Method for estimating errors in information processing device and acceleration sensor

Abstract

This system accurately estimates the error of the acceleration sensor installed in the vehicle. [Solution] The information processing device 100 includes an acquisition unit 103 that acquires the output values ​​ax, ay, and az of an acceleration sensor 20 mounted on the vehicle 10, and the output value V of a vehicle speed sensor 40 mounted on the vehicle, and an estimation unit 140 that estimates the error amount of the output value of the acceleration sensor using the output value of the acceleration sensor during the period in which the time integral value of the translational acceleration Ay in the left-right axis direction of the vehicle is zero, and the amount of change in the vehicle speed ΔV during the above period derived from the output value of the acceleration sensor.

Description

Technical Field

[0001] This disclosure relates to an information processing apparatus and a method for estimating an error of an acceleration sensor.

Background Art

[0002] Regarding a technique for estimating an error of an acceleration sensor mounted on a vehicle, a technique for estimating an error of an acceleration sensor using an output value of the acceleration sensor when the vehicle is stopped on a flat road surface is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above prior art, the error of the acceleration sensor cannot be accurately estimated unless the output value of the acceleration sensor during vehicle stop is obtained. Therefore, a technique for accurately estimating the error of the acceleration sensor using the output value of the acceleration sensor during vehicle travel is desired.

Means for Solving the Problems

[0005] This disclosure can be realized in the following forms.

[0006] According to one embodiment of the present disclosure, an information processing device (100) is provided. This information processing device includes an acquisition unit (103) that acquires output values ​​(ax, ay, az) from an acceleration sensor (20) mounted on a vehicle (10) and an output value (V) from a vehicle speed sensor (40) mounted on the vehicle, and an estimation unit (140) that estimates the error amount of the output value of the acceleration sensor using the output value of the acceleration sensor during a period in which the time integral value of the translational acceleration (Ay) in the left-right axis direction of the vehicle is zero, and the amount of change in the vehicle speed (ΔV) during the period derived from the output value of the vehicle speed sensor.

[0007] According to this type of information processing device, the error of the acceleration sensor can be accurately estimated using the output value of the acceleration sensor while the vehicle is in motion. [Brief explanation of the drawing]

[0008] [Figure 1] A diagram illustrating the configuration of the information processing device according to the first embodiment. [Figure 2] Functional diagram of the information processing device according to the first embodiment. [Figure 3] The first explanatory diagram shows the mounting angle error of the acceleration sensor. [Figure 4] A second explanatory diagram showing the mounting angle error of the acceleration sensor. [Figure 5] An explanatory diagram showing the most frequent values ​​of the vehicle's attitude angle. [Figure 6] A flowchart showing the procedure for error estimation processing in the first embodiment. [Figure 7] An explanatory diagram showing the estimated trajectory of a vehicle. [Figure 8] A flowchart showing the procedure for error estimation processing in the second embodiment. [Modes for carrying out the invention]

[0009] A. First Embodiment: As shown in Figure 1, the information processing device 100 in this embodiment is mounted on the vehicle 10. In addition to the information processing device 100, the vehicle 10 is equipped with an acceleration sensor 20 that detects acceleration in the three axes (X, Y, and Z axes) of the vehicle 10, an angular velocity sensor 30 that detects angular velocity around the three axes of the vehicle 10, and a vehicle speed sensor 40 that detects the vehicle speed of the vehicle 10. For example, the acceleration sensor 20 and the angular velocity sensor 30 can be inertial measurement units (IMUs) that detect acceleration in the three axes and angular velocity around the three axes. For example, the vehicle speed sensor 40 can be a wheel speed sensor that detects vehicle speed from the rotational speed of the wheels.

[0010] The information processing device 100 is comprised of a computer comprising a processor 101, a memory 102, an input / output interface 103, and an internal bus 104. The processor 101, the memory 102, and the input / output interface 103 are connected via the internal bus 104 to enable bidirectional communication. An acceleration sensor 20, an angular velocity sensor 30, and a vehicle speed sensor 40 are connected to the input / output interface 103, for example, via signal cables.

