ACCELERATION MEASURING DEVICE

• US 20090133466A1
• Filed: 12/27/2006
• Published: 05/28/2009
• Est. Priority Date: 01/05/2006
• Status: Active Grant

• Current Assignee: Asahi Kasei Corporation
• Original Assignee: Asahi Kasei Corporation
• Inventors: Kitamura, Toru, Yamashita, Masaya
• Granted Patent: US 7,881,900 B2
• Time in Patent Office: Days
• US Class Current: 73/1.370
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups

Abstract

A reference point defined on a two dimensional or three dimensional orthogonal coordinate space and scale reference of respective axes are estimated based on a distribution on the three dimensional orthogonal coordinate space at the time when respective axial components of an acceleration data group comprised of plural acceleration data including multi-axial components and a importance group pertaining to the acceleration data group, and the respective acceleration data are corrected based on the estimated reference point and scale reference of the respective axes.

Claims

1-16. -16. (canceled)

17. An acceleration measuring device, comprising:

acceleration detecting means for detecting accelerations in two-axis or three-axis directions;

acceleration data obtaining means for obtaining two-axis or three-axis acceleration data detected by the acceleration detecting means;

importance calculating means for calculating importance of the acceleration data obtained by the acceleration data obtaining means;

reference point estimating means for estimating a reference point defined on a two dimensional or three dimensional orthogonal coordinate space and scale reference of the respective axes based on both a distribution of respective axial components of the acceleration data in a group of two-axis or three-axis acceleration data obtained by the acceleration data obtaining means on the two dimensional orthogonal coordinate space or the three dimensional orthogonal space and a group of importance including importance of different values calculated by the importance calculating means corresponding to the group of two-axis or three-axis acceleration data; and

offset correcting means for correcting the respective acceleration data obtained by the acceleration data obtaining means, based on the reference point and the scale reference of the respective axes estimated by the estimating means.

18. An acceleration measuring device of claim 17, wherein

the reference point estimating means defines a circle on the two dimensional orthogonal coordinate plane or a spherical surface on the three dimensional orthogonal coordinate space based on both the distribution of a group of two-axis or three-axis acceleration data obtained by the acceleration data obtaining means on the two dimensional orthogonal coordinate plane or the three dimensional orthogonal coordinate space and the group of importance calculated by the importance calculating means pertaining to the acceleration data group, estimates a coordinate of center point and a radius of the circle or the sphere, sets the estimated coordinate of center point as the reference point, and sets the radius as the scale reference of the respective axes, and

the offset correcting means corrects offsets of the two-axis or three-axis acceleration data based on the reference point estimated by the reference point estimating means.

19. An acceleration measuring device of claim 17, wherein

the reference point estimating means may define an ellipse on the two dimensional orthogonal coordinate plane or an ellipsoidal surface on the three dimensional orthogonal coordinate space based on both the distribution of the group of two-axis or three-axis acceleration data obtained by the acceleration data obtaining means on the two dimensional orthogonal coordinate plane or the three dimensional orthogonal coordinate space and the group of importance calculated by the importance calculating means pertaining to the acceleration data group, estimates a coordinate of center point and radiuses of respective principal axes of the ellipse or the ellipsoidal surface, sets the estimated coordinate of center point as the reference point, and sets the radiuses of the respective principal axes as the scale reference of the respective axes, and

the offset correcting means corrects offsets and sensitivities of the respective two-axis or three-axis acceleration data based on the reference point and the scale reference of the respective axes estimated by the reference point estimating means.

20. An acceleration measuring device of claim 17, wherein

the reference point estimating means includes:

representative data calculating means for calculating a representative data of a group of a predetermined number M of acceleration data obtained by the acceleration data obtaining means;

first importance calculating means for calculating first importance of the representative data calculated by the representative data calculating means;

accumulating means for accumulating both the representative data calculated by the representative data calculating means and the first importance according to the representative data and additional information; and

second importance calculating means for calculating second importance according to the representative data based on both the first importance according to the representative data and the additional information accumulated in the accumulating means, and

the reference point estimating means estimates the reference point defined on the two dimensional orthogonal coordinate plane or the three dimensional orthogonal coordinate space and the scale reference of the respective axes based on both a distribution on the two dimensional orthogonal coordinate plane or the three dimensional orthogonal coordinate space when respective axial components of a predetermined number N of representative datas accumulated by the accumulating means are defined as coordinate values and a predetermined number N of second importance calculated by the second importance calculating means according to the representative datas.

21. An acceleration measuring device of claim 20, wherein

the second importance calculating means calculates the second importance based on importance calculated from the additional information accumulated in the accumulating means according to the representative data and the first importance accumulated in the accumulating means according to the representative data.

