Mobile body control device, mobile body control method, and storage medium

Abstract

The invention relates to a mobile body control apparatus, a mobile body control method, and a storage medium. A moving body control apparatus includes: an external environment detector configured to detect a peripheral moving body; an estimated heading calculator configured to calculate a first estimated heading and a second estimated heading; a front moving body determiner configured to determine a peripheral moving body overlapping with at least one of the first estimated heading and the second estimated heading as a front moving body; and a following controller configured to execute following control to follow the front moving body. In a case where there is no peripheral moving body to be determined as a front moving body, the front moving body determiner determines the peripheral moving body overlapping with an intermediate region defined between the first estimated heading and the second estimated heading as a preliminary front moving body, and the following controller performs following control to follow the preliminary front moving body.

Description

Technical Field

[0001] The present invention relates to a mobile body control device, a mobile body control method, and a non-transitory computer-readable storage medium. Background Art

[0002] In recent years, increasing efforts have been made to provide a sustainable transportation system that takes into account vulnerable road users. To achieve this goal, research and development of driving assistance technologies and autonomous driving technologies have been carried out to further improve traffic safety and convenience.

[0003] For example, Japanese Patent No. 5522157 discloses a method for determining a preceding vehicle that performs following driving. In this method, the preceding vehicle is determined based on the estimated course of the host vehicle and the position of the preceding vehicle. The estimated course of the host vehicle is determined based on the yaw rate.

[0004] Compared with the case of using the yaw rate, by using the steering angle to estimate the estimated course of the host vehicle, the estimated course of the host vehicle at the entrance and exit of a curve can be calculated faster because the yaw rate has a delay with respect to the steering angle. However, during steering, the difference between the first estimated course based on the yaw rate and the second estimated course based on the steering angle becomes larger, and a preceding vehicle that actually exists between the first estimated course and the second estimated course may not be detected as the preceding vehicle. In particular, when the steering angle decreases, the difference between the first estimated course and the second estimated course may become larger. In such a case, the host vehicle may lose sight of the preceding vehicle, which may cause unnecessary acceleration due to following control. Summary of the Invention

[0005] In view of the above background, an object of the present invention is to provide a mobile body control device, a mobile body control method, and a non-transitory computer-readable storage medium that appropriately detect a preceding mobile body and perform following control during steering. Therefore, the object of the present invention contributes to the development of a sustainable transportation system.

[0006] To achieve this object, an aspect of the present invention provides a mobile body control device (15) configured to perform travel control of a mobile body (1). The mobile body control device includes: an external environment detector (4) configured to detect at least one surrounding mobile body (105) present around the mobile body; an estimated course calculator (42) configured to calculate a first estimated course (101) based on the yaw rate of the mobile body and calculate a second estimated course (102) based on the steering angle of the mobile body; a preceding mobile body determiner (43) configured to determine, based on the first estimated course, the second estimated course, and the positions of the surrounding mobile bodies, a surrounding mobile body that overlaps at least one of the first estimated course and the second estimated course as a preceding mobile body (106); and a following controller (44) configured to perform following control to follow the preceding mobile body. Wherein, in the case where there is no surrounding mobile body to be determined as a preceding mobile body, the preceding mobile body determiner is configured to determine a surrounding mobile body that overlaps an intermediate region (103) defined between the first estimated course and the second estimated course as a preparatory preceding mobile body (107), and the following controller is configured to perform following control to follow the preparatory preceding mobile body.

[0007] According to this aspect, when steering while the first estimated course and the second estimated course are different, the preceding mobile body control device can appropriately detect a surrounding mobile body present between the first estimated course and the second estimated course as a preparatory preceding mobile body. In addition, the mobile body control device performs following control to follow the preparatory preceding mobile body, thereby avoiding unnecessary acceleration. Therefore, a mobile body control device that can appropriately detect a preceding mobile body and perform following control can be provided.

[0008] In the above aspect, preferably, after the following controller starts following control to follow the preparatory preceding mobile body and until the preceding mobile body determiner determines a new preceding mobile body, the following controller is configured to continue following control to follow the preparatory preceding mobile body.

[0009] According to this aspect, the mobile body control device can continue following control to follow the preparatory preceding mobile body until a preceding mobile body is detected.

[0010] In the above aspect, preferably, for the case where, after the following controller starts following control to follow the preparatory preceding mobile body, the preceding mobile body determiner determines a new preceding mobile body, the following controller performs following control to follow the new preceding mobile body.

[0011] According to this aspect, the mobile body control device can continue following control to follow the preparatory preceding mobile body until a preceding mobile body is detected.

[0012] In the above aspect, preferably, when a plurality of surrounding moving bodies overlap with the intermediate region, the front moving body determiner is configured to determine the surrounding moving bodies arranged at the shortest distance from the moving body as the preliminary front moving bodies.

[0013] According to this aspect, the moving body control device can determine the surrounding moving bodies arranged at the shortest distance from the moving body as the preliminary front moving bodies, and can perform following control to follow the preliminary front moving bodies.