[0011] As shown in Figure 2, the processor 101 functions as an acceleration correction unit 110, an angular velocity correction unit 120, a vehicle attitude estimation unit 130, a vehicle position motion estimation unit 140, and an acceleration error estimation unit 150 by executing a computer program PG pre-stored in memory 102. The acceleration correction unit 110 corrects the output values ​​of acceleration in the X, Y, and Z axes obtained from the acceleration sensor 20. The angular velocity correction unit 120 corrects the output values ​​of angular velocity around the X, Y, and Z axes obtained from the angular velocity sensor 30. The vehicle attitude estimation unit 130 estimates the attitude of the vehicle 10 using the output values ​​of various sensors 20, 30, and 40. Specifically, the vehicle attitude estimation unit 130 estimates the orientation of the X, Y, and Z axes of the vehicle 10 in three-dimensional space. The vehicle position and motion estimation unit 140 estimates the vehicle 10's trajectory in three-dimensional space using the output values ​​of various sensors 20, 30, and 40 and the vehicle attitude estimation unit 130. The vehicle position and motion estimation unit 140 estimates the vehicle 10's trajectory, for example, using a Kalman filter. The acceleration error estimation unit 150 estimates the error amount of the acceleration sensor 20. The acceleration correction unit 110 corrects the output value of the acceleration sensor 20 according to the error amount estimated by the acceleration error estimation unit 150.

[0012] Figures 3 and 4 illustrate the coordinate axes of the wheel coordinate system Cw, the vehicle body coordinate system Cb, and the sensor coordinate system Cs. The wheel coordinate system Cw is the coordinate system of the four wheels 12 of the vehicle 10, the vehicle body coordinate system Cb is the coordinate system of the vehicle body 11 of the vehicle 10, and the sensor coordinate system Cs is the coordinate system of the acceleration sensor 20. Each coordinate system Cs, Cb, and Cw is a Cartesian coordinate system and has X, Y, and Z coordinate axes. The X axis of the wheel coordinate system Cw is the longitudinal axis of the vehicle 10, the Y axis of the wheel coordinate system Cw is the lateral axis of the vehicle 10, and the Z axis of the wheel coordinate system Cw is the vertical axis of the vehicle 10.

[0013] The acceleration sensor 20 is mounted on the vehicle body 11. If there is no misalignment in the mounting angle of the acceleration sensor 20 to the vehicle body 11, and the vehicle body 11 is not tilted relative to the road surface, then the orientation of the coordinate axes of the wheel coordinate system Cw, the vehicle body coordinate system Cb, and the sensor coordinate system Cs will coincide. However, there may be a misalignment in the mounting angle of the acceleration sensor 20 to the vehicle body 11. If there is a misalignment in the mounting angle of the acceleration sensor 20 to the vehicle body 11, then a misalignment will occur between the orientation of the coordinate axes of the sensor coordinate system Cs and the orientation of the coordinate axes of the vehicle body coordinate system Cb. Furthermore, the weight of the occupants and cargo of the vehicle 10 may cause the vehicle body 11 to tilt relative to the road surface. If the vehicle body 11 is tilted relative to the road surface, then a misalignment will occur between the orientation of the coordinate axes of the vehicle body coordinate system Cb and the orientation of the coordinate axes of the wheel coordinate system Cw. The orientation of the coordinate axes of the sensor coordinate system Cs and the vehicle body coordinate system Cb does not change while the vehicle 10 is in motion. The orientation of the coordinate axes of the vehicle body coordinate system Cb and the wheel coordinate system Cw changes while the vehicle 10 is in motion due to the extension and contraction of the suspension, etc.

[0014] In the example shown in Figure 3, when viewed parallel to the road surface, there is an angle θs difference between the X-axis of the sensor coordinate system Cs and the X-axis of the vehicle coordinate system Cb, and further, an angle θb difference between the X-axis of the vehicle coordinate system Cb and the X-axis of the wheel coordinate system Cw. Therefore, there is an angle θ = θs + θb difference between the X-axis of the sensor coordinate system Cs and the X-axis of the wheel coordinate system Cw. In the example shown in Figure 4, when viewed perpendicular to the road surface, there is an angle ψ difference between the X and Y axes of the wheel coordinate system Cw and the X and Y axes of the sensor coordinate system Cs. When the orientation of the coordinate axes of the sensor coordinate system Cs and the orientation of the coordinate axes of the wheel coordinate system Cw are misaligned, an error occurs between the X, Y, Z output values ​​of the acceleration sensor 20 and the X, Y, Z acceleration of the vehicle 10. In the following explanation, the misalignment between the orientation of the coordinate axes of the sensor coordinate system Cs and the orientation of the coordinate axes of the wheel coordinate system Cw will be referred to as the mounting angle error.

[0015] Also, when the zero point of the acceleration sensor 20 is offset, even though no acceleration actually acts on the acceleration sensor 20, the output value of the acceleration sensor 20 becomes non-zero. Therefore, an error occurs between the output values of X, Y, and Z of the acceleration sensor 20 and the accelerations of X, Y, and Z of the vehicle 10. In the following description, the error due to the offset of the zero point of the acceleration sensor 20 is referred to as an offset error. The offset error may also be called a bias error or a zero point error.

