Position estimation device, automatic driving system, position estimation method and program

Abstract

To provide a position estimation device, an automatic driving system, a position estimation method and a program which can perform position estimation of a vehicle in which an error according to a characteristic of a sensor which detects behavior of the vehicle is suppressed.SOLUTION: A position estimation device (2) comprises: a weight determination unit (21) which determines a weight set to first yaw angle information of a vehicle A based on an angular velocity of the vehicle A, second yaw angle information of the vehicle A based on a moving distance of right and left wheels of the vehicle A, and third yaw angle information of the vehicle A based on a steering angle and a vehicle speed of the vehicle A; a yaw information acquisition unit (22) which acquires the first yaw angle information, the second yaw angle information and the third yaw angle information; a synthesizing unit (23) which generates synthesized yaw angle information obtained by synthesizing the first yaw angle information, the second yaw angle information and the third yaw angle information to which the determined weight is set; and a position estimation unit (24) which estimates a position of the vehicle A, by using positioning information of the vehicle A, and the vehicle speed and the synthesized yaw angle information on the vehicle A.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a position estimation device, an automated driving system, a position estimation method, and a program. [Background technology]

[0002] Absolute positioning requires interpolation of data not acquired during positioning intervals, compensation for data in unpositioned sections due to obstructions such as tunnels or buildings, and monitoring of positioning accuracy. For this reason, vehicle position estimation is performed by combining absolute positioning and relative positioning. An example of absolute positioning is GPS (Global Positioning System) satellite positioning. Relative positioning, which is an autonomous navigation method for vehicles, estimates the vehicle's position using sensor information from sensors that detect the vehicle's behavior while traveling.

[0003] Sensors that detect the behavior of a vehicle while it is running include, for example, a vehicle speed sensor, a gyro sensor, a wheel speed sensor, and a steering angle sensor. For example, relative positioning includes a first positioning method that uses the angular velocity of the vehicle detected by a gyro sensor, a second positioning method that uses the difference in travel distance between the left and right wheels detected by a wheel speed sensor, and a third positioning method that uses the steering angle of the vehicle detected by a steering angle sensor.

[0004] For example, Patent Document 1 describes an inertial navigation system that, when information from an external sensor is interrupted, estimates the position of a vehicle based on the accumulated amount of movement of the vehicle detected by an internal sensor. In Patent Document 1, external sensors detect conditions other than those of the vehicle, while internal sensors detect the state of the vehicle itself, such as an IMU (Inertial Measurement Unit), a vehicle speed sensor, and a steering angle sensor that can detect three-axial angular velocities (pitch rate, roll rate, and yaw rate) and three-axial accelerations (longitudinal acceleration, lateral acceleration, and vertical acceleration) that indicate the behavior of the vehicle while it is traveling. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7036080 Summary of the Invention [Problem to be solved by the invention]

[0006] The first, second, and third positioning methods, which are relative positioning methods, have the problem that errors occur depending on the characteristics of each method. The conventional technology described in Patent Document 1 selects sensor values ​​of the vehicle's acceleration, angular velocity, and steering angle from among the first and third positioning methods under certain conditions, and estimates the vehicle position using a positioning method that uses the selected sensor values. Therefore, if a positioning method with a small error is not appropriately selected, the vehicle position cannot be estimated accurately.

[0007] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a position estimation device, an autonomous driving system, a position estimation method, and a program that can suppress errors according to the characteristics of the positioning method. [Means for solving the problem]

[0008] The position estimation device according to the present disclosure includes a weight determination unit that determines weights to be set on first yaw information of a vehicle based on the angular velocity of the vehicle, second yaw information of the vehicle based on a difference in travel distance between the left and right wheels of the vehicle, and third yaw information of the vehicle based on the steering angle and vehicle speed of the vehicle, based on the vehicle's running state or the vehicle's surrounding state; a yaw information acquisition unit that acquires the first yaw information, the second yaw information, and the third yaw information; a synthesis unit that generates synthesized yaw information by synthesizing the first yaw information, the second yaw information, and the third yaw information to which the determined weights have been set; and a position estimation unit that estimates the position of the vehicle using the vehicle's positioning information, the vehicle speed, and the synthesized yaw information. [Effects of the Invention]

[0009] According to the present disclosure, based on the vehicle's running state or the vehicle's surrounding state, weights to be set for first yaw information based on the angular velocity of the vehicle, second yaw information based on the difference in travel distance between the left and right wheels of the vehicle, and third yaw information based on the steering angle and vehicle speed of the vehicle are determined, and the vehicle position is estimated using composite yaw information obtained by combining the first yaw information, the second yaw information, and the third yaw information to which the determined weights have been set, vehicle positioning information, the vehicle speed, and the composite yaw information. This allows the position estimation device according to the present disclosure to suppress errors according to the characteristics of the positioning method. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of an automatic driving system according to a first embodiment. [Figure 2] 1 is a block diagram showing a configuration of a position estimation device according to a first embodiment. [Figure 3] FIG. 2 is a block diagram showing the configuration of a weight determining unit according to the first embodiment. [Figure 4] 3 is a flowchart showing a position estimation method according to the first embodiment. [Figure 5] 5A and 5B are block diagrams showing a hardware configuration for realizing the functions of the position estimation device according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiment 1 (Autonomous Driving System Overview) Fig. 1 is a block diagram showing the configuration of an automatic driving system 1 according to a first embodiment. In Fig. 1, the automatic driving system 1 is a system that automatically controls the traveling of a vehicle A, and includes a position estimation device 2, an absolute position detection unit 3A, a road surface detection unit 3B, an attitude detection unit 3C, a gyro sensor 3D, a wheel speed sensor 3E, a steering angle sensor 3F, a vehicle speed sensor 3G, and an automatic vehicle control device 4. Note that the position estimation device 2 is not limited to a device mounted on the vehicle A whose position is to be estimated, but may be an external device that is capable of exchanging data between the sensors 3A to 3G mounted on the vehicle A and the automatic vehicle control device 4.

[0012] (Outline of location estimation device) Based on the traveling state of vehicle A or the surrounding state of vehicle A, the position estimation device 2 determines weights to be set for first yaw information based on the angular velocity of vehicle A, second yaw information based on the difference in travel distance between the left and right wheels of vehicle A, and third yaw information of vehicle A based on the steering angle and vehicle speed of vehicle A, generates composite yaw information by combining the first yaw information, second yaw information, and third yaw information to which the determined weights have been set, and estimates the position of vehicle A using the positioning information of vehicle A, the vehicle speed of vehicle A, and the composite yaw information.

[0013] In the following, unless otherwise specified, it is assumed that all of the functions of the position estimation device 2 are provided by a single computer. However, all of the functions of the position estimation device 2 may be realized by a single computer or by multiple computers. Details of the position estimation device 2 will be described later.

[0014] The first yaw information is first yaw angle information calculated based on the angular velocity of vehicle A using a first positioning method. The second yaw information is second yaw angle information calculated based on the difference in travel distance between the left and right wheels of vehicle A using a second positioning method. The third yaw information is third yaw angle information calculated based on the steering angle and vehicle speed of vehicle A using a third positioning method.

[0015] The first positioning method is a positioning method that uses the angular velocity of vehicle A detected by the gyro sensor 3D. In the first positioning method, the angular velocity of vehicle A detected by the gyro sensor 3D is used to calculate the amount of movement of vehicle A in the left-right direction. The amount of movement of vehicle A in the left-right direction is first yaw angle information that indicates the angular velocity of vehicle A about the yaw axis (hereinafter referred to as yaw angle). Furthermore, the vehicle speed or wheel speed pulse of vehicle A detected by the vehicle speed sensor 3G is used to calculate the amount of movement of vehicle A in the front-rear direction. The relative position of vehicle A is calculated using these calculation results.

