Positioning device

Abstract

The present invention provides a positioning device that can determine the position of a vehicle with high accuracy even in a low-speed zone. The positioning device of the present invention captures an image in front of the vehicle, obtains the position information of the vehicle, estimates the first position of the vehicle based on the position of the lane contained in the image, the obtained position information of the vehicle, and the map information, estimates the second position of the vehicle based on the most recently determined position of the vehicle and the movement amount of the vehicle, and synthesizes the first position and the second position to determine the position of the vehicle. Here, when the vehicle is traveling at a speed below a predetermined speed, a weight is assigned to the second position and the first position and the second position are synthesized to obtain the position of the vehicle.

Description

Technical Field

[0001] The present invention relates to a positioning device, for example, a vehicle for autonomous driving. Background Art

[0002] In the automatic driving of a vehicle, sensors monitor a specific direction or all directions of the vehicle, as well as the driver's status and the vehicle's driving status, and control the automatic driving of the vehicle on an appropriate path and at an appropriate speed based on these monitoring results. In such automatic driving, a vehicle control device (or also referred to as an automatic driving system) that controls the automatic driving can, for example, identify the dividing line of the road based on an image, and can identify a more accurate position of the vehicle on the road in combination with the position information obtained using a navigation satellite.

[0003] In addition to the position thus identified, the position is estimated by integrating the movement direction and movement amount from the reference position. In addition, a technique has been proposed in which the positions acquired by these different methods are combined and the result is used as the position (Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-56701 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, in the technology of estimating the position by identifying the demarcation line, the identified position in the width direction of the road may sometimes be offset due to the identification result of the demarcation line of the road. For example, sometimes dotted lines are drawn on both sides of the lane at a downhill slope to provide a prompt to urge deceleration. In this case, when the dotted line of the deceleration prompt is identified as a demarcation line, the identified position in the width direction of the road will be offset from the original position by an amount corresponding to the interval between the demarcation line and the deceleration prompt. The position offset in the width direction of the road may, for example, result in a judgment based on the offset that the demarcation line has been pressed or an adjacent lane has been entered. In addition, the judgment may sometimes result in intervention in autonomous driving and other actions or controls that are not originally necessary, such as intervention in steering and a change in the level of autonomous driving (e.g., reduction). This position offset in the width direction is prone to occur, for example, in a situation where the position in the width direction is determined only by relying on the demarcation line on one side of the lane, and this situation is particularly prone to occur in a low-speed zone.

[0009] The present invention has been made in view of the above-mentioned embodiments, and an object of the present invention is to provide a positioning device capable of determining a position with high accuracy even in a low-speed region.

[0010] Solutions for solving problems

[0011] In order to achieve the above object, the present invention has the following structure.

[0012] That is, according to one aspect of the present invention, there is provided a positioning device, characterized in that it comprises:

[0013] a photographing component that photographs an image of the front of the vehicle;

[0014] A position information acquisition component, which acquires the position information of the vehicle;

[0015] a first position estimating component, which estimates a first position of the vehicle according to the position of the lane contained in the image, the acquired position information of the vehicle, and the map information;

[0016] a second position estimating means for estimating a second position of the vehicle based on the most recently determined position and the amount of movement of the vehicle; and

[0017] a positioning component that combines the first position and the second position to determine a position,

[0018] When the vehicle is traveling at a speed lower than a predetermined speed, the positioning unit assigns a weight to the second position, synthesizes the first position and the second position,

[0019] The positioning component includes a complementary filter, and the complementary filter filters the first position with a low-pass filter and filters the second position with a high-pass filter to synthesize the first position and the second position.

[0020] Effects of the Invention

[0021] According to the present invention, the position can be determined with high accuracy even in a low-speed area. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram showing the structure of a vehicle system of an autonomous driving vehicle according to an embodiment.

[0023] Figure 2 It is a functional block diagram of the vehicle control system (control unit).

[0024] Figure 3 : is a block diagram showing the structure of the position recognition unit.

[0025] Figure 4 This is a diagram showing an example of the relationship between the time constant of the complementary filter included in the position recognition unit and the speed.

[0026] Figure 5This is a diagram showing an example of a change in characteristics due to a time constant of a complementary filter included in a position recognition unit.

[0027] Figure 6 This is a diagram showing an example of temporal change in position obtained by applying the present invention.

[0028] Description of Reference Numerals

[0029] 2: control unit; 130: automatic driving state control unit; 160: driving control unit. DETAILED DESCRIPTION

[0030] The following embodiments are described in detail with reference to the accompanying drawings. In addition, the following embodiments do not limit the invention involved in the claims, and the combination of features described in the embodiments is not necessarily all included in the invention. Two or more of the multiple features described in the embodiments can be combined arbitrarily. In addition, the same figure mark is marked on the same or similar structure, and repeated description is omitted.

