Device for validating measurements of a dynamic magnitude

• US 8,005,649 B2
• Filed: 09/05/2008
• Issued: 08/23/2011
• Est. Priority Date: 09/07/2007
• Status: Active Grant

• Current Assignee: Safran Aircraft Engine Company
• Original Assignee: Snecma (Safran SA)
• Inventors: Bornert, Pierre, Le Gonidec, Serge
• Primary Examiner(s): Nghiem; Michael P
• Assistant Examiner(s): Desta; Elias
• Application Number:
  US12/205,077
• Publication Number:
  US 20090071224A1
• Time in Patent Office: 1,082 Days
• Field of Search: 702/93, 702/104, 702141-142, 702/150, 701/200, 701/221, 324/245, 73/232.1
• US Class Current: 702/189
• CPC Class Codes: G01D 3/036 on measuring arrangements themselves
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups

Abstract

The invention relates to a device for validating measurements of a dynamic magnitude x coming from an article having main sensors placed thereon on three main axes for measuring of said dynamic magnitude x. The device includes at least two additional sensors for measuring at least two additional components of the dynamic magnitude. The additional sensors are placed on the article on at least two additional axes that are concurrent with the three main axes and that are not contained in any of the planes defined by any pair of the three main axes. The device further includes a unit for determining an estimator U representative of the dynamic magnitude from the components; and means for validating the determination of the estimator U representative of the dynamic magnitude, as well as an error detector and a localization unit for locating valid components of the dynamic magnitude.

Claims

1. A device for validating measurements of a dynamic magnitude x coming from an article having placed thereon three main sensors for sensing, respectively, along three concurrent main axes forming a basis e={e₁ e₂ . . . e_p} of a physical space having p=3 dimensions, the three main sensors serving to measure components V_j of said dynamic magnitude x along, respectively, the p=3 main axes, and the device comprising:

at least two additional sensors for measuring at least two additional components of said dynamic magnitude, said at least two additional sensors being placed on said article for sensing along at least two additional axes that are concurrent with said three main axes and that are not contained in any of the planes defined by any pair of said three main axes, said main and additional axes forming a set a={a₁, a₂, . . . , a_q} of q observation axes, where q>

p, and said three main and additional sensors together form a group of observation sensors;

determination means for determining an estimator U representative of said dynamic magnitude from said components V_j j ε

1;

q delivered by said observation sensors along, respectively, the q axes;

validation means for validating said determination of the estimator U representative of the dynamic magnitude;

error detector means for detecting a measurement error associated with said determination of the estimator U representative of the dynamic magnitude;

localization means for locating valid components of said dynamic magnitude not giving rise to said measurement error; and

reconstitution means for reconstituting a new estimator U representative of said dynamic magnitude from said valid components delivered by said observation sensors,

wherein the determination means for determining the estimator U representative of the dynamic magnitude comprise;

first calculation means for calculating an observation matrix M that synthesizes the geometrical configuration of said observation axes, the observation matrix M of dimension p×

q being defined by M=C.A, C being the matrix of the direction cosines of the basis e, and A being the matrix component of the set a of q axes;

first calculation means for calculating an estimation matrix L from said observation matrix M satisfying L.^TM=I_p; and

first calculation means for calculating said estimator U representative of the dynamic magnitude as a function of said estimation matrix L of said components V_j measured by said observation sensors.

2. A device according to claim 1, wherein the validation means and/or the error detector means comprise:

second calculation means for calculating a parity matrix N from said observation matrix M, the parity matrix N being defined by N.^TM=0; and

second calculation means for calculating a parity vector W associated with said parity matrix N and with said components V_j of the dynamic magnitude measured by the observation sensors, serving to verify the validity of the estimator U representative of the dynamic magnitude, or to detect a measurement error associated with said determination of the estimator U, the parity vector W being defined by W=N.Z where Z is a matrix representation of the measurement error.

3. A device according to claim 2, wherein the validation means and/or the error detector means further comprise:

third calculation means for calculating a matrix of weights P from said parity matrix N and from said components V_j of the dynamic magnitude, the matrix of weights P being equal to N.diag(V);

third calculation means for calculating a selection vector S from said matrix of weights P and from said parity vector W for discriminating between relationships that are representative of consistency or inconsistency between said components V_j of the dynamic magnitude;

third calculation means for calculating a consistency quantification matrix Q for quantifying the validity levels of said components V_j of the dynamic magnitude;

third calculation means for deducing a confidence vector R from the consistency quantification matrix Q to give the confidence level of each component of the dynamic magnitude measured by each of the observation sensors; and

third calculation means for deducing a list of said valid components of said dynamic magnitude.

4. A device according to claim 1, including initialization means for identifying the positions of said additional axes relative to the main axes with determined accuracy.

5. A device according to claim 1, wherein the main axes comprise a first axis, a second axis, and a third axis forming a right-handed orthogonal frame of reference, and wherein at least one additional axis forms an angle of 45°

relative to the second axis, with the directions of the first and third axes being symmetrical relative to the second axis.

6. A device according to claim 1, wherein the main axes form a right-handed orthogonal frame of reference, and wherein at least one additional axis occupies a position that is symmetrical relative to the three main axes.

