KR100604420B1 - Equi-angle sampling technique for precision amplitude and phase measurement, and precision amplitude and phase measurement apparatus using the same method - Google Patents

Abstract

The present invention provides three configuration methods that can implement the Equi-Angle Sampling Method (EASM), that is, output signal measurement of a vibration sensor, vibration amplitude measurement using a laser interferometer, and a linear or rotary encoder. The method of constructing the vibration amplitude measuring device is presented. A theoretical conversion method for accurately estimating the amplitude and phase corresponding to the calibration frequency from the measurement vibration signal obtained from the isometric measuring device of the vibration amplitude is also presented. The experimental results obtained by applying the isometric signal acquisition method to the actual rotation vibration calibration system are confirmed, and it is confirmed that the isometric signal collection method proposed by this patent provides improved vibration amplitude measurement accuracy than the existing precision vibration measurement method. can do.

Amplitude, Phase, Vibration Precise Measurements, Isometric Signal Acquisition

Description

Equi-Angle Sampling Technique for Precision Amplitude and Phase Measurement, and Precision Amplitude and Phase Measurement Apparatus Using the Same Method}

Figure 1 shows the configuration of the linear vibration absolute calibration system proposed in the existing ISO 16063-11,

2 shows a block diagram of an apparatus for implementing an isometric signal collection of the vibration sensor output signal according to the present invention,

3 is a block diagram of an apparatus for implementing an isometric signal collection of a vibration displacement signal using a laser interferometer according to the present invention,

4 is a block diagram of an apparatus for implementing an isometric signal collection of vibration displacement signals using linear and rotary encoders according to the present invention.

5 is a graph showing the characteristics of the amplitude estimation error according to the period division number (M) and the resolution of the analog-to-digital converter under ideal conditions without electrical noise.

6 is a graph showing the characteristics of the phase estimation error according to the period division number (M) and the resolution of the analog-to-digital converter under ideal conditions without electrical noise.

Figure 7 (a) shows a low frequency excitation generator for generating a large amplitude rotational vibration of less than 10 Hz, Figure 7 (b) shows an exciter for generating a high frequency of 10 Hz or more,

8 is a block diagram of a rotation vibration amplitude measuring apparatus using an isometric signal collection technique according to an embodiment of the present invention.

The present invention relates to a precise measuring technique of the amplitude and phase components of a periodic vibration correction apparatus and a device thereof. Specifically, a method of maintaining a constant number of digitally converted acceleration signals during a period, that is, an isometric signal collection technique (Equi-Angle) Sampling Method (EASM) The present invention relates to a precision measurement method of amplitude and phase components of a periodic vibration correction device and a device thereof.

In the domestic and foreign industries, precision measurement technology of mechanical vibration is becoming a very important part in the domestic and foreign industries, such as automobiles, railways, ships, vehicles, aircrafts, defense weapon systems and satellites, and the demand is continuously increasing. To meet these demands, the International Organization for Standards (ISO) has adopted the ISO 16062-1, Methods for the calibration of vibration and shock transducers-Part 1: Basic concepts, International Organization for Standards, 1998; ISO 16062-11, Methods for the calibration of vibration and shock transducers-Part 11: Primary vibration calibration by laser interferometry, International Organization for Standards, 1999].

Industrialized countries, including Korea, have established the National Metrology Institute (NMI) to build their own vibration correction system that satisfies international standards, and are disseminating vibration measurement technology to the industrial world. Since 2004, the Bureau International des Poids et Mesures (BIPM) has released the vibration measurement capabilities of Member States in BIPM Appendix C. Therefore, national measurement institutes, which represent the measurement capability of their own countries, are doing a lot of research to improve the measurement capability.

1 is a configuration diagram of a linear vibration absolute calibration system proposed in ISO 16063-11, the reference numeral 1 shown in FIG. 1 is a frequency generator, 2 is a power amplifier, 3 is an exciter, 4 is an upper part of an exciter, 5 is a vibration sensor (accelerometer) to be calibrated, 6 is an additional mass, 7 is a signal amplifier, 8 is a laser interferometer, 9 is a laser, 10 is a light detector, 11 is a digital recorder, 12 is a voltmeter, and 13 is a harmonic analyzer. Represent each.