[0016] The gyro sensor 3D detects the angular velocity, including skidding, of vehicle A. The offset or drift error of the gyro sensor 3D is an integral error accumulated as vehicle A travels. For example, the gyro sensor 3D generates an error that offsets the zero point over time. For this reason, the first positioning method requires so-called learning, which removes the error accumulated in the sensor value detected by the gyro sensor 3D over time. For example, learning involves assuming that the zero point of the gyro sensor 3D is a stationary vehicle A and removing the error. Another learning technique involves using satellite positioning results to remove the error from the sensor value detected by the gyro sensor 3D.

[0017] Satellite positioning is performed at regular time intervals of, for example, about one second. Therefore, when vehicle A is traveling at high speed, the frequency with which position estimation device 2 of vehicle A acquires satellite positioning results decreases, which reduces the learning frequency and decreases the positioning accuracy using the first positioning method. Furthermore, even when vehicle A is traveling at a low speed, the accuracy of estimating the direction of vehicle A using the satellite positioning results decreases, so the accuracy of positioning using the first positioning method decreases. Furthermore, while the vehicle A is traveling in a place where the position estimation device 2 cannot obtain satellite positioning results, such as a tunnel, learning cannot be performed, and an error occurs in the positioning by the first positioning method.

[0018] The second positioning method uses the travel distance of the left and right wheels of vehicle A detected by wheel speed sensor 3E. In the second positioning method, the difference in travel distance between the left and right wheels of vehicle A detected by wheel speed sensor 3E and the tread length are used to integrate the yaw rate of vehicle A, which is calculated geometrically, to calculate second yaw angle information. Furthermore, the amount of movement in the longitudinal direction of vehicle A is calculated using the average value of the movement speeds of the left and right wheels of vehicle A. In the second positioning method, the relative position of vehicle A is calculated using these calculation results.

[0019] In addition, the second positioning method calculates second yaw angle information using the difference in the amount of movement (difference in rotation) between the left and right wheels of vehicle A detected by wheel speed sensor 3E. Errors in the second yaw angle information are unlikely to become large even when vehicle A travels a long distance. On the other hand, when vehicle A is turning, the estimation accuracy of the second yaw angle information decreases. This is related to the fact that the tread changes due to a change in the point of application of force on the tires of vehicle A. Specifically, as vehicle A turns, the location where force is applied in the tire width direction changes, and the center of the tire width is no longer the location where the greatest force is applied. Therefore, the distance traveled by vehicle A per tire rotation (scale factor) changes as vehicle A turns. Changes in the scale factor are a cause of errors in positioning using the second positioning method.

[0020] The third positioning method is a positioning method that uses the steering angle of vehicle A detected by steering angle sensor 3F. In the third positioning method, the third yaw angle information is calculated by integrating the yaw rate of vehicle A, which is calculated according to the equation of motion, using the steering angle of the steering wheel of vehicle A detected by steering angle sensor 3F and the vehicle speed of vehicle A detected by vehicle speed sensor 3G. Furthermore, the amount of movement of vehicle A in the longitudinal direction is calculated using the vehicle speed of vehicle A detected by vehicle speed sensor 3G. In the third positioning method, the relative position of vehicle A is calculated using these calculation results.

[0021] In addition, in the third positioning method, the calculation of the yaw rate (the amount of change in yaw angle over a certain period of time) using the steering angle of vehicle A detected by steering angle sensor 3F is based on the assumption that vehicle A is making a steady circular turn. When the vehicle speed of vehicle A increases, a lateral force is generated in vehicle A, causing a sideslip angle of vehicle A, which increases the error in positioning using the third positioning method. On the other hand, the positioning results obtained using the third positioning method are generally stable and do not experience drift due to temperature, etc., so there is less integral error than with an IMU.

[0022] The first positioning method, the second positioning method, and the third positioning method may be used in, for example, the following ways: (1) to (3). The position estimation device 2 determines a weight based on the usage ways (1) to (3), and estimates the position and direction of the vehicle A using composite yaw information obtained by combining the yaw information of the first positioning method, the second positioning method, and the third positioning method using the determined weight. This makes it possible to suppress errors according to the characteristics of the positioning methods. (1) When the movement of vehicle A is close to a straight line, if the learning state is good, position estimation is performed using yaw information obtained by the first positioning method, and if the learning state is poor, position estimation is performed using yaw information obtained by the second positioning method. (2) When the motion of vehicle A is close to turning and vehicle A is traveling at a low speed, the accuracy of position estimation using yaw information obtained by the third positioning method is good. (3) When the motion of vehicle A is close to a turn and vehicle A is moving at high speed, the accuracy of position estimation using yaw information obtained by the first positioning method is good.

[0023] The absolute position detection unit 3A is a sensor that detects the absolute position of vehicle A. For example, the absolute position detection unit 3A receives GPS signals from GPS satellites at positioning intervals of about one second, and detects the absolute position on Earth, such as the latitude and longitude of vehicle A, the direction of vehicle A, and the reliability of the determined absolute position, which are included in the GPS signals. These pieces of detected information are output from the absolute position detection unit 3A to the position estimation device 2 as positioning information of vehicle A, and are stored in the absolute position storage unit 5.

[0024] Furthermore, the absolute position detection unit 3A is not limited to satellite positioning, and may be any device capable of detecting the absolute position of the vehicle A. For example, the absolute position detection unit 3A may calculate the absolute position of the vehicle A using information detected by a camera or a LiDAR (Light Detection And Ranging) mounted on the vehicle A, and map information. Furthermore, the absolute position detection unit 3A may use a positioning means that uses, for example, UWB (Ultra Wide Band) wireless communication.

[0025] The road surface detection unit 3B is a sensor that detects the road surface condition on which the vehicle A is traveling, and detects the unevenness, icy state, and wet state of the road surface. For example, the road surface detection unit 3B includes a camera that captures road surface images and an image analysis unit that detects the road surface condition using the results of analyzing the images captured by the camera. The road surface detection unit 3B may also detect, as road surface condition information, the amount of change in the pitch rate and roll rate of the vehicle A detected by the gyro sensor 3D. If at least one of the pitch rate and roll rate of vehicle A changes significantly, it can be determined that the road surface undulations are large enough to cause vehicle A to vibrate.

[0026] The attitude detection unit 3C is a sensor that detects the attitude of vehicle A. The attitude of vehicle A is, for example, the roll angle and pitch angle of vehicle A. Specifically, the attitude detection unit 3C detects the roll angle around a roll axis extending in the front-to-rear direction of vehicle A and the pitch angle around a pitch axis extending in the left-to-right direction of vehicle A. The attitude detection unit 3C outputs attitude information including the roll angle and pitch angle of vehicle A to the position estimation device 2.

[0027] The gyro sensor 3D is a sensor that detects the yaw angular velocity (ie, yaw rate) of the vehicle A around the yaw axis. For example, the gyro sensor 3D is a vibration gyro sensor that detects the angular velocity of the vehicle A based on the Coriolis force applied to a vibrated element. The gyro sensor 3D may also be an optical fiber gyro sensor using the Sagnac effect, or an optical gyro sensor such as a ring laser gyro. The gyro sensor 3D detects the yaw angular velocity (yaw rate) around the yaw axis, which is the vertical axis of the vehicle A.

[0028] The gyro sensor 3D may be a six-axis sensor that detects the acceleration in the longitudinal direction of the vehicle A, the acceleration in the lateral direction of the vehicle A, the acceleration in the vertical direction of the vehicle A, the angular velocity around the roll axis, the angular velocity around the pitch axis, and the angular velocity around the yaw axis. In other words, the gyro sensor 3D may be an IMU. The gyro sensor 3D may also be a three-axis sensor combined with a sensor that detects the acceleration of the vehicle A in the roll axis direction and the acceleration of the vehicle A in the pitch axis direction.