[0031] [First embodiment]

[0032] Overview of Autonomous Driving

[0033] First, an overview of an example of automatic driving is described. In automatic driving, the driver generally sets the destination from the navigation system installed in the vehicle before driving, and the path to the destination is predetermined by the server and the navigation system. When the vehicle starts, the vehicle control device (or driving control device) composed of an ECU, etc., which makes the vehicle drive along the path to the destination. During this period, appropriate actions are determined in a timely manner based on the external environment such as the path and road conditions, the state of the driver (or, sometimes also called the driver), etc. In order to perform the action, for example, drive control, wheel control, braking control, etc. are performed to make the vehicle drive. Sometimes these controls are collectively referred to as driving control.

[0034] In automatic driving, there are several control states (also called levels of automatic driving control states, or simply states) depending on the automation rate (or the amount of work required of the driver). Generally speaking, the higher the level of the automatic driving control state and therefore the higher the level of automation, the less work (i.e., load) required of the driver. For example, in the highest control state (the second control state, also called level 3) in this example, the driver (driver) can pay attention to situations other than driving. For example, the highest control state is executed in less complex environments such as following a vehicle ahead due to congestion on a highway, but in this embodiment, the highest control state can also be applied when cruising on a highway with few obstacles. In addition, in the lower first control state (also called level 2), the driver does not need to hold the steering wheel, but needs to pay attention to the surrounding conditions, etc. This first control state can also be applied to situations such as cruising on highways, etc. In addition, the driver status detection camera 41a (refer to Figure 1 ) to detect that the driver is paying attention to the surroundings, and a capacitive steering wheel grip sensor (not shown) can be used to detect that the driver is holding the steering wheel. The driver state detection camera 41a can, for example, recognize the driver's pupils to determine the direction he is looking at, but it can also simply recognize the face and estimate the direction of the face as the direction the driver is looking.

[0035] Furthermore, in its lower control state (sometimes also referred to as level 1, etc.), the driver does not need to operate the steering wheel or the throttle, but needs to hold the steering wheel and pay attention to the driving environment in preparation for the driving control to be handed back from the vehicle to the driver (also referred to as taking over or driving handover). Furthermore, its lower control state (sometimes also referred to as level 0, etc.) is manual driving, including automated driving assistance. The vehicle switches the level of automatic driving according to the detected state of the vehicle and the external conditions. For example, when the vehicle determines that the vehicle has pressed against the lane dividing line based on the determined position of the vehicle (sometimes also referred to as its own position), the level of automatic driving is reduced from level 3 to level 2, or from level 2 to level 1.

[0036] Structure of vehicle control device

[0037] Figure 1 FIG. 1 is a block diagram of a vehicle control device according to an embodiment of the present invention, and the vehicle control device is used to control a vehicle 1. Figure 1 1 and 2 show the outline of the vehicle 1 in a plan view and a side view. As an example, the vehicle 1 is a sedan-type four-wheeled passenger vehicle.

[0038] Figure 1The control device includes a control unit 2. The control unit 2 includes a plurality of ECUs 20 to 29 connected in a manner capable of communicating through an in-vehicle network. Each ECU includes a processor represented by a CPU, a storage device such as a semiconductor memory, an interface connected to an external device, etc. The storage device stores programs executed by the processor, data used by the processor in processing, etc. Each ECU may also have a plurality of processors, storage devices, interfaces, etc.

[0039] The following describes the functions and the like performed by each of the ECUs 20 to 29. The number of ECUs and the functions performed by them can be appropriately designed in the vehicle 1, and can be further refined or more integrated than in the present embodiment.

[0040] The ECU 20 performs control related to automatic driving of the vehicle 1. In automatic driving, at least one of turning and acceleration / deceleration of the vehicle 1 is automatically controlled. In a control example described later, both turning and acceleration / deceleration are automatically controlled.

[0041] ECU 21 is a steering ECU that controls the steering device 3. The steering device 3 includes a mechanism that turns the front wheels in response to the driver's driving operation (turning operation) of the steering wheel (also called steering wheel) 31. In addition, the steering device 3 is an electric power steering device, including a motor that generates a driving force to assist the turning operation or automatically turn the front wheels, a turning angle sensor for detecting the turning angle, etc. When the driving state of the vehicle 1 is the automatic driving state, the ECU 21 automatically controls the steering device 3 in response to the instruction from the ECU 20 to control the travel direction of the vehicle 1.