The system shown in FIG. 1 is a standardized absolute that allows simultaneous measurement of the amplitude and phase of the linear vibration of the calibrated vibration sensor (accelerometer) 5 with respect to the frequency with the modified Michelson interferometer (laser interferometer) 8. It is a calibration device.

The calibration apparatus uses two photodetectors 10 having a phase difference of 90 degrees, and the method of measuring amplitude and phase using these output signals has been described in previous studies [A. Link and H.-J. von Martens, "Amplitude and phase measurement of sinusoidal vibration in the nanometer range using laser interferomrtry," Measurement, 24, pp 55-67, 1998; H.-J. von Martens, "Current state and trends of ensuring traceability for vibration and shock measurements," Metrologia, 36, pp 267-373, 1999; H.-J. von Martens, et al, "Traceability of vibration and chock measurements by laser interferometry," Measurement, 28, pp. 3-20, 2000].

In order to measure the amplitude and phase of the amplified output signal of the accelerometer (5) for the frequency to be calibrated, [A. Link and H.-J. von Martens, "Amplitude and phase measurement of sinusoidal vibration in the nanometer range using laser interferomrtry," Measurement, 24, pp 55-67, 1998; H.-J. von Martens, "Current state and trends of ensuring traceability for vibration and shock measurements," Metrologia, 36, pp 267-373, 1999; H.-J. von Martens, et al, "Traceability of vibration and chock measurements by laser interferometry," Measurement, 28, pp. 3-20, 2000] proposed a sine-approximation method, and the ISO 16063-11 standard also proposes the measurement of the amplitude and phase of the amplified output signal of the accelerometer according to this technique.

However, the above-described periodic function-approximation method in the prior art has the following problems.

First, in the previous study and in the ISO 16063-11 standard, the amplified output signal (output signal from reference numeral 7) of the calibrated vibration sensor (accelerometer) is connected to the high speed digital recorder 11. Previous studies [A. Link and H.-J. von Martens, "Amplitude and phase measurement of sinusoidal vibration in the nanometer range using laser interferomrtry," Measurement, 24, pp 55-67, 1998] uses a high-speed digital converter with an 8-bit resolution and a 10 MHz conversion period. Therefore, a method of simultaneously collecting the output signals of the two optical detectors 10 of the laser interferometer and the amplified output signals of the vibration sensor (accelerometer) to be calibrated is adopted. Since the 8-bit resolution selected in the above measurement method is too lower than the resolution of 16-24 bits which is the resolution of the current commercially available analog-to-digital converter (ADC), the amplified output signal of the vibration sensor for calibration It is essential that the amplitude and phase measurements are accompanied by a relatively high measurement uncertainty. In addition, the 10 MHz digital conversion rate selection, which is 1000 times faster than the maximum oscillation frequency covered by the ISO 16063-11 standard, does not result in excessive computational time and computer performance, rather than providing effective uncertainty improvements in amplitude and phase measurements of the amplified output signal. It only causes memory overhead. The fixed digital conversion rate of 10 MHz has a different measurement uncertainty according to the excitation frequency because the number of digital signals converted in one cycle varies according to the excitation frequency.

In order to solve this problem, the present invention has developed a method of maintaining a constant number of digitally converted acceleration signals during one period, that is, an equi-angle sampling method (EASM). For example, by dividing a period by 360, an isometric signal collection technique (EASM) collects and provides one digital conversion signal whenever the phase of the rotating vector changes by 1 ° regardless of the frequency of excitation. More detailed technical matters will be described later.

On the other hand, another problem with the absolute calibration system proposed in ISO 16063-11 presented in Figure 1 is that the amplitude of the amplified signal (output signal from reference numeral 7) of the vibration sensor output for calibration It is a question about the necessity of a harmonic analyzer 13 analyzing the harmonic components of the voltmeter 12 and the periodic function to be measured. It is determined that the use of these two components in the system is inevitable due to the 8-bit resolution of the digital recorder 11 which converts the amplified output signal of the vibration sensor for calibration into a digital value. In other words, the 8-bit resolution digital converter is not only able to perform reliable precision measurement of the effective voltage, but also the precision harmonic analyzer uses not only 8-bit resolution but also a digital converter having at least 16-bit resolution. . The isometric signal collection technique proposed in the present invention will be described later on how to perform the function of the harmonic analyzer as well as the precise measurement of the amplitude and phase of the acceleration signal corresponding to the excitation frequency without using these two devices. Shall be.

