined acceleration / deceleration threshold, and within the limit of the drivable area in the direction perpendicular to the path, a steering command is generated that sets the vehicle's steering angle to be below a predetermined steering angle threshold.

[0007] This defines limits to the drivable area that must not be exceeded in both the path length direction and the direction perpendicular to the path. Within these limits, acceleration and deceleration commands that smooth the vehicle's acceleration and deceleration, and steering commands that smooth the vehicle's steering angle are generated. Thus, it is possible to achieve smooth vehicle driving behavior without getting too close to surrounding objects.

[0008] A block diagram showing the general configuration of the vehicle of this embodiment. A diagram showing an example of the three-dimensional space generated in this embodiment. A schematic diagram for explaining the generation of a planned trajectory around surrounding objects in this embodiment. A schematic diagram for explaining the method of extracting points of interest by the point of interest extraction unit in this embodiment. A schematic diagram for explaining the method of extracting the first point of interest in this embodiment. A schematic diagram showing the method of setting a virtual second point of interest in this embodiment. A diagram showing an example of mapping data showing the relationship between the distance from the planned trajectory to the first point of interest and the distance from the first point of interest to the third point in this embodiment. A schematic diagram showing the method of setting the limit of the drivable area in the direction orthogonal to the path in this embodiment. A schematic diagram showing the method of setting the limit of the drivable area in the direction of the path length in this embodiment. A diagram showing an example of a planned trajectory modified by the steering command unit in this embodiment and comparative example. A flowchart showing the vehicle speed control method executed by the controller of this embodiment.

[0009] [First Embodiment] The first embodiment of the present disclosure will be described below. Figure 1 is a block diagram showing the schematic configuration of the vehicle of this embodiment. The vehicle of this embodiment (vehicle 1) is an autonomous driving vehicle capable of autonomous driving by a controller 20. As shown in Figure 1, vehicle 1 is equipped with a sensor 10, a controller 20, and an actuator 30.

[0010] [Configuration of Sensor 10] Sensor 10 includes an ambient detection sensor 11, a position detection sensor 12, a wheel speed sensor 13, and a yaw rate sensor 14, etc. However, the sensors 10 provided on the vehicle 1 are not limited to those described above, and various other sensors may be provided as needed.

[0011] The surrounding detection sensor 11 includes, for example, an image sensor and a distance measuring sensor. The image sensor is installed at a predetermined position on the vehicle 1 and captures images of the area around the vehicle to detect objects on or outside the vehicle's travel path. Objects to be detected include, for example, moving objects (vehicles, pedestrians, etc.) and non-moving objects (parked vehicles, stopped vehicles, structures erected on the road, etc.) as well as road markings (road markings such as white lines, stop lines, and pedestrian crossings). Multiple image sensors may be installed on the vehicle 1. The distance measuring sensor can be of various types, such as laser radar, millimeter-wave radar, ultrasonic radar, and laser rangefinder, and a combination of several of these may be used. The distance measuring sensor emits electromagnetic waves and receives the electromagnetic waves reflected by an object to detect the position of the electromagnetic waves on the object, thereby measuring the position of the object relative to the vehicle 1 (direction and distance from the vehicle 1).

[0012] The position detection sensor 12 is a sensor that detects the current position of the vehicle 1. Examples of the position detection sensor 12 include a receiver that receives satellite signals from GNSS (Global Navigation Satellite System) to determine the current position.

[0013] The wheel speed sensors 13 are installed on each of the four wheels and detect the wheel speed of each wheel. The average of the wheel speeds of the left and right driven wheels is then used as the current vehicle speed detection value.

[0014] The yaw rate sensor 14 is an attitude sensor that detects the yaw rate of the vehicle (the angular velocity of rotation around the vertical axis passing through the vehicle's center of gravity). The attitude sensor may include a gyro sensor capable of detecting the pitch angle, yaw angle, and roll angle of the vehicle.

[0015] [Configuration of Actuator 30] The actuator 30 includes an engine actuator 31, a brake hydraulic actuator 32, and a steering angle actuator 33. The engine actuator 31 is an actuator that controls the engine driving force based on an acceleration command input from the controller 20. In the case of a hybrid vehicle, an engine actuator and a motor actuator may be used. In the case of an electric vehicle, a motor actuator may be used.

[0016] The brake hydraulic actuator 32 is a hydraulic booster that controls the brake hydraulic braking force based on a deceleration command input from the controller 20. In the case of an electric vehicle not equipped with a hydraulic booster, an electric booster may be used.

[0017] The steering angle actuator 33 is a steering angle control motor that controls the steering angle of the steering wheel based on a steering command from the controller 20.

[0018] [Schematic Configuration of Controller 20] The controller 20 is an automatic driving control unit for controlling the automatic driving of the host vehicle 1. This controller 20 is a computer composed of an arithmetic circuit such as a CPU (Central Processing Unit) and a storage device such as a memory, and constitutes the driving control device of the present disclosure.

[0019] The memory device stores various programs and various data for realizing the automatic driving of the host vehicle 1. The various data includes map information for setting the traveling route of the host vehicle 1. The map information is information in which latitude and longitude are associated with the map information. The map information has road information associated with each point, and the road information is defined by nodes and links connecting between the nodes. The road information includes information for specifying a road by the position / area of the road, the road type for each road, the road width for each road, and the shape information of the road. The road information stores, for each identification information of each road link, the position of an intersection, the entry direction of the intersection, the type of the intersection, and other information related to the intersection. Also, the road information stores, for each identification information of each road link, the road type, the road width, the road shape, the possibility of going straight, the priority relationship of traveling, the possibility of overtaking (the possibility of entering an adjacent lane), the speed limit, and other information related to the road in association with each other.

