Position estimation device and position estimation method

Abstract

To switch to position estimation using a locator at appropriate timing.SOLUTION: A position estimation device 30 according to the present invention includes: an acquisition unit 321 that acquires the illuminance around the vehicle; an estimation unit 322 that estimates the position and orientation of the vehicle at a second time that is a first hour after the first time based on the position of the vehicle at a first time, the vehicle speed, and map information including lane information; and a switching unit 323 that switches from a first position estimation that estimates the position of the vehicle using the imaging device 10 to a second position estimation that estimates the position of the vehicle using a locator provided in the vehicle, at least before the second time, when the illuminance around the vehicle at the first time is equal to or greater than a threshold and the imaging direction of the imaging device 10 provided in the vehicle at the second time is facing the sun.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a position estimation device and a position estimation method. [Background technology]

[0002] If the adverse environment judgment device of Patent Document 1 determines that the camera equipped in the vehicle may be affected by the setting sun, it avoids a situation where it cannot estimate the vehicle's position by switching from position estimation based on images captured by the camera to position estimation using a locator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-14729 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, in response to a decline in the reliability of position estimation based on an image captured by a camera, position estimation using a locator is switched to, and therefore the accuracy of position estimation declines immediately before switching to position estimation using a locator. As a result, there is a problem in that there are times when the behavior of the vehicle becomes unstable when automatic steering of the vehicle is performed based on position estimation.

[0005] Therefore, the present invention has been made in consideration of these points, and an object of the present invention is to switch to position estimation using a locator at an appropriate timing. [Means for solving the problem]

[0006] A position estimation device according to a first aspect of the present invention includes an acquisition unit that acquires illuminance around a vehicle; an estimation unit that estimates a position and orientation of the vehicle at a second time that is one hour after a first time based on the position of the vehicle at a first time, the vehicle speed, and map information including lane information; and a switching unit that switches from a first position estimation that estimates the position of the vehicle using the imaging device to a second position estimation that estimates the position of the vehicle using a locator provided in the vehicle, at least before the second time, when the illuminance around the vehicle at the first time is equal to or greater than a threshold and the imaging direction of an imaging device provided in the vehicle at the second time is facing the sun.

[0007] The switching unit may switch from the second position estimation to the first position estimation under the condition that, at a time after the time of switching from the first position estimation to the second position estimation, the illuminance changes from a state where it is greater than or equal to the threshold to a state where it is less than the threshold, or the imaging direction changes from a state where it is facing the sun to a state where it is not facing the sun.

[0008] The estimation unit may estimate a position and orientation of the vehicle during a second time from the second time to a third time, and the switching unit may switch from the second position estimation to the first position estimation when the illuminance at the first time is equal to or greater than the threshold value, on the condition that the period during which the imaging direction is determined to be facing the sun based on the position and height of the sun and the position and orientation of the vehicle during the second time is less than a predetermined number of times during the second time.

[0009] The vehicle steering system may further include a determination unit that determines a steering angle and a steering torque of the vehicle based on a first error between an estimated position of the vehicle estimated using the imaging device and a target position of the vehicle based on an image captured by the imaging device, or a second error between an estimated position of the vehicle estimated using the locator and a target position based on the map information, and the determination unit may correct the first error or the second error so that the first error and the second error match at a time when a predetermined time has elapsed since the switching unit switched between the first position estimation and the second position estimation.

[0010] When the switching unit determines that the illuminance around the vehicle is less than the threshold, or that the illuminance is greater than or equal to the threshold and the imaging direction is not toward the sun, the switching unit may switch from the first position estimation to the second position estimation, on the condition that a lane branch or merging point is present within a predetermined range from the position of the vehicle at the second time estimated by the estimation unit.

[0011] The switching unit may switch from the second position estimation to the first position estimation under the following conditions: at a time after the time of switching from the first position estimation to the second position estimation, the illuminance is less than the threshold or the imaging direction is not facing the sun, and a state has changed from one in which there is a lane branching or merging point within the specified range from the position of the vehicle to one in which there is no lane branching or merging point within the specified range from the position of the vehicle.

[0012] When the switching unit determines that the illuminance around the vehicle is less than the threshold, or that the illuminance is greater than or equal to the threshold and the imaging direction is not toward the sun, the switching unit may switch from the first position estimation to the second position estimation, on the condition that the distance between the position of the vehicle at the first time and the position of a vehicle preceding the vehicle at the first time is less than a predetermined distance.

[0013] The switching unit may switch from the second position estimation to the first position estimation under the condition that, at a time after the time of switching from the first position estimation to the second position estimation, the illuminance is less than the threshold or the imaging direction is not facing the sun, and the distance between the position of the vehicle and the position of a vehicle preceding the vehicle has changed from less than the specified distance to greater than the specified distance.