In the present invention, in recognition of the above problems, three types of configuration methods capable of implementing an equi-angular sampling method (EASM) according to the present invention, that is, measuring the output signal of the vibration sensor, using a laser interferometer The vibration amplitude measuring device and the method of constructing a vibration amplitude measuring device using a linear or rotary encoder are presented respectively, and the amplitude and phase corresponding to the calibration frequency are precisely determined from the measured vibration signal obtained from the isometric measuring device of the vibration amplitude. The theoretical conversion method of estimating is also presented to provide improved vibration amplitude measurement accuracy compared to the fringe-counting method, which is a conventional precision vibration measuring method, and thus effectively eliminates measurement uncertainty.

In order to achieve the above object, the present invention provides three methods for the configuration of devices for realizing an isometric signal collection technique in a vibration correction apparatus using a periodic function. That is, the implementation method of the first isometric signal collection method is the method of collecting the output signal of the object to be calibrated, that is, the accelerometer, and the implementation method of the second isometric signal collection method is the vibration displacement measurement method using a laser interferometer, and the third isometric The method of implementing the signal collection technique is an implementation method of the vibration amplitude measuring technique using a linear and a rotary encoder.

Specifically, the object described above is, firstly, in an isometric signal collection device for an output signal to be calibrated using an analog-to-digital converter, an exciter drive signal having an oscillation frequency f ₀ for supplying to an exciter, and the exciter drive. A main function generator for outputting a phase synchronization synchronization signal whose phase is synchronized with the signal; The phase synchronizing synchronization signal is input, and in order to synchronize the phase with the synchronizing signal, an equal angle collection having a frequency of M × f ₀ is obtained by dividing phase 360 ° of one period of the frequency of the excitation drive signal at equal intervals by M. An auxiliary function generator for outputting a control signal; And a high precision analog-to-digital converter that implements digital conversion according to an isometric acquisition control signal of the auxiliary function generator and uses a phase synchronization synchronization signal of the main function generator as an external trigger input signal. Is achieved by an isometric signal collector for precise measurement of

Further, in an isometric signal collection device for vibration displacement signals using a laser interferometer, an excitation drive signal having an oscillation frequency f ₀ for supplying to an excitation device, and a phase synchronization synchronization signal whose phase is synchronized with the excitation drive signal Main function generator for outputting; The phase synchronizing synchronization signal is input, and in order to synchronize the phase with the synchronizing signal, an equal angle collection having a frequency of M × f ₀ is obtained by dividing phase 360 ° of one period of the frequency of the excitation drive signal at equal intervals by M. An auxiliary function generator for outputting a control signal; And storing contents of an up / down counter in a position information register according to an isometric acquisition control signal of the auxiliary function generator, and using a phase synchronization synchronization signal of the main function generator as an external trigger input signal. A laser interferometer displacement measuring board; is achieved by an isometric signal collection device for precise measurement of amplitude and phase components, including.

In addition, in an isometric signal collection device of an oscillation displacement signal using an encoder, an excitation drive signal having an oscillation frequency f ₀ for supplying to an excitation device, and a phase synchronization synchronization signal in phase with the excitation drive signal are synchronized. Outputting main function generator; The synchronizing signal for the synchronism is input, and for synchronizing phase with the synchronizing signal, an equiangular collection having a frequency of M × f ₀ is obtained by dividing phase 360 ° of one period of the frequency of the excitation drive signal at equal intervals by M An auxiliary function generator for outputting a control signal; And storing contents of an up / down counter in a position information register according to an isometric acquisition control signal of the auxiliary function generator, and using a phase synchronization synchronization signal of the main function generator as an external trigger input signal. It is achieved by an isometric signal collector for precise measurement of amplitude and phase components, including a high speed counter / timer.

In addition, in the isometric signal collecting device, the main function generator preferably includes outputting a reference clock signal for phase synchronization and frequency stabilization of the auxiliary function generator.

In the isometric signal collecting device, the frequency of the excitation drive signal of the main function generator may be set through an interface connected to an external calibration computer.

In addition, the isometric signal collecting device, the isometric partition number M is set by the user through an interface connected to an external computer, and when the partition number M value is received by the auxiliary function generator, the synchronization signal of the main function generator And phase synchronization is characterized in that to perform.