[0042] ECU 22, 23 controls detection units 41-43 for detecting the surrounding conditions of the vehicle and performs information processing on the detection results. The surrounding conditions are also called surrounding states, external environments, etc., and the information obtained by detecting these surrounding conditions is called surrounding condition information, surrounding state information, or external environment information, etc. In addition, the detection units for detecting these surrounding states and the ECUs that control them are collectively referred to as surrounding monitoring devices or surrounding monitoring units. The detection unit 41 is a camera that captures the front of the vehicle 1 (hereinafter, sometimes described as camera 41), and in the case of this embodiment, two of the cameras are provided in the cabin of the vehicle 1. By analyzing the image captured by the camera 41, the outline of the target object and the dividing line (white line, etc.) of the lane on the road can be extracted. The detection unit 41a is a camera for detecting the state of the driver (hereinafter, sometimes described as driver state detection camera 41a), which is set to obtain the driver's expression. Although not shown in the figure, it is connected to the ECU that processes its image data. In addition, as a sensor for detecting the driver's state, there is a steering wheel grip sensor that is not shown in the figure. In this way, it is possible to detect whether the driver is holding the steering wheel. The driver state detection camera 41 a and the steering wheel grip sensor 210I are also collectively referred to as a driver state detection unit.

[0043] The detection unit 42 is a laser radar (LiDAR: Light Detection and Ranging, or Laser Imaging Detection and Ranging) (hereinafter, sometimes referred to as a laser radar 42), which detects targets around the vehicle 1, or measures the distance to the target. In the case of the present embodiment, five laser radars 42 are provided, one at each corner of the front of the vehicle 1, one at the center of the rear, and one at each side of the rear. The detection unit 43 is a millimeter wave radar (hereinafter, sometimes referred to as a radar 43), which detects targets around the vehicle 1, or measures the distance to the target. In the case of the present embodiment, five radars 43 are provided, one at the center of the front of the vehicle 1, one at each corner of the front, and one at each corner of the rear.

[0044] ECU 22 controls the camera 41 and each laser radar 42 on one side and performs information processing on the detection results. ECU 23 controls the camera 41 and each radar 43 on the other side and performs information processing on the detection results. Since there are two sets of devices for detecting the surrounding conditions of the vehicle, the reliability of the detection results can be improved. In addition, since there are different types of detection units such as cameras, laser radars, radars, etc., the surrounding environment of the vehicle (also called surrounding conditions) can be analyzed in many aspects.

[0045] ECU 24 controls the gyro sensor 5, GPS sensor 24b, and communication device 24c and performs information processing on the detection results or communication results. Gyro sensor 5 detects the turning movement of vehicle 1. The travel path of vehicle 1 can be determined based on the detection results of gyro sensor 5, wheel speed, etc. GPS sensor 24b detects the current position of vehicle 1. That is, GPS sensor 24b functions as a position information acquisition unit of the vehicle. Communication device 24c wirelessly communicates with a server that provides map information and traffic information to obtain this information. ECU 24 can access database 24a of map information constructed in a storage device, and ECU 24 performs route search from the current location to the destination, etc. ECU 24 can also be used to implement Figure 2 The vehicle position recognition unit 140 (also referred to as the position recognition unit 140) is shown. The ECU 25 has a communication device 25a for inter-vehicle communication. The communication device 25a wirelessly communicates with other surrounding vehicles to exchange information between vehicles.

[0046] ECU 26 controls the powertrain 6. The powertrain 6 is a mechanism that outputs a driving force that rotates the driving wheels of the vehicle 1, and includes, for example, an engine and a transmission. The powertrain 6 is also referred to as a driving force output device 6. For example, ECU 26 controls the output of the engine in accordance with the driver's driving operation (accelerator operation or acceleration operation) detected by the operation detection sensor (i.e., accelerator opening sensor) 7a provided on the accelerator pedal 7A, or switches the gear of the transmission according to information such as the vehicle speed detected by the vehicle speed sensor 7c. When the driving state of the vehicle 1 is automatic driving, ECU 26 automatically controls the powertrain 6 in accordance with the instruction from ECU 20 to control the acceleration and deceleration of the vehicle 1. In addition, the acceleration in each direction detected by the gyro sensor 5, the angular acceleration around the axis, and the vehicle speed detected by the vehicle speed sensor 7c are information indicating the driving state of the vehicle, and these sensors are also collectively referred to as a driving state monitoring unit. Furthermore, the driving state monitoring unit may include an operation detection sensor 7a for the accelerator pedal 7A and an operation detection sensor (i.e., brake pedal force sensor) 7b for the brake pedal 7B described later. However, in the present example, these detection units are collectively referred to as an operation state detection unit together with an unillustrated detection unit for detecting the operation state of other equipment.

[0047] The ECU 27 controls the vehicle lights (headlights, taillights, etc.) including the direction indicator 8. Figure 1 In the example of FIG. 2 , the direction indicators 8 are provided at the front, door mirrors, and rear of the vehicle 1 .

[0048] ECU 28 controls the input-output device 9. The input-output device 9 outputs information to the driver and receives information input from the driver. The sound output device 91 notifies the driver of information by sound. The display device 92 notifies the driver of information by displaying an image. The display device 92 is, for example, arranged in front of the driver's seat and constitutes an instrument panel. In addition, here, the example of notifying information by sound and display, but the information can also be notified by vibration or light. The input device 93 is arranged at a position where the driver can operate, and is a switch group that instructs the vehicle 1, but it can also include a sound input device.