[0020] Then, by reading and executing various programs recorded in the memory device by the arithmetic circuit, as shown in FIG. 1, the controller 20 functions as a surrounding object acquisition unit 21, a lane information acquisition unit 22, a host vehicle information acquisition unit 23, a traveling lane information generation unit 24, a planned trajectory generation unit 25, a traveling area limit generation unit 26, a lateral area boundary integration unit 27, a steering command unit 28, and an acceleration / deceleration command unit 29. Here, an example is shown in which the functional configurations of the surrounding object acquisition unit 21, the lane information acquisition unit 22, the host vehicle information acquisition unit 23, the traveling lane information generation unit 24, the planned trajectory generation unit 25, the traveling area limit generation unit 26, the lateral area boundary integration unit 27, the steering command unit 28, and the acceleration / deceleration command unit 29 are realized by the arithmetic circuit executing the program, but some or all of these may be realized by an individual hardware configuration.

[0021] The surrounding object acquisition unit 21 acquires surrounding object information regarding the objects around the host vehicle 1 based on the detection signal input from the surrounding detection sensor 11 of the sensor 10. The surrounding objects are objects that can become an obstacle in the traveling of the host vehicle 1, and examples thereof include a preceding vehicle, a parallel traveling vehicle, an oncoming vehicle, a following vehicle, a parked vehicle, and a structure standing on the road.

[0022] The lane information acquisition unit 22 acquires lane information based on signals input from the surrounding detection sensor 11, specifically the boundary lines (white lines, yellow lines, guardrails, etc.) on the road on which the vehicle 1 is traveling. If road information including lane information is associated with a map information link or node, the lane information acquisition unit 22 may acquire road information corresponding to the current location of the vehicle 1 from the map information and extract lane information from the acquired road information.

[0023] The vehicle information acquisition unit 23 acquires the current position of the vehicle 1 based on signals input from the position detection sensor 12. The vehicle information acquisition unit 23 also acquires the current driving state (driving speed and steering state) of the vehicle 1 based on signals input from the wheel speed sensor 13 and the yaw rate sensor 14. The vehicle information acquisition unit 23 generates vehicle information including the current position and driving state of the vehicle 1. The vehicle information may also include route information acquired from a navigation device (not shown). The route information is the route on a map from the current position of the vehicle 1 to the destination entered by the user (e.g., the driver).

[0024] The driving lane information generation unit 24 acquires driving lane information regarding the driving lane on the road in which the vehicle 1 is traveling, based on lane information and the current position of the vehicle 1. The driving lane information includes information on the vehicle's own lane as well as information on adjacent lanes adjacent to the vehicle's own lane.

[0025] The planned trajectory generation unit 25 generates a planned trajectory for the vehicle 1 to travel on the road based on surrounding object information, lane information, and driving lane information. Figure 2 is a schematic diagram showing the three-dimensional space 90 generated in the calculation of the planned trajectory 80. The planned trajectory generation unit 25 generates the planned trajectory 80 using the three-dimensional space 90 shown in Figure 2. Specifically, the road surface on which the vehicle 1 travels is defined as the XY plane, the direction toward the front of the vehicle is the X direction, and the direction toward the side of the vehicle (for example, from right to left) is the Y direction. In addition, in the three-dimensional space 90, the axis that intersects (for example, is orthogonal to) the X direction and the Y direction is defined as the time axis. Here, in the following explanation, time t ｉ In this context, the XY plane parallel to the road surface is defined as t ｉThis is referred to as the plane. In Figure 2, 901 indicates the current position of vehicle 1, and 902 is the target route based on route information.

[0026] In the three-dimensional space 90, surrounding objects 91 are placed based on surrounding object information. For example, if the surrounding objects 91 are non-moving objects such as buildings erected on a road or parked vehicles, they are placed in the same position at all times. On the other hand, if the surrounding objects 91 are moving objects such as vehicles traveling side by side, the surrounding objects 91 are placed at each time t ｉ t that corresponds to ｉ Each t is in a different position on the plane. ｉ The position of the surrounding object 91 as a moving object on a plane can be estimated by calculating the acceleration, velocity, and direction of movement of the surrounding object 91 from the change in the position of the surrounding object 91 over a predetermined period of time detected by the surrounding detection sensor 11.

[0027] The planned trajectory generation unit 25 calculates the trajectory that the vehicle should take in the three-dimensional space 90 in which the surrounding objects 91 described above are arranged. That is, the trajectory of the vehicle is calculated based on the road surface (t = t ０ t that corresponds to ０ In a planar view, the current position 901 of the vehicle 1 is plotted, a target point 903 is set at a distant point at a predetermined distance or more from the vehicle 1 along the target route 902, and the trajectory that the vehicle 1 travels from its current position 901 to the target point 903 at a predetermined speed is set as the planned trajectory 80. The target point 903 is, for example, a distant point on the vehicle's lane 904 that is recognizable from the vehicle 1. In the example in Figure 2, since a preceding vehicle is detected as a surrounding object 91 in front of the vehicle 1, the recognizable distant point is the position of the preceding vehicle. The predetermined speed may be the current speed of the vehicle 1, the legal speed limit, or an appropriate speed in accordance with the surrounding traffic conditions and traffic rules.

[0028] In this case, if there are surrounding objects 91 that could potentially come into contact with the vehicle 1, the planned trajectory generation unit 25 generates a planned trajectory 80 that avoids those surrounding objects 91. For example, in the example shown in Figure 2, a planned trajectory 80 is generated that connects the current position 901 of the vehicle 1 to the target point 903 and does not intersect with other surrounding objects 91.

