Vehicle control device

Abstract

To provide a vehicle control device capable of preventing erroneous detection caused by displacement of an optical axis of a radar in a height direction.SOLUTION: A vehicle control device comprises a plurality of radars which detects an object around a vehicle and an optical axis correction section which corrects an optical axis of the radars by collating detection results of object height information obtained by each of the plurality of radars. The optical axis correction section corrects the optical axis of the radars based on a majority vote of the height information by collating the detection results of the object height information obtained by three or more radars among the plurality of radars.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In an AD / ADAS (Advanced Driver Assistance Systems) system equipped with a plurality of LiDARs (an example of a radar) to detect the vehicle surroundings without omission, alignment of the optical axes of the LiDARs is essential. As methods for aligning the optical axes of LiDARs, methods such as adjusting the optical axes using dedicated equipment such as markers in the free space of a horizontal road surface and automatically adjusting the optical axes based on the relative speed with roadside structures have been developed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the method of adjusting the optical axis using dedicated equipment in the free space of a horizontal road surface, when the optical axis is displaced due to some cause such as vibration of the sensor, the vehicle must be brought to a place where the optical axis can be corrected. Although the vehicle surroundings can be detected with high accuracy, the optical axis remains displaced until it is corrected. In addition, the method of automatically adjusting the optical axis based on the relative speed with roadside structures can always adjust the lateral displacement of the optical axis even when the vehicle is in a running state, but cannot cope with the displacement in the height direction.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a vehicle control device that can prevent false detection caused by displacement of the optical axis of the radar in the height direction.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a vehicle control device according to the present invention includes a plurality of radars that detect targets around the vehicle, and an optical axis correction unit that collates detection results of height information of the targets by each of the plurality of radars and performs optical axis correction of the radars. The optical axis correction unit collates detection results of height information of the targets by three or more of the plurality of radars and performs optical axis correction of the radars based on a majority vote of the height information.

[0007] According to this configuration, false detection caused by misalignment of the optical axis in the height direction of the lidar can be prevented.

[0008] Further, in the vehicle control device according to the present invention, the optical axis correction unit collates detection results of height information of the same target by each of the plurality of radars and performs optical axis correction of the radars.

[0009] According to this configuration, the accuracy of optical axis correction of the lidar can be improved.

[0010] Further, in the vehicle control device according to the present invention, the plurality of radars are provided on the vehicle such that at least a part of the detection ranges thereof overlap with each other, and the optical axis correction unit collates detection results of height information of the targets detected by the plurality of radars within the overlapping detection range.

[0011] According to this configuration, the same target can be collated under the same position conditions, and the collation accuracy of the detection results of the target can be improved.

[0012] Further, in the vehicle control device according to the present invention, the optical axis correction unit performs optical axis correction of the radars when there is a difference of a predetermined threshold value or more between the height information detected by the plurality of radars.

[0013] According to this configuration, it is possible to suppress overly sensitive detection of optical axis misalignment due to detection errors of height information by the lidar.

[0014] Further, in the vehicle control device according to the present invention, the optical axis correction unit collates the height information detected within a predetermined time.

[0015] According to this configuration, it is possible to prevent the optical axis correction of the radar 36 from being performed based on old data among the height information detected by the lidar.

Effect of the Invention

[0016] The vehicle control device according to the present invention has an effect of being able to prevent false detection caused by misalignment of the optical axis of the radar in the height direction.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0018] Hereinafter, an example of the vehicle control device according to the present invention will be described in detail with reference to the drawings.

[0019] FIG. 1 is a block diagram showing an example of a system configuration of a vehicle on which the vehicle control device according to the present embodiment is mounted. FIG. 2 is a diagram showing an example of a configuration of a lidar included in the vehicle according to the present embodiment. The vehicle 1 is equipped with an automatic driving function and can travel by automatic driving without depending on the driving operation of the user (driver). Note that the automatic driving includes semi-automatic driving in which a part of the operations in the running of the vehicle 1 is automated (requiring partial driving operations by the user).

[0020] Vehicle 1 is equipped with a plurality of ECUs (Electronic Control Units) to control each part. Each ECU includes a microcomputer (Micro Controller Unit), and the microcomputer incorporates, for example, a CPU (Central Processing Unit), a non-volatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory).

[0021] The plurality of ECUs includes 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 so as to enable communication according to the CAN (Controller Area Network) communication protocol, that is, CAN communication.