[0049] ECU 29 controls the braking device 10 and the parking brake (not shown). The braking device 10 is, for example, a disc brake device, which is provided on each wheel of the vehicle 1 and applies resistance to the rotation of the wheel, thereby slowing down or stopping the vehicle 1. ECU 29 controls the operation of the braking device 10 in accordance with the driver's driving operation (brake operation) detected by the operation detection sensor 7b provided on the brake pedal 7B. When the driving state of the vehicle 1 is automatic driving, ECU 29 automatically controls the braking device 10 in accordance with the instruction from ECU 20 to control the deceleration and stopping of the vehicle 1. The braking device 10 and the parking brake can also be operated to keep the vehicle 1 in a stopped state. In addition, when the transmission of the powertrain 6 has a parking lock mechanism, it can also be operated to keep the vehicle 1 in a stopped state.

[0050] Vehicle Control Systems

[0051] Figure 2 The functional structure of the control unit 2 in this embodiment is shown. The control unit 2 is also called a vehicle control system, and is implemented by executing programs and the like by each ECU represented by the ECU 20. Figure 2 The functional blocks shown. Figure 2 In the embodiment, the vehicle 1 includes: a detection device DD, which includes a camera 41, a laser radar 42, a radar 43, etc.; a navigation device 50; a GPS sensor 24b, a communication device 24c, 25a; and a vehicle sensor 60, which includes a gyro sensor 5, a steering wheel grip sensor, a driver state detection camera 41a, etc. In addition, the vehicle 1 includes: an accelerator pedal 7A; an accelerator opening sensor 7a; a brake pedal 7B; a brake pedal amount sensor 7b; a display device 92; a sound output device 91 (such as a speaker); and a switch 93 including an automatic driving switch. In addition, the vehicle 1 is equipped with a vehicle control system 2, a driving force output device 6, a steering device 3, and a brake device 220. These devices or equipment are connected to each other through multi-channel communication lines such as CAN (Controller Area Network) communication lines, serial communication lines, wireless communication networks, etc.

[0052] The navigation device 50 has a GNSS (Global Navigation Satellite System) receiver, map information (navigation map), a touch screen display device that functions as a user interface, a speaker, a microphone, etc. The navigation device 50 determines the position of the vehicle 1 (also referred to as the vehicle itself) through the GNSS receiver and derives a path from the position to the destination specified by the user. The path derived by the navigation device 50 is provided to the target lane determination unit 110 of the vehicle control system 2. In addition, the structure for determining the position of the vehicle 1 can also be provided independently of the navigation device 50.

[0053] The GPS sensor 24b and the communication devices 24c and 25a perform wireless communication using, for example, a cellular network, a Wi-Fi network, Bluetooth (a registered trademark), DSRC (Dedicated Short Range Communication), etc. The vehicle control system can obtain information related to the current driving road, such as speed limit information (including upper speed limit, acceleration and deceleration degree), etc. through these communication devices.

[0054] The vehicle sensor 60 includes: a vehicle speed sensor for detecting vehicle speed; an acceleration sensor for detecting acceleration; a yaw rate sensor for detecting angular velocity around a vertical axis; and an azimuth sensor for detecting the direction of the vehicle 1. All or part of these sensors are implemented by the gyro sensor 5. In addition, the vehicle sensor 60 may also include a steering wheel grip sensor (not shown) and a driver state detection camera 41a.

[0055] The accelerator pedal 7A is an operating member for receiving the driver's acceleration instruction (or deceleration instruction based on the return operation). The accelerator opening sensor 7a detects the amount of depression on the accelerator pedal 7A, and outputs an accelerator opening signal indicating the amount of depression to the vehicle control system 2. In addition, instead of outputting to the vehicle control system 2, it can also be directly output to the driving force output device 6, the steering device 3, or the braking device 220. The structure of other driving operating systems described below is also the same.

[0056] The brake pedal 7B is an operating element for receiving a deceleration instruction from the driver. The brake pedal amount sensor 7b detects the pedal amount (or pedal force) of the brake pedal 7B and outputs a brake signal indicating the detection result to the vehicle control system 2 .

[0057] The display device 92 is, for example, an LCD (Liquid Crystal Display), an organic EL (Electroluminescence) display device, etc., which is provided in various parts of the instrument panel, any part facing the front passenger seat or the rear seat, etc. In addition, the display device 92 may also be a HUD (Head Up Display) that projects images on the front windshield or other windows. The sound output device 91 is, for example, a speaker that outputs sound.

[0058] The driving force output device 6 outputs the driving force (torque) for driving the vehicle to the drive wheels. The driving force output device 6 includes, for example, an engine, a transmission, and an engine ECU (Electronic Control Unit) for controlling the engine. In addition, the driving force output device 6 may be an electric motor or a hybrid mechanism combining an internal combustion engine and an electric motor.