[0029] FIG. 3 is a schematic diagram for explaining in more detail the generation of the planned trajectory 80 around the surrounding object 91, at a predetermined time t ｉ at t ｉ shows a view in which the planned trajectory 80 is projected onto a part of the plane. Here, as shown in FIG. 3, the surrounding object 91 described in the present embodiment includes a detected object 91A detected by the surrounding detection sensor 11 and a surrounding object region 91S expanded by a predetermined margin range (for example, 1 to 5 m, etc.) from the outer peripheral edge 911 of the detected object 91A. The planned trajectory generation unit 25 generating the planned trajectory 80 for the host vehicle 1 to avoid the surrounding object 91 means generating, as the planned trajectory, a trajectory in which the planned trajectory 80 does not enter the surrounding object region 91S. As shown in FIG. 3, the planned trajectory 80 generated by the planned trajectory generation unit 25 is a trajectory along the region boundary 912 of the surrounding object region 91S and is not a smooth trajectory for running the vehicle on the road.

[0030] The travel region limit generation unit 26 defines the travelable region limit within which the host vehicle 1 can travel. As shown in FIG. 1, this travel region limit generation unit 26 includes a focus point extraction unit 261 and a travel region limit setting unit 262.

[0031] The focus point extraction unit 261 extracts, as focus points, points on the surrounding object 91 that have a risk of intersecting with the host vehicle 1. Specifically, the focus point extraction unit 261 includes a first focus point extraction unit 261A and a second focus point extraction unit 261B. The first focus point extraction unit 261A searches for focus points in the direction orthogonal to the path length direction (left and right sides of the host vehicle 1) from the host vehicle 1 when the direction along the planned trajectory 80 is defined as the path length direction and the direction orthogonal to the path length direction is defined as the path orthogonal direction. The second focus point extraction unit 261B searches for focus points in the forward direction of the path length direction from the host vehicle 1.

[0032] FIG. 4 is a schematic diagram for explaining the method of extracting the focus points by the focus point extraction unit 261, showing the t[[ID=]14] ｉ plane corresponding to a certain time t ｉ in the three-dimensional space 90. The first focus point extraction unit 261A projects the planned trajectory 80 set in the three-dimensional space 90 at each time t ｉ corresponding to t ｉFind the first projection line 81 projected onto the plane. Also, t ｉ The intersection point of the plane and the planned trajectory 80 is determined as the first point 92. The first point 92 is determined at time t. ｉ This is the predicted position of the vehicle 1 in the diagram. The first point of interest extraction unit 261A finds a second point 93 by shifting the first point 92 of the first projection line 81 by a length along the path length direction of the vehicle 1 (the total length of the vehicle 1) in the front-rear direction of the path length. The second point 93 is generated on the front side and the rear side of the vehicle 1, respectively. The first point of interest extraction unit 261A searches for a point of interest (first point of interest 94A) on the side away from the vehicle 1 along the normal 82 of the first point 92 on the first projection line 81 and the normal 84 of the pair of second points 93 on the first projection line 81.

[0033] By the way, in this embodiment, each time t in the three-dimensional space 90 ｉ t that corresponds to ｉ From the plane, the first point of interest 94A is extracted. Therefore, at the time t ｉ The extraction interval of the first point of interest 94A varies depending on the sampling interval. In particular, when the size of the surrounding object 91 is small, the extraction accuracy of the first point of interest 94A, which is the intersection point of the normals 82, 84 and the surrounding object 91 (region boundary 912), may decrease depending on the sampling interval. Therefore, in this embodiment, the first point of interest extraction unit 261A virtually increases the length along the path length of the detected surrounding object 91.

[0034] Figure 5 is a schematic diagram illustrating the method for extracting the first point of interest 94A. Based on Figure 5, the process of virtually expanding the length along the path length of the surrounding object 91 will be explained in detail. Note that in Figure 5, the time t sampled continuously is shown. ｉ ,t ｉ＋１ Two t corresponding to ｉ Plane and t ｉ＋１This is a diagram integrating the extraction results of the first point of interest 94A in the plane. Also, in Figure 5, for the sake of simplicity of explanation, only the first point of interest 94A, which is searched along the normal 82 from the first point 92, is shown, but the second point of interest 94B, which is searched along the normal 84 from the second point 93, is extracted in the same way. As shown in Figure 5, the first point of interest extraction unit 261A extracts the region boundary 912 of the detected surrounding object 91 at time t ｉ Depending on the sampling interval, a virtual object boundary 913 is set that is expanded along the path length. For example, in the example in Figure 5, a parabolic virtual object boundary 913 that is convex toward the vehicle 1 side is set, and the parabolic shape of the virtual object boundary 913 is deformed so that the length along the path length direction increases as the sampling interval increases. Then, the first point of interest extraction unit 261A extracts the intersection points of the normals 82, 84 and the virtual object boundary 913 as points of interest (first points of interest 94A) in the direction perpendicular to the path.

[0035] Next, the second point of interest extraction unit 261B will be described. Similar to the first point of interest extraction unit 261A, the second point of interest extraction unit 261B extracts the planned trajectory 80 set in the three-dimensional space 90 at each time t ｉ t that corresponds to ｉ Projected onto a plane, each t ｉ The first projection line 81 is determined in a plane. Furthermore, as shown in Figure 4, the second point of interest extraction unit 261B determines a second projection line 83 by shifting the first projection line 81 by the vehicle width W of the vehicle 1 in the normal direction (direction along the normal 82) of the first projection line 81 at the first point 92. The second projection line 83 is generated on the left and right sides of the vehicle 1, respectively.

[0036] The second point of interest extraction unit 261B then searches for a point of interest along the first projection line 81 and the pair of second projection lines 83 on the side in front of the vehicle 1 in the direction of travel. In other words, the intersection of the first projection line 81 and the pair of second projection lines 83 with the surrounding objects 91 (region boundary 912) in front of the vehicle 1 is extracted as a point of interest (second point of interest 94B) in the direction of the path length.