[0014] In the above aspect, preferably, when a plurality of surrounding moving bodies overlap with the intermediate region, the front moving body determiner is configured to obtain a lane change direction, and determine the surrounding moving body arranged closest to the lane change direction side among the plurality of surrounding moving bodies as the preliminary front moving body.

[0015] According to this aspect, the moving body control device can determine the surrounding moving body arranged closest to the lane change direction side among the plurality of surrounding moving bodies arranged in the intermediate region as the preliminary front moving body.

[0016] In the above aspect, preferably, the front moving body determiner is configured to: when a surrounding moving body is detected to overlap with the intermediate region at a specified determination frequency, determine the surrounding moving body as the preliminary front moving body, obtain the lane change direction, divide the intermediate region into a first region and a second region based on the lane change direction, the first region being the region on the lane change direction side, the second region being the region on the side opposite to the lane change direction, and set a second determination frequency greater than the first determination frequency, the second determination frequency being the determination frequency for determining the surrounding moving bodies in the second region as the preliminary front moving bodies, and the first determination frequency being the determination frequency for determining the surrounding moving bodies in the first region as the preliminary front moving bodies.

[0017] According to this aspect, the moving body control device can determine the surrounding moving bodies arranged on the lane change direction side among the plurality of surrounding moving bodies arranged in the intermediate region as the preliminary front moving bodies.

[0018] Another aspect of the present invention provides a moving body control method executed by a computer for controlling the travel of a moving body (1), the moving body control method including: detecting at least one surrounding moving body (105) present around the moving body; calculating a first estimated course (101) based on the yaw rate of the moving body; calculating a second estimated course (102) based on the steering angle of the moving body; based on the first estimated course, the second estimated course, and the positions of the surrounding moving bodies, determining a surrounding moving body that overlaps with at least one of the first estimated course and the second estimated course as a preceding moving body (106); causing the moving body to follow the preceding moving body; in the case where there is no surrounding moving body to be determined as a preceding moving body, determining a surrounding moving body that overlaps with an intermediate area (103) defined between the first estimated course and the second estimated course as a preliminary preceding moving body (107); and causing the moving body to follow the preliminary preceding moving body.

[0019] Another aspect of the present invention provides a non-transitory computer-readable storage medium including a program for controlling the travel of a moving body (1), wherein the program, when executed by a computer (15), executes a moving body control method, the method including: detecting at least one surrounding moving body (105) present around the moving body; calculating a first estimated course (101) based on the yaw rate of the moving body; calculating a second estimated course (102) based on the steering angle of the moving body; based on the first estimated course, the second estimated course, and the positions of the surrounding moving bodies, determining a surrounding moving body that overlaps with at least one of the first estimated course and the second estimated course as a preceding moving body (106); causing the moving body to follow the preceding moving body; in the case where there is no surrounding moving body to be determined as a preceding moving body, determining a surrounding moving body that overlaps with an intermediate area (103) defined between the first estimated course and the second estimated course as a preliminary preceding moving body (107); and causing the moving body to follow the preliminary preceding moving body.

[0020] Therefore, according to the above aspects, a moving body control device, a moving body control method, and a non-transitory computer-readable storage medium that can appropriately detect a preceding moving body and execute follow-up control during steering can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a block diagram of a vehicle equipped with a vehicle control device;

[0022] Figure 2 is a flowchart of a preceding vehicle determination process;

[0023] Figures 3A to 3D is an explanatory diagram showing a method for determining a preliminary preceding vehicle and a preceding vehicle during a lane change;

[0024] Figure 4It is an explanatory diagram showing a method for determining a preparatory preceding vehicle in the case where there are a plurality of surrounding vehicles in the middle area; and

[0025] Figure 5 It is an explanatory diagram showing another method for determining a preparatory preceding vehicle in the case where there are a plurality of surrounding vehicles in the middle area. Detailed implementation

[0026] Hereinafter, with reference to the accompanying drawings, embodiments of a moving body control device, a moving body control method, and a non-transitory computer-readable storage medium according to the present invention will be described. The moving body includes vehicles such as automobiles, trucks, and motorcycles, electric scooters, etc. In the present embodiment, an example where the moving body is a vehicle will be described.

[0027] As Figure 1 shown, the vehicle 1 (moving body) includes a propulsion device 3, a braking device 4, a steering device 5, an external environment sensor 6, a vehicle sensor 7, a communication device 8, a navigation device 9, a driving operation device 10, a human-machine interface 12 (HMI), and a vehicle control device (15) (moving body control device).