On the other hand, the above object is, in the isometric signal collection method of the sensor output signal to be calibrated using an analog-to-digital converter, the exciter drive signal having a vibration frequency f ₀ for supplying the exciter by the main function generator, and Outputs a phase synchronization synchronization signal whose phase is synchronized with the exciter drive signal, inputs the output phase synchronization synchronization signal to an auxiliary function generator, wherein the auxiliary function generator is a phase synchronization with the phase synchronization synchronization signal; In order to equalize the phase 360 ° of one period of the excitation drive signal frequency at equal intervals M and output an isometric acquisition control signal having a frequency of M × f ₀ , and to the isometric acquisition control signal of the auxiliary function generator. A digital conversion is implemented in a high precision analog-to-digital converter, and the high-precision analog signal of the phase synchronization synchronization signal of the main function generator is - is achieved by using as an external trigger input signal of the digital converter.

In addition, in an isometric signal collection method of a vibration displacement signal using a laser interferometer, a phase shifter and a phase of the exciter drive signal having a vibration frequency f ₀ for supplying to the exciter by the main function generator, the phase is synchronized with the exciter drive signal Outputs a phase synchronizing synchronization signal, inputs the output phase synchronizing synchronization signal to an auxiliary function generator, and the auxiliary function generator is configured to generate a phase synchronizing drive signal frequency for synchronizing with the phase synchronization synchronizing signal; Outputs an equiangular acquisition control signal having a frequency of M × f ₀ by dividing phase 360 ° of one cycle by M at equal intervals, and outputting to the laser interferometer displacement measuring board according to the equiangular acquisition control signal of the auxiliary function generator. The contents of the provided up / down counter are stored in the position information register, and the synchronization signal for phase synchronization of the main function generator is stored. It is achieved by using as an external trigger input signal from the group laser interferometric displacement measuring board.

In addition, in the isometric signal collection method of the vibration displacement signal using the encoder, the excitation device driving signal having a vibration frequency f ₀ for supplying the excitation device by the main function generator, the phase in which the phase is synchronized with the excitation drive signal Outputs a synchronization synchronizing signal, inputs the output phase synchronization synchronizing signal to an auxiliary function generator, and the auxiliary function generator is one of the exciter driving signal frequencies for phase synchronization with the phase synchronization synchronizing signal; The phase angle 360 ° of the period is equally divided by M to output an isometric acquisition control signal having a frequency of M × f ₀ , and an increase / definition provided to the high speed counter / timer according to the isometric acquisition control signal of the auxiliary function generator. The contents of the up / down counter are stored in the position information register, and the phase synchronization synchronization signal of the main function generator is stored in the high speed counter / tagging. This is accomplished by using the external trigger input signal of the e-mailer.

In addition, in the isometric signal collection method, the main function generator preferably includes outputting a reference clock signal for phase synchronization and frequency stabilization of the auxiliary function generator.

In the isometric signal collection method, the frequency of the excitation drive signal of the main function generator is set through an interface connected to an external calibration computer.

In the isometric signal collection method, the isometric dividing number M is set by a user through an interface connected to an external computer, and the main function generator is synchronized when the dividing number M value is received by the auxiliary function generator. It is characterized in that the signal and phase synchronization.

Hereinafter, the present invention will be described in detail based on specific examples.

1. Configuration of Isometric Signal Acquisition

This section describes three methods for the configuration of devices that realize an isometric signal collection technique in a vibration correction device using a periodic function.

That is, the implementation method of the first isometric signal collection method is the method of collecting the output signal of the object to be calibrated, that is, the accelerometer, and the implementation method of the second isometric signal collection method is the vibration displacement measurement method using a laser interferometer, and the third isometric The method of implementing the signal collection technique is an implementation method of the vibration amplitude measuring technique using a linear and a rotary encoder.

1.1 Isometric Collection Method of the Sensor Output Signal

2 is a block diagram of an apparatus for implementing an isometric signal collection of the vibration sensor output signal according to the present invention.

In FIG. 2, first, in the components, reference numeral 1 denotes a master function generator, 2 a power amplifier, 7 a signal amplifier, 14 an auxiliary function generator (slave or frequency multiplier), and 15 a high precision analogue- In the signal input and output with the following configuration, 101 is the main function generator signal output, 102 is the main function generator synchronization signal, 103 is the phase synchronization reference signal, 104 is the auxiliary function generator (or frequency multiplier) output , 105 denotes an output signal of the calibrated vibration sensor, 106 denotes an amplified output signal of the calibrated vibration sensor, 107 denotes a low speed interface bus, 108 denotes a high speed interface bus, and 109 denotes a power amplifier output signal.