[0037] Furthermore, the second point of interest extraction unit 261B sets a virtual second point of interest to reduce the speed of the vehicle 1 when traveling near the surrounding object 91, based on the first point of interest 94A, which is the intersection of the normal 82 of the first point 92 and the virtual object boundary 913 of the surrounding object 91. Figure 6 is a schematic diagram showing the method of setting the virtual second point of interest. As shown in Figure 6, the second point of interest extraction unit 261B sets a point located a predetermined distance d2 forward of the vehicle along the first projection line 81 from the first point 92 as the virtual second point of interest 94C. In this case, the distance d2 is increased as the distance d1 between the planned trajectory 80 and the first point of interest 94A increases. Figure 7 is a diagram showing an example of mapping data that shows the relationship between the distance d1 from the planned trajectory 80 to the first point of interest 94A and the distance d2 from the first point of interest 94A to the third point 95. If the distance d1 is less than the first threshold th1, the distance d2 is set to 0. In other words, if the first point of interest 94A is close to the planned trajectory 80, the virtual second point of interest 94C is set to the first point 92. If the distance d1 is greater than or equal to the first threshold th1 and less than the second threshold th2, the distance d2 is gradually increased according to the distance d1. If the distance d1 is greater than or equal to the second threshold th2, the distance d2 is gradually increased according to the distance d1 with a steeper slope than when the distance d1 is greater than or equal to the first threshold th1 and less than the second threshold th2.

[0038] Then, the second point of interest extraction unit 261B is t ｉ Of the second point of interest 94B that intersects the first projection line 81, the second point of interest 94B that intersects the second projection line 83, and the virtual second point of interest 94C, extracted in a plane, the point with the smallest distance in the direction of the path length from the vehicle 1 is selected as t ｉ It is adopted as the second point of interest 94Di on the plane. The second point of interest extraction unit 261B performs a sampling at each time t which is a predetermined sampling interval. ｉ For each of these, one secondary point of interest, 94Di, is extracted.

[0039] The driving area limit setting unit 262 sets the limits of the drivable area, that is, the boundary line for generating a smooth driving trajectory for the vehicle 1. Specifically, the driving area limit setting unit 262 includes a first driving area limit setting unit 262A and a second driving area limit setting unit 262B.

[0040] Figure 8 is a schematic diagram showing how to set the limit of the drivable area in the direction perpendicular to the path. The first drivable area limit setting unit 262A is a two-dimensional plane (t) which is the driving surface. ０ The point cloud (first projection point 95A) obtained by projecting the first point of interest 94A onto a plane is connected to define the limit of the drivable area in the direction perpendicular to the path. Hereafter, the limit of the drivable area in the direction perpendicular to the path will be referred to as the first area limit 85A. Since the first point of interest 94A is extracted on the left and right sides of the vehicle 1, the first area limit 85A is set on the left and right sides of the vehicle 1, respectively.

[0041] Figure 9 is a schematic diagram showing the method for setting the limit of the drivable area in the direction of the path length. The second drivable area limit setting unit 262B is a plane that is along the direction of the path length and parallel to the road surface (each time t ｉ t ｉ A point cloud (second projection point 95B) is formed by projecting the second point of interest 94Di perpendicularly onto a two-dimensional curved surface 70 perpendicular to the plane, and this is used to define the limit of the drivable area in the direction of the path length. Hereafter, the limit of the drivable area in the direction of the path length will be referred to as the second area limit 85B. Note that the example in Figure 8 is one in which the preceding vehicle traveling in front of the vehicle 1 is stopped and a virtual second point of interest 94C has not been set. In this case, as shown in Figure 9, each time t ｉ The position of the second projection point 95B in the two-dimensional curved surface 70 remains constant. That is, the distance of each second projection point 95B on the two-dimensional curved surface 70 from the current position of the vehicle 1 is constant. In contrast, when a preceding vehicle is moving, or when the target point is at infinity or far away, the position of the second projection point 95B moves forward in the direction of the path length over time. That is, the distance of each second projection point 95B on the two-dimensional curved surface 70 from the current position of the vehicle 1 gradually increases over time. Furthermore, when a virtual second point of interest 94C is set and selected as the second point of interest 94Di, the second projection point 95B corresponding to the virtual second point of interest 94C is positioned close to the current position of the vehicle 1 until the vehicle 1 approaches and passes the surrounding object 91.

[0042] The lateral region boundary integration unit 27 integrates the driving lane information generated by the driving lane information generation unit 24 with the first region limit 85A set by the first driving region limit setting unit 262A. In other words, the first region limit 85A may include buildings, guardrails, etc., located outside the driving lane where vehicle travel is permitted. If such a first region limit 85A is used as is, there is a possibility that a driving trajectory that extends beyond the lane markings defining the driving lane will be calculated. Therefore, the lateral region boundary integration unit 27 corrects the first region limit 85A using the driving lane information so that the limit of the drivable region of the vehicle 1 falls within the driving lane.

[0043] The steering command unit 28 modifies the planned trajectory 80 to become a smoother trajectory between the left and right first region limits 85A corrected by the lateral region boundary integration unit 27, and outputs a steering command based on the obtained trajectory to the steering angle actuator 33. A "smooth trajectory" is a trajectory in which the steering angle controlled by the steering angle actuator 33 is less than or equal to a predetermined angle, and the predetermined angle is set by the driving speed of the vehicle 1, etc. In other words, it is a trajectory that can be realized with a gentle steering angle without abrupt changes in the direction of travel due to sudden steering, and without causing discomfort to the occupants of the vehicle 1. The method for generating a smooth trajectory from the planned trajectory 80 can utilize known technologies, for example, the technology described in "Akiyuki Goto, et al., "Real-time trajectory planning using dynamic programming method for autonomous driving in urban areas", Transactions of the Society of Automotive Engineers of Japan, Vol. 52, No. 3, Society of Automotive Engineers of Japan, May 2021" can be used.