[0022] The drive ECU 11 is a control unit that controls the drive device 21 of the vehicle 1. The drive device 21 may be configured to include an engine as a drive source, may be configured to include a motor as a drive source, or may be configured to include both an engine and a motor as drive sources. The drive device 21 includes a transmission that shifts and outputs the driving force from the drive source as necessary.

[0023] The steering ECU 12 is a control unit that controls the steering device 22 of the vehicle 1. The steering device 22 is, for example, an electric power steering device that applies the torque of an electric motor to a steering mechanism. The steering mechanism includes, for example, a rack and pinion type steering gear, and is configured such that when the rack shaft moves in the vehicle width direction by the torque of the electric motor, the left and right steering wheels steer left and right as the rack shaft moves.

[0024] The brake ECU 13 is a control unit that controls the 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 by the function of this brake actuator, hydraulic pressure is distributed to the wheel cylinders of the brakes provided on each wheel, and braking force is applied to the wheels including the drive wheels by this hydraulic pressure.

[0025] The meter ECU 14 is a control unit that controls each part of the meter panel (not shown) of the vehicle 1. The meter panel is provided with indicators for displaying vehicle speed, engine speed, etc., and a display such as a liquid crystal display for displaying various information. Further, an emergency stop switch 24 that is operated to instruct an emergency stop of the automatic driving is connected to the meter ECU 14.

[0026] The body ECU 15 is a control unit that controls each part that needs to operate even when the ignition switch of the vehicle 1 is off, for example, the left and right turn signals, door lock motors, etc.

[0027] Further, the plurality of ECUs include an automatic driving ECU 31, a rider ECU 32, and a monocular camera ECU 33 as control units for the automatic driving function.

[0028] The automatic driving ECU 31 is the control center of the automatic driving control. The automatic driving ECU 31 is communicably connected to the drive ECU 11, the steering ECU 12, the brake ECU 13, the meter ECU 14, and the body ECU 15 via CAN.

[0029] The automatic driving ECU 31 is connected to an omnidirectional LiDAR (Light Detection And Ranging) 34 via a communication cable conforming to the Ethernet (registered trademark) standard, for example. The omnidirectional LiDAR 34 can acquire ranging information indicating the distance from the vehicle 1 to an object existing around the vehicle 1. The omnidirectional LiDAR 34 irradiates laser light in a 360° omnidirectional manner, receives reflected light from an object existing within the search range with an optical sensor, and outputs a detection signal corresponding to the reflected light as ranging information. The ranging information can take the form of, for example, point cloud information indicating the distance from the vehicle 1 to an object at each position (voxel) in a three-dimensional space. The detection signal of the omnidirectional LiDAR 34 is input to the automatic driving ECU 31.

[0030] In addition, the automatic driving ECU 31 is connected to a GPS receiver 35 via a communication cable conforming to the USB (Universal Serial Bus) standard, for example. The GPS receiver 35 is a receiver that receives a positioning signal from a GPS (Global Positioning System) satellite. The GPS receiver 35 can acquire positioning information indicating a position on the earth (for example, latitude, longitude, altitude, etc.). The positioning signal received by the GPS receiver 35 is input from the GPS receiver 35 to the automatic driving ECU 31 as positioning information.

[0031] The radar ECU 32 (an example of a vehicle control device) is communicably connected to the autonomous driving ECU 31 via, for example, an Ethernet-standard communication cable. Four radars 36 (front radar 36, right-side radar 36, rear radar 36, left-side radar 36) are connected to the radar ECU 32. The radar 36 irradiates a search range with laser light, receives reflected light from an object (target) existing within the search range with an optical sensor, and outputs a detection signal corresponding to the reflected light. As shown in FIG. 2, the front radar 36 is disposed on the front bumper of the vehicle 1. As shown in FIG. 2, the right-side radar 36 is disposed on the right side door. As shown in FIG. 2, the left-side radar 36 is disposed on the left side door. As shown in FIG. 2, the rear radar 36 is disposed on the rear bumper. The front radar 36, the right-side radar 36, the left-side radar 36, and the rear radar 36 are an example of a plurality of radars that detect targets around the vehicle 1.