[0028] The propulsion device 3 is a device that applies a driving force to the vehicle 1, and includes, for example, a power source and a transmission device. The power source includes at least one of internal combustion engines such as gasoline engines and diesel engines, and electric motors. The braking device 4 is a device that applies a braking force to the vehicle 1, and includes, for example, a brake caliper that presses a brake pad against a brake disc, and an electric cylinder that supplies hydraulic pressure to the brake caliper. The braking device 4 may also include a parking braking device that restricts the rotation of the wheels through a cable. The steering device 5 is a device that changes the steering angle of the wheels, and includes, for example, a rack and pinion mechanism that steers the wheels, and an electric motor that drives the rack and pinion mechanism. The propulsion device 3, the braking device 4, and the steering device 5 are controlled by the vehicle control device 15.

[0029] The external environment sensor 6 is a sensor that captures electromagnetic waves or light from the periphery of the vehicle 1 and detects objects outside the vehicle 1, etc. The external environment sensor 6 includes, for example, a radar 6A, a lidar 6B (LiDAR), and a camera 6C (external camera). The external environment sensor 6 outputs the detection result to the vehicle control device 15.

[0030] The radar 6A detects the positions (distance and direction) of various objects by emitting radio waves such as millimeter waves toward the periphery of the vehicle 1 and capturing the reflected waves. At least one radar 6A is attached to any part of the vehicle 1. Preferably, the radar 6A includes at least a front radar that emits radio waves toward the front of the vehicle 1, a rear radar that emits radio waves toward the rear of the vehicle 1, and a pair of left and right radars that emit radio waves toward the lateral sides of the vehicle 1.

[0031] The lidar 6B detects the positions (distance and direction) of various objects by emitting light such as infrared rays toward the periphery of the vehicle 1 and capturing the reflected light. At least one lidar 6B is provided at any part of the vehicle 1.

[0032] The camera 6C captures images of the periphery of the vehicle 1, such as objects existing in the periphery of the vehicle 1 (e.g., the surrounding vehicle 105 (surrounding moving body) and pedestrians), guardrails, curbs, walls, median strips, and the shape of the road, as well as road markings drawn on the road. The camera 6C can be, for example, a digital camera using a solid-state image sensing device such as a CCD or CMOS. At least one camera 6C is provided at any part of the vehicle 1. The camera 6C includes at least a front camera that captures images in front of the vehicle 1. The camera 6C may further include a rear camera that captures images behind the vehicle 1 and a pair of side cameras that capture images of the lateral sides of the vehicle 1. The camera 6C can be, for example, a stereo camera.

[0033] The vehicle sensor 7 includes a speed sensor 7A that detects the speed (vehicle speed) of the vehicle 1, an acceleration sensor 7B that detects the acceleration of the vehicle 1, a yaw rate sensor 7C that detects the yaw rate of the vehicle 1, and a steering angle sensor 7D that detects the steering angle of the front wheels as the steering wheels.

[0034] The communication device 8 performs intermediate communication between devices provided inside the vehicle 1 (the vehicle control device 15 and the navigation device 9) and devices provided outside the vehicle 1 (the surrounding vehicle 105 and the server). The vehicle control device 15 can perform wireless communication with the surrounding vehicle 105 via the communication device 8.

[0035] The navigation device 9 is a device that acquires the current position of the vehicle 1 and provides route guidance to a destination or the like. The navigation device 9 includes: a GNSS receiving unit 21, a map storage unit 22, a navigation interface 23, and a route determination unit 24. The GNSS receiving unit 21 identifies the position (latitude and longitude) of the vehicle 1 based on signals received from artificial satellites (positioning satellites). The map storage unit 22 is composed of a known storage device such as a flash memory or a hard disk and stores map information.

[0036] The map information includes road information, and the road information includes: road types such as highways, toll roads, national roads, and county roads, the number of lanes of each road, the central position of each lane (three-dimensional coordinates including longitude, latitude, and altitude), the shape of road markings such as road dividers and lane boundaries, the presence or absence of sidewalks, curbs, fences, etc., the positions of intersections, the positions of lane merging points and lane bifurcation points, the area of emergency stopping areas, the width of each lane, road markings, etc. The map information may also include traffic rule information, address information (address and postal code), facility information, telephone number information, etc. The route determination unit 24 determines a route to the destination based on the position of the vehicle 1 identified by the GNSS receiving unit 21, the destination input from the navigation interface 23, and the map information. In addition, when determining the route, the route determination unit 24 can also determine the target lane that the vehicle 1 should travel by referring to the positions of lane merging points and lane bifurcation points in the map information.

[0037] The driving operation device 10 receives input operations performed by the driver to control the vehicle 1. The driving operation device 10 includes, for example, a steering wheel, an accelerator pedal, and a brake pedal. The driving operation device 10 may also include a gear shift lever, a parking brake lever, etc. Sensors for detecting the operation amounts of the input operations are attached to respective components of the driving operation device 10. The driving operation device 10 outputs a signal indicating the operation amount to the vehicle control device 15.

[0038] The HMI 12 notifies various information to the occupants (e.g., the driver) through display and sound, and accepts input operations from the occupants.

