Vehicle control device

Abstract

To provide a vehicle control device capable of performing control close to a human driving operation.SOLUTION: A first threshold for starting constant speed driving and a second threshold for starting speed reduction are set to speed reduction targets (curve, reduction of legal speed, crosswalk, stop line, etc.,) in a direction of travel during travel of a vehicle 1. The first threshold and the second threshold are then compared to a reduction speed which is calculated with respect to the speed reduction target, thereby starting speed reduction after performing constant speed driving when reducing the speed of the vehicle 1.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device that controls a vehicle. [Background technology]

[0002] In recent years, research has been progressing on autonomous driving, which allows a vehicle to travel without user operation.

[0003] Because humans perform driving operations according to various situations, the vehicle's acceleration, deceleration, and other movements are not uniform. In order to make the movements of an autonomous vehicle closer to those of a human driver, autonomous driving control is required to be similar to human driving operations. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 230685 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when a vehicle is traveling and there is a deceleration target (such as a curve, a deceleration to the legal speed limit, a crosswalk, or a stop line) in the direction of travel, the vehicle needs to decelerate in order to achieve the target vehicle speed at the location of the deceleration target.

[0006] For example, when a process is executed to start deceleration when the deceleration calculated by subtracting the current vehicle speed from the target vehicle speed and dividing the result by the distance from the current location to the deceleration target falls below a threshold, the vehicle may suddenly switch from an accelerating state to decelerating. This can cause problems, such as unnecessary acceleration when the vehicle should immediately switch to deceleration, which can be a burden on the vehicle and passengers, compared to manual driving.

[0007] An object of the present invention is to provide a vehicle control device that can perform control similar to human driving operations. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a vehicle control device according to one aspect of the present invention includes a calculation means for calculating a deceleration amount obtained by subtracting a target vehicle speed at a position where the deceleration target is located from a current vehicle speed for a deceleration target located in the driving direction while the vehicle is traveling, and dividing the result by the distance from the current position to the deceleration target; and a setting means for setting the acceleration of the vehicle to a first acceleration if the deceleration is equal to or less than a first threshold, and for setting the acceleration of the vehicle to a second acceleration if the deceleration is equal to or less than a second threshold.

[0009] According to this configuration, the acceleration of the vehicle is set to two stages depending on the deceleration, thereby enabling control that is similar to human driving operations when decelerating the vehicle.

[0010] The first acceleration may be an acceleration that causes the vehicle to travel at a constant speed.

[0011] In this configuration, the vehicle starts accelerating, travels at a constant speed, and then starts decelerating. This allows for control that closely resembles human driving during deceleration.

[0012] The second acceleration may be an acceleration that decelerates the vehicle.

[0013] According to this configuration, the vehicle starts accelerating at the first acceleration, then starts decelerating at the second acceleration, thereby enabling control similar to human driving during deceleration of the vehicle.

[0014] The first threshold may be greater than the second threshold.

[0015] In this configuration, a first acceleration is set at a first threshold value, and a second acceleration is set at a second threshold value that is smaller than the first threshold value. Therefore, when decelerating the vehicle, control can be performed that is similar to human driving operations. [Effects of the Invention]

[0016] According to the present invention, when a vehicle is decelerated, control can be performed that is similar to a human driving operation. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram showing the electrical configuration of a vehicle equipped with a collision avoidance control device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing the functional configuration of an autonomous driving ECU. [Figure 3] 10 is a flowchart showing the flow of deceleration processing. [Figure 4] FIG. 10 is a diagram illustrating a first threshold value. [Figure 5] FIG. 10 is a diagram illustrating a second threshold value. [Figure 6] FIG. 4 is a diagram showing the vehicle speed up to the deceleration target. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0019] <Vehicle configuration> FIG. 1 is a block diagram showing the electrical configuration of a vehicle 1 equipped with a collision avoidance control device according to one embodiment of the present invention.

[0020] Vehicle 1 is equipped with an automatic driving function and is capable of running automatically without user operation.

[0021] A plurality of ECUs (Electronic Control Units) are mounted on the vehicle 1 to control various parts. Each ECU has a microcontroller unit (microcomputer), and the microcomputer has built-in, for example, a CPU, a non-volatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory).