[0044] Figure 10 shows an example of a planned trajectory 80 modified by the steering command unit 28. In Figure 10, the thin dashed line represents the planned trajectory 80, and the thick dashed line represents the first area limit 85A. The solid line shows the travel trajectory 86 obtained when the steering command unit 28 modifies the planned trajectory 80 between the left and right first area limits 85A. The dashed line shows the travel trajectory 87 of a comparative example in which the planned trajectory 80 is smoothed without setting the first area limits 85A. In the travel trajectory 87 of the comparative example, the correction is to smooth the planned trajectory 80 as is without defining the drivable area limit, and a part of the travel trajectory 87 passes inside the surrounding object area 91S. In this case, the vehicle 1 enters the surrounding object area 91S and approaches the detected object 91A (an actual object detected by the surrounding detection sensor 11), which is undesirable. In contrast, in this embodiment, the steering command unit 28 generates the travel trajectory 86 so as to stay within the area sandwiched between the defined left and right first area limits 85A. In other words, the travel trajectory 86 does not pass through the interior of the surrounding object region 91S. Therefore, the inconvenience of the vehicle 1 traveling too close to the detected object 91A can be suppressed.

[0045] The acceleration / deceleration command unit 29 generates acceleration / deceleration commands (acceleration command, deceleration command) that enable the vehicle 1 to reach the target point as quickly as possible between its current position and the second area limit 85B, and to accelerate or decelerate gradually. The unit outputs the acceleration command to the engine actuator 31 and the deceleration command to the brake hydraulic actuator 32. "To accelerate or decelerate gradually" means that the acceleration by the engine actuator 31 is below a predetermined acceleration, and the deceleration by the engine actuator 31 is below a predetermined deceleration. In other words, it means that speed control is performed with gradual acceleration and deceleration so as not to cause sudden acceleration or sudden stops and so as not to cause discomfort to the occupants of the vehicle 1. For example, if the distance from the vehicle 1's current position to the second area limit 85B is above a predetermined threshold, the acceleration / deceleration command unit 29 generates an acceleration command or a deceleration command to accelerate or decelerate to the legal speed, or to an appropriate speed in accordance with the surrounding traffic conditions and traffic rules. If the distance from the current position of the vehicle 1 to the second area limit 85B is less than the threshold, a deceleration command corresponding to the distance from the current position of the vehicle 1 to the second area limit 85B is generated.

[0046] [Vehicle Control Method] Next, the vehicle control method in this embodiment will be described. Figure 11 is a flowchart showing the vehicle speed control method executed by the controller 20 in this embodiment. In this embodiment, when the controller 20 performs the automatic driving process for the vehicle 1, the surrounding object acquisition unit 21 detects surrounding objects 91 around the vehicle 1 based on the input signal from the surrounding detection sensor 11 and acquires surrounding object information (step S1). The lane information acquisition unit 22 acquires lane information of the road on which the vehicle 1 is traveling based on the input signal from the surrounding detection sensor 11 or based on map information (step S2). Furthermore, the vehicle information acquisition unit 23 acquires vehicle information including the current position of the vehicle 1 based on the input signal from the position detection sensor 12 (step S3). The order of steps S1 to S3 is not particularly limited, and the processes may be performed in parallel. Then, the driving lane information generation unit 24 acquires driving lane information including the lane on which the vehicle 1 is traveling based on the lane information and the current position of the vehicle 1 (step S4).

[0047] Next, the planned trajectory generation unit 25 generates a planned trajectory using the obtained surrounding object information, lane information, and driving lane information (step S5). In other words, the planned trajectory generation unit 25 generates a planned trajectory 80 in three-dimensional space 90 that connects the vehicle 1 to its current position 901 and to the distant target point 903, without intersecting with surrounding objects 91.

[0048] Subsequently, the point of interest extraction unit 261 of the driving area limit generation unit 26 extracts the first point of interest 94A and the second point of interest 94Di (step S6). In step S6, as described above, the first point of interest extraction unit 261A finds the second point 93 which is shifted by the total length L of the vehicle 1 in front of and behind the first point 92 of the first projection line 81 in the path length direction. Furthermore, time t in the three-dimensional space 90 ｉBased on the sampling interval, the virtual object boundary 913 is calculated by correcting the region boundary 912 of the detected surrounding object 91, that is, the boundary of the surrounding object region 91S when the length in the path length direction of the surrounding object 91 is expanded. Then, the first point of interest extraction unit 261A extracts the intersection point of the normals 82, 84 of the first point 92 and the second point 93 with the virtual object boundary 913 as the first point of interest 94A. The second point of interest extraction unit 261B performs calculations at each time t in the three-dimensional space 90. ｉ t ｉ A first projection line 81 is generated by projecting the planned track 80 onto a plane, and a second projection line 83 is generated by shifting the first projection line 81 by the vehicle width W of the vehicle 1 in the direction normal to the first point 92. Then, the intersection points of the first projection line 81 and the second projection line 83 with the region boundary 912 in the surrounding object region 91S of the surrounding object 91 are extracted as second points of interest 94B. The second point of interest extraction unit 261B also performs t ｉ Once the first point of interest 94A on the plane is extracted, the distance d2 corresponding to the distance d1 from the first point of interest 94A to the planned track 80 is obtained from the mapping data stored in memory beforehand. Furthermore, the second point of interest extraction unit 261B extracts a virtual second point of interest 94C located a predetermined distance d2 forward of the vehicle along the first projection line 81 from the first point 92. Then, the second point of interest extraction unit 261B selects the point among the extracted second point of interest 94B and the virtual second point of interest 94C that is the closest point to the current position of the vehicle 1, t ｉ This will be adopted as the second point of interest in the plane, 94Di.

[0049] Subsequently, the driving range limit setting unit 262 sets the first range limit 85A and the second range limit 85B based on the extracted first point of interest 94A and second point of interest 94Di (step S7). In step S7, as described above, the first driving range limit setting unit 262A sets t ０ The first point of interest 94A is projected onto a plane to become the first projection point 95A, and the first region limit 85A is set by connecting the first projection points 95A. The second travel region limit setting unit 262B projects the second point of interest 94Di onto a two-dimensional curved surface 70 that is perpendicular to the travel surface and along the length of the path to become the second projection point 95B, and sets the second region limit 85B by connecting the second projection points 95B.