7. A device according to claim 1, wherein the main sensors correspond to accelerometers measuring axial, radial, and tangential components of the dynamic magnitude, and wherein said additional sensors correspond to redundant accelerometers.

8. A device according to claim 1, wherein the dynamic magnitude corresponds to a vibration magnitude.

9. A device according to claim 1, wherein said article constituting the source of the dynamic magnitude is a rotary machine.

10. A computer implemented method of validating measurements of a dynamic magnitude coming from an article, on which there are placed three main sensors on three respective concurrent main axes forming a basis e={e1 e2 . . . ep} of a physical space having p=3 dimensions, the three main sensors serving to measure components V_j of said dynamic magnitude x, along, respectively, the p=3 main axes, using a computer having a non-transitory computer-readable medium having computer executable instructions stored therein for implementing the method, the method comprising the following steps:

measuring at least two additional components of said dynamic magnitude by means of at least two additional sensors placed on said article on at least two additional axes that are concurrent with said three main axes and that are not contained in any of the planes defined by any two of said three main axes, said main and additional axes forming a set a={a1, a2, a3 . . .aq} of q observation axes, where q>

p and said three main and additional sensors together form a group of observation sensors;

determining an estimator U representative of said dynamic magnitude from said components Vj delivered by said observation sensors;

validating said determination of the estimator U representative of the dynamic magnitude;

detecting a measurement error associated with said determination of the estimator U representative of the dynamic magnitude;

locating valid components of said dynamic magnitude that do not generate said measurement error; and

reconstituting a new estimator U representative of said dynamic magnitude from said valid components delivered by said observation sensors,

wherein the determination of the estimator U representative of the dynamic magnitude comprises the following steps;

calculating an observation matrix M synthesizing the geometrical configuration of said observation axes, the observation matrix M of dimension pxq being defined by M=C.A, C being the matrix of the direction cosines of the basis e, and A being the matrix component of the set a ofq axes;

calculating an estimation matrix L from said observation matrix M satisfying L.TM=Ip; and

calculating said estimator U representative of the dynamic magnitude as a function of said estimation matrix L and of said components Vj measured by said observation sensors.

11. A method according to claim 10, wherein the validation and/or error detection steps comprise the following steps:

calculating a parity matrix N from said observation matrix M, the parity matrix N being defined by N.^TM=0; and

calculating a parity vector W associated with said parity matrix N and with said components V_j of the dynamic magnitude measured by the observation sensors, serving to verify the validity of the estimator U representative of the dynamic magnitude, or to detect a measurement error associated with said determination of the estimator U, the parity vector W being defined by W=N.Z where Z is a matrix representation of the measurement error.

12. A method according to claim 11, wherein the validation and/or error detector steps further comprise the following steps:

calculating a matrix of weights P from said parity matrix N and from said components V_j of the dynamic magnitude, the matrix of weights P being equal to N.diag(V);

calculating a selection vector S from said matrix of weights P and from said parity vector W making it possible to discriminate between relationships that represent consistency or inconsistency between said components V_j of the dynamic magnitude;

calculating a consistency quantification matrix Q serving to quantify the validity levels of said components V_j of the dynamic magnitude;

deducing a confidence vector R from the coherent quantification matrix Q serving to give the confidence level of each component of the dynamic magnitude as measured by each of the observation sensors; and

deducing a list of said valid components of said dynamic magnitude.

13. A method according to claim 10, including an initialization step of identifying the positions of said additional axes relative to the main axes with determined accuracy.

14. A method according to claim 10, wherein the dynamic magnitude corresponds to a vibration magnitude.

15. A non-transitory computer readable medium containing computer instructions stored therein for causing a computer processor to perform a method of validating measurements of a dynamic magnitude x coming from an article on which there are placed three main sensors on three respective concurrent main axes forming a basis e={e1 e2 . . . ep} of a physical space having p=3 dimensions, the three main sensors serving to measure components Vj of said dynamic magnitude x, along, respectively, the p=3 main axes, the method comprising:

measuring at least two additional components of said dynamic magnitude by means of at least two additional sensors placed on said article on at least two additional axes that are concurrent with said three main axes and that are not contained in any of the planes defined by any two of said three main axes, said main and additional axes forming a set a={a1, a2, a3, . . . aq} of q observation axes, where q>

p and said three main and additional sensors together form a group of observation sensors;

determining an estimator U representative of said dynamic magnitude from said components Vj delivered by said observation sensors;

Validating said determination of the estimator U representative of the dynamic magnitude;

detecting a measurement error associated with said determination of the estimator U representative of the dynamic magnitude;

locating valid components of said dynamic magnitude that do not generate said measurement error; and

reconstituting a new estimator U representative of said dynamic magnitude from said valid components delivered by said observation sensors,

wherein the determination of the estimator U representative of the dynamic magnitude comprises the following steps;

calculating an observation matrix M synthesizing the geometrical configuration of said observation axes, the observation matrix M of dimension p′

q being defined by M=C.A, C being the matrix of the direction cosines of the basis e, and A being the matrix component of the set a of q axes;

calculating an estimation matrix L from said observation matrix M satisfying L.TM=Ip; and

calculating said estimator U representative of the dynamic magnitude as a function of said estimation matrix L and of said components Vj measured by said observation sensors.