[0059] The brake device 220 is, for example, an electric servo brake device, which includes: a brake caliper; a cylinder that transmits hydraulic pressure to the brake caliper; an electric motor that generates hydraulic pressure in the cylinder; and a brake control unit. The brake control unit of the electric servo brake device controls the electric motor based on information input from the travel control unit 160, and outputs a brake torque corresponding to the brake operation to each wheel. In addition, the brake device 220 may also include a regenerative brake, which may be composed of a travel motor included in the travel drive force output device 6.

[0060] In addition, the vehicle control system 2 includes, for example, a target lane determination unit 110, an automatic driving control unit 120, a driving control unit 160, an HMI (human machine interface) control unit 170, and a storage unit 180. The automatic driving control unit 120 includes, for example, an automatic driving state control unit 130, a position recognition unit 140, an external recognition unit 142, an action plan generation unit 144, a trajectory generation unit 146, and a switching control unit 150. The target lane determination unit 110, each unit of the automatic driving control unit 120, and a part or all of the driving control unit 160 and the HMI control unit 170 are implemented by a processor executing a program (software). In addition, a part or all of these components can be implemented by hardware such as LSI (Large Scale Integration) and ASIC (Application Specific Integrated Circuit), or can be implemented by a combination of software and hardware.

[0061] In the storage unit 180, for example, high-precision map information 182 including information on the center of the lane or information on the lane boundary, target lane information 184, action plan information 186 and other information are stored. The target lane determination unit 110 divides the path provided by the navigation device 50 into a plurality of sections (for example, divided every 100 [m] in the direction of vehicle travel), and determines the target lane for each section with reference to the high-precision map information 182. The target lane determination unit 110 determines, for example, which lane to drive on from the left. For example, in the case where there is a diverging position, a merging position, etc. in the path, the target lane determination unit 110 determines the target lane in order to enable the vehicle 1 to travel on a reasonable driving path to the diverging destination. The target lane determined by the target lane determination unit 110 is stored in the storage unit 180 as the target lane information 184. The high-precision map information 182 may be a map of the vicinity of the driving position, or may be a map information of a new position obtained by the communication device 24c or the like as the vehicle moves. The map of the vicinity of the driving position is also called a local map.

[0062] The automatic driving state control unit 130 determines the control state of the automatic driving (also referred to as the automatic driving state) implemented by the automatic driving control unit 120. The automatic driving control state in this embodiment includes a first control state and a second control state as described initially. In addition, the following is only an example, and the number of the automatic driving control states can be determined arbitrarily.

[0063] The position recognition unit 140 of the automatic driving control unit 120 recognizes the lane in which the vehicle 1 is traveling (driving lane) and the relative position of the vehicle 1 relative to the driving lane based on the high-precision map information 182 stored in the storage unit 180 and the information input from the laser radar 42, the radar 43, the camera 41, the navigation device 50 or the vehicle sensor 60. Specifically, the relative position relative to the driving lane is, for example, a position based on the center of the width direction of the lane. As described later Figure 3 to Figure 5 As described above, the first position (also called map matching position) is estimated based on the global navigation satellite system (GNSS) signal such as GPS, map information, and camera images. On the other hand, the second position (also called odometer position or dead reckoning position) is estimated, which is a position obtained by adding the movement amount of the vehicle 1 estimated based on the signal such as the vehicle speed input from the vehicle sensor 60 to the reference position, such as the latest determined position. The first position and the second position are synthesized by a complementary filter to determine the position.

[0064] The driving control unit 160 controls the driving force output device 6, the steering device 3, and the braking device 220 so that the vehicle 1 passes through the trajectory generated by the trajectory generation unit 146 at a predetermined time. The HMI control unit 170 causes the display device 92 to display images and pictures, and causes the sound output device 91 to output sound. The driving control unit 160 determines the steering angle (system turning angle) for example, in order to perform automatic driving according to the action plan information 186, and inputs it to the steering device 3 to perform wheel control. In addition, for example, the curve of the lane in which the vehicle is traveling can be identified through the high-precision map information 182 and the external recognition unit 142 described later.

[0065] The external recognition unit 142 recognizes the position, speed, acceleration and other states of the target objects such as surrounding vehicles based on the information input from the camera 41, the laser radar 42, the radar 43 and the like. In addition, in addition to identifying surrounding vehicles, the external recognition unit 142 can also identify the positions of guardrails, telephone poles, parked vehicles, pedestrians and other objects. And, in this embodiment, the traffic signs on the roadside contained in the captured image are identified. The identified road signs are referred to for automatic driving control. In this example, in particular, the speed signs in the form of electronic bulletins are identified to determine the speed limit displayed. The action plan generation unit 144 prepares an action plan in a manner not to exceed the speed limit, and the driving control unit 160 controls driving according to the action plan.