[0032] In this embodiment, a lidar is used as the radar, but a millimeter-wave radar or the like may also be used. Further, the plurality of radars 36 may be provided on the vehicle 1 such that at least a part of the detection ranges thereof overlap with each other. The detection signals output from the respective radars 36 are input to the radar ECU 32. The radar ECU 32 processes the detection signals output from the respective radars 36, and transmits the data obtained by the 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 capable of continuously capturing still images of a search range in front of the vehicle 1 at a predetermined frame rate. The 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 the image data obtained by the processing to the autonomous driving ECU 31.

[0034] FIG. 3 is a block diagram showing an example of the functional configuration of the lidar ECU of the vehicle according to the present embodiment. The lidar ECU 32 of the present embodiment includes an optical axis correction unit 321. The optical axis correction unit 321 is configured by the cooperation of the hardware and software (programs, etc.) that make up the vehicle 1 as illustrated in FIG. 1. Further, at least one of the functions of the optical axis correction unit 321 may be configured by dedicated hardware (circuits, etc.). Note that the functional configuration of the lidar ECU 32 is not limited to this.

[0035] The optical axis correction unit 321 is an example of an optical axis correction means that collates the detection results of the height information of the target by each of the plurality of lidars 36 and corrects the optical axis of the lidar 36. Further, the optical axis correction unit 321 collates the detection results of the height information of the target by three or more of the plurality of lidars 36 and corrects the optical axis of the lidar 36 based on the majority vote of the height information.

[0036] For example, when the height information of the target detected by the left-side lidar 36 is lower than the height information of the target detected by the front lidar 36, the height information of the target detected by the front lidar 36 is higher than the height information of the target detected by the left-side lidar 36, and there is no difference between the height information of the target detected by the front lidar 36 and the height information of the target detected by the right-side lidar 36, the optical axis correction unit 321 determines, based on the logic of the majority vote, that the optical axis of the left-side lidar 36 is shifted upward. In this case, the optical axis correction unit 321 corrects the optical axis of the left-side lidar 36 downward to correct the recognition front point of the left-side lidar 36.

[0037] Thereby, it is possible to correct the optical axis in the height direction of the lidar 36 even while the vehicle 1 is running without using a camera. Further, by collating the height information from at least three or more lidars 36, it is possible to prevent the loss of knowledge of which lidar 36 has the correct optical axis. As a result, false detection caused by a shift in the optical axis in the height direction of the lidar 36 (for example, misdetecting a sign at a high place as being on the road, misdetecting the ground as an obstacle on the road) can be prevented.

[0038] Further, the optical axis correction unit 321 may perform optical axis correction of the lidar 36 by collating the detection results of the height information of the same target by each of the plurality of lidars 36. Thereby, the accuracy of the optical axis correction of the lidar 36 can be improved.

[0039] Also, when a plurality of lidars 36 are provided on the vehicle 1 such that at least a part of their detection ranges overlap with each other, the optical axis correction unit 321 may collate the detection results of the height information of the target by the plurality of lidars 36 that have detected the target within the overlapping detection range. Thereby, since the detection results of the target in the mutually overlapping detection ranges of the plurality of lidars 36 are collated, the same target can be collated under the same position conditions, and the collation accuracy of the detection results of the target can be improved. Further, when only two lidars 36 with overlapping detection ranges among the plurality of lidars 36, even if a target enters the overlapping detection range, optical axis correction based on a majority vote cannot be performed. However, when a target enters the detection range of a lidar 36 whose detection range does not overlap among the remaining lidars 36, optical axis correction based on a majority vote is performed.

[0040] Further, the optical axis correction unit 321 may perform optical axis correction of the lidar 36 when there is a difference of a predetermined threshold value (for example, 10 cm) or more between the height information detected by the plurality of lidars 36. On the other hand, when the difference between the height information detected by the plurality of lidars 36 is equal to or less than the predetermined threshold value, the optical axis correction unit 321 determines that there is no deviation in the height direction of the optical axis of the lidar 36. Thereby, it is possible to suppress overly sensitive detection of the deviation of the optical axis due to the detection error of the height information by the lidar 36. In the present embodiment, the optical axis correction unit 321 performs optical axis correction of the lidar 36 when there is a difference of a predetermined threshold value or more between the height information detected by the plurality of lidars 36. However, it is also possible to perform optical axis correction of the lidar 36 even when the difference between the height information detected by the plurality of lidars 36 is less than the predetermined threshold value.