[0022] The multiple ECUs include a drive ECU 11, a steering ECU 12, a brake ECU 13, a meter ECU 14, and a body ECU 15. The drive ECU 11, the steering ECU 12, the brake ECU 13, the meter ECU 14, and the body ECU 15 are connected to each other so as to be able to communicate using a CAN (Controller Area Network) communication protocol, that is, to communicate via CAN.

[0023] The drive ECU 11 is a control unit that controls a drive unit 21 of the vehicle 1. The drive unit 21 may be configured to include an engine as a drive source, a motor as a drive source, or both an engine and a motor as drive sources. The drive unit 21 includes a transmission that changes the speed of the drive force from the drive source and outputs it as necessary.

[0024] The steering ECU 12 is a control unit that controls a steering device 22 of the vehicle 1. The steering device 22 is, for example, an electric power steering device that applies torque from an electric motor to a steering mechanism. The steering mechanism includes, for example, a rack-and-pinion steering gear, and is configured so that when a rack shaft moves in the vehicle width direction due to the torque of the electric motor, the left and right steered wheels are turned left and right in accordance with the movement of the rack shaft.

[0025] The brake ECU 13 is a control unit that controls a braking device 23 of the vehicle 1. The braking device 23 may be hydraulic or electric. The hydraulic braking device 23 includes a brake actuator, and the function of this brake actuator distributes hydraulic pressure to wheel cylinders of the brakes provided on each wheel, and the hydraulic pressure applies braking force from each brake to the wheels, including the drive wheels, on the wheels.

[0026] The meter ECU 14 is a control unit that controls each part of a meter panel (not shown) of the vehicle 1. The meter panel is provided with indicators such as a liquid crystal display for displaying various information, as well as instruments that display vehicle speed and engine RPM. An emergency stop switch 24 that is operated to issue an emergency stop command for the autonomous driving is also connected to the meter ECU 14.

[0027] The body ECU 15 is a control unit that controls various parts that need to operate even when the ignition switch of the vehicle 1 is off, such as the left and right turn signals and door lock motors.

[0028] The plurality of ECUs also include an automatic driving ECU 31, a lidar ECU 32, and a monocular camera ECU 33 as control units for the automatic driving function.

[0029] The automatic driving ECU 31 is a control center for automatic driving control. The automatic driving ECU 31 is connected to the drive ECU 11, the steering ECU 12, the brake ECU 13, the meter ECU 14, and the body ECU 15 so as to be able to communicate via CAN.

[0030] An omnidirectional LiDAR (Light Detection And Ranging) 34 is connected to the autonomous driving ECU 31 via, for example, an Ethernet (registered trademark) standard communication cable. The omnidirectional LiDAR 34 emits laser light in all directions of 360°, receives reflected light from objects present within a search range with an optical sensor, and outputs a detection signal according to the reflected light. The detection signal from the omnidirectional LiDAR 34 is input to the autonomous driving ECU 31.

[0031] Furthermore, a GPS receiver 35 is connected to the autonomous driving ECU 31 via, for example, a USB (Universal Serial Bus) standard communication cable. The GPS receiver 35 is a receiver that receives positioning signals from GPS (Global Positioning System) satellites. The positioning signals received by the GPS receiver 35 are input from the GPS receiver 35 to the autonomous driving ECU 31.

[0032] The LIDAR ECU 32 is communicatively connected to the autonomous driving ECU 31 via, for example, an Ethernet-compliant communication cable. Six LIDARs 36 are connected to the LIDAR ECU 32. Each LIDAR 36 irradiates a search range with laser light, receives reflected light from objects present within the search range with an optical sensor, and outputs a detection signal corresponding to the reflected light. The LIDARs 36 are, for example, disposed at the left, center, and right ends of the front bumper and the left, center, and right ends of the rear bumper of the vehicle 1. The LIDAR ECU 32 receives the detection signals output from each LIDAR 36 as input. The LIDAR ECU 32 processes the detection signals output from each LIDAR 36 and transmits the data obtained by this processing to the autonomous driving ECU 31.