[0039] The vehicle 1 also includes turn signals (blinkers) 26 for indicating the lane change direction and the turning direction. The turn signals 26 are flashing light-emitting devices, and are provided on the lateral sides of the front and rear parts of the vehicle 1. The turn signals 26 are connected to the vehicle control device 15. The vehicle 1 also includes a turn signal lever 27 operated by the occupant. The turn signal lever 27 is connected to the vehicle control device 15.

[0040] The vehicle 1 also includes a mode change switch 28 for accepting an operation to switch the autonomous driving level.

[0041] The vehicle control device 15 is an electronic control unit (ECU) composed of an MPU (microprocessor), ROM, RAM, etc., that is, a computer. The vehicle control device 15 executes various vehicle controls as the MPU executes a calculation process according to a program. The vehicle control device 15 can be configured as a single piece of hardware or can be configured as a unit composed of multiple pieces of hardware. Moreover, at least a part of each functional unit of the vehicle control device 15 can be implemented by hardware such as LSI, ASIC, and FPGA, or can be implemented by a combination of software and hardware. The program can be stored in a non-volatile storage device such as an HDD and a flash memory of the vehicle control device 15. Alternatively, the program can be stored in a removable storage medium such as a DVD or a CD-ROM and installed in the storage device of the vehicle control device 15 as the storage medium is read by a reading device. Alternatively, the program can be downloaded to the storage device of the vehicle control device 15 via a communication line such as the Internet and installed in the storage device. The vehicle control device 15, which is a computer, executes the driving control method described later for executing the driving control of the vehicle 1. This program causes the vehicle control device 15 to execute the driving control of the vehicle 1 (mobile body). As Figure 1 shown, the vehicle control device 15 includes a non-transitory computer-readable storage medium 15A, and the storage medium 15A includes a program 15B for executing the driving control of the vehicle 1. When the program 15B is executed by the vehicle control device 15, which is a computer, it executes the vehicle control method (mobile body control method) described later.

[0042] As Figure 1 shown, the vehicle control device 15 includes an autonomous driving control unit 35 and a driving control unit 36. The autonomous driving control unit 35 includes an external environment detector 40, a host vehicle position detector 41, an estimated heading calculator 42, a preceding vehicle determiner 43 (preceding mobile body determiner), a following controller 44, a motion planner 45, and a mode changer 46.

[0043] The autonomous driving control unit 35 combines various vehicle controls to execute autonomous driving control at various levels. For example, in level 0 autonomous driving, the vehicle control device 15 does not control the vehicle 1, but the driver executes all driving operations. Level 1 autonomous driving includes constant speed and inter-vehicle distance control (adaptive cruise control: ACC) and lane keeping assist control (lane keeping assist: LKA). In level 2 and level 3 autonomous driving, the driver monitors the periphery of the vehicle 1, and the vehicle control device 15 executes all driving operations. In level 2 and level 3 autonomous driving, the degree to which the driver monitors the periphery of the vehicle 1 is different.

[0044] The external environment detector 40 detects obstacles present in the vicinity of the vehicle 1, the shape of the road, the presence or absence of a sidewalk, and road markings based on signals from the external environment sensors 6. Obstacles include, for example, guardrails, utility poles, surrounding moving objects, and people such as pedestrians. The surrounding moving objects include vehicles (surrounding vehicle 105). The external environment detector 40 can detect the position and distance of obstacles, the surrounding vehicle 105, etc. relative to the vehicle 1 based on signals from at least one of the radar 6A, lidar 6B, and camera 6C.

[0045] The host vehicle position detector 41 calculates the host vehicle position based on signals (GNSS signals) received by the GNSS receiving unit 21. In addition, the host vehicle position detector 41 identifies the driving lane that is the lane in which the vehicle 1 is traveling, and the relative position and angle of the vehicle 1 with respect to the driving lane. The host vehicle position detector 41 can, for example, identify the driving lane based on the map information stored in the map storage unit 22 and the position of the vehicle 1 acquired (identified) by the GNSS receiving unit 21. In addition, the host vehicle position detector 41 can identify the relative position and angle of the vehicle 1 with respect to the driving lane by extracting the dividing lines around the vehicle 1 drawn on the road surface from the map information and comparing the shape of the extracted dividing lines with the shape of the dividing lines captured by the camera 6C.

[0046] The estimated heading calculator 42 calculates a first estimated heading 101 based on the yaw rate of the vehicle 1, and calculates a second estimated heading 102 based on the steering angle of the vehicle 1. As Figures 3A to 3D shown, the first estimated heading 101 and the second estimated heading 102 are represented as curves (or straight lines) connecting the estimated positions of the vehicle 1 at each future time. The estimated heading calculator 42 can calculate the first estimated heading 101 based on the yaw rate and vehicle speed of the vehicle 1. In addition, the estimated heading calculator 42 can calculate the second estimated heading 102 based on the steering angle and vehicle speed of the vehicle 1. Since the yaw rate changes in accordance with a change in the steering angle, the change in the yaw rate occurs with a delay with respect to the change in the steering angle. Therefore, when the steering angle changes, the first estimated heading 101 changes with a delay with respect to the change in the second estimated heading 102, which results in a difference between the first estimated heading 101 and the second estimated heading 102 (see Figure 3B and Figure 3C ). When the steering angle is constant, the first estimated heading 101 and the second estimated heading 102 are substantially the same (see Figure 3D ).