[0041] In addition, the optical axis correction unit 321 associates the height information detected by the plurality of lidars 36 with the detection time and stores the information in a storage unit (for example, a storage unit such as a RAM (Random Access Memory) or HDD (Hard Disk Drive) included in the lidar ECU 32). Here, the detection time may be the time included in the positioning signal received by the GPS receiver 35. In the present embodiment, when there is a difference of a predetermined threshold value or more between the height information detected by the plurality of lidars 36, the optical axis correction unit 321 stores difference data indicating the difference in the storage unit in association with the detection time.

[0042] Further, the optical axis correction unit 321 may collate the height information detected within a predetermined time (for example, one day). Specifically, the optical axis correction unit 321 collates the height information associated with the detection time within a predetermined time among the height information stored in the storage unit. This can prevent the optical axis correction of the lidar 36 from being performed based on old data among the height information detected by the lidar 36. In the present embodiment, the optical axis correction unit 321 may perform the optical axis correction of the lidar 36 based on the difference data associated with the detection time within a predetermined time among the difference data stored in the storage unit.

[0043] FIG. 4 is a flowchart showing an example of the flow of optical axis correction of a lidar by a lidar ECU of a vehicle according to the present embodiment. First, when an obstacle exists in a location where the detection ranges of the lidars 36 overlap (LiDAR boundary region), or when an object exists across the boundary of the detection ranges of the plurality of lidars 36, the optical axis correction unit 321 detects a difference in the height information of an object (for example, an obstacle) detected by the plurality of lidars 36 (step S401).

[0044] Next, the optical axis correction unit 321 determines whether there are differences in the height information detected by the plurality of lidars 36 within a predetermined time (for example, one day) (step S402). If there are no differences in the height information detected by the plurality of lidars 36 within the predetermined time (step S402: No), the optical axis correction unit 321 stores the difference data indicating the differences in the height information detected by the plurality of lidars 36 within the predetermined time in association with the detection time of the height information (step S403).

[0045] If there are differences in the height information detected by the plurality of lidars 36 within the predetermined time (step S402: Yes), the optical axis correction unit 321 determines whether the difference data of the height information of three adjacent lidars 36 is complete (step S404). If the difference data of the height information of three adjacent lidars 36 is not complete (step S404: No), the optical axis correction unit 321 proceeds to step S403.

[0046] If the difference data of the height information of three adjacent lidars 36 is complete (step S404: Yes), the optical axis correction unit 321 corrects the optical axis of one lidar 36 (sensor) having a difference in height information among the three adjacent lidars 36 and corrects the recognized front point of the lidar 36 (step S405). Thereafter, the optical axis correction unit 321 erases the difference data between the height information detected by the plurality of lidars 36 including the lidar 36 whose optical axis has been corrected (the lidar 36 whose recognized front point has been corrected) (step S406).

[0047] Thus, according to the vehicle 1 according to the present embodiment, it is possible to correct the optical axis in the height direction of the lidar 36 even while the vehicle 1 is running without using a camera. In addition, by collating the height information from at least three or more lidars 36, it is possible to prevent the inability to determine which lidar 36 has a correct optical axis. As a result, it is possible to prevent false detection caused by a deviation of the optical axis in the height direction of the lidar 36.

Explanation of Reference Numerals

[0048] 1 Vehicle 31 Autonomous Driving ECU 32 Lidar ECU 35 GPS receiver 36 rider 321 Optical axis correction unit

Claims

1. A plurality of radars for detecting object targets around a vehicle, an optical axis correction unit that collates detection results of height information of the object targets by each of the plurality of radars to perform optical axis correction of the radars, wherein the optical axis correction unit collates detection results of the height information of the object targets by three or more of the plurality of radars and performs optical axis correction of the radars based on a majority vote of the height information, a vehicle control device.

2. The vehicle control device according to claim 1, wherein the optical axis correction unit collates detection results of height information of the same object target by each of the plurality of radars to perform optical axis correction of the radars.

3. The plurality of radars are provided on the vehicle such that at least a part of their detection ranges overlap with each other, and the optical axis correction unit collates detection results of the height information of the object targets by the plurality of radars that have detected the object target within the overlapping detection range. The vehicle control device according to claim 1 or 2.

4. The vehicle control device according to claim 1 or 2, wherein the optical axis correction unit performs optical axis correction of the radars when there is a difference of a predetermined threshold or more between the height information detected by the plurality of radars.

5. The vehicle control device according to claim 1 or 2, wherein the optical axis correction unit collates the height information detected within a predetermined time.

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