[0029] The wheel speed sensor 3E is a sensor that detects the wheel speeds of the left and right wheels of the vehicle A. For example, the wheel speed sensor 3E calculates the wheel speeds of the front and rear wheels on the left side and the wheel speeds of the front and rear wheels on the right side from the rotation of the left and right wheels of the vehicle A. The wheel speed sensor 3E also outputs wheel speed information indicating the wheel speeds of the left and right wheels to the position estimation device 2.

[0030] The steering angle sensor 3F is a sensor that detects the steering angle, which is the rotation angle of the steering wheel of the vehicle A. The steering angle sensor 3F outputs steering angle information indicating the steering angle to the position estimation device 2.

[0031] The vehicle speed sensor 3G is a sensor that detects the vehicle speed of the vehicle A. For example, the vehicle speed sensor 3G detects the vehicle speed of the vehicle A by measuring wheel speed pulses, which are pulse signals generated in accordance with the rotation of the wheels of the vehicle A. The vehicle speed sensor 3G outputs vehicle speed information indicating the vehicle speed to the position estimation device 2.

[0032] The automatic vehicle control device 4 controls the movement of vehicle A based on the position of vehicle A estimated by the position estimation device 2 or the position and orientation of vehicle A estimated by the position estimation device 2. For example, the automatic vehicle control device 4 determines the position and orientation to which vehicle A should move next based on the position of vehicle A estimated by the position estimation device 2 or the position and orientation of vehicle A, and controls the movement of vehicle A so that it moves to the determined position and orientation.

[0033] (Details of the location estimation device) Fig. 2 is a block diagram showing the configuration of the position estimation device 2. In Fig. 2, the absolute position storage unit 5 and the map information storage unit 6 are storage units provided independently of the position estimation device 2. The route calculation unit 7 is provided in a navigation device not shown in Fig. 2. The position estimation device 2 can access the absolute position storage unit 5 and the route calculation unit 7, for example, via a network not shown in Fig. 2, and can acquire positioning information of vehicle A from the absolute position storage unit 5 and can acquire driving route information of vehicle A from the route calculation unit 7.

[0034] (Absolute position memory unit) The absolute position storage unit 5 is a storage unit that stores the positioning information of the vehicle A detected by the absolute position detection unit 3A. For example, the absolute position storage unit 5 is a storage device that is provided independently of the position estimation device 2 and can be accessed by the position estimation device 2. The absolute position storage unit 5 may be provided in the position estimation device 2.

[0035] (Map information storage section) The map information storage unit 6 is a storage unit that stores map information. For example, the map information storage unit 6 is a storage device that is provided independently of the position estimation device 2 and can be accessed by the position estimation device 2. The map information storage unit 6 may be provided in the position estimation device 2 or in the navigation device.

[0036] (Route calculation section) The route calculation unit 7 calculates a driving route for vehicle A to travel using the map information read out from the map information storage unit 6. For example, the route calculation unit 7 calculates a target driving route for automatic driving of vehicle A. Note that the automatic vehicle control device 4 controls vehicle A to travel along the target driving route based on the position of vehicle A or the position and orientation of vehicle A estimated by the position estimation device 2.

[0037] 2, the position estimation device 2 includes a weight determination unit 21, a yaw information acquisition unit 22, a synthesis unit 23, and a position estimation unit 24. The functions of the weight determination unit 21, the yaw information acquisition unit 22, the synthesis unit 23, and the position estimation unit 24 are realized by a calculation unit (not shown in FIG. 2) included in the position estimation device 2 executing an information processing application.

[0038] (Weight determination section) The weight determination unit 21 determines weights to be set for the first yaw angle information of vehicle A based on the angular velocity of vehicle A, the second yaw angle information of vehicle A based on the difference in travel distance between the left and right wheels of vehicle A, and the third yaw angle information of vehicle A based on the steering angle and vehicle speed of vehicle A, based on the traveling state of vehicle A or the surrounding state of vehicle A. The traveling state of vehicle A is, for example, a state indicated by at least one of the angular velocity of vehicle A or the vehicle speed of vehicle A. The surrounding state of vehicle A is, for example, the road surface state of the traveling route on which vehicle A is traveling, which is determined by the positioning information of vehicle A.

[0039] For example, when the vehicle speed of vehicle A is equal to or greater than a first threshold, the angular velocity of vehicle A is less than a second threshold, and the time during which the error in the angular velocity of vehicle A is not eliminated is less than a certain time, the weight determination unit 21 may increase the weight of the first yaw angle information, decrease the weight of the second yaw angle information, and decrease the weight of the third yaw angle information. Here, the first threshold is a threshold related to vehicle speed for determining whether vehicle A is traveling at a low speed or a high speed. Furthermore, the second threshold is a threshold related to angular velocity for determining whether the amount of turning of vehicle A is small or large. That is, when the vehicle speed of vehicle A is equal to or greater than the first threshold and the angular velocity of vehicle A is less than the second threshold, vehicle A is traveling at high speed with a small amount of turning.

[0040] When the amount of turning of vehicle A is small and the vehicle is moving at high speed, the movement of vehicle A is close to a straight line. In this case, as shown in usage mode (1), if the state of learning about the sensor values ​​detected by the gyro sensor 3D is good, position estimation is performed using yaw information obtained by the first positioning method, and if the state of learning is poor, position estimation is performed using yaw information obtained by the second positioning method. The detection accuracy of the second yaw angle information using the wheel speeds detected by the wheel speed sensor 3E decreases when vehicle A turns. On the other hand, because the time during which the error in the angular velocity of vehicle A is not eliminated is less than a certain time, the sensor value detected by the gyro sensor 3D does not accumulate much error, and the learning state is good. Therefore, the first positioning method, which uses the sensor value detected by the gyro sensor 3D, can detect yaw angle information more stably than the second and third positioning methods. Therefore, the weight determining unit 21 increases the weight of the first yaw angle information using the angular velocity detected by the gyro sensor 3D, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information.

[0041] For example, when the vehicle speed of vehicle A is equal to or greater than a first threshold, the angular velocity of vehicle A is less than a second threshold, and the time during which the error in the angular velocity of vehicle A is not eliminated is equal to or greater than a certain time, the weight determiner 21 may decrease the weight of the first yaw angle information and increase the weight of the second yaw angle information. When the angular velocity of vehicle A is less than the second threshold and vehicle A is not substantially turning, the detection accuracy of the second yaw angle information using the wheel speeds detected by the wheel speed sensor 3E is maintained. On the other hand, if the error in the angular velocity of vehicle A detected by gyro sensor 3D is not eliminated for a certain period of time or longer, for example, when vehicle A is traveling in a place where satellite positioning results cannot be obtained, such as a tunnel, the sensor value detected by gyro sensor 3D will have accumulated a sufficient amount of error. Therefore, the weight determination unit 21 reduces the weight of the first yaw angle information that uses the angular velocity detected by the gyro sensor 3D, and increases the weight of the second yaw angle information that uses the difference in travel distance between the left and right wheels of vehicle A that is detected by the wheel speed sensor 3E. This allows the position estimation device 2 to stably calculate the composite yaw information used to estimate the position of vehicle A.