[0014] A position estimation method according to a second aspect of the present invention includes an acquisition step executed by a processor to acquire illuminance around a vehicle; an estimation step to estimate a position and orientation of the vehicle at a second time that is one hour after a first time based on a position of the vehicle at a first time, a vehicle speed of the vehicle, and map information including lane information; and a switching step to switch, at least before the second time, from a first position estimation that estimates the position of the vehicle using an imaging device to a second position estimation that estimates the position of the vehicle using a locator provided in the vehicle, if the illuminance around the vehicle at the first time is equal to or greater than a threshold and the imaging direction of an imaging device provided in the vehicle at the second time is facing the sun. Effect of the Invention

[0015] According to the present invention, an effect of switching to location estimation using a locator at an appropriate timing is achieved. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a diagram for explaining an overview of a vehicle S according to the present embodiment. [Diagram 2] 2 is a diagram showing the imaging direction of an imaging device 10 provided in a vehicle S. FIG. [Diagram 3] FIG. 11 is a diagram for explaining an operation of switching the position estimation process. [Figure 4] FIG. 1 is a diagram for explaining a vehicle S traveling on a lane including multiple curves. [Diagram 5] 11 is a sequence showing an operation for switching from a first position estimation to a second position estimation. [Figure 6]11 is a sequence showing an operation for switching from the second position estimation to the first position estimation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] <Overview of Vehicle S> Fig. 1 is a diagram for explaining an overview of a vehicle S according to this embodiment. The vehicle S shown in Fig. 1 includes an imaging device 10, a white line recognition device 11, a receiving device 12, an inertial measurement device 13, a self-position recognition device 14, an illuminance sensor 15, a vehicle speed sensor 16, a steering control device 20, and a position estimation device 30.

[0018] The vehicle S has a function of performing automatic steering by identifying the lane in which the vehicle S is traveling and the position and orientation of the vehicle S on that lane every time a predetermined time (e.g., 20 milliseconds) has elapsed, and determining the steering angle and steering torque so that the vehicle S travels along a target trajectory on the lane. The target trajectory is, for example, a line connecting the center position of the lane in the width direction of the lane (hereinafter, sometimes referred to as the "target position") in the length direction of the lane along the shape of the lane. Furthermore, when automatic steering is not performed, the vehicle S travels by manual steering performed by the operator.

[0019] The imaging device 10 is a camera for capturing an image of the surroundings of the vehicle S to generate a captured image, and generates a captured image of an area including lane markings (e.g., white lines) of the lane on which the vehicle S is traveling.

[0020] The white line recognition device 11 is a first position estimation device for estimating the distance (hereinafter referred to as the "first estimated distance") between the position of the vehicle S and a target position corresponding to the position of the vehicle S on the lane on which the vehicle S is traveling. As an example, the position of the vehicle S is the center of the vehicle S in the vehicle width direction of the vehicle S and the center of the vehicle S in the length direction of the vehicle S, but is not limited to this. The position of the vehicle S may be a position indicating the center of the driver's seat of the vehicle S, or may be the center of the vehicle S in the vehicle width direction at the front end of the vehicle S. The target position corresponding to the position of the vehicle S is, for example, a center position in the width direction of the lane on which the vehicle S is traveling.

[0021] The white line recognition device 11, for example, extracts a white line from the captured image generated by the imaging device 10 to identify a target position corresponding to the position of the vehicle S and the center position of the vehicle S, and estimates a first estimated distance. The white line recognition device 11 also estimates the orientation of the vehicle S (hereinafter referred to as "first estimated orientation") by extracting the white line from the captured image. In the following description, the process in which the white line recognition device 11 estimates the first estimated distance and the first estimated orientation is referred to as "first position estimation."

[0022] The receiving device 12 is a device for receiving radio waves from an external positioning system such as a Global Navigation Satellite System (GNSS). The receiving device 12 calculates the position (e.g., latitude and longitude) of the vehicle S and identifies the current time (including date and time) based on information included in the received radio waves. Note that the "time" in this embodiment includes the "date and time". The inertial measurement unit 13 is, for example, an IMU (Inertial Measurement Unit), and includes a gyro sensor that detects the angular velocity of the vehicle S and an acceleration sensor that detects the acceleration of the vehicle S. The inertial measurement unit 13 identifies the orientation of the vehicle S (hereinafter, may be referred to as a "second estimated orientation") based on the detected angular velocity. By the inertial measurement unit 13 identifying the second estimated orientation, the vehicle S can perform automatic steering using the second estimated orientation even when the white line recognition device 11 cannot estimate the first estimated orientation.

[0023] The self-location recognition device 14 is a second position estimation device for estimating a distance (hereinafter referred to as a "second estimated distance") between the position of the vehicle S and a target position corresponding to the position of the vehicle S in the lane in which the vehicle S is traveling, and is a so-called locator. The self-location recognition device 14 estimates a target position corresponding to the position of the vehicle S in the lane in which the vehicle S is traveling and the position of the vehicle S based on, for example, the position of the vehicle S acquired from the receiving device 12 and map information including the position of the lane's lane markings. Then, the self-location recognition device 14 estimates a second estimated distance based on the estimated target position and the position of the vehicle S. By estimating the second estimated distance by the self-location recognition device 14, the vehicle S can perform automatic steering using the second estimated distance estimated by the self-location recognition device 14 even if the white line recognition device 11 cannot estimate the first estimated distance. In the following description, the process in which the self-location recognition device 14 estimates the second estimated distance and the inertial measurement device 13 specifies the second estimated orientation is referred to as a "second position estimation".

[0024] The illuminance sensor 15 is a sensor for detecting the illuminance around the vehicle S. The vehicle speed sensor 16 is a sensor for detecting the vehicle speed of the vehicle S. The steering control device 20 is a device for adjusting the direction in which the vehicle S travels, based on the steering angle and steering torque of the vehicle S determined by the position estimation device 30.

[0025] The position estimation device 30 is a housing including electronic components or a printed circuit board on which electronic components are mounted. The position estimation device 30 executes a process of determining a steering angle and a steering torque for the vehicle S to travel along a target trajectory based on a first estimated distance and a first estimated orientation estimated by the white line recognition device 11, or a second estimated distance estimated by the self-position recognition device 14 and a second estimated orientation specified by the inertial measurement device 13. The position estimation device 30 outputs the determined steering angle and steering torque to the steering control device 20, thereby executing automatic steering of the vehicle S.