First, in the calibration field of the vibration sensor (accelerometer, speed pickup, etc.), the calibration frequency is selected and supplied using the main function generator 1 which generates a stabilized sine function of several ppm level. Therefore, the frequency and amplitude of the periodic signal applied to the exciter are very accurate and stable signals. The reason for using these high stability periodic signals is that the frequency and amplitude stability of the vibration sensor calibration, as recommended in ISO 16063-11, directly affects the measurement uncertainty. That is, FIG. 2 is a block diagram of an apparatus for implementing an isometric signal collection of the vibration sensor output signal using the output signal of the function generator having frequency and amplitude stability as described above.

The main function generator 1 is a function generator having an external temperature adaptive frequency and amplitude stability, and has two types of output signals, that is, a sine wave analog output signal 101 and a digital output signal whose phase is synchronized with the sine wave signal. It is a function generator for calibration that outputs 102). The frequency of the output sine wave of the main function generator, i.e., the frequency with oscillation, f ₀ [Hz] is set via the interface 107 connected to the external calibration computer. A reference clock signal 103 for phase synchronization and frequency stabilization of the auxiliary function generator (or frequency multiplier) 14 is output.

The analog output signal 101 is input to the power amplifier 2, the high current output signal 109 is converted into the exciter.

The auxiliary function generator (or frequency multiplier) 14 uses the digital output signal 102 whose phase is synchronized with the oscillating frequency f ₀ [Hz] to perform the digital signal 104 for start of conversion (SOC). If the multiplication ratio (or frequency division ratio) of the excitation frequency is M, the output signal of the auxiliary function generator (or frequency multiplier 14), that is, the frequency of the signal acquisition start signal (SOC) is f _SOC = M × f. ₀ [Hz]. The magnification ratio (or frequency division ratio) M of the auxiliary function generator is also set by the user through the interface 107 connected to the external PC, and when the magnification ratio value is received by the auxiliary function generator 14, the function generator becomes the main function. Phase synchronization is performed with the synchronization signal 102 of the generator.

Therefore, the output signal of the phase-locked auxiliary function generator 14, that is, the signal acquisition start signal SOC, is input to the high precision analog-to-digital converter 15 to control the digital conversion, that is, the signal acquisition speed. Therefore, digital conversion is implemented according to the Equi-Angle Sampling Method (EASM), which divides one period of an excitation frequency into equal intervals, that is, equally divides one phase phase 360 ° into equal intervals. .

The high-precision analog-to-digital converter 15 externally triggers the phase-synchronized digital output signal 102 for synchronization with the sine wave output signal of the main function generator 1 after the preparation point. Input by signal. The time synchronization of the initial digital conversion using the phase synchronization digital output signal 102 of the main signal generator 1 as the external trigger input signal 102 of the high precision analog-to-digital converter 15 is performed by the phase of the periodic function. It is an effective way to increase the precision of the measurement.

The isometric signal collection technique (EASM) introduced above provides the advantage of digital acquisition of vibration measurement signals for M constant isophases in a period, even if the excitation frequency changes. And since the excitation level for most calibrated low frequencies, except for some low frequency components, is kept constant during accelerometer calibration, the isometric signal collection technique uses the oscillation signal measured from constant M digital values over a period of time, even if the excitation frequency changes. Estimating amplitude and phase provides the advantage of substantially maintaining the uncertainty of amplitude and phase measurements.

On the other hand, the low output signal 105 of the calibrated vibration sensor 5 which is bolted to the upper end 4 of the exciter 3 is input to the dedicated voltage amplifier 7 and amplified to the desired output voltage range. The amplified output voltage signal 106 is input to the high precision analog-to-digital converter 15. The voltage signal converted into a digital value is transmitted in real time to the external calibration computer via the high speed transfer interface 108. The high-precision analog-to-digital converters 15 currently available not only provide 16 to 24-bit resolution, but also digital conversion rates of several MHz. Using this high-performance analog-to-digital converter, measurement uncertainties based on ISO 16063-11 have been previously studied [A. Link and H.-J. von Martens, "Amplitude and phase measurement of sinusoidal vibration in the nanometer range using laser interferomrtry," Measurement, 24, pp 55-67, 1998; H.-J. von Martens, "Current state and trends of ensuring traceability for vibration and shock measurements," Metrologia, 36, pp 267-373, 1999; H.-J. von Martens, et al, "Traceability of vibration and chock measurements by laser interferometry," Measurement, 28, pp. Uncertainty of the amplitude and phase measurement of the vibration signal can be improved significantly compared to the 8-bit model used in [3-20, 2000].