[0042] When the vehicle speed of vehicle A is less than the first threshold and the angular velocity of vehicle A is less than the second threshold, the weight determination unit 21 increases the weight of the second yaw angle information, decreases the weight of the first yaw angle information, and decreases the weight of the third yaw angle information. When the vehicle speed of vehicle A is less than the first threshold value and the angular velocity of vehicle A is less than the second threshold value, the amount of turning of vehicle A is small and the vehicle speed is low. When the amount of turning of vehicle A is small and the vehicle speed is low, the movement of vehicle A is close to a straight line. In this case, when vehicle A is barely turning, the second yaw angle information using the wheel speeds detected by wheel speed sensor 3E maintains its detection accuracy, and the reliability of the second yaw angle information is high. Therefore, the weight determination unit 21 increases the weight of the second yaw angle information that uses the difference in travel distance between the left and right wheels of the vehicle A detected by the wheel speed sensor 3E. This allows the position estimation device 2 to stably calculate the composite yaw information used to estimate the position of the vehicle A.

[0043] When the vehicle speed of vehicle A is less than the first threshold and the angular velocity of vehicle A is greater than or equal to the second threshold, the weight determination unit 21 increases the weight of the third yaw angle information, decreases the weight of the first yaw angle information, and decreases the weight of the second yaw angle information. When vehicle A is turning a large amount and traveling at a low speed, the motion of vehicle A is close to turning and the vehicle A is traveling at a low speed. In this case, no lateral force is generated in vehicle A, and no sideslip angle of vehicle A occurs. As shown in usage mode (2), this improves the accuracy of position estimation using the third yaw angle information calculated by the third positioning method. Therefore, the weight determination unit 21 increases the weight of the third yaw angle information that uses the steering angle detected by the steering angle sensor 3F. This allows the position estimation device 2 to stably calculate the composite yaw information used to estimate the position of vehicle A.

[0044] In addition, when the vehicle speed of vehicle A is equal to or greater than the first threshold and the angular velocity of vehicle A is equal to or greater than the second threshold, the weight determination unit 21 increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information. When the turning amount of vehicle A is large and the vehicle is moving at high speed, the motion of vehicle A is close to turning and the vehicle is moving at high speed. In this case, a lateral force is generated in vehicle A, causing a sideslip angle of vehicle A. Therefore, as shown in the usage mode (3), the accuracy of position estimation using the first yaw information obtained by the first positioning method is improved. Therefore, the weight determination unit 21 increases the weight of the first yaw angle information that uses the angular velocity detected by the gyro sensor 3D, decreases the weight of the second yaw angle information that uses the difference in travel distance between the left and right wheels of vehicle A detected by the wheel speed sensor 3E, and decreases the weight of the third yaw angle information that uses the steering angle detected by the steering angle sensor 3F. This allows the position estimation device 2 to stably calculate the composite yaw information used to estimate the position of vehicle A.

[0045] The first threshold value for vehicle speed and the second threshold value for angular velocity may be empirically determined fixed values, or may be dynamically changed depending on the magnitude of the vehicle speed or angular velocity of vehicle A.

[0046] When the undulations of the road surface on which vehicle A is traveling are equal to or greater than a third threshold, weight determination unit 21 may increase the weight of the first yaw angle information, decrease the weight of the second yaw angle information, and decrease the weight of the third yaw angle information. The third threshold value is a threshold value relating to the undulations of the road surface, for example, the amount of change in pitch rate and the amount of change in roll rate for determining whether vehicle A is vibrating. When the road surface unevenness is equal to or greater than the third threshold, vehicle A on the road surface vibrates, reducing the accuracy with which the wheel speed sensor 3E detects the difference in travel distance between the left and right wheels of vehicle A, and reducing the accuracy with which the steering angle sensor 3F detects the steering angle. Therefore, the weight determination unit 21 increases the weight of the first yaw angle information, which is less affected by the vibration of vehicle A, and decreases the weight of the second yaw angle information and the third yaw angle information, which are affected by the vibration of vehicle A and have large errors. This allows the position estimation device 2 to stably calculate the composite yaw information used to estimate the position of vehicle A.

[0047] When the degree of slipperiness of the road surface on which vehicle A is traveling is equal to or greater than a fourth threshold, weight determination unit 21 may increase the weight of the first yaw angle information, decrease the weight of the second yaw angle information, and decrease the weight of the third yaw angle information. The fourth threshold is a threshold related to the degree of slipperiness of the road surface, and is, for example, a threshold related to a feature amount indicating the degree of wetness or snow accumulation of the road surface in an image of the road surface. When the degree of slipperiness of the road surface is equal to or greater than the fourth threshold, vehicle A on the road surface is in a state in which the accuracy of the wheel speed sensor 3E in detecting the difference in travel distance between the left and right wheels of vehicle A decreases, and the accuracy of the steering angle detection by steering angle sensor 3F also decreases. Therefore, the weight determination unit 21 increases the weight of the first yaw angle information, which is less affected by the vibration of vehicle A, and decreases the weight of the second yaw angle information and the third yaw angle information, which are affected by the vibration of vehicle A and have large errors. This allows the position estimation device 2 to stably calculate the composite yaw information used to estimate the position of vehicle A.

[0048] The third threshold value relating to the undulations of the road surface and the fourth threshold value relating to the slipperiness of the road surface may be fixed values ​​determined empirically, or may be dynamically changed depending on the magnitude of the vehicle speed or angular velocity of vehicle A.

[0049] (Yaw information acquisition section) The yaw information acquisition unit 22 acquires first yaw angle information, second yaw angle information, and third yaw angle information. For example, the yaw information acquisition unit 22 calculates the first yaw angle information, second yaw angle information, and third yaw angle information using the attitude angle (roll angle and pitch angle) of the vehicle A detected by the attitude detection unit 3C, the angular velocity of the vehicle A detected by the gyro sensor 3D, the wheel speeds of the left and right wheels of the vehicle A detected by the wheel speed sensor 3E, the steering angle of the vehicle A detected by the steering angle sensor 3F, and the vehicle speed of the vehicle A detected by the vehicle speed sensor 3G. The yaw information acquisition unit 22 may also acquire yaw angle information of the vehicle A calculated by a calculation device (not shown) provided independently of the position estimation device 2. That is, the acquisition of yaw information by the yaw information acquisition unit 22 includes not only inputting yaw information from an external device but also calculating the yaw information. The yaw information acquisition unit 22 that calculates the yaw angle information includes a first yaw angle calculation unit 221, a second yaw angle calculation unit 222, and a third yaw angle calculation unit 223, as shown in FIG.

[0050] (First yaw angle calculation unit) The first yaw angle calculation unit 221 calculates first yaw angle information of the vehicle A based on the angular velocity of the vehicle A. For example, the first yaw angle calculation unit 221 calculates the first yaw angle information by integrating the angular velocity (yaw rate) of the vehicle A detected by the gyro sensor 3D for each sampling time.

[0051] (Second yaw angle calculation unit) The second yaw angle calculation unit 222 calculates second yaw angle information of the vehicle A based on the difference in travel distance between the left and right wheels of the vehicle A. For example, the second yaw angle calculation unit 222 geometrically calculates the yaw rate of the vehicle A using the difference in travel distance between the left and right wheels of the vehicle A detected by the wheel speed sensor 3E and the tread length, and calculates the second yaw angle information by integrating the calculated yaw rate for each sampling time.

[0052] (Third yaw angle calculation unit) The third yaw angle calculation unit 223 calculates third yaw angle information of the vehicle A based on the steering angle and vehicle speed of the vehicle A. For example, the third yaw angle calculation unit 223 calculates the yaw rate of the vehicle A according to the equation of motion using the steering angle of the steering wheel of the vehicle A detected by the steering angle sensor 3F and the vehicle speed of the vehicle A detected by the vehicle speed sensor 3G, and calculates the third yaw angle information by integrating the calculated yaw rate for each sampling time.