[0026] The first estimated distance estimated by the white line recognition device 11 has a smaller error from the actual distance than the second estimated distance estimated by the self-location recognition device 14. Therefore, the position estimation device 30 can perform automatic steering with high accuracy by determining the steering torque using the first estimated distance estimated by the white line recognition device 11 without using the second estimated distance estimated by the self-location recognition device 14. However, when the imaging direction of the imaging device 10 is facing the sun (so-called backlit state), the white line recognition device 11 may erroneously estimate the first estimated distance and the first estimated direction because it cannot extract the lane markings from the captured image.

[0027] Therefore, when the conventional vehicle S detects a backlighting state, it switches from the first position estimation to the second position estimation. That is, when the conventional position estimation device 30 does not detect a backlighting state, it determines the steering angle and steering torque using the first estimated distance and the first estimated orientation, and when it detects a backlighting state, it determines the steering angle and steering torque using the second estimated distance and the second estimated orientation.

[0028] However, it takes time from the detection of backlight to the completion of switching to the second position estimation. Therefore, if the error between the first estimated distance and the first estimated direction estimated by the white line recognition device 11 and the actual distance and direction becomes large during the switching from the detection of backlight to the second position estimation, the position estimation device 30 will determine an incorrect steering angle and steering torque.

[0029] Therefore, the position estimation device 30 estimates the position and orientation of the vehicle S at a time when a predetermined time (e.g., 3 minutes) has elapsed, and determines whether the imaging direction is backlit based on the estimated position and orientation of the vehicle S and the position and height of the sun at that time. Then, when the position estimation device 30 determines that the imaging direction is backlit at the time when the predetermined time has elapsed, it switches from the first position estimation to the second position estimation. In this way, by the position estimation device 30 switching from the first position estimation to the second position estimation at the current time that is sufficiently before the time when the imaging direction becomes backlit, it is possible to prevent the steering angle and steering torque from being determined using an erroneous estimation result at the time when the predetermined time has elapsed. As a result, the position estimation device 30 can prevent the behavior of the vehicle S from being disturbed due to automatic steering. The configuration and operation of the position estimation device 30 will be described in detail below.

[0030] <Configuration of position estimation device 30> The position estimation device 30 includes a storage unit 31 and a control unit 32. The control unit 32 includes an acquisition unit 321, an estimation unit 322, a switching unit 323, and a determination unit 324.

[0031] The storage unit 31 has a storage medium such as a read only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), or a solid state drive (SSD). The storage unit 31 stores a program executed by the control unit 32, and various information for determining the steering angle and steering torque of the vehicle S. As an example of the various information, the storage unit 31 stores map information including lane information indicating the positions of lane markings, and solar radiation information indicating the position and height of the sun for each date and time.

[0032] The control unit 32 is a processor such as a CPU (Central Processing Unit) or an ECU (Electronic Control Unit). The control unit 32 executes a program stored in the storage unit 31 to function as an acquisition unit 321, an estimation unit 322, a switching unit 323, and a determination unit 324. The control unit 32 may be configured with one processor, or may be configured with multiple processors or a combination of one or more processors and an electronic circuit. The configuration of each unit realized by the control unit 32 will be described below.

[0033] The acquisition unit 321 acquires, at each unit time elapsed, the distance between the target position of the vehicle S on the lane and the position of the vehicle S, the orientation of the vehicle S, the illuminance around the vehicle S, the vehicle speed of the vehicle S, the position of the vehicle S, and the current time. The unit time is, for example, 20 milliseconds. The acquisition unit 321 acquires, for example, a first estimated distance between the target position of the vehicle S on the lane and the position of the vehicle S estimated by the white line recognition device 11, and a first estimated orientation of the vehicle S. The acquisition unit 321 acquires, for example, a second estimated distance between the target position of the vehicle S on the lane and the position of the vehicle S estimated by the self-position recognition device 14, and a second estimated orientation of the vehicle S identified by the inertial measurement unit 13.

[0034] The acquisition unit 321 acquires the illuminance around the vehicle S detected by the illuminance sensor 15. The acquisition unit 321 acquires the vehicle speed of the vehicle S detected by the vehicle speed sensor 16. The acquisition unit 321 acquires the position of the vehicle S and the current time from the receiving device 12. The acquisition unit 321 acquires point cloud data measured and generated by a three-dimensional laser measuring device (not shown) such as a LiDAR (Light Detection And Ranging) equipped in the vehicle S, or an inter-vehicle distance calculated by an external device (not shown) from an image captured and generated by the imaging device 10. The inter-vehicle distance is the distance between the vehicle S and a vehicle preceding the vehicle S. The acquisition unit 321 may acquire the above parameters from a device other than the above devices. That is, the source (output source) of the data acquired by the acquisition unit 321 is not limited to the above configuration, and may be a detector or a detection method other than the above.

[0035] The estimation unit 322 estimates the position and orientation of the vehicle S at a second time when a first hour has elapsed since the first time, based on the position of the vehicle S at the first time, the vehicle speed of the vehicle S, and map information stored in the memory unit 31. The first time is, for example, the current time (date and time) acquired by the acquisition unit 321. The time when a unit time has elapsed and the first time may be the same time or different times. The first time is, for example, a fixed value of 3 minutes or more and 5 minutes or less. The estimation unit 322 estimates the position and orientation of the vehicle S at the second time, for example, for each unit time.