[0066] The action plan generation unit 144 sets the starting point of the automatic driving and / or the destination of the automatic driving. The starting point of the automatic driving may be the current position of the vehicle 1 or the location where the operation of instructing the automatic driving is performed. The action plan generation unit 144 generates an action plan for the interval between the starting point and the destination of the automatic driving. In addition, the action plan generation unit 144 is not limited to this, and the action plan generation unit 144 may also generate an action plan for an arbitrary interval.

[0067] The action plan is composed of, for example, a plurality of events that are executed in sequence. The events include, for example: a deceleration event that decelerates the vehicle 1; an acceleration event that accelerates the vehicle 1; a lane keeping event that causes the vehicle 1 to travel without deviating from the driving lane; a lane change event that changes the driving lane; an overtaking event that causes the vehicle 1 to overtake the vehicle in front; a diverging event that causes the vehicle 1 to travel at a diverging point in a manner of changing to a desired lane or in a manner of not deviating from the current driving lane; a merging event that causes the vehicle 1 to change the driving lane by accelerating or decelerating in a merging lane for merging into a main road; a handover event that switches from an automatic driving control state to a manual driving control state at a predetermined end point of the automatic driving, and the like. The action plan generation unit 144 sets a lane change event, a diverging event, or a merging event at the position where the target lane determined by the target lane determination unit 110 is switched. Information indicating the action plan generated by the action plan generation unit 144 is stored in the storage unit 180 as action plan information 186.

[0068] Structure of the Position Recognition Unit

[0069] Figure 3 1 shows a block diagram of the position recognition unit 140. The map matching position estimation unit 301 estimates a first position (map matching position) based on a basic position determined by a GNSS signal, detailed map information, and a camera image captured by the camera 41. The basic position contains an error, and the map matching position estimation unit 301 corrects the error by, for example, comparing the map information of the position determined by the basic position information with the camera image. It is also possible to identify the boundary marking line of the lane being traveled based on the camera image, and estimate the position in the width direction of the road based on the position of the identified boundary marking line.

[0070] The odometer position estimation unit 302 estimates the second position (odometer position) using the position determined last time (previous local map position) and the movement amount of the vehicle 1 as input. For example, the movement amount of the vehicle 1 can be determined by integrating the velocity vector from the time when the previous position was determined to the present time, wherein the velocity vector is determined based on the vehicle speed detected by the vehicle speed sensor 7c and the travel direction detected by the azimuth sensor or the steering angle sensor. The odometer position is estimated by adding the movement amount of the vehicle to the previous local map position as the reference position.

[0071] The complementary filter 303 uses the map matching position as the input of the low-pass filter and the odometer position as the input of the high-pass filter, and outputs a new local map position obtained by synthesizing the two. During synthesis, the overlapping frequency band of the two filters can also be multiplied by a predetermined coefficient and adjusted as a complementary filter so that the overall frequency band has the same gain. That is, the complementary filter 303 functions as a positioning unit. In addition, the complementary filter 303 is configured to be able to set a time constant. The determined local map position is stored in the latch 305 until a new local map position is output again. The stored local map position is fed back to the odometer position estimation unit 302 and used as a reference position for the next positioning.

[0072] The time constant determination unit 304 determines the time constant of the complementary filter 303 using the vehicle speed as a parameter, and sets the time constant in the complementary filter 303. In addition, the position includes, for example, longitude and latitude and the direction (azimuth) of the vehicle. Therefore, filtering is performed on the longitude, latitude, and azimuth respectively. A complementary filter with the same characteristics can be used for longitude and latitude, and a complementary filter with different characteristics from the former can also be used for azimuth.

[0073] Vehicle speed and time constant

[0074] Figure 4 An example of the relationship between the vehicle speed and the time constant output by the time constant determination unit 304 is shown. Figure 4 (A) shows the time constant of the complementary filter of latitude and longitude, Figure 4 (B) shows the time constant of the complementary filter of the azimuth angle. In this way, different time constants can be set for longitude and latitude and azimuth angle. Figure 4 In (A), if the vehicle speed is below the first threshold value V1, the time constant determination unit 304 outputs the maximum value, i.e., the first value CG1, as the time constant. When the vehicle speed reaches the second threshold value V3 after passing V2, the time constants CG2 and CG3 that decrease linearly according to the vehicle speed are output as the time constants. When the vehicle speed exceeds the second threshold value V3, the minimum value, i.e., the second value CG3, is output as the time constant. Figure 4 The azimuth of (B) is the same, but the maximum value is CD1 and the minimum value is CD3. Figure 4 In addition, Figure 4 (A) and Figure 4 In (B), the vehicle speed thresholds V1 and V3 are the same value, but may be different values.

[0075] Figure 5 An example of a characteristic diagram of the complementary filter 303 is shown. Figure 5The following figure shows the general characteristics of the complementary filters for longitude and latitude and for azimuth included in the complementary filter 303. Although these filters have different specific values, they have the same characteristics. The vehicle speeds V1 and V3 as thresholds may be, for example, V1 at a value of about 0.5 km / h and V3 at a value of about 2 km / h. It is desirable that V1 is a value greater than 0.