[0050] Next, the lateral region boundary integration unit 27 integrates each driving lane on the road included in the driving lane information with the first region limit 85A and corrects the first region limit 85A so that it is within the range of driving lanes that the vehicle can travel in (step S8).

[0051] Subsequently, the steering command unit 28 and the acceleration / deceleration command unit 29 modify the planned trajectory 80 into a smoother trajectory according to the set first domain limit 85A and second domain limit 85B, and perform automatic driving control of the vehicle 1 (step S9). Specifically, the steering command unit 28 modifies the planned trajectory 80 into a smoother trajectory between the left and right first domain limits 85A modified by the lateral domain boundary integration unit 27, generates a steering command corresponding to the modified trajectory, and outputs it to the steering angle actuator 33. The acceleration / deceleration command unit 29 also generates acceleration and deceleration commands that enable the vehicle 1 to reach the target point as quickly as possible and achieve gradual acceleration and deceleration, according to the distance from the vehicle 1's current position to the second domain limit 85B, and outputs the acceleration command to the engine actuator 31 and the deceleration command to the brake hydraulic actuator 32. As a result, the vehicle 1 can autonomously drive on a smooth trajectory that does not approach surrounding objects 91 excessively closely, and with gradual acceleration and deceleration.

[0052] [Effects of this embodiment] The controller 20 mounted on the vehicle 1 in this embodiment uses a planned trajectory generation unit 25 to set a planned trajectory 80 in a three-dimensional space 90 that includes a two-dimensional plane (XY plane) along the road surface of the vehicle 1 and a time axis (t-axis) intersecting the two-dimensional plane, connecting the current position of the vehicle 1 to a target point which is a distant point at a predetermined distance or more, and ensuring that the vehicle 1 does not intersect with surrounding objects 91. Then, the first point of interest extraction unit 261A of the driving area limit generation unit 26 determines each t ｉ Points on surrounding objects 91 that pose a risk of intersecting with the vehicle 1 in a direction perpendicular to the path on the plane are extracted as the first point of interest 94A. In addition, the second point of interest extraction unit 261B of the driving area limit generation unit 26 extracts points at each time t in the three-dimensional space 90. ｉ t that corresponds to ｉOn a plane, points on surrounding objects 91 that pose a risk of intersecting with the vehicle 1 in the direction of the path length are extracted as second points of interest 94B. Then, the first driving area limit setting unit 262A of the driving area limit generation unit 26 determines t ０ The first region limit 85A is defined by connecting the first projection point 95A obtained by projecting the first point of interest 94A perpendicularly onto a plane. In addition, the second running region limit setting unit 262B of the running region limit generation unit 26 is defined along the path length direction and on the running road surface (each t ｉ The second point of interest 94Di is projected perpendicularly onto a two-dimensional curved surface 70 perpendicular to the plane to obtain the second projection point 95B, and the second projection points 95B are connected to form the second region limit 85B. After this, the steering command unit 28 generates a steering command that corrects the planned trajectory 80 to a smooth trajectory between the left and right first region limits 85A, and outputs it to the steering angle actuator 33. In addition, the acceleration / deceleration command unit 29 generates acceleration and deceleration commands that allow the vehicle 1 to reach the target point as quickly as possible within the region from the vehicle's current position to the second region limit 85B, and to accelerate and decelerate gradually, and outputs them to the engine actuator 31 and the brake hydraulic actuator 32.

[0053] This clearly defines the first and second area limits 85A and 85B that the vehicle 1 must not exceed when traveling. Therefore, when calculating a smooth travel trajectory from the planned trajectory 80, it is possible to calculate a trajectory that does not exceed the first and second area limits 85A and 85B, that is, a trajectory that does not come excessively close to surrounding objects 91.

[0054] In this embodiment, the first point of interest extraction unit 261A performs each time t ｉ t corresponding to ｉ The intersection point of the normal 82 at the first point 92 of the first projection line 81, obtained by projecting the planned trajectory 80 onto a plane, and the surrounding object 91 (a virtual object boundary 913 obtained by expanding the domain boundary 912) is extracted as the second point of interest 94B. This allows information to be aggregated into a two-dimensional plane during the search for the first point of interest 94A along the direction orthogonal to the path, making it easy to extract the first point of interest 94A.

[0055] In this embodiment, the first point of interest extraction unit 261A identifies a second point 93 as a point shifted from the first point 92 by a length (total length L) along the path length direction of the vehicle 1 in the front-rear direction of the path length direction. The intersection of the normals 82 and 84 of the first projection line 81 at the first point 92 and second point 93 with the surrounding object 91 (a virtual object boundary 913 obtained by expanding the region boundary 912) is extracted as the first point of interest 94A. This makes it possible to extract the first point of interest 94A considering the length of the vehicle 1 in the direction perpendicular to the path. In other words, a point on the surrounding object 91 that may come into contact with either the left or right side of the vehicle 1 can be extracted as the first point of interest 94A.

[0056] In this embodiment, the first point of interest extraction unit 261A determines a virtual object boundary 913 for the surrounding object 91 detected by the surrounding detection sensor 11, by setting the length along the path length direction of the surrounding object 91 to be virtually larger than the actual surrounding object 91, and extracts the intersection points of the normals 82 and 84 of the first projection line 81 and the virtual object boundary 913 as the first point of interest 94A. As a result, each t where the size of the surrounding object 91 is small and the first point of interest 94A is extracted ｉ Even when the sampling interval on the plane is large, it is possible to suppress the omission of extracting the first point of interest 94A corresponding to the surrounding object 91.