[0016] When the vehicle 10 is stationary, the gravitational acceleration g generated by gravity acts on the acceleration sensor 20. When the vehicle 10 is running, the translational accelerations Ax and Ay generated by the running of the vehicle 10 and the gravitational acceleration g generated by gravity act on the acceleration sensor 20. Usually, since the running vehicle 10 moves parallel to the road surface, the translational accelerations Ax and Ay act parallel to the road surface.

[0017] The acceleration sensor output values gx, gy, and gz when the vehicle 10 is stationary can be expressed by the following equation (1). gx is the acceleration sensor output value in the X-axis direction, gy is the acceleration sensor output value in the Y-axis direction, and gz is the acceleration sensor output value in the Z-axis direction. gx, gy, and gz are values in the sensor coordinate system Cs.

Equation

[0018] Here, when expressing the mounting angle error as an offset error, the acceleration sensor output values gx, gy, and gz can be expressed by the following formula (2).

Number

[0019] Here, when expressing the offset error as a mounting angle error, the acceleration sensor output values gx, gy, and gz can be expressed by the following formula (3). For example, when the influence of the mounting angle error is greater than that of the offset error, such as when the mounting angle error is 5 deg or more, the offset error may be expressed as a mounting angle error.

Number

[0020] The acceleration sensor output values ax, ay, and az when the vehicle 10 is running can be expressed by the following formula (4). ax is the acceleration sensor output value in the X-axis direction, ay is the acceleration sensor output value in the Y-axis direction, and az is the acceleration sensor output value in the Z-axis direction. ax, ay, and az are values in the sensor coordinate system Cs.

Number

[0021] For ease of understanding, the case where the vehicle 10 is parked on a horizontal road surface and the case where the vehicle 10 runs only on a horizontal road surface will be described. When the vehicle 10 is parked on a horizontal road surface, the acceleration sensor output values gx, gy, and gz can be expressed by the following formula (5).

Number

[0022] When vehicle 10 is stopped on a level road surface, and the mounting angle error is expressed as an offset error, the acceleration sensor output values ​​gx, gy, and gz can be expressed by the following equation (6).

number

[0023] When vehicle 10 is stopped on a level road surface, and the offset error is expressed as the mounting angle error, the acceleration sensor output values ​​gx, gy, and gz can be expressed by the following equation (7).

number

[0024] When vehicle 10 is traveling only on a level road surface, the acceleration sensor output values ​​ax, ay, and az can be expressed by the following equation (8).

number

[0025] <Method for estimating the error amount of acceleration sensor output values> This section describes a method for estimating the error amount of the output values ​​of the acceleration sensor 20 (hereinafter referred to as acceleration sensor output values). If the time integral of the translational acceleration Ax during the period from time t to time t+Δt can be considered to be zero, and the translational acceleration Ay during the same period can always be considered to be zero (or the time integral of the translational acceleration Ay during the same period can be considered to be zero), then the time integrals of the acceleration sensor output values ​​ax, ay, and az during that period will not include the translational acceleration component, and will only contain the gravitational acceleration component and the error component. This property is used to estimate the error amount of the acceleration sensor output values ​​ax, ay, and az. Note that even if the time integral of the translational acceleration Ax during the period from time t to time t+Δt cannot be considered to be zero, if the change in vehicle speed ΔV during the period from time t to time t+Δt can be determined, the error amount of the acceleration sensor output values ​​ax, ay, and az can be estimated.

[0026] As shown in equation (4), the error in the accelerometer output value ax is (-gθcos(roll)cos(pitch)+bx), the error in the accelerometer output value ay is (gφcos(roll)cos(pitch)+by), and the error in the accelerometer output value az is (bz). In the following explanation, the period during which the time integral of the translational acceleration Ax from time t to time t+Δt can be considered zero, and the translational acceleration Ay from time t to time t+Δt can always be considered zero, is referred to as the target period.