[0053] (Synthesis section) The synthesis unit 23 generates synthesized yaw angle information by synthesizing the first yaw angle information, the second yaw angle information, and the third yaw angle information to which the weights determined by the weight determination unit 21 have been set. For example, the synthesis unit 23 adjusts the synthesis ratio of the first yaw angle information, the second yaw angle information, and the third yaw angle information based on the determined weight, and calculates the synthesized yaw angle information. When the synthesis ratio of the first yaw angle information γ1 is K1, the synthesis ratio of the second yaw angle information γ2 is K2, and the synthesis ratio of the third yaw angle information γ3 is K3, the synthesis yaw angle information γsum is calculated by the following formula (1). γsum=K1γ1+K2γ2+K3γ3 (1) K1+K2+K3=1

[0054] Before combining the first yaw angle information, the second yaw angle information, and the third yaw angle information, the combining unit 23 aligns the coordinate systems of these pieces of yaw angle information. For example, if the attitude of vehicle A is rolling with respect to the world coordinate system, the synthesis unit 23 converts the second yaw angle information based on the difference in travel distance between the left and right wheels of vehicle A from the vehicle coordinate system to the world coordinate system, thereby reducing its value. This makes it possible to calculate synthesis yaw angle information γsum in which the influence of the roll of vehicle A is reduced.

[0055] When the weight determination unit 21 dynamically changes the weight based on changes in the running state of vehicle A or the surrounding state of vehicle A, the synthesis unit 23 sequentially sets the changed weight to the first yaw angle information, the second yaw angle information, and the third yaw angle information to generate synthesized yaw angle information. The weight determination unit 21 and the synthesis unit 23 may be AI (Artificial Intelligence) that uses a trained model that outputs synthesized yaw rate information of the first yaw angle information, the second yaw angle information, and the third yaw angle information when information indicating the traveling state of vehicle A or the surrounding state of vehicle A and the first yaw angle information, the second yaw angle information, and the third yaw angle information are input. This allows vehicle A to generate synthesized yaw angle information in response to changes in the traveling state of vehicle A or the surrounding state of vehicle A.

[0056] (Position estimation part) The position estimation unit 24 estimates the position of vehicle A using the positioning information, vehicle speed, and composite yaw angle information of vehicle A. For example, if the traveling direction of vehicle A is the x-axis and the left-right direction of vehicle A is the y-axis, the position estimation unit 24 calculates the position (x, y) of vehicle A from the reference position for position estimation based on the following equation (2). In the following equation (2), L is the travel distance of vehicle A, and γsum is the composite yaw angle. x=L·sin(γsum), y=L·cos(γsum) (2)

[0057] The first yaw angle information, the second yaw angle information, and the third yaw angle information may be subjected to filtering to remove variations in the values ​​and abnormal values. For example, after the first yaw angle calculation unit 221, the second yaw angle calculation unit 222, and the third yaw angle calculation unit 223 calculate the yaw angle information, the calculated yaw angle information is subjected to filtering processing. This makes it possible to suppress a decrease in the accuracy of position estimation of vehicle A due to variations in the yaw angle information and abnormal values.

[0058] 3 is a block diagram showing the configuration of weight determining section 21. As shown in FIG. 3, weight determining section 21 includes first weight setting section 211 and second weight setting section 212. The weight determining unit 21 dynamically changes the weights set for the first yaw angle information, the second yaw angle information, and the third yaw angle information based on changes in the surrounding conditions of the vehicle A.

[0059] (First weight setting unit) The first weight setting unit 211 determines weights to be set for the first yaw angle information, the second yaw angle information, and the third yaw angle information for each section of the driving route traveled by the vehicle A. For example, the first weight setting unit 211 acquires driving route information from the route calculation unit 7, and divides the route indicated by the acquired driving route information into a plurality of sections based on the road shape, etc. For sections that include tunnels and where it is expected that the time during which learning about the gyro sensor 3D error is not possible will be longer than a certain period of time, the first weight setting unit 211 reduces the weight of the first yaw angle information and increases the weight of the second yaw angle information. In addition, in the section where vehicle A is traveling at a low speed in the early stages of its travel and moving in a nearly straight line, the first weight setting unit 211 increases the weight of the second yaw angle information that uses the difference in travel distance between the left and right wheels of vehicle A detected by the wheel speed sensor 3E, and decreases the weight of the first yaw angle information that uses the angular velocity detected by the gyro sensor 3D. Furthermore, in sections where vehicle A is moving at high speed and in a nearly straight line, the first weight setting unit 211 increases the weight of the first yaw angle information using the angular velocity detected by the gyro sensor 3D, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information. Furthermore, in sections that include road curves where vehicle A is expected to turn and travel at low speed, weight determination unit 21 increases the weight of the third yaw angle information that uses the steering angle detected by steering angle sensor 3F, and decreases the weight of the second yaw angle information that uses the difference in travel distance between the left and right wheels of vehicle A detected by wheel speed sensor 3E. Furthermore, for example, in a section of a highway that includes a curve and where vehicle A is expected to turn at high speed, the weight determination unit 21 increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information. This allows the position estimation device 2 to stably calculate the composite yaw information used to estimate the position of the vehicle A.

[0060] (Second weight setting unit) The second weight setting unit 212 changes the weights set for the first yaw angle information, the second yaw angle information, and the third yaw angle information in accordance with changes in the state of the driving route while vehicle A is traveling. For example, if the road surface on which vehicle A is traveling is uneven, the second weight setting unit 212 increases the weight of the first yaw angle information and decreases the weights of the second yaw angle information and the third yaw angle information among the weights set by the first weight setting unit 211 for the section on which vehicle A is traveling. Furthermore, if the road surface on which vehicle A is traveling is slippery, the second weight setting unit 212 increases the weight of the first yaw angle information and decreases the weights of the second yaw angle information and the third yaw angle information, which have large errors due to the influence of vibrations of vehicle A. This allows the position estimation device 2 to stably calculate the composite yaw information used to estimate the position of the vehicle A.

[0061] (Position estimation method) 4 is a flowchart showing a position estimation method according to the first embodiment, and shows a series of steps of the position estimation method executed by the position estimation device 2. The series of steps shown in FIG. 4 is assumed to be repeatedly executed while the vehicle A is traveling. The weight determining unit 21 determines weights to be set for the first yaw angle information, the second yaw angle information, and the third yaw angle information based on the traveling state of the vehicle A or the surrounding state of the vehicle A (step ST1). The yaw information acquisition unit 22 acquires the first yaw angle information, the second yaw angle information, and the third yaw angle information (step ST2). The synthesis unit 23 generates synthesized yaw angle information by synthesizing the first yaw angle information, the second yaw angle information, and the third yaw angle information to which the weights determined by the weight determination unit 21 have been set (step ST3). The position estimation unit 24 estimates the position and direction of the vehicle A using the positioning information of the vehicle A, the vehicle speed of the vehicle A, and the combined yaw angle information (step ST4). 4 shows a case where the position and orientation of vehicle A are estimated, but the position estimation device 2 only needs to estimate the position of vehicle A. In other words, the automatic vehicle control device 4 can control the movement of vehicle A based on the position of vehicle A estimated by the position estimation device 2. By having the position estimation device 2 execute the position estimation method shown in FIG. 4, it is possible to suppress errors according to the characteristics of the positioning method.

[0062] (supplement) In the first embodiment, it is assumed that the sensors used in the first, second, and third positioning methods have been trained to the greatest extent possible for error factors. For example, if the learning situation of the gyro sensor 3D is poor, the sensor value detected by the gyro sensor 3D does not need to be used for estimating the position of the vehicle A from the beginning of the vehicle A's travel. The same applies to the wheel speed sensor 3E and the steering angle sensor 3F. In other words, if the detection accuracy of the wheel speed sensor 3E or the detection accuracy of the steering angle sensor 3F is poor as described above, it is not necessary to use these sensor values ​​for estimating the position of vehicle A from the early stage of vehicle A's travel.