[0057] In this case, the first point of interest extraction unit 261A extracts each t of the first point of interest 94A. ｉ The length along the path length direction of the surrounding object 91 is increased according to the sampling interval of the plane. In other words, the larger the sampling interval, the larger the length along the path length direction of the virtual object boundary 913 is increased. This allows each t ｉ As the sampling interval of the plane increases, the length of the virtual object boundary 913 along the path length direction also increases, thus further suppressing the omission of the first point of interest 94A. Conversely, when the sampling interval is small, the length of the virtual object boundary 913 along the path length direction decreases, becoming closer to the length of the actual surrounding objects 91, thus improving the positional accuracy of the first point of interest 94A.

[0058] In this embodiment, the second point of interest extraction unit 261B performs the extraction of each time t in the three-dimensional space 90. ｉ t corresponding toｉ The intersection of the first projection line 81, obtained by projecting the planned trajectory 80 onto a plane, and the surrounding object 91 (more specifically, the region boundary 912 of the surrounding object region 91S) is extracted as the second point of interest 94B. This allows information to be aggregated into a two-dimensional plane during the search for the second point of interest 94B along the path length, making it easy to extract the second point of interest 94B.

[0059] In this embodiment, the second point of interest extraction unit 261B is t ｉ On the first projection line 81 projected onto the plane, t ｉ The intersection of the plane and the planned trajectory 80 (i.e., time t ｉ The first point 92 is defined as the position where the vehicle is predicted to be located. A second projection line 83 is obtained by moving the first projection line 81 by the width W of the vehicle 1 in the direction normal to the first point 92 of the first projection line 81. The second point of interest extraction unit 261B then searches for the intersection of the first projection line 81 and the surrounding object 91 (more specifically, the region boundary 912 of the surrounding object region 91S), and the intersection of the second projection line 83 and the surrounding object 91, respectively, and extracts the intersection point with the minimum length in the path length direction from the vehicle 1 as the second point of interest 94B. This makes it possible to extract the first point of interest 94A considering the width of the vehicle 1 with respect to the path length direction. In other words, a point on the surrounding object 91 that may come into contact with any part of the front surface of the vehicle 1 can be extracted as the second point of interest 94B.

[0060] In this embodiment, the second point of interest extraction unit 261B sets a virtual second point of interest 94C located a predetermined distance d2 forward of the vehicle along the first projection line 81 from the first point 92. Then, the second driving area limit setting unit 262B selects the point among the second point of interest 94B, which is the intersection of the first projection line 81 and the surrounding object 91, the second point of interest 94B, which is the intersection of the second projection line 83 and the surrounding object 91, and the virtual second point of interest 94C, that is the point with the minimum distance from the vehicle 1, at time t ｉ t that corresponds to ｉThis will be adopted as the second point of interest 94Di on the plane. Furthermore, the distance d2 will be increased according to the distance d1 between the first point of interest 94A and the first projection line 81. By setting such a virtual second point of interest 94C, it is possible to achieve a behavior in which the vehicle 1's speed is reduced when it passes to the side of surrounding objects 91 that are close to the planned track 80.

[0061] [Modifications] The present invention is not limited to the embodiments described above, but also includes the following modifications to the extent that the objectives of the present invention can be achieved.

[0062] [Modification 1] In the above embodiment, the first point of interest extraction unit 261A sets second points 93 before and after the first point 92 in the path length direction, and extracts the intersection points of the normal vector 82 of the first point 92 and the normal vector 84 of the second point 93 with the surrounding object 91 as the first point of interest 94A, but is not limited to this. For example, the first point of interest extraction unit 261A may extract only the intersection points of the normal vector 82 of the first point 92 and the surrounding object 91 as the first point of interest 94A. In this case, it is preferable to improve the detection accuracy of the first point of interest 94A corresponding to the surrounding object 91 such as an obstacle by, for example, making the surrounding object region 91S larger or making the length of the virtual object boundary 913 along the path length direction longer.

[0063] The same applies to the second point of interest extraction unit 261B; extraction of the second point of interest 94B, which is the intersection of the second projection line 83 and the surrounding object 91, is not mandatory. For example, the second point of interest 94B, which is the intersection of the first projection line 81 and the surrounding object 91, and a virtual second point of interest 94C may be extracted, and the one with the smaller distance in the path length direction from the vehicle 1 may be adopted as the second point of interest 94Di.

[0064] [Modification 2] In the above embodiment, the first point of interest extraction unit 261A calculates a virtual object boundary 913 by expanding the length in the path length direction of the surrounding object 91 according to the sampling interval of time ti, and extracts the intersection point of the normals 82, 84 and the virtual object boundary 913 as the first point of interest 94A. In contrast, the calculation of the virtual object boundary 913 is not essential, and the intersection point of the region boundary 912 of the surrounding object region 91S in the surrounding object 91 and the normals 82, 84 may be extracted as the first point of interest 94A. In this case, as described above, each time t ｉ If the sampling interval is too large, there is a risk of missing the first point of interest 94A; therefore, the sampling interval should be set to be close.

[0065] [Modification 3] In the above embodiment, the first point of interest extraction unit 261A extracted the intersection points of the normal 82 of the first point 92 on the first projection line 81 and the normal 84 of the second point 93 on the first projection line 81 with the surrounding object 91 as the first point of interest 94A. Alternatively, the first point of interest extraction unit 261A may extract the intersection points of the normal 82 of the first point 92 with the surrounding object 91, and the intersection points of a straight line parallel to the normal 82 from the second point 93 with the surrounding object 91 as the first point of interest 94A.