[0036] For example, by referring to map information stored in the memory unit 31, the estimation unit 322 identifies a lane including the position of the vehicle S acquired by the acquisition unit 321, and identifies the traveling direction of the vehicle S based on the second estimated orientation acquired by the acquisition unit 321 from the inertial measurement unit 13. Then, the estimation unit 322 estimates the position and orientation of the vehicle S at a second time that is a first time after the current time, based on the vehicle speed of the vehicle S acquired by the acquisition unit 321.

[0037] The estimation unit 322 may estimate the second estimated position and the second estimated orientation by referring to driving plan information indicating a driving path (driving route) set in advance by an operator of the vehicle S. The estimation unit 322, for example, identifies the position of the vehicle S acquired by the acquisition unit 321 on the driving route (the position of the vehicle S at the first time) by referring to the driving plan information stored in the storage unit 31. Then, the estimation unit 322 estimates the position of the vehicle S on the driving route at the second time based on the vehicle speed and the driving route of the vehicle S, and estimates the second estimated position and the second estimated orientation based on the estimated position of the vehicle S and the driving route.

[0038] The estimation unit 322 may further estimate the position and orientation of the vehicle S during the second time period from the second time to the third time period. The second time period is, for example, a fixed value of 3 minutes or more and 5 minutes or less, but may be the same as the first time period or may be different from the first time period. The estimation unit 322, for example, by referring to map information stored in the storage unit 31, estimates a route in the case where the vehicle S travels at the vehicle speed acquired by the acquisition unit 321 from the position of the vehicle S at the second time period estimated by the estimation unit 322 during the second time period. Then, the estimation unit 322 estimates the position and orientation of the vehicle S for each time period after a predetermined time has elapsed from the second time period based on the estimated route. By the estimation unit 322 operating in this manner, the switching unit 323 can know the number of times that the state in which the imaging direction faces the sun and the state in which the imaging direction does not face the sun are switched. Details of the switching unit 323 will be described later.

[0039] The switching unit 323 switches between the position estimation process (i.e., the first position estimation and the second position estimation) of the vehicle S for determining the steering angle and steering torque by the determination unit 324. That is, the switching unit 323 controls whether the determination unit 324 determines the steering angle and steering torque using the first estimated distance and the first estimated orientation, or determines the steering angle and steering torque using the second estimated distance and the second estimated orientation.

[0040] When the illuminance around the vehicle S at the first time is equal to or greater than the threshold and the imaging direction of the imaging device 10 included in the vehicle S faces the sun at the second time, the switching unit 323 switches from the first position estimation to the second position estimation at least before the second time is reached. The threshold is a lower limit value when direct sunlight hits the angle of view of the imaging device 10, and is determined by experiment or simulation. Below, we will explain in detail the operation of the switching unit 323 to switch from the first position estimation, which estimates the position of the vehicle S using the imaging device 10, to the second position estimation, which estimates the position of the vehicle S using a self-location recognition device (i.e., a locator) equipped in the vehicle S.

[0041] First, when the illuminance around the vehicle S at a first time is equal to or greater than a threshold value, the switching unit 323 determines whether or not the imaging direction of the imaging device 10 provided in the vehicle S faces the sun, based on the position and height of the sun at a second time and the position and orientation of the vehicle S at the second time. Note that, in this embodiment, for ease of explanation, an operation of determining whether or not the imaging direction faces the sun based on the position of the sun, out of the position and height of the sun, will be described.

[0042] Fig. 2 is a diagram showing the imaging direction of the imaging device 10 provided in the vehicle S. In Fig. 2, the vehicle S1 shown by the solid line is the vehicle S at the first time (i.e., the current time), the vehicle S2 shown by the dashed line is the vehicle S at the second time, and the vehicle S3 shown by the dashed line is the vehicle S at the third time. Fig. 2 shows the imaging direction D1 and imaging range A1 of the imaging device 10 at the first time, the imaging direction D2 and imaging range A2 of the imaging device 10 at the second time, the imaging direction D3 and imaging range A3 of the imaging device 10 at the third time, the lane R1, the sun F, and the sunlight L. At the first time, the imaging direction D1 of the imaging device 10 and the sunlight L are perpendicular to each other, so the imaging direction of the imaging device 10 provided in the vehicle S1 does not face the sun.

[0043] For example, when the illuminance around the vehicle S1 at the first time acquired by the acquisition unit 321 is equal to or greater than a threshold value, the switching unit 323 identifies the position of the sun F at the second time by referring to the solar radiation information stored in the storage unit 31. The switching unit 323 determines whether the imaging direction D2 faces the direction of the sun F or not, based on the position and orientation of the vehicle S (i.e., the vehicle S2) at the second time estimated by the estimation unit 322 and the identified position of the sun F. Specifically, when the angle θ between the imaging direction D2 and the direction of the sunlight L shown in FIG. 2 is equal to or greater than a predetermined angle, the switching unit 323 determines that the imaging direction faces the sun, and when the angle θ is less than the predetermined angle, the switching unit 323 determines that the imaging direction does not face the sun. The predetermined angle is an angle at which a backlit state can be identified, and is determined by an experiment or a simulation.

[0044] Next, the switching unit 323 switches from the first position estimation of the vehicle S using the imaging device 10 to the second position estimation using a locator (self-location recognition device 14 shown in FIG. 1) included in the vehicle S before the second time arrives, on the condition that it is determined that the imaging direction is facing the sun. FIG. 3 is a diagram for explaining the operation of switching the position estimation process. The horizontal axis of FIG. 3 indicates time. The vertical axis of FIG. 3 indicates the "illuminance" acquired by the acquisition unit 321, the "imaging direction" at each time, the "estimated imaging direction" at the second time when the first hour has elapsed from each time, the "position estimation process" switched by the switching unit 323, the "branch / junction" indicating the presence or absence of a branch point or junction around the vehicle S at the second time, and the "inter-vehicle distance" between the vehicle S and the preceding vehicle of the vehicle S at each time. In FIG. 3, the state in which the imaging direction is facing the sun is indicated as "backlit," and the state in which the imaging direction is not facing the sun is indicated as "frontlit."

