US 12,467,942 B2 · On-site reciprocity calibration method for piezoelectric accelerometer

Abstract

An on-site reciprocity calibration method for a piezoelectric accelerometer, including a vibration test and a reciprocity test. In the vibration test, a sine excitation with a corresponding frequency and amplitude is provided by a vibration exciting device to the piezoelectric accelerometer fixed on a motion plane, and output signals of a drive port and a signal port of the reciprocal piezoelectric accelerometer are collected by a data acquisition device. In the reciprocity test, a sine voltage excitation is provided by a signal generator to the drive port, and then an excitation signal and an output signal of the signal port are collected by the data acquisition device. An amplitude ratio of the two signals is obtained based on signal sine-fitting. Finally, the on-site calibration is enabled according the sensitivity amplitude ratio obtained in the vibration test and the sensitivity amplitude product obtained in the reciprocity test.

An on-site calibration method for a reciprocal piezoelectric accelerometer, comprising:

(S1) fixing an installation base of the reciprocal piezoelectric accelerometer on a motion plane of a vibration exciting device;
and outputting, by the vibration exciting device, a sinusoidal vibration excitation at a ⅓ octave band under a condition that an output amplitude of the vibration exciting device is greater than a minimum signal-to-noise ratio of an output signal of the reciprocal piezoelectric accelerometer;
(S2) under the sinusoidal vibration excitation, acquiring, by a data acquisition device, a first signal output from a drive port of the reciprocal piezoelectric accelerometer and a second signal output from a signal port of the reciprocal piezoelectric accelerometer, and sending the first signal and the second signal to an upper computer for signal processing;
(S3) based on a signal sine-fitting method, acquiring an amplitude of the first signal and an amplitude of the second signal;
and calculating a ratio of the amplitude of the first signal to the amplitude of the second signal, so as to acquire a sensitivity amplitude ratio of the drive port and the signal port;
(S4) placing the reciprocal piezoelectric accelerometer on a stable work plane, and connecting an output port of a signal generator to the drive port of the reciprocal piezoelectric accelerometer;
and outputting a sinusoidal voltage excitation at the ⅓ octave band and an output voltage of 1-5 V;
(S5) under the sinusoidal voltage excitation, acquiring, by the data acquisition device, an electric excitation signal of the signal generator and a third signal output from the signal port of the reciprocal piezoelectric accelerometer, and sending the electric excitation signal and the third signal to the upper computer for signal processing;
(S6) based on the signal sine-fitting method, acquiring an amplitude of the electric excitation signal and an amplitude of the third signal;
and calculating a ratio of the amplitude of the electric excitation signal to the amplitude of the third signal, so as to acquire a sensitivity amplitude product of the drive port and the signal port;
and
(S7) according to the sensitivity amplitude ratio and the sensitivity amplitude product, calculating a sensitivity amplitude of the drive port and a sensitivity amplitude of the signal port, so as to realize on-site calibration for the reciprocal piezoelectric accelerometer, and saving and displaying sensitivity calibration results;
wherein in each of step (S2) and step (S5), signal U1(tj) and signal U2(tj) collected by two channels of the data acquisition device at time tj are fitted by the following sine-approximation methods, respectively:
{
U
1
(
t
j
)
=
A
1
⁢
cos
⁢
(
ω
v
⁢
t
j
)
-
B
1
⁢
sin
⁢
(
ω
v
⁢
t
j
)
+
C
1
U
2
(
t
j
)
=
A
2
⁢
cos
⁢
(
ω
v
⁢
t
j
)
-
B
2
⁢
sin
⁢
(
ω
v
⁢
t
j
)
+
C
2
;
(
1
)
wherein ωv represents a vibration angular frequency;
parameters A1, B1, C1, A2, B2 and C2 are sine-fitting coefficients to be solved, and are obtained by solving corresponding N equations based on the sine-approximation methods, respectively;
and
a peak value Ŝ1 of the signal U1(tj) is obtained according to parameters A1 and B1, and a peak value Ŝ2 of the signal U2(tj) is obtained according to parameters A2 and B2, represented by:
{
S
1
^
=
A
1
2
+
B
1
2
S
2
^
=
A
2
2
+
B
2
2
;
(
2
)
wherein the sensitivity amplitude Sa1 of the drive port and the sensitivity amplitude Sa2 of the signal port acquired in the on-site calibration of the reciprocal piezoelectric accelerometer are determined by an amplitude ratio u1 of the first signal to the second signal obtained in step (S3) and an amplitude ratio u2 of the electric excitation signal to the third signal obtained in step (S6), represented by:
{
u
1
=
S
1
′
^
S
2
′
^
=
S
a
⁢
1
S
a
⁢
2
u
2
=
S
1
″
^
S
2
″
^
=
c
⁢
S
a
⁢
1
⁢
S
a
⁢
2
;
(
3
)
wherein Ŝ1′ represents the amplitude of the first signal, and Ŝ2′ represents the amplitudes of the second signal;
Ŝ1″ represents the amplitude of the electric excitation signal, and Ŝ2″ represents the amplitude of the third signal;
c represents a self-calibration coefficient which is determined by structure parameters of the reciprocal piezoelectric accelerometer and is a known value;
and the sensitivity amplitude Sa1 and the sensitivity amplitude Sa2 are obtained as follows:
{
S
a
⁢
1
=
u
1
⁢
u
2
c
S
a
⁢
2
=
u
2
c
⁢
u
1
.

193 more elements

On-site reciprocity calibration method for piezoelectric accelerometer

Life of this patent

On-site reciprocity calibration method for piezoelectric accelerometer

Life of this patent

Abstract

Claims1