[0076] Complementary filter characteristics

[0077] Figure 5 (A) shows the characteristics of the complementary filter 303 when the vehicle speed is below V1, that is, the vehicle speed is below a predetermined speed, and the time constant is CG1 or CD1. The cutoff frequency F1 in this case is the frequency corresponding to the maximum value of the time constant CG1 or CD1. In this case, the cutoff frequencies of the low-pass filter characteristic 501 and the high-pass filter characteristic 502 are both the lowest, and the output components of the complementary filter 303 are such that the components on the high-pass filter side are dominant up to the low-frequency region. That is, the odometer position is dominant. That is, the position weighted by the odometer position is output as the local map position. It can also be set as the following feature: the map matching position is shielded across all frequency components, and the odometer position is output as the local map position as is.

[0078] Figure 5 (C) shows the characteristic of the complementary filter 303 when the vehicle speed exceeds V3, that is, the time constant is CG3 or CD3. The cutoff frequency F3 in this case is the frequency corresponding to the minimum value CG3 or CD3 of the time constant. In this case, the cutoff frequencies of the characteristic 521 of the low-pass filter and the characteristic 522 of the high-pass filter are both the highest, and the output of the complementary filter 303 is that up to the high-frequency region, the low-pass filter side, that is, the map matching position becomes the dominant component. That is, the position weighted by the map matching position is output as the local map position. It can also be set to the following characteristics: the odometer position is shielded throughout all frequency components, and the map matching position is output as the local map position as it is.

[0079] Figure 5 (B) shows the characteristics of the complementary filter 303 when the vehicle speed is V2, which is between V1 and V3. The cutoff frequency F2 is a value between the frequencies F1 and F3. In the intermediate region, as the vehicle speed increases, the time constant decreases, and the cutoff frequency of the complementary filter 303 increases continuously or in stages. Accordingly, the local map position output from the complementary filter 303 is, and the map matching position becomes an increasingly dominant component.

[0080] The change in the characteristics of the complementary filter 303 corresponding to the setting of such a time constant can be realized, for example, as follows. In the case of a digital filter, the values ​​of the latitude, longitude, and azimuth input in time sequence are stored for a predetermined time and transformed into the frequency domain by discrete cosine transform. For the transformed values, the filter matrix is ​​used to weight each frequency component, and an inverse transform is performed to restore it to the original spatial region. Here, Figure 5 A filter matrix of the characteristics shown is prepared in advance in association with a time constant, and filtering is performed using the filter matrix associated with the input time constant. The number of filter matrices that can be prepared is limited, so a filter matrix associated with a time constant that is similar to the input time constant may also be used. Alternatively, the following filter matrix may be used: a matrix generated by selecting filter matrices associated with two pre-prepared time constants sandwiching the input time constant and performing linear interpolation on these filter matrices.

[0081] Alternatively, the input latitude and longitude or azimuth values ​​may be converted into analog values ​​and filtered using a complementary filter of an analog structure. In this case, a complementary filter having characteristics corresponding to a time constant may be prepared in advance and switched according to the time constant for filtering.

[0082] In either case, by preparing filters having characteristics according to the time constant in advance and switching and using these filters according to the time constant, it is possible to use complementary filters having characteristics according to the vehicle speed.

[0083] Example of control

[0084] Figure 6 Show Figures 3 to 5 An example of positioning of a vehicle shown. The lowermost portion shows the temporal variation of the vehicle speed. The middle portion shows the variation of the time constant of the complementary filter 303 corresponding to the vehicle speed. The time constant is illustrated using one filter as an example. The upper portion shows examples of local map positions that have passed through an adaptive complementary filter 303 that sets the time constant according to the vehicle speed, and a local map position that has passed through a complementary filter whose time constant is fixed to a value corresponding to a second threshold value V3 of the vehicle speed, such as CG1 or CD1. The values ​​obtained using the adaptive complementary filter 303 are represented by circles, and the values ​​obtained using the fixed complementary filter are represented by dots and lines. In addition, the local map position is represented by a relative position with respect to the center line in the width direction of the driving lane.

[0085] When the vehicle speed exceeds the second threshold value V3, the time constant is fixed to CG3, for example. In this case, the local map position obtained using any complementary filter indicates the same position. When the vehicle speed is below the second threshold value V3, that is, it becomes an extremely low speed, the time constant increases according to the speed and reaches a maximum value at the vehicle speed V1. At this time, the characteristics of the adaptive complementary filter 303 change, and the high-pass filter side, that is, the odometer position, is dominant until the low-frequency component. As a result, in the output from the complementary filter 303, the position deviation caused by the misrecognition of the demarcation line from the camera image, etc. can be suppressed, and the position during the stop also stably shows the same position.