[0027] Vehicle 10 frequently travels on level roads. When the roll angle and pitch angle of vehicle 10 are sufficiently small, cos(roll)=1 and cos(pitch)=1 can be assumed. The roll angle and pitch angle of vehicle 10 while in motion fluctuate due to road surface shape and suspension extension / retraction, but the roll angle and pitch angle of vehicle 10 while in motion are often sufficiently small. For this reason, the mode of the acceleration sensor output value ax during the target period can be estimated to be (-gθcos(roll)cos(pitch)+bx), the mode of the acceleration sensor output value ay during the target period can be estimated to be (gφcos(roll)cos(pitch)+by), and the mode of the acceleration sensor output value az during the target period can be estimated to be (g·cos(roll)cos(pitch)+bz). Therefore, the mode of ax during the period can be estimated to be the error amount of ax, the mode of ay during the period can be estimated to be the error amount of ay, and the value obtained by subtracting the gravitational acceleration g from the mode of az during the period can be estimated to be the error amount of az.

[0028] In addition to methods that estimate the amount of error using the mode of the acceleration sensor output values ​​ax, ay, and az during the target period, it is also possible to estimate the amount of error using the median of the acceleration sensor output values ​​ax, ay, and az during the target period, to estimate the amount of error using the σ value of the acceleration sensor output values ​​ax, ay, and az during the target period excluding the stationary period, and to estimate the amount of error using the average value of the acceleration sensor output values ​​ax, ay, and az during the target period.

[0029] Figure 5 shows an example of a histogram of the pitch angle of vehicle 10. The error amount of the acceleration sensor output value can be estimated using the most frequent values ​​of the roll angle and pitch angle of vehicle 10. Vehicle 10 frequently travels on level roads. Therefore, if there is no offset error or mounting angle error in the acceleration sensor 20, the most frequent values ​​of the roll angle and pitch angle of vehicle 10 will be zero. Thus, the amount of correction when the acceleration sensor output value is corrected so that the most frequent values ​​of the roll angle and pitch angle are zero can be estimated to be the error amount of the acceleration sensor output value. In Figure 5, the most frequent value of the pitch angle of vehicle 10 is 1.1 degrees. The pitch angle and roll angle of vehicle 10 follow a normal distribution. A peak with a relatively high number of detections appears around -2.0 degrees, but this can be considered an outlier due to a temporary stop on an inclined road surface, so it is preferable to exclude it when calculating the mode.

[0030] <Method for estimating mounting angle error of acceleration sensor> Next, we will explain how to estimate the mounting angle errors φ, θ, and ψ of the acceleration sensor 20. If the mounting angle errors φ, θ, and ψ of the acceleration sensor 20 can be estimated, it becomes possible to separate the amount of error due to offset error from the amount of error due to mounting angle error among the error amounts included in the acceleration sensor output values ​​ax, ay, and az.

[0031] If the change in vehicle speed over time Δt during straight-line acceleration and deceleration of vehicle 10 is ΔV, the mounting angle error θ around the Y axis and the mounting angle error ψ around the Z axis can be estimated using the acceleration sensor output values ​​ax, ay, az during straight-line acceleration and deceleration of vehicle 10 and the acceleration sensor output values ​​gx, gy, gz while vehicle 10 is stationary. The mounting angle error θ around the Y axis can be expressed by equation (9) below, and the mounting angle error ψ around the Z axis can be expressed by equation (10) below.

number

number

[0032] For example, when Δt = 5 seconds and ΔV = 10 m / s, if equations (11) and (12) below are true, then θ = 0.5 deg can be estimated. Note that the change in vehicle speed ΔV can be derived using the vehicle speed V obtained from the vehicle speed sensor 40.

number

number

[0033] Furthermore, the mounting angle error φ around the X-axis can be estimated using the acceleration sensor output values ​​ay,az while the vehicle 10 is traveling on a curve and the acceleration sensor output values ​​gy,gz while the vehicle 10 is stationary. The mounting angle error φ around the X-axis can be expressed by the following equation (13).

number

[0034] The error estimation process for estimating the error of the acceleration sensor 20 shown in Figure 6 is repeatedly performed at predetermined intervals by the acceleration error estimation unit 150 after the vehicle 10 is started. In step S110, the acceleration error estimation unit 150 determines whether or not the vehicle 10 has started moving. For example, the acceleration error estimation unit 150 determines that the vehicle 10 has started moving if the vehicle speed obtained from the vehicle speed sensor 40 is not zero. If it is not determined in step S110 that the vehicle 10 has started moving, the acceleration error estimation unit 150 waits for a predetermined time in step S115 to record the acceleration and attitude angle of the vehicle 10, and then returns to step S110.

[0035] If it is determined in step S110 that the vehicle 10 has started moving, the acceleration error estimation unit 150 starts recording the acceleration and attitude angle of the vehicle 10 in step S120. The acceleration error estimation unit 150 records the acceleration obtained from the acceleration sensor 20 and the attitude angle of the vehicle 10 obtained from the vehicle attitude estimation unit 130 in the memory 102.