[0047] The leading vehicle determiner 43 determines the leading vehicle 106 or the preparatory leading vehicle 107 among the surrounding vehicles 105. The leading vehicle determiner 43 determines the leading vehicle 106 or the preparatory leading vehicle 107 by performing a leading vehicle determination process described later.

[0048] The following controller 44 performs following control to follow the preceding vehicle 106 or the preparatory preceding vehicle 107. When the vehicle speed of the preceding vehicle 106 is slower than the set vehicle speed of vehicle 1, the following controller 44 sets the target vehicle speed of vehicle 1 through following control so that the inter-vehicle distance between vehicle 1 and the preceding vehicle 106 becomes a specified value.

[0049] The motion planner 45 sequentially generates a motion plan for vehicle 1 to travel along the route. More specifically, first, the motion planner 45 determines an event in which vehicle 1 travels within the target lane determined by the route determination unit 24 without contacting any obstacles. The motion planner 45 generates a target trajectory that vehicle 1 should travel in the future based on the determined event. The target trajectory is a sequence of trajectory points that are the points that vehicle 1 should reach each time. The motion planner 45 can generate the target trajectory based on the target vehicle speed and the target acceleration set for each event. When the motion planner 45 detects the preceding vehicle 106 on the target trajectory, similar to the following controller 44, the motion planner 45 can perform following control to follow the preceding vehicle 106.

[0050] The mode changer 46 changes the level of autonomous driving based on a signal from the mode change switch 28. When level 0 is selected by the mode change switch 28, the mode changer 46 stops the calculations of the following controller 44 and the motion planner 45. When level 1 is selected by the mode change switch 28, the mode changer 46 performs the calculations of the following controller 44 and stops the calculations of the motion planner 45. When level 2 or a higher level is selected by the mode change switch 28, the mode changer 46 performs the calculations of the motion planner 45 and stops the calculations of the following controller 44.

[0051] The driving control unit 36 controls the propulsion device 3, the braking device 4, and the steering device 5 based on the target vehicle speed generated (set) by the following controller 44. In addition, the driving control unit 36 controls the propulsion device 3, the braking device 4, and the steering device 5 so that vehicle 1 passes through the target trajectory generated by the motion planner 45 within the planned time.

[0052] The vehicle control device 15 further includes a turn signal control unit 48 that controls the illumination of the turn signal 26. The turn signal control unit 48 receives a signal from the turn signal lever 27 and outputs a control signal for controlling the turn signal 26.

[0053] Hereinafter, the preceding vehicle determination process performed by the preceding vehicle determiner 43 will be described. The preceding vehicle determiner 43 can repeat at time intervals of, for example, a few microseconds. Figure 2The front vehicle determination process shown below. First, the front vehicle determiner 43 obtains information about the positions of the respective surrounding vehicles 105 and the distances between the respective surrounding vehicles 105 and the vehicle 1 from the external environment detector 40 (S1). The number of surrounding vehicles 105 is equal to or greater than zero. The distance between each surrounding vehicle 105 and the vehicle 1 can be the Euclidean distance.

[0054] Next, the front vehicle determiner 43 obtains the first estimated course 101 and the second estimated course 102 calculated by the estimated course calculator 42 (S2).

[0055] Next, based on the first estimated course 101, the second estimated course 102, and the positions of the respective surrounding vehicles 105, the front vehicle determiner 43 determines the surrounding vehicle 105 that overlaps both the first estimated course 101 and the second estimated course 102 as the front vehicle 106 (S3). In the case where a plurality of surrounding vehicles 105 overlap both the first estimated course 101 and the second estimated course 102, the front vehicle determiner 43 may determine the surrounding vehicle 105 arranged at the shortest distance from the vehicle 1 among the plurality of surrounding vehicles 105 that overlap both the first estimated course 101 and the second estimated course 102 as the front vehicle 106.

[0056] Next, the front vehicle determiner 43 determines whether the front vehicle 106 can be determined in step S3 (in step S3, whether there is a surrounding vehicle 105 to be determined as the front vehicle 106) (S4). In the case where the front vehicle 106 can be determined in step S3 (the determination result in S4 is yes), the front vehicle determiner 43 ends the front vehicle determination process.