[0086] On the other hand, the output from the complementary filter with a fixed time constant reflects the position deviation caused by the misrecognition of the demarcation line from the camera image, and the position of the vehicle is unstable even when stopped, and the output value deviates with the passage of time. When the vehicle starts to move and the vehicle speed exceeds the second threshold value V3, the characteristics of the complementary filters of both sides are consistent again and stably show the same position.

[0087] As described above, according to the present embodiment, a complementary filter whose characteristics can be changed according to the vehicle's driving speed is used to synthesize the map matching position and the odometer position. In particular, the map matching position is used as the input of the low-pass filter, and the odometer position is used as the input of the high-pass filter, and the cutoff frequency is increased as the vehicle speed decreases. Accordingly, a position with the odometer position as the main component can be obtained even in a low-speed area, thereby stabilizing the position with high precision. Therefore, intervention in the automatic driving due to an error in the determined position can be prevented, for example, the change of the automatic driving level can be prevented.

[0088] [Other embodiments]

[0089] In the above embodiment, a complementary filter is used to synthesize the map matching position and the odometer position, but it can also be configured so that a switch is used to selectively output either one. For example, it can also be configured so that when more than Figure 4 When the vehicle speed is higher than the first threshold V1, the map matching position is output as the local map position, and when the vehicle speed is lower than the first threshold V1, the odometer position is output as the local map position. According to this structure, in addition to the effects of the above embodiment, the structure is simpler and the responsiveness can be improved.

[0090] Summary of implementation methods

[0091] The present embodiment described above is summarized as follows.

[0092] (1) According to a first aspect of the present invention, there is provided a positioning device, characterized in that it comprises:

[0093] a photographing component that photographs an image of the front of the vehicle;

[0094] A position information acquisition component, which acquires the position information of the vehicle;

[0095] a first position estimating component, which estimates a first position of the vehicle according to the position of the lane contained in the image, the acquired position information of the vehicle, and the map information;

[0096] a second position estimating means for estimating a second position of the vehicle based on the most recently determined position and the amount of movement of the vehicle; and

[0097] a positioning component that combines the first position and the second position to determine a position,

[0098] When the vehicle is traveling at a speed equal to or lower than a predetermined speed, the positioning unit assigns a weight to the second position and combines the first position and the second position.

[0099] This makes it possible to determine the position with high accuracy even in a low-speed range.

[0100] (2) According to a second aspect of the present invention, there is provided the positioning device according to aspect (1), wherein the positioning means increases the weight of the second position as the speed of the vehicle decreases.

[0101] According to this, as the speed decreases, more weight can be given to the second position based on the movement amount of the vehicle, thereby preventing the influence of the error of the first position.

[0102] (3) According to a third aspect of the present invention, there is provided a positioning device according to aspect (1) or (2), wherein before the vehicle stops, the positioning component determines the position based only on the information of the second position.

[0103] According to this, positioning can be performed using only the second position based on the movement amount of the vehicle, especially at an extremely low speed before stopping, and the influence of the error of the first position can be eliminated.

[0104] (4) According to a fourth embodiment of the present invention, a positioning device as described in any one of embodiments (1) to (3) is provided, characterized in that the positioning component includes a complementary filter, which filters the first position with a low-pass filter and filters the second position with a high-pass filter to synthesize the first position and the second position.

[0105] Thereby, it is possible to weight the first position and the second position corresponding to the frequency components.

[0106] (5) According to a fifth aspect of the present invention, there is provided a positioning device according to aspect (4), wherein the positioning means changes a time constant of the complementary filter according to a speed of the vehicle, thereby assigning a weight to the second position.

[0107] According to this, by using a complementary filter whose time constant is changed according to the speed, it is possible to continuously change the characteristics of the filter and weight the first position and the second position.

[0108] The invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the gist of the invention.

Claims

1. A positioning device, characterized in that: have: a photographing component that photographs an image of the front of the vehicle; A position information acquisition component, which acquires the position information of the vehicle; a first position estimating component, which estimates a first position of the vehicle according to the position of the lane contained in the image, the acquired position information of the vehicle, and the map information; a second position estimating means for estimating a second position of the vehicle based on the most recently determined position of the vehicle and the amount of movement of the vehicle; as well as a positioning component that combines the first position and the second position to determine the position of the vehicle, When the vehicle is traveling at a speed lower than a predetermined speed, the positioning unit assigns a weight to the second position, synthesizes the first position and the second position, The positioning component includes a complementary filter, and the complementary filter filters the first position with a low-pass filter and filters the second position with a high-pass filter to synthesize the first position and the second position.

2. The positioning device according to claim 1, characterized in that: The positioning unit increases the weight of the second position as the speed of the vehicle decreases.

3. The positioning device according to claim 1, characterized in that: Before the vehicle stops, the positioning component determines the position of the vehicle based only on the information of the second position.

4. The positioning device according to claim 1, characterized in that: The positioning means changes a time constant of the complementary filter according to a speed of the vehicle, thereby giving a weight to the second position.

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