[0036] In step S130, the acceleration error estimation unit 150 determines whether the vehicle 10 is moving in a straight line. In this embodiment, the acceleration error estimation unit 150 determines that the vehicle 10 is moving in a straight line if the angular velocity ωz around the Z axis obtained from the angular velocity sensor 30 is less than a predetermined threshold ωn.

[0037] If it is determined in step S130 that the vehicle 10 is moving in a straight line, the acceleration error estimation unit 150 estimates in step S140 the Z-axis offset error bz of the acceleration sensor 20 for the target period in which the time integral of the translational acceleration Ax in the X-axis direction of the vehicle 10 from time t to time t+Δt is zero, and the angular velocity ωz of the vehicle 10 around the Z-axis is less than the threshold ωn. When the time integral of the translational acceleration Ax in the X-axis direction of the vehicle 10 is zero, the vehicle speed at time t and the vehicle speed at time t+Δt are the same. The vehicle speed can be detected by the vehicle speed sensor 40, and the angular velocity ωz around the Z-axis can be detected by the angular velocity sensor 30. Therefore, the acceleration error estimation unit 150 can determine the target period using the vehicle speed detected by the vehicle speed sensor 40 and the angular velocity detected by the angular velocity sensor 30. The acceleration error estimation unit 150 estimates that the offset error bz is the value obtained by subtracting the gravitational acceleration from the mode of the Z-axis output value az of the acceleration sensor 20 during the target period. The acceleration error estimation unit 150 records the estimated offset error bz (error amount of az) in the memory 102.

[0038] After step S140, in step S145, the acceleration error estimation unit 150 estimates the error amount of the X-direction output value ax of the acceleration sensor 20 and the error amount of the Y-direction output value ay of the acceleration sensor 20. In this embodiment, the acceleration error estimation unit 150 estimates that the mode of the X-direction output value ax of the acceleration sensor 20 during the target period is the error amount of ax, and estimates that the mode of the Y-direction output value ay of the acceleration sensor 20 during the target period is the error amount of ay. The acceleration error estimation unit 150 records the estimated error amounts of ax and ay in the memory 102. In step S147, the acceleration error estimation unit 150 estimates the mode of the roll angle and pitch angle of the vehicle 10 during the target period from the attitude angle of the vehicle 10 during the target period estimated by the vehicle attitude estimation unit 130. The acceleration error estimation unit 150 records the mode of the estimated roll angle and pitch angle in the memory 102. Subsequently, the acceleration error estimation unit 150 proceeds to step S170. Note that the processing in step S147 is not required.

[0039] If it is determined in step S130 that the vehicle 10 is moving in a straight line, the acceleration error estimation unit 150 further determines in step S150 whether the vehicle 10 is accelerating or decelerating. In this embodiment, the acceleration error estimation unit 150 determines that the vehicle 10 is accelerating or decelerating if the absolute value of the translational acceleration Ax in the X-axis direction estimated by the vehicle position motion estimation unit 140 exceeds a predetermined threshold Ah, and determines that the vehicle 10 is not accelerating or decelerating if the absolute value of the translational acceleration Ax in the X-axis direction is less than or equal to the predetermined threshold Ah. If it is determined in step S150 that the vehicle 10 is accelerating or decelerating, the acceleration error estimation unit 150 estimates the mounting angle error θ around the Y-axis and the mounting angle error ψ around the Z-axis in step S155. The acceleration error estimation unit 150 records the estimated mounting angle error θ around the Y-axis and the mounting angle error ψ around the Z-axis in the memory 102. If it is determined in step S150 that the vehicle 10 is not accelerating or decelerating, the acceleration error estimation unit 150 skips the processing in step S155 and proceeds to step S170.

[0040] If it is determined in step S130 that the vehicle 10 is not moving in a straight line, the acceleration error estimation unit 150 determines in step S160 whether or not the vehicle 10 is traveling on a curve. In this embodiment, the acceleration error estimation unit 150 determines that the vehicle 10 is traveling on a curve if the absolute value of the centripetal acceleration ωV (radial acceleration of circular motion) of the vehicle 10 around the Z axis exceeds a predetermined threshold Ah, and determines that the vehicle 10 is not traveling on a curve if the absolute value of the centripetal acceleration around the Z axis is less than or equal to the predetermined threshold Ah. If it is determined in step S160 that the vehicle 10 is traveling on a curve, the acceleration error estimation unit 150 estimates the mounting angle error φ around the X axis in step S165. The acceleration error estimation unit 150 records the estimated mounting angle error φ around the X axis in the memory 102. After that, the acceleration error estimation unit 150 proceeds to step S170. If it is determined in step S160 that the vehicle 10 is not on a curve, the acceleration error estimation unit 150 returns to step S130.