[0045] For example, at a time when time T1 has passed, the switching unit 323 determines that the imaging direction at time T2 when a first time has passed since time T1 (i.e., the "estimated imaging direction" at the time when time T1 has passed) is backlit. Then, at a time before time T2, the switching unit 323 switches the position estimation process from the first position estimation using the imaging device 10 to the second position estimation using the self-location recognition device 14 (i.e., a locator). By the switching unit 323 operating as described above, the switching unit 323 can switch from the first position estimation to the second position estimation at a time sufficiently before the time when the imaging direction becomes backlit. The operation of the switching unit 323 for switching from the first position estimation to the second position estimation has been described above in detail.

[0046] Incidentally, in the first position estimation using the white line recognition device 11, even if the imaging direction of the imaging device 10 is not facing the sun, the accuracy of estimating the first estimated distance and the first estimated direction decreases at a position where the width of the lane markings changes, such as a branching point or a merging point of the lanes. Therefore, when the switching unit 323 determines that the illuminance around the vehicle S is less than a threshold value, or that the illuminance is equal to or greater than the threshold value and the imaging direction is not facing the sun, the switching unit 323 may switch from the first position estimation to the second position estimation by satisfying a predetermined condition. The predetermined condition is that a branching point or a merging point of the lanes is present within a predetermined range from the position of the vehicle S at the second time estimated by the estimation unit 322. The predetermined range is, for example, one kilometer.

[0047] The switching unit 323 determines whether or not there is a branch point or a junction within a predetermined range from the position of the vehicle S at the second time by, for example, referring to map information indicating branch points and junctions of lanes stored in the storage unit 31. The switching unit 323 switches from the first position estimation to the second position estimation by determining, for example, at the time when time T4 in Fig. 3 has elapsed, that there is a branch point or a junction around the position of the vehicle S at the time when the first time has elapsed. By operating in this manner, the switching unit 323 can estimate a decrease in accuracy of the first position estimation and switch to the second position estimation even if the imaging direction is not facing the sun at the time when the predetermined time has elapsed.

[0048] Furthermore, in the first position estimation using the white line recognition device 11, when the distance between the vehicle S and the vehicle ahead of the vehicle S (so-called inter-vehicle distance) is short, the imaging device 10 may not be able to capture an image including lane markings even if the imaging direction of the imaging device 10 is not facing the sun. In this case, the white line recognition device 11 cannot extract the lane markings from the captured image, and the accuracy of estimating the first estimated distance and the first estimated orientation decreases.

[0049] Therefore, when the switching unit 323 determines that the illuminance around the vehicle is less than a threshold value, or that the illuminance is equal to or greater than the threshold value and the imaging direction is not directed toward the sun, the switching unit 323 may set a predetermined condition that the distance between the position of the vehicle S at the first time and the position of the vehicle preceding the vehicle S at the first time is less than a predetermined distance. The predetermined distance is, for example, 5 meters, and is determined by experiment or simulation. By operating the switching unit 323 in this manner, even when the imaging direction is not directed toward the sun, if the inter-vehicle distance between the vehicle S and the vehicle preceding is short and the lane markings are not included in the captured image, the first position estimation can be switched to the second position estimation.

[0050] The switching unit 323 switches from the second position estimation to the first position estimation when a predetermined condition is satisfied at a time after the time when the first position estimation is switched to the second position estimation. The predetermined condition is that the illuminance has changed from a state in which the illuminance is equal to or greater than the threshold to a state in which the illuminance is less than the threshold, or that the imaging direction has changed from a state in which the imaging direction is directed toward the sun to a state in which the imaging direction is not directed toward the sun. For example, at a time after the first position estimation is switched to the second position estimation, the switching unit 323 determines, for each unit time that has elapsed, whether the illuminance at that time is equal to or greater than the threshold and whether the imaging direction based on the position and orientation of the vehicle S at that time is directed toward the sun. Then, the switching unit 323 switches from the second position estimation to the first position estimation when the determination result satisfies the predetermined condition.

[0051] For example, as shown in Fig. 3, the switching unit 323 switches from the second position estimation to the first position estimation upon determining that the imaging direction at the time when time T3 has elapsed ("imaging direction" shown in Fig. 3) is "forward lighting." By operating in this manner, the switching unit 323 can quickly switch from the second position estimation to the first position estimation, which is more accurate than the second position estimation, when the imaging device 10 changes from a backlit state to a non-backlit state.

[0052] The switching unit 323 may switch from the second position estimation to the first position estimation when a predetermined condition related to a branch point or a junction is satisfied at a time after the time of switching from the first position estimation to the second position estimation. The predetermined condition is that the illuminance is less than a threshold or the imaging direction is not facing the sun, and that a state where a branch point or a junction of lanes is present within a predetermined range from the position of the vehicle S has changed to a state where a branch point or a junction of lanes is not present within the predetermined range from the position of the vehicle S.