[0057] For the case where the front vehicle 106 cannot be determined in step S3 (the determination result in S4 is no), that is, for the case where there is no surrounding vehicle 105 to be determined as the front vehicle 106, the front vehicle determiner 43 determines the surrounding vehicle 105 that overlaps the intermediate area 103 defined between the first estimated course 101 and the second estimated course 102 as the preliminary front vehicle 107 (S5). In this regard, "the surrounding vehicle 105 overlaps the intermediate area 103" means that "the representative position of the surrounding vehicle 105 is arranged in the intermediate area 103". The representative position of the surrounding vehicle 105 can be, for example, the center position of the surrounding vehicle 105. In addition, in the case where the surrounding vehicle 105 is represented by a plurality of outer edge positions corresponding to the outer edge of the surrounding vehicle 105, "the surrounding vehicle 105 overlaps the intermediate area 103" may mean that "at least one of the plurality of outer edge positions is arranged in the intermediate area 103". The front vehicle determiner 43 can calculate the intermediate area 103 based on the estimated positions at each time included in the first estimated course 101 and the second estimated course 102.

[0058] In one aspect, when a plurality of surrounding vehicles 105 overlap with the intermediate area 103, the leading vehicle determiner 43 may determine the surrounding vehicle 105 arranged at the shortest distance from the vehicle 1 as the preparatory leading vehicle 107. The distance between the vehicle 1 and each surrounding vehicle 105 may be, for example, the distance between the central portion of the front end of the vehicle 1 and the central portion of the rear end of each surrounding vehicle 105. Alternatively, the distance between the vehicle 1 and each surrounding vehicle 105 may be the distance between the central portion of the vehicle 1 and the central portion of each surrounding vehicle 105.

[0059] In step S5, when there is no surrounding vehicle 105 overlapping with the intermediate area 103, the leading vehicle determiner 43 determines that there is no preparatory leading vehicle 107. After the process of step S5 is executed, the leading vehicle determiner 43 ends the leading vehicle determination process. The leading vehicle determiner 43 repeats the leading vehicle determination process at a prescribed interval to update the leading vehicle 106 and the preparatory leading vehicle 107.

[0060] The following controller 44 executes following control to follow the leading vehicle 106 or the preparatory leading vehicle 107. The following controller 44 may make the control mode in the following control of following the leading vehicle 106 the same as or different from the control mode in the following control of following the preparatory leading vehicle 107.

[0061] The functions and effects of the vehicle control device 15 configured as described above, the vehicle control method executed by the vehicle control device 15, and the non-transitory computer-readable storage medium 15A for causing the vehicle control device 15 to execute the vehicle control method will be described.

[0062] When the steering angle is constant, the first estimated course 101 calculated based on the yaw rate and the second estimated course 102 calculated based on the steering angle substantially match each other. Therefore, when the vehicle 1 is traveling on a straight road, both the first estimated course 101 and the second estimated course 102 extend straight ahead and match each other. Therefore, when a surrounding vehicle 105 is present in front of the vehicle 1, the surrounding vehicle 105 overlaps with the first estimated course 101 and the second estimated course 102 and is determined as the leading vehicle 106. Further, when the vehicle 1 is traveling along a curve with a constant curvature, both the first estimated course 101 and the second estimated course 102 are curved along the curve and match each other. Therefore, when a surrounding vehicle 105 is present in the course of the vehicle 1, the surrounding vehicle 105 overlaps with the first estimated course 101 and the second estimated course 102 and is determined as the leading vehicle 106.

[0063] Conversely, immediately after the wheels are steered, the yaw rate is delayed with respect to the steering angle, which results in a difference between the first estimated course 101 and the second estimated course 102. In particular, as Figures 3A to 3CAs shown, when the steering angle increases first and then decreases within a short period of time (e.g., during a lane change), when the steering angle decreases, the difference between the first estimated course 101 and the second estimated course 102 becomes larger. At the start of a lane change, the steering angle increases, and the yaw rate is delayed with respect to the increase in the steering angle, causing the first estimated course 101 to be delayed with respect to the second estimated course 102 (see Figure 3A ). In the latter half of the lane change, the steering angle decreases in a direction opposite to the direction of the yaw rate, making the difference between the first estimated course 101 and the second estimated course 102 larger (see Figure 3B and Figure 3C ). In such a case, even if a surrounding vehicle 105 actually exists in front of vehicle 1, the surrounding vehicle 105 cannot overlap with both the first estimated course 101 and the second estimated course 102 and is not determined as the preceding vehicle 106.

[0064] In such a case, the preceding vehicle determiner 43 of the vehicle control device 15 determines the surrounding vehicle 105 that overlaps with the intermediate area 103 defined between the first estimated course 101 and the second estimated course 102 as the preparatory preceding vehicle 107, and the following controller 44 performs following control to follow the preparatory preceding vehicle 107. Since the vehicle control device 15 can perform following control to follow the preparatory preceding vehicle 107, the vehicle control device 15 does not overlook the surrounding vehicle 105 that actually exists in front of vehicle 1, thereby avoiding unnecessary acceleration. Therefore, even during a lane change, the vehicle control device 15 can appropriately perform following control.