[0041] In step S170, the acceleration error estimation unit 150 separates the error amount due to offset error and the error amount due to mounting angle error from the error amounts of the acceleration sensor output values ​​ax, ay, az recorded in the memory 102, if it is possible to separate them. Also in step S170, the acceleration error estimation unit 150 determines the validity of the estimated error amount. In this embodiment, the acceleration error estimation unit 150 determines that the estimated error amount is valid if the absolute value of the difference between the current estimated value and the previous estimated value is less than a predetermined threshold, and determines that the estimated error amount is not valid if the absolute value of the difference between the current estimated value and the previous estimated value is greater than or equal to the predetermined threshold.

[0042] In step S180, the acceleration error estimation unit 150 determines whether or not to update the correction value for correcting the error of the acceleration sensor 20. In this embodiment, the acceleration error estimation unit 150 determines to update the correction value if the estimated amount of error is reasonable, and determines not to update the correction value if the estimated amount of error is not reasonable.

[0043] If it is determined in step S180 to update the correction value, the acceleration error estimation unit 150 updates the correction value in step S190. The acceleration error estimation unit 150 determines a correction value according to the estimated error amount so that the error of the acceleration sensor 20 is eliminated, and transmits the correction value to the acceleration correction unit 110. If it is determined in step S180 not to update the correction value, the acceleration error estimation unit 150 skips the process in step S190. After that, the acceleration error estimation unit 150 terminates the error estimation process.

[0044] Figure 7 shows the trajectory of a vehicle 10 traveling through a multi-story parking garage. The trajectory of the vehicle 10 is shown as viewed parallel to the horizontal plane. In Figure 7, the estimated trajectory Le, which is the trajectory estimated by the vehicle position motion estimation unit 140, is shown as a solid line, and the actual trajectory La, which is the actual trajectory, is shown as a dashed line. If the error of the acceleration sensor 20 is not corrected, the difference between the actual trajectory La and the estimated trajectory Le is large. In contrast, by correcting the error of the acceleration sensor 20 according to the amount of error estimated by the error estimation process described above, the difference between the actual trajectory La and the estimated trajectory Le can be reduced.

[0045] As described above, the information processing device 100 of this embodiment can accurately estimate the error amounts in the X, Y, and Z axes of the acceleration sensor 20 using the output values ​​in the X, Y, and Z axes of the acceleration sensor 20 while the vehicle 10 is in motion. Therefore, the attitude angle of the vehicle 10 and the driving trajectory of the vehicle 10 can be accurately estimated using the acceleration of the vehicle 10 detected by the acceleration sensor 20.

[0046] Furthermore, according to the information processing device 100 of this embodiment, the error of the acceleration sensor 20 can be estimated even if the vehicle 10 is not traveling on a flat road surface. Moreover, according to the information processing device 100 of this embodiment, the error of the acceleration sensor 20 can be estimated without using other means such as GNSS (Global Navigation Satellite System) or cameras. Furthermore, according to the information processing device 100 of this embodiment, it is not necessary to distinguish between the amount of error due to offset error and the amount of error due to mounting angle error, as this does not affect the correction of the error of the acceleration sensor 20. Moreover, according to the information processing device 100 of this embodiment, even if a mounting angle error occurs in the acceleration sensor 20, the error of the acceleration sensor 20 caused by the mounting angle error can be corrected, thus simplifying the installation work of the acceleration sensor 20 on the vehicle body 11.

[0047] Furthermore, the information processing device 100 of this embodiment can estimate both the offset error and the mounting angle error, making it possible to distinguish between the two. For example, if the mounting angle error is large, it becomes possible to notify the user or others to correct the mounting angle of the acceleration sensor 20 during maintenance.

[0048] Furthermore, in the information processing device 100 of this embodiment, the mode of the output values ​​in the X, Y, and Z axes of the acceleration sensor 20 is used to estimate the error amount in the X, Y, and Z axes of the acceleration sensor 20. Therefore, the error amount in the X, Y, and Z axes of the acceleration sensor 20 can be estimated with simple processing.

[0049] B. Second Embodiment: As shown in Figure 8, in the information processing device 100 of the second embodiment, the content of the error estimation process performed by the acceleration error estimation unit 150 differs from that of the first embodiment. The other configurations are the same as those of the first embodiment unless otherwise specified.