[0033] The monocular camera ECU 33 is communicably connected to the autonomous driving ECU 31 via, for example, a USB standard communication cable. A monocular camera 37 is connected to the monocular camera ECU 33. The monocular camera 37 is a camera that can continuously capture still images of the search range ahead of the vehicle 1 at a predetermined frame rate. Image signals of the still images continuously output from the monocular camera 37 are input to the monocular camera ECU 33. The monocular camera ECU 33 processes the image signals input from the monocular camera 37 and transmits image data obtained by this processing to the autonomous driving ECU 31.

[0034] <Autonomous driving ECU> FIG. 2 is a block diagram showing the functional configuration of the automatic driving ECU 31.

[0035] The autonomous driving ECU 31 includes an object recognition unit 41, a self-position estimation unit 42, a surrounding information integration unit 43, a route planning unit 44, and a vehicle control unit 45. These functional processing units are realized in software by program processing, or by hardware such as a logic circuit.

[0036] The object recognition unit 41 recognizes objects such as other vehicles and pedestrians around the vehicle 1 from information on the distance to objects (vehicles, pedestrians, buildings, curbs, and other obstacles) obtained from the detection signal of the omnidirectional lidar 34 and from images captured by the monocular camera 37.

[0037] The self-position estimation unit 42 matches point cloud data acquired from the detection signals of the omnidirectional LIDAR 34 with high-precision map data (point cloud data) 46, which is data on a high-precision map, to estimate the position (self-position) of the vehicle 1. The high-precision map is a high-precision three-dimensional map, and the high-precision map data 46 includes, for example, information on road width and gradient, as well as information on features such as lane markings, shoulder lines, intersections, railroad crossings, stop lines, pedestrian crossings, and signs. The high-precision map data 46 may be stored in a non-volatile memory built into a microcomputer of the autonomous driving ECU 31, or may be stored in an HDD (Hard Disk Drive) connected to the autonomous driving ECU 31. The self-position estimation unit 42 also integrates the self-position estimated by matching the point cloud data with the self-position based on the positioning signal received by the GPS receiver 35 to improve the accuracy of the self-position estimation.

[0038] The surrounding information integrating unit 43 receives as input the object recognition results from the object recognition unit 41, the self-position estimation results from the self-position estimation unit 42, and data obtained by the LIDAR ECU 32 (see FIG. 1) processing detection signals output from each LIDAR 36. High-precision map data 46 is also input to the surrounding information integrating unit 43. The surrounding information integrating unit 43 creates surrounding information integrated map data in which the vehicle 1, vehicles other than the vehicle 1, and objects such as pedestrians are arranged on a high-precision map. The surrounding information integrating unit 43 then outputs the map information and object recognition information to an HMI (Human Machine Interface) device 47, such as a display, arranged inside the vehicle 1.

[0039] The route planning unit 44 receives the peripheral information integrated map data from the peripheral information integrating unit 43. The route planning unit 44 plans a travel route to the destination of the vehicle 1 from the peripheral information integrated map data. The plan includes a target vehicle speed at each point on the travel route. The travel route plan also includes the setting of deceleration sections. The setting of deceleration sections will be described later. The route planning unit 44 then outputs the planned target vehicle speed and route data of the travel route including the deceleration sections to the HMI device 47.

[0040] The vehicle control unit 45 receives route data from the route planning unit 44. Based on the route data, the vehicle control unit 45 outputs commands to ECUs that control the operation of each part of the vehicle 1, such as the drive ECU 11, the steering ECU 12, and the brake ECU 13, so that the vehicle 1 travels along the travel route by automatic driving.

[0041] <Deceleration processing> Fig. 3 is a flowchart showing the flow of the deceleration section setting process. Figs. 4 and 5 are diagrams for explaining the first and second threshold values, respectively.

[0042] For example, after the destination of vehicle 1 is input on HMI device 47, an autonomous driving start button displayed on HMI device 47 is pressed, which inputs an instruction to start autonomous driving from HMI device 47 to autonomous driving ECU 31. When the instruction to start autonomous driving is input to autonomous driving ECU 31, route planner 44 plans a travel route to the destination of vehicle 1. The travel route is re-planned at predetermined intervals while vehicle 1 is traveling in autonomous driving. Then, during autonomous driving, vehicle 1 travels through each point on the travel route at a target vehicle speed for each point, following the most recently planned travel route. Autonomous driving ends, for example, when vehicle 1 arrives at the destination or when emergency stop switch 24 is pressed and an instruction to stop autonomous driving is input from meter ECU 14 to autonomous driving ECU 31.