[0066] 1...Own vehicle, 11...Surroundings detection sensor, 12...Position detection sensor, 20...Controller (computer), 21...Surroundings object acquisition unit, 22...Lane information acquisition unit, 23...Own vehicle information acquisition unit, 24...Driving lane information generation unit, 25...Planned trajectory generation unit, 26...Driving area limit generation unit, 27...Lateral area boundary integration unit, 28...Steering command unit, 29...Acceleration / deceleration command unit, 70...2D curved surface, 80...Planned trajectory, 81...First projection line, 82, 84...Normal vector, 83...Second projection line, 85A...First area limit, 85B...Second area limit, 90...3D space, 91...Surroundings Body, 91A...Detected object, 91S...Surrounding object region, 92...First point, 93...Second point, 94A...First point of interest, 94B...Second point of interest, 94C...Virtual second point of interest, 94Di...Second point of interest, 95...Third point, 95A...First projection point, 95B...Second projection point, 261...Point of interest extraction unit, 261A...First point of interest extraction unit, 261B...Second point of interest extraction unit, 262...Travel area limit setting unit, 262A...First travel area limit setting unit, 262B...Second travel area limit setting unit, 901...Current position, 903...Target point, 912...Region boundary, 913...Virtual object boundary.

Claims

1. A vehicle control method for controlling the automatic driving of a vehicle using a computer, wherein the computer sets a planned trajectory in a three-dimensional space including a two-dimensional plane along the road surface of the vehicle and a time axis intersecting the two-dimensional plane, connecting the vehicle's current position to a target point at a predetermined distance or more away, and not intersecting with surrounding objects present around the vehicle; on each time plane parallel to the road surface in the three-dimensional space, the direction along the planned trajectory is defined as the path length direction, and the direction perpendicular to the planned trajectory is defined as the path orthogonal direction, extracting points on the surrounding objects that pose a risk of intersecting the vehicle in the path orthogonal direction as first points of interest, extracting points on the surrounding objects that pose a risk of intersecting the vehicle in the path length direction as second points of interest, and connecting a point cloud obtained by projecting the first points of interest perpendicularly onto the two-dimensional plane that constitutes the road surface, setting the limit of the drivable area in the path orthogonal direction. A vehicle control method comprising: connecting a point cloud obtained by projecting the second point of interest perpendicularly onto a two-dimensional curved surface along the length of the path and perpendicular to the road surface, setting the limit of the drivable area in the direction of the length of the path; generating a steering command that corrects the planned trajectory to a smooth trajectory within the limit of the drivable area in the direction perpendicular to the path; and generating an acceleration / deceleration command that slows down the acceleration and deceleration of the vehicle in the area from the current position of the vehicle to the limit of the drivable area in the direction of the length of the path.

2. The vehicle control method according to claim 1, wherein the computer identifies the intersection point of the plane and the planned trajectory on a first projection line obtained by projecting the planned trajectory onto a plane parallel to the road surface in the three-dimensional space at a predetermined time as the first point, and extracts the intersection point of the normal of the first projection line at the first point and the surrounding object as the first point of interest.

3. The vehicle control method according to claim 2, wherein the computer defines a second point as a point shifted from the first point by a length along the vehicle's path length direction in the front-rear direction of the path length, and extracts the intersection point of the normal of the first projection line at the first point and the second point with the surrounding object as the first point of interest.

4. The vehicle control method according to claim 2 or 3, wherein the computer virtually sets the length of the surrounding object along the path length direction of the surrounding object detected by the surrounding detection sensor to be larger than that of the actual surrounding object, and extracts the intersection point of the normal of the first projection line and the virtually set surrounding object as the first point of interest.

5. The vehicle control method according to claim 4, wherein the computer extracts the first point of interest from a plane of time parallel to the road surface in the three-dimensional space, and increases the length of the surrounding object along the path length direction according to the sampling interval of each time.

6. The vehicle control method according to any one of claims 1 to 5, wherein the computer extracts the intersection point between the first projection line, obtained by projecting the planned trajectory onto a plane parallel to the road surface in the three-dimensional space at a predetermined time, and the surrounding object as the second point of interest.

7. The vehicle control method according to claim 6, wherein the computer determines a second projection line by moving the first projection line by the width of the vehicle in the direction normal to the first point of the first projection line by the width of the vehicle, the intersection of the first projection line and the surrounding object, and the intersection of the second projection line and the surrounding object, respectively, and extracts the intersection point where the distance from the vehicle in the direction of the path length is minimized as the second point of interest.

8. The vehicle control method according to claim 6 or 7, wherein the computer sets a virtual second point of interest at a point shifted by a predetermined distance forward in the direction of the path length from the first point, and adopts the intersection point of the second point of interest and the virtual second point of interest, where the distance from the vehicle in the direction of the path length is the minimum, as the second point of interest, and the predetermined distance is increased according to the distance between the first point of interest and the first projection line.

9. A planned trajectory setting unit sets a planned trajectory in a three-dimensional space including a two-dimensional plane along the road surface of the vehicle and a time axis intersecting the two-dimensional plane, connecting the current position of the vehicle to a target point at a predetermined distance or more away, and not intersecting with surrounding objects present around the vehicle; a surrounding object detection unit detects surrounding objects present around the vehicle from surrounding detection sensors; a point of interest extraction unit extracts points on the surrounding objects that pose a risk of intersecting the vehicle in the orthogonal direction, on each time plane parallel to the road surface in the three-dimensional space, with the direction along the planned trajectory as the path length direction and the direction perpendicular to the planned trajectory as the orthogonal direction, as first points of interest, and extracts points on the surrounding objects that pose a risk of intersecting the vehicle in the path length direction as second points of interest; a first driving area limit setting unit sets a limit of the drivable area in the orthogonal direction by connecting a point cloud obtained by projecting the first points of interest perpendicularly onto the two-dimensional plane that is the road surface; A vehicle control device comprising: a second driving area limit setting unit that connects a group of points obtained by projecting the second point of interest perpendicularly onto a two-dimensional curved surface along the length of the path and perpendicular to the road surface, thereby setting the limit of the drivable area in the direction of the length of the path; a steering command unit that generates a steering command that corrects the planned trajectory to a smooth driving trajectory within the limit of the drivable area in the direction perpendicular to the path; and an acceleration / deceleration command unit that generates an acceleration / deceleration command that slows down the acceleration and deceleration of the vehicle in the area from the current position of the vehicle to the limit of the drivable area in the direction of the length of the path.

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