[0050] When the error estimation process shown in Figure 8 is started, in step S210 the acceleration error estimation unit 150 determines whether or not the vehicle 10 has started moving. If it is not determined in step S210 that the vehicle 10 has started moving, the acceleration error estimation unit 150 waits for a predetermined time in step S215 before recording the acceleration and attitude angle of the vehicle 10, and then returns to step S210. If it is determined in step S210 that the vehicle 10 has started moving, the acceleration error estimation unit 150 starts recording the acceleration and attitude angle of the vehicle 10 to the memory 102 in step S220.

[0051] After step S220, the acceleration error estimation unit 150 determines in step S242 whether a predetermined time Th has elapsed since the start of recording the acceleration and attitude angles of the vehicle 10. The length of time Th is preferably, for example, 10 to 20 minutes. The acceleration error estimation unit 150 repeats the process in step S242 until it is determined in step S242 that the predetermined time Th has elapsed. If it is determined in step S242 that the predetermined time Th has elapsed, the acceleration error estimation unit 150 determines in step S247 the most frequent values ​​of the roll angle and pitch angle of the vehicle 10 during the target period from the attitude angles of the vehicle 10 during the target period estimated by the vehicle attitude estimation unit 130. The acceleration error estimation unit 150 records the most frequent values ​​of the estimated roll angle and pitch angle in memory 102. After that, the acceleration error estimation unit 150 proceeds to step S270.

[0052] After step S220, the acceleration error estimation unit 150 further determines in step S230 whether the vehicle 10 is moving in a straight line. If it is determined in step S230 that the vehicle 10 is moving in a straight line, the acceleration error estimation unit 150 determines in step S250 whether the vehicle 10 is accelerating or decelerating. If it is determined in step S250 that the vehicle 10 is accelerating or decelerating, the acceleration error estimation unit 150 estimates the mounting angle error θ around the Y axis and the mounting angle error ψ around the Z axis in step S255. The acceleration error estimation unit 150 records the estimated mounting angle error θ around the Y axis and the mounting angle error ψ around the Z axis in memory 102. If it is determined in step S250 that the vehicle 10 is not accelerating or decelerating, the acceleration error estimation unit 150 skips the processing in step S255 and proceeds to step S270.

[0053] If it is determined in step S230 that the vehicle 10 is not moving in a straight line, the acceleration error estimation unit 150 determines in step S260 whether or not the vehicle 10 is traveling on a curve. If it is determined in step S260 that the vehicle 10 is traveling on a curve, the acceleration error estimation unit 150 estimates the mounting angle error φ around the X axis in step S265. The acceleration error estimation unit 150 records the estimated mounting angle error φ around the X axis in memory 102. After that, the acceleration error estimation unit 150 proceeds to step S270. If it is determined in step S260 that the vehicle 10 is not traveling on a curve, the acceleration error estimation unit 150 returns to step S230.

[0054] In step S270, the acceleration error estimation unit 150 estimates the error amount of the acceleration sensor output values ​​ax, ay, and az using the most frequent roll angle and pitch angle of the vehicle 10 recorded in memory 102. If it is possible to separate the error amount due to offset error and the error amount due to mounting angle error from the error amount of the acceleration sensor output values ​​ax, ay, and az, the unit separates the error amount due to offset error and the error amount due to mounting angle error. As described above, the acceleration error estimation unit 150 can estimate the error amount of the acceleration sensor output values ​​ax, ay, and az using the most frequent roll angle and pitch angle of the vehicle 10. Also in step S270, the acceleration error estimation unit 150 determines the validity of the estimated error amount. In step S280, the acceleration error estimation unit 150 determines whether or not to update the correction value for correcting the error of the acceleration sensor 20. If it is determined in step S280 to update the correction value, the acceleration error estimation unit 150 updates the correction value in step S290 and sends the correction value to the acceleration correction unit 110. If it is determined in step S280 not to update the correction value, the acceleration error estimation unit 150 skips the process in step S290. After that, the acceleration error estimation unit 150 terminates the error estimation process.

[0055] As described above, the information processing device 100 of this embodiment can accurately estimate the amount of error in the X, Y, and Z axes of the acceleration sensor 20 using the output values ​​of the acceleration sensor 20 in the X, Y, and Z axes while the vehicle 10 is in motion.