[0063] Next, a hardware configuration for realizing the functions of the position estimation device 2 will be described. The functions of the weight determination unit 21, the yaw information acquisition unit 22, the synthesis unit 23, and the position estimation unit 24 included in the position estimation device 2 are realized by a processing circuit. That is, the position estimation device 2 includes a processing circuit for executing the processes from step ST1 to step ST4 shown in Fig. 4. The processing circuit may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in a memory.

[0064] Fig. 5A is a block diagram showing a hardware configuration for realizing the functions of the position estimation device 2. Fig. 5B is a block diagram showing a hardware configuration for executing software for realizing the functions of the position estimation device 2. In Figs. 5A and 5B, an input interface 100 is an interface that relays detection data acquired by the position estimation device 2 from sensors 3A to 3G, absolute position information of vehicle A acquired from the absolute position storage unit 5, and driving route information of vehicle A acquired from the route calculation unit 7. An output interface 101 is an interface that relays the position estimation result of vehicle A output from the position estimation device 2 to the automatic vehicle control device 4.

[0065] 5A, the processing circuit 102 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. The functions of the weight determination unit 21, the yaw information acquisition unit 22, the synthesis unit 23, and the position estimation unit 24 included in the position estimation device 2 may be realized by separate processing circuits, or these functions may be realized together by a single processing circuit.

[0066] 5B, the functions of the weight determination unit 21, the yaw information acquisition unit 22, the synthesis unit 23, and the position estimation unit 24 included in the position estimation device 2 are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 104.

[0067] (program) The processor 103 reads and executes the programs stored in the memory 104 to realize the functions of the weight determination unit 21, the yaw information acquisition unit 22, the synthesis unit 23, and the position estimation unit 24 provided in the position estimation device 2. For example, the position estimation device 2 includes a memory 104 for storing a program that, when executed by the processor 103, results in the processing of steps ST1 to ST4 shown in FIG. These programs cause a computer to execute the procedures or methods of the processes performed by the weight determining unit 21, the yaw information acquiring unit 22, the combining unit 23, and the position estimating unit 24. The memory 104 may be a computer-readable storage medium that stores a program for causing a computer to function as the weight determining unit 21, the yaw information acquiring unit 22, the combining unit 23, and the position estimating unit 24.

[0068] Memory 104 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically-EPROM) (registered trademark), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD, etc.

[0069] Some of the functions of the weight determination unit 21, the yaw information acquisition unit 22, the synthesis unit 23, and the position estimation unit 24 included in the position estimation device 2 may be realized by dedicated hardware, and the other functions may be realized by software or firmware. For example, the function of the yaw information acquisition unit 22 may be realized by a processing circuit 102 that is dedicated hardware, and the functions of the weight determination unit 21, the synthesis unit 23, and the position estimation unit 24 may be realized by a processor 103 reading and executing a program stored in a memory 104. In this way, the processing circuit can realize the above functions by hardware, software, firmware, or a combination of these.

[0070] The position estimation device 2 may estimate the position of vehicle A using composite yaw rate information obtained by combining the yaw rates calculated using the first, second, and third positioning methods. In this case, the first yaw information is first yaw rate information based on the angular velocity of vehicle A, the second yaw information is second yaw rate information based on the travel distances of the left and right wheels of vehicle A, and the third yaw information is third yaw rate information based on the steering angle and vehicle speed of vehicle A. For example, the yaw information acquisition unit 22 acquires first yaw rate information, second yaw rate information, and third yaw rate information. The weight determination unit 21 determines a weight to be used when combining the first yaw rate information, the second yaw rate information, and the third yaw rate information based on the traveling state of vehicle A or the surrounding state of vehicle A. The combination unit 23 generates combined yaw rate information by combining the first yaw rate information, the second yaw rate information, and the third yaw rate information to which the determined weights have been set. The position estimation unit 24 estimates the position of vehicle A using the positioning information of vehicle A, the vehicle speed of vehicle A, and the combined yaw rate information. Even with the position estimation device 2 configured in this way, it is possible to suppress errors that depend on the characteristics of the positioning method.

[0071] As described above, the position estimation device 2 according to the first embodiment includes a weight determination unit 21 that determines weights to be set on the first yaw angle information of vehicle A based on the angular velocity of vehicle A, the second yaw angle information of vehicle A based on the difference in travel distance between the left and right wheels of vehicle A, and the third yaw angle information of vehicle A based on the steering angle and vehicle speed of vehicle A, based on the traveling state of vehicle A or the surrounding state of vehicle A; a yaw information acquisition unit 22 that acquires the first yaw angle information, the second yaw angle information, and the third yaw angle information; a synthesis unit 23 that generates synthesized yaw angle information by synthesizing the first yaw angle information, the second yaw angle information, and the third yaw angle information to which the determined weights have been set; and a position estimation unit 24 that estimates the position of vehicle A using the positioning information of vehicle A, the vehicle speed of vehicle A, and the synthesized yaw angle information. By combining the three types of yaw information calculated by the first, second, and third positioning methods with weights determined based on the traveling state of vehicle A or the surrounding state of vehicle A, it is possible to stably calculate the yaw information of vehicle A and improve the estimation accuracy of the position and orientation (attitude angle) of vehicle A. This allows position estimation device 2 to suppress errors according to the characteristics of the positioning methods.

[0072] In the position estimation device 2 according to the first embodiment, the yaw information acquisition unit 22 includes a first yaw angle calculation unit 221 that calculates first yaw angle information of the vehicle A based on the angular velocity of the vehicle A, a second yaw angle calculation unit 222 that calculates second yaw angle information of the vehicle A based on the difference in travel distance between the left and right wheels of the vehicle A, and a third yaw angle calculation unit 223 that calculates third yaw angle information of the vehicle A based on the steering angle and vehicle speed of the vehicle A. The three types of yaw angle information calculated by the first, second, and third positioning methods can be combined with weights determined based on the traveling state of vehicle A or the surrounding state of vehicle A, improving the estimation accuracy of the position and orientation (attitude angle) of vehicle A. This allows position estimation device 2 to suppress errors according to the characteristics of the positioning methods.

[0073] In the position estimation device 2 according to the first embodiment, when the speed of vehicle A is equal to or greater than a first threshold, the angular velocity of vehicle A is less than a second threshold, and the time during which an error in the angular velocity of vehicle A is not eliminated is less than a certain time, the weight determination unit 21 increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information; when the time during which an error in the angular velocity of vehicle A is not eliminated is equal to or greater than the certain time, the weight determination unit 21 decreases the weight of the first yaw angle information and increases the weight of the second yaw angle information. This allows the position estimation device 2 to stably calculate the yaw information of vehicle A.

[0074] In the position estimation device 2 according to the first embodiment, when the vehicle speed of the vehicle A is less than the first threshold and the angular velocity of the vehicle A is less than the second threshold, the weight determination unit 21 increases the weight of the second yaw angle information, decreases the weight of the first yaw angle information, and decreases the weight of the third yaw angle information. This allows the position estimation device 2 to stably calculate the yaw information of the vehicle A.

[0075] In the position estimation device 2 according to the first embodiment, when the speed of vehicle A is less than the first threshold and the angular velocity of vehicle A is equal to or greater than the second threshold, the weight determination unit 21 increases the weight of the third yaw angle information, decreases the weight of the first yaw angle information, and decreases the weight of the second yaw angle information; when the speed of vehicle A is equal to or greater than the first threshold and the angular velocity of vehicle A is equal to or greater than the second threshold, the weight determination unit 21 increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information. This allows the position estimation device 2 to stably calculate the yaw information of vehicle A.