[0053] For example, assume that the illuminance is below a threshold or the imaging direction is not facing the sun at a time after the first position estimation is switched to the second position estimation. In this case, the switching unit 323 determines that there is a lane branch or junction within a predetermined range from the position of the vehicle S at a time after the first position estimation is switched to the second position estimation, and then switches from the second position estimation to the first position estimation because the determination has changed to that there is no branch or junction of the lane. By operating in this manner, the switching unit 323 can use the first position estimation, which is more accurate than the second position estimation, at an appropriate timing.

[0054] The switching unit 323 may switch from the second position estimation to the first position estimation when a predetermined condition related to the illuminance or the imaging direction, and the distance between the vehicle S and the vehicle preceding the vehicle S is satisfied at a time after the time of switching from the first position estimation to the second position estimation. The predetermined condition is that the illuminance is less than a threshold or the imaging direction is not facing the sun, and the distance between the position of the vehicle S and the position of the vehicle preceding the vehicle S has changed from less than a predetermined distance to equal to or greater than the predetermined distance.

[0055] For example, assume that the illuminance is less than a threshold or the imaging direction is not directed toward the sun at a time after the first position estimation is switched to the second position estimation. In this case, the switching unit 323 determines that the inter-vehicle distance between the vehicle S and the vehicle preceding the vehicle S is equal to or greater than a predetermined distance at a time after the first position estimation is switched to the second position estimation, and then switches from the second position estimation to the first position estimation because the determination has changed to that the inter-vehicle distance is less than the predetermined distance. By operating in this manner, the switching unit 323 can use the first position estimation, which is more accurate than the second position estimation, at an appropriate timing.

[0056] When the lane on which the vehicle S is traveling includes multiple curved roads, the state in which the imaging direction faces the sun and the state in which the imaging direction does not face the sun may change in a short time. In such a case, if the switching unit 323 frequently switches between the first position estimation and the second position estimation, the behavior of the vehicle S may become unstable. Therefore, after switching from the first position estimation to the second position estimation, the switching unit 323 may determine whether to switch from the second position estimation to the first position estimation based on the position and height of the sun and the position and orientation of the vehicle S in the second time period from the second time to the third time. The switching unit 323 switches from the second position estimation to the first position estimation when, for example, the illuminance at the first time period is equal to or greater than a threshold value and a predetermined condition is satisfied. The predetermined condition is that the period during which it is determined that the imaging direction faces the sun is less than a predetermined number of times in the second time period. The predetermined number of times is, for example, two times.

[0057] Fig. 4 is a diagram for explaining a vehicle S traveling on a lane including multiple curved roads. In lane R2 shown in Fig. 4, sections B1, B3, and B5 indicated by diagonal lines are sections in which it is determined that the imaging direction is not directed toward the sun. In addition, section B2 between sections B1 and B3, and section B4 between sections B3 and B5 are sections in which it is determined that the imaging direction is directed toward the sun. The vehicle S travels from section B1 to section B5 in a second time period.

[0058] The switching unit 323 identifies the position and height of the sun at the second time by referring to the map information estimated by the estimation unit 322 and stored in the storage unit 31. The switching unit 323 acquires the position and orientation of the vehicle S at the second time estimated by the estimation unit 322. When the illuminance is equal to or greater than the threshold in the lane R2 shown in FIG. 4, the switching unit 323 determines that the imaging direction has changed to a period in which it was determined that the imaging direction was facing the sun at the time when the vehicle S moved from section B1 to section B2 and at the time when the vehicle S moved from section B3 to section B4. Since the period in which it was determined that the imaging direction was facing the sun occurred twice, the switching unit 323 determines that the predetermined condition is not satisfied and does not switch from the second position estimation to the first position estimation. By operating in this manner, the switching unit 323 can prevent the behavior of the vehicle S from becoming unstable due to frequent switching of the position estimation process.

[0059] The determination unit 324 acquires a first estimated distance between the estimated position of the vehicle S estimated using the imaging device 10 and a target position of the vehicle S based on an image captured by the imaging device 10, and a first estimated orientation of the vehicle S. The determination unit 324 acquires a second estimated distance between the estimated position of the vehicle S estimated using a locator (self-location recognition device 14 shown in FIG. 1) and a target position based on map information, and a second estimated orientation identified by the inertial measurement unit 13. Then, the determination unit 324 determines a steering angle and a steering torque of the vehicle S based on the first estimated distance and the first estimated orientation, or the second estimated distance and the second estimated orientation.

[0060] For example, when the switching unit 323 switches from the first position estimation to the second position estimation, the determination unit 324 determines the steering angle and steering torque of the vehicle S based on the second estimated distance and the second estimated orientation. When the switching unit 323 switches from the second position estimation to the first position estimation, the determination unit 324 determines the steering angle and steering torque of the vehicle S based on the first estimated distance and the first estimated orientation. For example, the determination unit 324 determines the steering angle and steering torque of the vehicle S such that the first estimated distance or the second estimated distance becomes smaller every time a unit time elapses.

[0061] However, the first estimated distance based on the position of the lane markings extracted from the captured image has a smaller error from the actual distance than the second estimated distance based on the position of the vehicle S identified by the receiving device 12, so that different distances are estimated even when the distances are estimated at the same time. Therefore, the distance between the position of the vehicle S and the target position is significantly changed immediately after the first position estimation and the second position estimation are switched. Therefore, the determination unit 324 corrects the first estimated distance or the second estimated distance at a predetermined time so that the first estimated distance and the second estimated distance match each other at a time when a predetermined time has elapsed since the switching unit 323 switched between the first position estimation and the second position estimation. The predetermined time is, for example, 0.5 seconds.