[0056] C. Other embodiments: (C1) In each of the embodiments described above, the information processing device 100 is mounted on the vehicle 10. In contrast, in other embodiments, the information processing device 100 may be located outside the vehicle 10. In this case, the information processing device 100 may acquire the output values ​​of various sensors 20, 30, and 40 mounted on the vehicle 10 via wireless communication.

[0057] (C2) In each of the embodiments described above, the information processing device 100 estimates the error of the acceleration sensor 20, corrects the error of the acceleration sensor 20 using the estimation result, and uses the corrected acceleration sensor output value to estimate the driving trajectory of the vehicle 10. In contrast, in other embodiments, the information processing device 100 may use the corrected acceleration sensor output value for vehicle control such as automatic parking.

[0058] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments can be replaced or combined as appropriate to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Form 1] The information processing device (100) includes an acquisition unit (103) that acquires the output values ​​(ax, ay, az) of an acceleration sensor (20) mounted on a vehicle (10) and the output value (V) of a vehicle speed sensor (40) mounted on the vehicle, and an estimation unit (140) that estimates the error amount of the output value of the acceleration sensor using the output value of the acceleration sensor during a period in which the time integral value of the translational acceleration (Ay) in the left-right axis direction of the vehicle is zero, and the amount of change in the vehicle speed (ΔV) of the vehicle during the said period derived from the output value of the vehicle speed sensor. [Form 2] In the information processing device described in Embodiment 1, the estimation unit may estimate the error amount of the output value of the acceleration sensor, which includes the error amount due to the mounting angle error (φ,θ,ψ) of the acceleration sensor to the vehicle and the error amount due to the offset error (bx,by,bz) of the acceleration sensor, using the output value of the acceleration sensor during the period and the amount of change in vehicle speed during the period. [Form 3] In the information processing device described in Embodiment 1 or Embodiment 2, the estimation unit may estimate the amount of error using the mode of the output value of the acceleration sensor. [Form 4] The method for estimating the error of an acceleration sensor involves acquiring the output values ​​(ax, ay, az) of an acceleration sensor (20) mounted on a vehicle (10) and the output value (V) of a vehicle speed sensor (40) mounted on the vehicle. The method then estimates the error in the output value of the acceleration sensor using the output value of the acceleration sensor during the period in which the time integral of the translational acceleration (Ay) in the left-right axis direction of the vehicle is zero, and the amount of change in the vehicle speed (ΔV) during the same period, which is derived from the output value of the vehicle speed sensor. [Explanation of Symbols]

[0059] 10...Vehicle, 11...Body, 12...Wheels, 20...Accelerometer, 30...Angular velocity sensor, 40...Vehicle speed sensor, 100...Information processing unit, 101...Processor, 102...Memory, 103...Input / Output interface, 104...Internal bus, 110...Accelerometer correction unit, 120...Angular velocity correction unit, 130...Vehicle attitude estimation unit, 140...Vehicle position motion estimation unit, 150...Accelerometer error estimation unit

Claims

1. Information processing device (100), An acquisition unit (103) acquires the output values ​​(ax, ay, az) of an acceleration sensor (20) mounted on the vehicle (10), and the output value (V) of a vehicle speed sensor (40) mounted on the vehicle, An estimation unit (140) estimates the error amount of the output value of the acceleration sensor using the output value of the acceleration sensor during the period in which the time integral value of the translational acceleration (Ay) in the left-right axis direction of the vehicle is zero, and the amount of change in the vehicle speed (ΔV) during the same period derived from the output value of the vehicle speed sensor, An information processing device equipped with the following features.

2. An information processing apparatus according to claim 1, The estimation unit is an information processing device that estimates the amount of error in the output value of the acceleration sensor, including the amount of error due to the mounting angle error (φ, θ, ψ) of the acceleration sensor to the vehicle and the amount of error due to the offset error (bx, by, bz) of the acceleration sensor, using the output value of the acceleration sensor during the period and the amount of change in vehicle speed during the period.

3. An information processing apparatus according to claim 1, The estimation unit is an information processing device that estimates the amount of error using the mode of the output value of the acceleration sensor.

4. A method for estimating the error of an acceleration sensor, The output values ​​(ax, ay, az) of the acceleration sensor (20) mounted on the vehicle (10) and the output value (V) of the vehicle speed sensor (40) mounted on the vehicle are acquired. The error amount of the output value of the acceleration sensor is estimated using the output value of the acceleration sensor during the period in which the time integral of the translational acceleration (Ay) in the left-right axis direction of the vehicle is zero, and the amount of change in the vehicle speed (ΔV) during the same period, which is derived from the output value of the vehicle speed sensor. Method for estimating the error of an acceleration sensor.

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