[0065] As Figure 3D shown, when the lane change is completed and the steering angle returns to zero degrees, the yaw rate also becomes zero with a delay with respect to the steering angle, and the first estimated course 101 and the second estimated course 102 extend straight ahead of vehicle 1. Therefore, the surrounding vehicle 105 that has been determined as the preparatory preceding vehicle 107 overlaps with both the first estimated course 101 and the second estimated course 102. Therefore, the preceding vehicle determiner 43 determines the surrounding vehicle 105 as the preceding vehicle 106. In this way, until the preceding vehicle determiner 43 determines a new preceding vehicle 106 after the following controller 44 starts following control to follow the preparatory preceding vehicle 107, the following controller 44 continues following control to follow the preparatory preceding vehicle 107. In addition, for the case where the preceding vehicle determiner 43 determines a new preceding vehicle 106 after the following controller 44 starts following control to follow the preparatory preceding vehicle 107, the following controller 43 performs following control to follow the new preceding vehicle 106. Thereby, the vehicle control device 15 can continue following control without losing sight of the surrounding vehicle 105 existing in front of vehicle 1.

[0066] As Figure 4As shown, when multiple surrounding vehicles 105 overlap with the intermediate area 103, the leading vehicle determiner 43 determines the surrounding vehicle 105 arranged at the minimum distance from the vehicle 1 as the preparatory leading vehicle 107. In Figure 4 , the first surrounding vehicle 105A and the second surrounding vehicle 105B overlap with the intermediate area 103, and the distance D1 between the first surrounding vehicle 105A and the vehicle 1 is less than the distance D2 between the second surrounding vehicle 105B and the vehicle 1, such that the first surrounding vehicle 105A is determined as the preparatory leading vehicle 107. Therefore, for the case where there are multiple surrounding vehicles 105 in the intermediate area 103, the preparatory leading vehicle 107 can be appropriately determined.

[0067] On the other hand, when multiple surrounding vehicles 105 overlap with the intermediate area 103, the leading vehicle determiner 43 can obtain the lane change direction and determine the surrounding vehicle 105 arranged closest to the lane change direction side among the multiple surrounding vehicles 105 as the preparatory leading vehicle 107. The leading vehicle determiner 43 can obtain the lane change direction based on the control signal of the turn signal 26. Alternatively, the leading vehicle determiner 43 can obtain the lane change direction based on the signal from the turn signal lever 27.

[0068] On the other hand, the leading vehicle determiner 43 can determine the surrounding vehicle 105 as the preparatory leading vehicle 107 when detecting the overlap of the surrounding vehicle 105 with the intermediate area 103 at a specified determination frequency (when detecting a specified number of times). In such a case, the leading vehicle determiner 43 can make the determination frequencies of the respective parts of the intermediate area 103 different. As Figure 5 shown, for example, the leading vehicle determiner 43 can divide the intermediate area 103 into a first area 103A and a second area 103B based on the lane change direction. The first area 103A is the area on one side of the lane change direction. The second area 103B is the area on the side opposite to the lane change direction. That is, the intermediate area 103 can be divided into two areas along the center line 110 with respect to the lateral direction. The center line 110 can be calculated as a line extending from the vehicle 1 through the center of the intermediate area 103 between the first estimated course 101 and the second estimated course 102. The second determination frequency can be set to be greater than the first determination frequency. The second determination frequency is the determination frequency for determining the surrounding vehicle 105 in the second area 103B as the preparatory leading vehicle 107. The first determination frequency is the determination frequency for determining the surrounding vehicle 105 in the first area 103A as the preparatory leading vehicle 107. The center line 110 can also be defined as a line extending forward from the vehicle 1 with respect to the vehicle 1, that is, a line passing through the center of gravity of the vehicle 1 and extending in the longitudinal direction (length direction) of the vehicle 1.

[0069] Figure 5An example is shown in which, when changing lanes, the first surrounding vehicle 105A and the second surrounding vehicle 105B are arranged in the middle area 103. The first surrounding vehicle 105A is in the first area 103A on the side of the lane change direction of the middle area 103, and the second surrounding vehicle 105B is in the second area 103B on the side opposite to the lane change direction of the middle area 103. When the surrounding vehicle 105 (the first surrounding vehicle 105A) is detected to overlap with the first area 103A twice, the preceding vehicle determiner 43 determines the surrounding vehicle 105 (the first surrounding vehicle 105A) as the preparatory preceding vehicle 107. In addition, when the surrounding vehicle 105 (the second surrounding vehicle 105B) is detected to overlap with the second area 103B three times, the preceding vehicle determiner 43 determines the surrounding vehicle 105 (the second surrounding vehicle 105B) as the preparatory preceding vehicle 107. In Figure 5 the example, the determination frequency (the first determination frequency) of the first area 103A is set to be less than the determination frequency (the second determination frequency) of the second area 103B. Therefore, the first surrounding vehicle 105A existing in the first area 103A is preferentially determined as the preparatory preceding vehicle 107. Therefore, the surrounding vehicle 105 arranged on the side of the lane change direction of the middle area 103 is determined as the preparatory preceding vehicle 107.