[0043] When planning and re-planning a travel route, the route planning unit 44 performs deceleration processing shown in FIG.

[0044] In the deceleration process, the high-precision map data 46 included in the surrounding information integrated map data is searched for at predetermined intervals within a predetermined search range in the direction of travel from the current position of the vehicle 1, among features present on the travel route, to determine deceleration targets that require the vehicle 1 to decelerate before reaching that position, such as curves, deceleration limits, pedestrian crossings, and stop lines. When a deceleration target is detected, a deceleration rate for the deceleration target is calculated (step S1). The deceleration rate is calculated by subtracting the current vehicle speed from the target vehicle speed, and dividing the result by the distance from the current position to the deceleration target. In other words, slowing down the vehicle speed of the vehicle 1 corresponds to a negative deceleration rate, and a lower deceleration rate (a negative value with a larger absolute value) indicates a situation in which more rapid deceleration is required.

[0045] The relationship between the deceleration target and the deceleration rate included in the high-precision map data 46 is stored in a non-volatile memory built into the microcomputer of the autonomous driving ECU 31. The relationship between the deceleration target and the deceleration rate is stored in the form of a table, for example, a deceleration rate table. The deceleration rate for the deceleration target may be set for each deceleration target or for each type of deceleration target. For example, a uniform deceleration rate may be set for a curve, or the deceleration rate may be set individually depending on the curvature of the curve.

[0046] For each deceleration target or each type of deceleration target, a target vehicle speed is set at the location where the deceleration target is located so that the vehicle 1 can safely pass through or stop at the location of the deceleration target. The deceleration table associates the deceleration target with the deceleration such that the lower the target vehicle speed at the location where the deceleration target is located, the lower the deceleration (a negative value with a larger absolute value). For example, as shown in FIG. 4 , curves, decelerations at legal speeds, crosswalks, stop lines, and the like are detected as deceleration targets from the high-precision map data 46. A deceleration is set as a first threshold for each detected deceleration target. Since it is not necessary to stop the vehicle 1 by deceleration alone when decelerating around a curve or at legal speeds, if the target vehicle speed is set to decrease in that order from the curve, the deceleration is set to decrease in that order. Furthermore, for crosswalks and stop lines, the target vehicle speed is set to 0, and therefore a deceleration lower than the deceleration for the speed sign is set. The second threshold values ​​shown in FIG. 5 may be the same as the first threshold values, but the decelerations are set lower than the first threshold values.

[0047] Then, it is determined whether the deceleration calculated for the deceleration target is greater than a first threshold value (step S2). If the deceleration is greater than the first threshold value (step S2: Yes), there is no need to decelerate, so a process to accelerate the vehicle 1 is executed (step S3). Then, a process to control the drive device 21 of the vehicle 1 via the drive ECU 11 is executed so that the vehicle 1 travels according to the set acceleration (step S4).

[0048] In step S2, if it is determined that the deceleration is equal to or less than the first threshold (step S2: No), it is determined whether the deceleration is greater than the second threshold (step S5). If the deceleration is greater than the second threshold (step S5: Yes), the point where deceleration will start is approaching, so a process is executed to make the vehicle 1 travel at a constant speed (step S6). Then, a process is executed to control the drive unit 21 of the vehicle 1 via the drive ECU 11 so that the vehicle 1 travels at the set speed (step S4).

[0049] In step S5, if it is determined that the deceleration is equal to or less than the second threshold (step S5: No), it is necessary to start deceleration, so a process to decelerate the vehicle 1 is executed (step S7). Then, the drive device 21 and the brake device 23 of the vehicle 1 are controlled via the drive ECU 11 and the brake ECU 13 so that the vehicle 1 travels according to the set acceleration (step S4).

[0050] <Example of deceleration processing> FIG. 6 is a diagram showing the vehicle speed up to the deceleration target.