[0062] As an example, the determination unit 324 calculates a difference between the first estimated distance and the second estimated distance when the switching unit 323 switches between the first position estimation and the second position estimation. The determination unit 324 calculates a division value by dividing the calculated difference by the number of times a unit time elapses in a predetermined time (for example, 25 times when the predetermined time is 0.5 seconds and the unit time is 20 milliseconds). The determination unit 324 corrects the first estimated distance or the second estimated distance by adding or subtracting the calculated division value to the first estimated distance or the second estimated distance acquired by the position estimation process before the switching unit 323 switches in the predetermined time.

[0063] By operating the determination unit 324 in this manner, even if the estimated distance changes significantly by switching between the first position estimation and the second position estimation, after a predetermined time has elapsed, the steering angle and steering torque can be determined to be values ​​similar to or matching the estimated distance after switching. Furthermore, even if the estimated distance changes significantly by switching between the first position estimation and the second position estimation, it is possible to prevent the behavior of the vehicle S from becoming unstable due to a large change in the steering angle and steering torque.

[0064] <Processing sequence in the position estimation device 30> Fig. 5 and Fig. 6 are diagrams showing an example of a processing sequence in the position estimation device 30. The processing sequence shown in Fig. 5 is a sequence showing an operation of switching from the first position estimation to the second position estimation, and the processing sequence shown in Fig. 6 is a sequence showing an operation of switching from the second position estimation to the first position estimation. Fig. 6 shows an operation at a time after the switching unit 323 switches from the first position estimation to the second position estimation. The position estimation device 30 repeats the processing sequences shown in Fig. 5 and Fig. 6 at regular time intervals (for example, every time a unit time has elapsed).

[0065] First, the operation of switching from the first position estimation to the second position estimation will be described. The acquisition unit 321 acquires the position of the vehicle S, the vehicle speed of the vehicle S, and the illuminance around the vehicle S calculated by the receiving device 12 at the first time (S10). If the illuminance around the vehicle S is equal to or greater than the threshold Y1 (YES in S11), the estimation unit 322 estimates the position and orientation of the vehicle S at the second time (S12). The switching unit 323 identifies the position and height of the sun at the second time by referring to the solar radiation information stored in the storage unit 31 (S13).

[0066] The switching unit 323 calculates the angle between the direction of sunlight and the imaging direction (angle θ shown in FIG. 2) based on the position and orientation of the vehicle S and the position and height of the sun (S14). If the calculated angle is less than threshold Y2 (YES in S15), the switching unit 323 determines that the imaging direction is toward the sun, and switches from the first position estimation to the second position estimation (S16). If the calculated angle is equal to or greater than threshold Y2 (NO in S15), the switching unit 323 continues the first position estimation (S21).

[0067] If the illuminance around the vehicle S is less than the threshold Y1 (NO in S11), the switching unit 323 acquires a map of the positions around the position of the vehicle S at the second time by referring to the storage unit 31 (S17). If there is a branch point or a junction in the range around the position of the vehicle S at the second time (NO in S18), the switching unit 323 switches from the first position estimation to the second position estimation (S16). If there is no branch point or a junction in the range around the position of the vehicle S at the second time (YES in S18), the switching unit 323 acquires the distance between the vehicle S and the preceding vehicle at the first time (S19). If the acquired distance is equal to or greater than a predetermined distance (YES in S20), the switching unit 323 continues the first position estimation (S21). If the acquired distance is less than the predetermined distance (NO in S20), the switching unit 323 switches from the first position estimation to the second position estimation (S16).

[0068] Next, an operation of switching from the second position estimation to the first position estimation will be described. The acquisition unit 321 acquires the position of the vehicle S, the vehicle speed of the vehicle S, and the illuminance around the vehicle S, which are calculated by the receiving device 12 at the first time (S30). In FIG. 6, the first time is, for example, the current time. The estimation unit 322 estimates the position and orientation of the vehicle S at the first time (S31). The switching unit 323 identifies the position and height of the sun at the first time by referring to the solar radiation information stored in the storage unit 31 (S32). The switching unit 323 calculates the angle between the direction of the sunlight and the imaging direction (angle θ shown in FIG. 2) based on the position and orientation of the vehicle S and the position and height of the sun (S33).

[0069] If the illuminance does not change from a state equal to or greater than the threshold to a state less than the threshold, and the angle between the sunlight and the imaging direction does not change from a state in which the imaging direction faces the sun to a state in which the imaging direction does not face the sun (NO in S34), the switching unit 323 continues the second position estimation (S35). If the illuminance changes from a state equal to or greater than the threshold to a state less than the threshold, or if the imaging direction changes from a state in which the imaging direction faces the sun to a state in which the imaging direction does not face the sun (YES in S34), the switching unit 323 acquires a map of the surroundings of the vehicle S at the first time by referring to the storage unit 31 (S36).

[0070] The switching unit 323 continues the second position estimation (S35) when the state has not changed from a state in which there is a branch point or a junction around the vehicle S to a state in which there is no branch point or a junction around the vehicle S (NO in S37). When the state has changed from a state in which there is a branch point or a junction around the vehicle S to a state in which there is no branch point or a junction around the vehicle S (YES in S37), the switching unit 323 acquires the distance between the vehicle S and the preceding vehicle at the first time (S38). When the acquired distance has not changed from less than a predetermined distance to a predetermined distance or more (NO in S39), the switching unit 323 continues the second position estimation (S35). When the acquired distance has changed from less than a predetermined distance to a predetermined distance or more (YES in S39), the switching unit 323 switches from the second position estimation to the first position estimation (S40).