[0076] In the position estimation device 2 according to the first embodiment, when the undulations of the road surface on which the vehicle A is traveling are equal to or greater than a third threshold, the weight determination unit 21 increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information. This allows the position estimation device 2 to stably calculate the yaw information of the vehicle A.

[0077] In the position estimation device 2 according to the first embodiment, when the degree of slipperiness of the road surface on which the vehicle A is traveling is equal to or greater than a fourth threshold, the weight determination unit 21 increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information. This allows the position estimation device 2 to stably calculate the yaw information of the vehicle A.

[0078] In the position estimation device 2 according to the first embodiment, the weight determination unit 21 includes a first weight setting unit 211 that determines weights to be set for the first yaw angle information, the second yaw angle information, and the third yaw angle information for each section of the driving route on which the vehicle A is traveling, and a second weight setting unit 212 that changes the weights to be set for the first yaw angle information, the second yaw angle information, and the third yaw angle information in accordance with changes in the state of the driving route while the vehicle A is traveling. This allows the position estimation device 2 to stably calculate the yaw information of the vehicle A.

[0079] In the position estimation device 2 according to the first embodiment, the first yaw information is first yaw rate information based on the angular velocity of the vehicle A, the second yaw information is second yaw rate information based on the travel distance of the left and right wheels of the vehicle A, and the third yaw information is third yaw rate information based on the steering angle and vehicle speed of the vehicle A. By combining the three types of yaw rate information calculated by the first, second, and third positioning methods with weights determined based on the traveling state of vehicle A or the surrounding state of vehicle A, it is possible to stably calculate the yaw rate information of vehicle A and improve the estimation accuracy of the position and orientation of vehicle A. This allows position estimation device 2 to suppress errors according to the characteristics of the positioning methods.

[0080] The autonomous driving system 1 according to the first embodiment includes a position estimation device 2 and an automatic vehicle control device 4 that controls the movement of vehicle A based on the position of vehicle A estimated by the position estimation device 2. The autonomous driving system 1 can accurately control the movement of vehicle A by using the position estimation result of vehicle A obtained from the position estimation device 2, in which errors according to the characteristics of the positioning method are suppressed.

[0081] The position estimation method according to the first embodiment includes the steps of: a weight determination unit 21 determining, based on the traveling state of vehicle A or the surrounding state of vehicle A, weights to be set for first yaw angle information of vehicle A based on the angular velocity of vehicle A, second yaw angle information of vehicle A based on the difference in travel distances between the left and right wheels of vehicle A, and third yaw angle information of vehicle A based on the steering angle and vehicle speed of vehicle A; a yaw information acquisition unit 22 acquiring the first yaw angle information, the second yaw angle information, and the third yaw angle information; a synthesis unit 23 generating synthesized yaw angle information by synthesizing the first yaw angle information, the second yaw angle information, and the third yaw angle information to which the determined weights are set; and a position estimation unit 24 estimating the position of vehicle A using the positioning information of vehicle A, the vehicle speed of vehicle A, and the synthesized yaw angle information. This allows the position estimation method according to the first embodiment to suppress errors according to the characteristics of the positioning method.

[0082] The program according to the first embodiment can be executed by one or more computers to cause the one or more computers to function as a position estimation device 2 that can suppress errors according to the characteristics of the positioning method.

[0083] Various aspects of the present disclosure are summarized below as appendices.

[0084] (Appendix 1) a weight determination unit that determines weights to be set to first yaw information of the vehicle based on the angular velocity of the vehicle, second yaw information of the vehicle based on a difference in moving distance between left and right wheels of the vehicle, and third yaw information of the vehicle based on a steering angle and a vehicle speed of the vehicle, based on a running state of the vehicle or a surrounding state of the vehicle; a yaw information acquisition unit that acquires the first yaw information, the second yaw information, and the third yaw information; a synthesis unit that generates synthesized yaw information by synthesizing the first yaw information, the second yaw information, and the third yaw information to which the determined weights are set; a position estimation unit that estimates the position of the vehicle using the positioning information of the vehicle, the vehicle speed of the vehicle, and the composite yaw information. A position estimation device characterized by: (Appendix 2) The yaw information acquisition unit a first yaw angle calculation unit that calculates first yaw angle information of the vehicle based on an angular velocity of the vehicle; a second yaw angle calculation unit that calculates second yaw angle information of the vehicle based on a difference in moving distance between left and right wheels of the vehicle; a third yaw angle calculation unit that calculates third yaw angle information of the vehicle based on the steering angle and vehicle speed of the vehicle. 2. A position estimation device according to claim 1. (Appendix 3) The weight determination unit When the vehicle speed of the vehicle is equal to or greater than a first threshold, the angular velocity of the vehicle is less than a second threshold, and the time during which the error in the angular velocity of the vehicle is not eliminated is less than a certain time, increasing the weight of the first yaw angle information, decreasing the weight of the second yaw angle information, and decreasing the weight of the third yaw angle information; If the time during which the error in the angular velocity of the vehicle is not removed is equal to or longer than a certain time, the weight of the first yaw angle information is decreased and the weight of the second yaw angle information is increased. 3. The position estimation device according to claim 2, (Appendix 4) The weight determination unit When the vehicle speed of the vehicle is less than the first threshold and the angular velocity of the vehicle is less than the second threshold, the weight of the second yaw angle information is increased, the weight of the first yaw angle information is decreased, and the weight of the third yaw angle information is decreased. 4. A position estimation device according to claim 3. (Appendix 5) The weight determination unit When the vehicle speed of the vehicle is less than the first threshold and the angular velocity of the vehicle is equal to or greater than the second threshold, increasing the weight of the third yaw angle information, decreasing the weight of the first yaw angle information, and decreasing the weight of the second yaw angle information; When the vehicle speed is equal to or greater than the first threshold and the angular velocity of the vehicle is equal to or greater than the second threshold, the weight of the first yaw angle information is increased, the weight of the second yaw angle information is decreased, and the weight of the third yaw angle information is decreased. 5. The position estimation device according to claim 3 or 4, (Appendix 6) When the undulation of the road surface on which the vehicle is traveling is equal to or greater than a third threshold, the weight determination unit increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information. 6. The position estimation device according to claim 3, wherein: (Appendix 7) When the degree of slipperiness of the road surface on which the vehicle is traveling is equal to or greater than a fourth threshold, the weight determination unit increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information. 7. The position estimation device according to claim 3, wherein: (Appendix 8) The weight determination unit a first weight setting unit that determines weights to be set to the first yaw angle information, the second yaw angle information, and the third yaw angle information for each section of a travel route on which the vehicle travels; a second weight setting unit that changes weights set to the first yaw angle information, the second yaw angle information, and the third yaw angle information in accordance with a change in the state of the traveling route while the vehicle is traveling. 8. The position estimation device according to claim 3, wherein: (Appendix 9) the first yaw information is first yaw rate information based on an angular velocity of the vehicle; the second yaw information is second yaw rate information based on a difference in moving distance between left and right wheels of the vehicle, The third yaw information is third yaw rate information based on the steering angle and vehicle speed of the vehicle. 2. A position estimation device according to claim 1. (Appendix 10) A location estimation device according to any one of Supplementary Note 1 to Supplementary Note 9; an automatic vehicle control device that controls the movement of the vehicle based on the position of the vehicle estimated by the position estimation device; An automated driving system characterized by: (Appendix 11) A method for estimating a position of a position estimation device, comprising: a weight determination unit determining weights to be set to first yaw information of the vehicle based on an angular velocity of the vehicle, second yaw information of the vehicle based on a difference in moving distances between left and right wheels of the vehicle, and third yaw information of the vehicle based on a steering angle and a vehicle speed of the vehicle, based on a running state of the vehicle or a surrounding state of the vehicle; a yaw information acquisition unit acquiring the first yaw information, the second yaw information, and the third yaw information; A synthesis unit generates synthesized yaw information by synthesizing the first yaw information, the second yaw information, and the third yaw information to which the determined weights are set; a position estimation unit estimating a position of the vehicle using the positioning information, the vehicle speed, and the composite yaw information. A position estimation method comprising: (Appendix 12) Computer, a weight determination unit that determines weights to be set to first yaw information of the vehicle based on an angular velocity of the vehicle, second yaw information of the vehicle based on a difference in moving distances between left and right wheels of the vehicle, and third yaw information of the vehicle based on a steering angle and a vehicle speed of the vehicle, based on a running state of the vehicle or a surrounding state of the vehicle; a yaw information acquisition unit that acquires the first yaw information, the second yaw information, and the third yaw information; a synthesis unit that generates synthesized yaw information by synthesizing the first yaw information, the second yaw information, and the third yaw information to which the determined weights have been set; a program for causing the computer to function as a position estimation unit that estimates the position of the vehicle using the positioning information, the vehicle speed, and the composite yaw information;