22. An acceleration measuring device of claim 20, wherein

the reference point estimating means defines a circle on the two dimensional orthogonal coordinate plane or a spherical surface on the three dimensional orthogonal coordinate space based on both a distribution of a group of a predetermined number N of representative datas accumulated by the accumulating means on the two dimensional orthogonal coordinate plane or the three dimensional orthogonal coordinate plane representative data and a group of a predetermined number N of second importance calculated by the second importance calculating means corresponding to the representative datas, estimates a coordinate of center point and a radius of the circle or the spherical surface, sets the estimated coordinate of center point as the reference point, and sets the radius of the respective axes as the scale reference, and

the offset correcting means corrects offsets of the respective two-axis or three-axis acceleration data based on the reference point estimated by the reference point estimating means.

23. An acceleration measuring device of claim 20, wherein

the reference point estimating means defines an ellipse on the two dimensional orthogonal coordinate plane or an ellipsoidal surface on the three dimensional orthogonal coordinate space based on both a distribution of a group of a predetermined number N of representative datas accumulated by the accumulating means on the two dimensional orthogonal coordinate plane or the three dimensional orthogonal coordinate space representative data and a group of a predetermined number N of second importance calculated by the second importance calculating means corresponding to the representative datas, estimates a coordinate of center point and radiuses of respective principal axes of the ellipse or the ellipsoidal surface, sets the estimated coordinate of center point as the reference point, sets the radiuses of the respective principal axes as the scale reference, and

the offset correcting means corrects offsets and sensitivities of the respective two-axis or three-axis acceleration data based on the reference point and the scale reference of the respective axes estimated by the reference point estimating means.

24. An acceleration measuring device of any one of claims 20 to 23, wherein

the representative data calculating means calculates an average of the group of a predetermined number M of acceleration data as a representative data.

25. An acceleration measuring device of any one of claims 20 to 23, wherein

the first importance calculating means includes:

means for calculating fluctuation in the group of a predetermined number M of acceleration data; and

means for calculating importance A while the importance is higher as the fluctuation is smaller.

26. An acceleration measuring device of claim 25, wherein

the fluctuation is a sum of variances on the respective axes of the group of a predetermined number M of acceleration data or a maximum value of the variances on the respective axes.

27. An acceleration measuring device of claim 25, wherein

the fluctuation is a square sum of differences between maximum values and minimum values on the respective axes of the group of a predetermined number M of acceleration data or the square of a maximum value of the differences between the maximum values and the minimum values on the respective axes.

28. An acceleration measuring device of any one of claims 20 to 23, wherein

one of the additional information is temperature when the acceleration detecting means detects the group of acceleration data used in that the representative data calculating means calculates the representative data, and

the second importance calculating means includes means for calculating importance B, said importance B is lower in the case that a difference between temperature, one of the additional information, when the acceleration detecting means detects data and temperature when importance is calculated by the second importance calculating means is larger.

29. An acceleration measuring device of any one of claims 20 to 23, wherein

one of the additional information is time when the acceleration detecting means detects the group of data used in that the representative data calculating means calculates the representative data, and

the second importance calculating means includes means for calculating importance C, said importance C is lower in the case that a difference between time when the acceleration detecting means detects data and time when importance is calculated by the second importance calculating means is larger.

30. An acceleration measuring device of any one of claims 20 to 23,

further comprising selecting means for selecting in the case the representative data calculated by the representative data calculating means is appropriate, and wherein

the selecting means judges that the representative data calculated by the representative data calculating means is appropriate and then selects the representative data when the first importance calculated by the first importance calculating means is higher than a predetermined value.

31. An acceleration measuring device of any one of claims 20 to 23,

the accumulating means sets further linear axes that have linear relation with detection axes of the acceleration detecting means, compares values that obtained by subtracting the second importance corresponding to the representative datas from the representative datas when comparing maximum values, compares values that obtained by adding the representative datas to the second importance corresponding to the representative datas when comparing minimum values, and selectively accumulates a representative data such that a component of the detection axis or linear axis of the acceleration detecting means becomes a maximum or minimum value among a representative data newly selected by the selecting means and representative datas accumulated in the accumulating means.

32. An acceleration measuring device of claim 17,

further comprising processed data storing means for storing the number of acceleration data weighted by the importance of the group of acceleration data obtained by the acceleration data obtaining means, a sum of respective axial components weighted by the importance of the group of acceleration data, a sum of values obtained by weighting squares of the respective axial components of the group of acceleration data with the importance, a group of coefficient of simultaneous equations for calculating the reference point and the scale reference of the respective axes, and the reference point and the scale reference, and wherein

the reference point and the scale reference of the respective axes are estimated based on latest data obtained by the acceleration data obtaining means, importance calculated by the importance calculating means corresponding to the data, and the latest various processed data stored by the processed data storing means.