[0071] <Effects of the position estimation device 30> As described above, the position estimation device 30 includes an estimation unit 322 that estimates the position and orientation of the vehicle S at a second time, which is a first hour after the first time, based on the position of the vehicle S at a first time, the vehicle speed of the vehicle S, and map information, and a switching unit 323 that switches from a first position estimation of the vehicle S using the imaging device 10 to a second position estimation using a locator provided in the vehicle S, on condition that the imaging direction of the imaging device 10 provided in the vehicle S is determined to be facing the sun, based on the position and height of the sun at the second time and the position and orientation of the vehicle S at the second time, if the illuminance around the vehicle S at the first time is equal to or greater than a threshold value.

[0072] By configuring the position estimation device 30 in this manner, when it is determined that the imaging direction is directed toward the sun at a second time when a first time has elapsed from a first time (e.g., the current time), it is possible to determine to switch from the first position estimation to the second position estimation at the first time. As a result, the position estimation device 30 can switch to the second position estimation at the first time before the second time at which the errors in the first estimated distance and the first estimated orientation by the first position estimation become large because the imaging direction is directed toward the sun. As a result, it is possible to prevent the steering angle and steering torque from being determined based on an erroneous estimated distance and estimated orientation.

[0073] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0074] 10. Imaging device 11 White line recognition device 12 Receiving device 13 Inertial Measurement Unit 14 Self-location recognition device 15 Illuminance sensor 16 Vehicle speed sensor 20 Steering control device 30 Position estimation device 31 Storage section 32 Control section 321 Acquisition Department 322 Estimation Department 323 Switching section 324 Decision Section

Claims

1. An acquisition unit that acquires illuminance around the vehicle; an estimation unit that estimates a position and a direction of the vehicle at a second time when a first time has elapsed from the first time, based on a position of the vehicle at a first time, a vehicle speed of the vehicle, and map information including lane information; a switching unit that switches, when the illuminance around the vehicle at the first time is equal to or greater than a threshold and the imaging direction of an imaging device included in the vehicle is facing the sun at the second time, at least before the second time is reached, from a first position estimation that estimates the position of the vehicle using the imaging device to a second position estimation that estimates the position of the vehicle using a locator included in the vehicle; A position estimation device having the following:

2. the switching unit switches from the second position estimation to the first position estimation on a condition that, at a time after a time when the first position estimation is switched to the second position estimation, the illuminance changes from a state where it is equal to or greater than the threshold value to a state where it is less than the threshold value, or the imaging direction changes from a state where it is facing the sun to a state where it is not facing the sun. The position estimation device according to claim 1 .

3. The estimation unit estimates a position and an orientation of the vehicle during a second time period from the second time to a third time period; when the illuminance at the first time is equal to or greater than the threshold, the switching unit switches from the second position estimation to the first position estimation on the condition that a period during which it is determined that the imaging direction is directed toward the sun based on the position and height of the sun and the position and orientation of the vehicle at the second time is less than a predetermined number of times during the second time. The position estimation device according to claim 1 .

4. a determination unit that determines a steering angle and a steering torque of the vehicle based on a first error between an estimated position of the vehicle estimated using the imaging device and a target position of the vehicle based on an image captured by the imaging device, or a second error between an estimated position of the vehicle estimated using the locator and a target position based on the map information, the determination unit corrects the first error or the second error so that the first error and the second error match each other at a time when a predetermined time has elapsed since the switching unit switched between the first position estimation and the second position estimation. The position estimation device according to claim 1 .

5. when it is determined that the illuminance around the vehicle is less than the threshold value, or that the illuminance is equal to or greater than the threshold value and the imaging direction is not toward the sun, the switching unit switches from the first position estimation to the second position estimation on the condition that a branch point or a junction of lanes is present within a predetermined range from the position of the vehicle at the second time estimated by the estimation unit. The position estimation device according to claim 1 .

6. the switching unit switches from the second position estimation to the first position estimation under the conditions that, at a time after the time of switching from the first position estimation to the second position estimation, the illuminance is less than the threshold or the imaging direction is not facing the sun, and a state has changed from a state where there is a lane branching point or junction within the predetermined range from the position of the vehicle to a state where there is no lane branching point or junction within the predetermined range from the position of the vehicle. The position estimation device according to claim 5 .

7. when it is determined that the illuminance around the vehicle is less than the threshold value, or when it is determined that the illuminance is equal to or greater than the threshold value and the imaging direction is not toward the sun, the switching unit switches from the first position estimation to the second position estimation on the condition that a distance between a position of the vehicle at the first time and a position of a vehicle preceding the vehicle at the first time is less than a predetermined distance. The position estimation device according to claim 1 .

8. the switching unit switches from the second position estimation to the first position estimation under the condition that, at a time after the time of switching from the first position estimation to the second position estimation, the illuminance is less than the threshold or the imaging direction is not facing the sun, and the distance between the position of the vehicle and the position of a vehicle preceding the vehicle has changed from less than the predetermined distance to equal to or greater than the predetermined distance. The position estimation device according to claim 7.

9. The processor executes An acquisition step of acquiring an illuminance around a vehicle; an estimation step of estimating a position and a direction of the vehicle at a second time when a first time has elapsed from the first time, based on a position of the vehicle at a first time, a vehicle speed of the vehicle, and map information including lane information; a switching step of switching from a first position estimation step of estimating a position of the vehicle using the imaging device to a second position estimation step of estimating a position of the vehicle using a locator provided in the vehicle, at least before the second time, when the illuminance around the vehicle at the first time is equal to or greater than a threshold value and the imaging direction of an imaging device provided in the vehicle is facing the sun at the second time; A location estimation method comprising:

Images