[0085] Any of the components of the embodiments may be modified or omitted. [Explanation of symbols]

[0086] 1 Autonomous driving system, 2 Position estimation device, 3A Absolute position detection unit, 3B Road surface detection unit, 3C Attitude detection unit, 3D gyro sensor, 3E Wheel speed sensor, 3F Steering angle sensor, 3G Vehicle speed sensor, 4 Automatic vehicle control device, 5 Absolute position memory unit, 6 Map information memory unit, 7 Route calculation unit, 100 Input impedance, 101 Output impedance, 102 Processing circuit, 103 Processor, 104 Memory, 211 First weight setting unit, 212 Second weight setting unit, 221 First yaw angle calculation unit, 222 Second yaw angle calculation unit, 223 Third yaw angle calculation unit.

Claims

1. a weight determination unit that determines weights to be set to first yaw information of the vehicle based on an angular velocity of the vehicle, second yaw information of the vehicle based on a difference in moving distances between left and right wheels of the vehicle, and third yaw information of the vehicle based on a steering angle and a vehicle speed of the vehicle, based on a running state of the vehicle or a surrounding state of the vehicle; a yaw information acquisition unit that acquires the first yaw information, the second yaw information, and the third yaw information; a synthesis unit that generates synthesized yaw information by synthesizing the first yaw information, the second yaw information, and the third yaw information to which the determined weights are set; a position estimation unit that estimates the position of the vehicle using the positioning information of the vehicle, the vehicle speed of the vehicle, and the composite yaw information. A position estimation device characterized by:

2. The yaw information acquisition unit a first yaw angle calculation unit that calculates first yaw angle information of the vehicle based on an angular velocity of the vehicle; a second yaw angle calculation unit that calculates second yaw angle information of the vehicle based on a difference in moving distance between left and right wheels of the vehicle; a third yaw angle calculation unit that calculates third yaw angle information of the vehicle based on a steering angle and a vehicle speed of the vehicle.

2. The position estimation device according to claim 1.

3. The weight determination unit When the vehicle speed of the vehicle is equal to or greater than a first threshold, the angular velocity of the vehicle is less than a second threshold, and the time during which the error in the angular velocity of the vehicle is not eliminated is less than a certain time, the weight of the first yaw angle information is increased, the weight of the second yaw angle information is decreased, and the weight of the third yaw angle information is decreased; If the time during which the error in the angular velocity of the vehicle is not removed is equal to or longer than a certain time, the weight of the first yaw angle information is decreased and the weight of the second yaw angle information is increased.

3. The position estimation device according to claim 2.

4. The weight determination unit When the vehicle speed of the vehicle is less than the first threshold and the angular velocity of the vehicle is less than the second threshold, the weight of the second yaw angle information is increased, the weight of the first yaw angle information is decreased, and the weight of the third yaw angle information is decreased.

4. The position estimation device according to claim 3.

5. The weight determination unit When the vehicle speed of the vehicle is less than the first threshold and the angular velocity of the vehicle is equal to or greater than the second threshold, increasing the weight of the third yaw angle information, decreasing the weight of the first yaw angle information, and decreasing the weight of the second yaw angle information; When the vehicle speed of the vehicle is equal to or greater than the first threshold and the angular velocity of the vehicle is equal to or greater than the second threshold, the weight of the first yaw angle information is increased, the weight of the second yaw angle information is decreased, and the weight of the third yaw angle information is decreased.

4. The position estimation device according to claim 3.

6. When the undulation of the road surface on which the vehicle is traveling is equal to or greater than a third threshold, the weight determination unit increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information.

3. The position estimation device according to claim 2.

7. When the degree of slipperiness of the road surface on which the vehicle is traveling is equal to or greater than a fourth threshold, the weight determining unit increases the weight of the first yaw angle information, decreases the weight of the second yaw angle information, and decreases the weight of the third yaw angle information.

3. The position estimation device according to claim 2.

8. The weight determination unit a first weight setting unit that determines weights to be set to the first yaw angle information, the second yaw angle information, and the third yaw angle information for each section of a travel route on which the vehicle travels; a second weight setting unit that changes weights set to the first yaw angle information, the second yaw angle information, and the third yaw angle information in accordance with a change in the state of the traveling route while the vehicle is traveling.

3. The position estimation device according to claim 2.

9. the first yaw information is first yaw rate information based on an angular velocity of the vehicle; the second yaw information is second yaw rate information based on movement distances of left and right wheels of the vehicle, The third yaw information is third yaw rate information based on the steering angle and vehicle speed of the vehicle.

2. The position estimation device according to claim 1.

10. A position estimation device according to any one of claims 1 to 9; an automatic vehicle control device that controls the movement of the vehicle based on the position of the vehicle estimated by the position estimation device; An automated driving system characterized by:

11. A method for estimating a position of a position estimation device, comprising: a weight determination unit determining weights to be set to first yaw information of the vehicle based on an angular velocity of the vehicle, second yaw information of the vehicle based on a difference in moving distances between left and right wheels of the vehicle, and third yaw information of the vehicle based on a steering angle and a vehicle speed of the vehicle, based on a running state of the vehicle or a surrounding state of the vehicle; a yaw information acquisition unit acquiring the first yaw information, the second yaw information, and the third yaw information; a synthesis unit generating synthesized yaw information by synthesizing the first yaw information, the second yaw information, and the third yaw information to which the determined weights are set; a position estimation unit estimating the position of the vehicle using the positioning information of the vehicle, the vehicle speed of the vehicle, and the composite yaw information. A position estimation method comprising:

12. Computer, a weight determination unit that determines weights to be set to first yaw information of the vehicle based on an angular velocity of the vehicle, second yaw information of the vehicle based on a difference in moving distances between left and right wheels of the vehicle, and third yaw information of the vehicle based on a steering angle and a vehicle speed of the vehicle, based on a running state of the vehicle or a surrounding state of the vehicle; a yaw information acquisition unit that acquires the first yaw information, the second yaw information, and the third yaw information; a combining unit that generates combined yaw information by combining the first yaw information, the second yaw information, and the third yaw information to which the determined weights have been set; a program for causing the computer to function as a position estimation unit that estimates the position of the vehicle using the positioning information of the vehicle, the vehicle speed, and the composite yaw information;

Images