[0070] This concludes the description of the specific embodiments, but the present invention can be widely modified and implemented without being limited to the above embodiments. In another embodiment, when there are multiple surrounding vehicles 105 in the middle area 103, the preceding vehicle determiner 43 may also determine the surrounding vehicle 105 arranged closest to the center line 110 of the middle area 103 as the preparatory preceding vehicle 107.

[0071] In the above embodiment, in step S3, the preceding vehicle determiner 43 determines the surrounding vehicle 105 that overlaps both the first estimated course 101 and the second estimated course 102 as the preceding vehicle 106. In another embodiment, the preceding vehicle determiner 43 may determine the surrounding vehicle 105 that overlaps at least one of the first estimated course 101 and the second estimated course 102 as the preceding vehicle 106.

Claims

1. A mobile body control device, the mobile body control device being configured to perform driving control of a mobile body, the mobile body control device comprising: an external environment detector configured to detect at least one surrounding moving object existing around the moving object; an estimated heading calculator configured to calculate a first estimated heading based on a yaw rate of the mobile body and to calculate a second estimated heading based on a steering angle of the mobile body; a front moving object determiner configured to determine, based on the first estimated heading, the second estimated heading, and the position of the surrounding moving object, the surrounding moving object overlapping at least one of the first estimated heading and the second estimated heading as a front moving object; as well as a following controller configured to perform following control to follow the preceding moving body, wherein, in the absence of the surrounding moving object to be determined as the front moving object, the front moving object determiner is configured to determine the surrounding moving object overlapping with the intermediate area defined between the first estimated heading and the second estimated heading as a preliminary front moving object, and The following controller is configured to perform the following control to follow the preparatory moving body.

2. The mobile body control device according to claim 1, wherein: After the following controller starts the following control to follow the preparatory front moving body and until the front moving body determiner determines a new front moving body, the following controller is configured to continue the following control to follow the preparatory front moving body.

3. The mobile body control device according to claim 2, wherein: In the case where the front moving body determiner determines the new front moving body after the following controller starts the following control to follow the preparatory front moving body, the following controller performs the following control to follow the new front moving body.

4. The mobile body control device according to claim 1, wherein: In a case where a plurality of surrounding moving objects overlap the middle area, the front moving object determiner is configured to determine the surrounding moving objects arranged at the shortest distance from the moving object as the preliminary front moving object.

5. The mobile body control device according to claim 1, wherein: In a case where a plurality of surrounding moving objects overlap the middle area, the front moving object determiner is configured to acquire a lane change direction and determine the surrounding moving object arranged closest to the lane change direction among the plurality of surrounding moving objects as the preliminary front moving object.

6. The mobile body control device according to claim 1, wherein: The front moving body determiner is configured to: When the surrounding moving object is detected to overlap with the middle area at a predetermined determination frequency, the surrounding moving object is determined as the pre-preparation moving object. Get lane change directions, dividing the middle area into a first area and a second area based on the lane changing direction, the first area being an area on one side of the lane changing direction and the second area being an area on the side opposite to the lane changing direction, and The second determination frequency is set to be greater than the first determination frequency, the second determination frequency is the determination frequency used to determine the surrounding moving objects in the second area as the pre-preparation moving objects, and the first determination frequency is the determination frequency used to determine the surrounding moving objects in the first area as the pre-preparation moving objects.

7. A mobile body control method for executing driving control of a mobile body executed by a computer, the mobile body control method comprising the following steps: Detecting at least one surrounding moving object existing around the moving object; calculating a first estimated heading based on the yaw rate of the mobile object; calculating a second estimated heading based on the steering angle of the mobile object; determining the surrounding moving object overlapping at least one of the first estimated heading and the second estimated heading as a front moving object based on the first estimated heading, the second estimated heading, and the position of the surrounding moving object; causing the moving object to follow the preceding moving object; determining, in a case where the surrounding moving object to be determined as the preceding moving object does not exist, the surrounding moving object overlapping an intermediate area defined between the first estimated heading and the second estimated heading as a preliminary preceding moving object; as well as The moving body is caused to follow the preparatory moving body.

8. A non-transitory computer-readable storage medium including a program for executing driving control of a mobile body, in, When the program is executed by a computer, a moving object control method is performed, and the moving object control method includes the following steps: Detecting at least one surrounding moving object existing around the moving object; calculating a first estimated heading based on the yaw rate of the mobile object; calculating a second estimated heading based on the steering angle of the mobile object; determining the surrounding moving object overlapping at least one of the first estimated heading and the second estimated heading as a front moving object based on the first estimated heading, the second estimated heading, and the position of the surrounding moving object; causing the moving object to follow the preceding moving object; in a case where there is no surrounding moving object to be determined as the preceding moving object, determining the surrounding moving object overlapping with an intermediate area defined between the first estimated heading and the second estimated heading as a preliminary preceding moving object; and The moving body is caused to follow the preparatory moving body.

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