[0051] For example, as shown in Fig. 6, assume that a crosswalk, which is a deceleration target, is located at position P1 within a predetermined search range in the traveling direction from the current position of vehicle 1. At the crosswalk, the target vehicle speed is set to 0, the first threshold value is set to T1, and the second threshold value is set to T2. Both the first threshold value T1 and the second threshold value T2 are negative values, and the relationship of first threshold value T1 > second threshold value T2 holds.

[0052] First, in the area to the left of the position P3, the deceleration is greater than the first threshold T1, and the vehicle 1 accelerates.

[0053] At position P3, the deceleration rate = first threshold value T1 holds. At position P3, the vehicle speed is V1, and the distance to the deceleration target position is P1-P3, so the deceleration rate = (0-V1) / (P1-P3) = T1 holds. Between position P3 and position P2, the first threshold value T1 ≥ deceleration rate > second threshold value T2 holds, and the vehicle 1 travels at a constant speed.

[0054] Next, at position P2, the deceleration = second threshold T2 holds. At position P2, the vehicle speed is V1, and the distance to the deceleration target position is P1-P2, so the deceleration = (0-V1) / (P1-P2) = T2 holds. Between position P2 and position P1, the second threshold T2 ≥ deceleration holds, and the vehicle 1 is decelerated.

[0055] <Action and effect> As described above, the first and second thresholds are set for the deceleration target in the traveling direction while the vehicle 1 is traveling, and the deceleration is compared with the first and second thresholds to set the acceleration in two stages according to the deceleration. This allows control similar to human driving operations to be performed when decelerating the vehicle 1.

[0056] Furthermore, the first acceleration is an acceleration that causes vehicle 1 to travel at a constant speed, and the second acceleration is an acceleration that causes vehicle 1 to decelerate, and since the first threshold is greater than the second threshold, unnecessary acceleration that would otherwise cause immediate deceleration and burden on vehicle 1 and passengers are prevented.

[0057] The search for the deceleration target feature uses the high precision map data 46. Therefore, by updating the high precision map data 46, it is possible to set the deceleration rate according to the deceleration target feature based on the latest feature information.

[0058] <Modification> Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

[0059] For example, in the above embodiment, an example has been described in which environmental information is acquired from high-precision map data 46, but environmental information may also be acquired by monocular camera 37. In this case, if a curve, a sign indicating a legal speed limit, a crosswalk, a stop line, or the like is captured in an image captured by monocular camera 37, the deceleration is calculated for these deceleration targets, and deceleration processing is executed.

[0060] Furthermore, in the above-described embodiment, the instruction to start autonomous driving is input from the HMI device 47 to the autonomous driving ECU 31, but the instruction to start autonomous driving may also be input from a server external to the vehicle 1 to the autonomous driving ECU 31 via a gateway ECU by data communication such as mobile wireless data communication. Furthermore, the instruction to start autonomous driving may also be input to the autonomous driving ECU 31 when the vehicle 1 reaches an autonomous driving start point set on the travel route.

[0061] In addition, various design modifications can be made to the above-described configuration within the scope of the claims. [Explanation of symbols]

[0062] 1: Vehicle 11: Drive ECU (vehicle control device, setting means) 13: Brake ECU (vehicle control device, setting means) 31: Autonomous driving ECU (vehicle control device, calculation means, setting means) 46: High-precision map data (map information)

Claims

1. a calculation means for calculating a deceleration amount obtained by subtracting a current vehicle speed from a target vehicle speed at a position where the deceleration target is located, with respect to a deceleration target located in the traveling direction of the vehicle while the vehicle is traveling, and dividing the result by a distance from the current position to the deceleration target; and a setting means for setting the acceleration of the vehicle to a first acceleration when the deceleration is equal to or less than a first threshold, and for setting the acceleration of the vehicle to a second acceleration when the deceleration is equal to or less than a second threshold.

2. The vehicle control device according to claim 1 , wherein the first acceleration is an acceleration that causes the vehicle to travel at a constant speed.

3. The vehicle control device according to claim 1 , wherein the second acceleration is an acceleration that decelerates the vehicle.

4. The vehicle control device according to claim 1 , wherein the first threshold value is greater than the second threshold value.

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