1.2 Isometric Collection Method of Vibration Displacement Signal Using Laser Interferometer

3 is a high precision displacement measuring apparatus using a laser interferometer [F.C. Demarest, “High-resolution, high-speed, low data age uncertainty, heterodyne displacement measuring interferometer electronics,” Measurement Science Technology, 9, 1024-1030, 1998]. Is showing the road.

In FIG. 3, first, in the components, reference numeral 1 denotes a main function generator (master), 2 denotes a power amplifier, 7 denotes a signal amplifier, 14 denotes an auxiliary function generator (slave or frequency multiplier), 16 denotes an optical fiber pickup, 17 represents a displacement measuring board, in which signals are input and output with the above configuration, 101 is a main function generator signal output, 102 is a main function generator synchronization signal, 103 is a phase synchronization reference signal, and 104 is an auxiliary function generator (or Frequency multiplier) output, 107 represents a low speed interface bus, 108 represents a high speed interface bus, 109 represents a power amplifier output signal, 110 represents a laser interferometer output light signal, and 111 represents an optical fiber pickup output signal.

Recent high precision vibration displacement measuring apparatus using laser interferometer provides measurement accuracy of 0.16 [nm] using the output optical signal 110 of the interferometer and the reference optical signal of a laser source that provides wavelength stabilization characteristics. [Operating Manual of ZMI 4000 Series Measurement Board, OMP-0460N, Zygo Cooperation, 2004]. The displacement measuring board 17 using the laser interferometer has an ultra-fast up / down counter and a register for storing position information therein, and the user reads the position information register to perform displacement measurement. Done.

In the present invention, an auxiliary function generator (or frequency multiplier) 14 is used to store a trigger signal used to store the contents of an up / down counter of the laser interferometer displacement measuring board 17 in a position information register. It provides a method of controlling the output signal (104).

That is, the auxiliary function generator 14 which is phase-locked with the synchronization signal 102 of the main function generator 1 as mentioned in Section 1.1, divides one period of the excitation frequency at equal intervals, that is, The up / down counter of the laser interferometer displacement measuring board 17 is stored in the position information register according to an isometric signal collection control signal that divides the phase 360 ° by M at equal intervals. Therefore, the laser interferometer displacement measuring board 17 can implement an isometric vibration amplitude signal collection technique (EASM) by dividing one period of the excitation frequency at equal intervals.

Then, in order to synchronize the first conversion point with the sine wave output signal 101 of the main function generator 1 after the laser interferometer displacement measuring board 17 is ready to acquire the signal, the phase synchronization digital output signal 102 is used. It is input to the laser interferometer displacement measurement board 17 as an external trigger signal. The time synchronization of the initial digital conversion using the phase synchronization digital output signal 102 of the main signal generator 1 as the external trigger input signal 102 of the laser interferometer displacement measurement board 17 corresponds to the phase of the periodic function. It is an effective way to increase the precision of the measurement.

The isometric signal acquisition technique (EASM) applied to the vibration displacement measuring board using the laser interferometer described above collects the vibration measurement signals for M constant isometric phases in a period as a digital value, even if the excitation frequency changes. It offers the advantage of being able to. This iso-acquisition signal collection technique estimates the amplitude and phase of a vibration signal measured from a constant M digital values over a period of time, even if the excitation frequency is changed, thereby substantially maintaining the uncertainty of the amplitude and phase measurements. It will give you an advantage.

1.3 Isometric Collection Method of Vibration Displacement Signal Using Linear and Rotating Encoder

4 is a block diagram of an apparatus for implementing an isometric signal collection of vibration displacement signals using linear and rotary encoders.

In Fig. 4, in the first component, reference numeral 1 denotes a main function generator (master), 2 denotes a power amplifier, 7 denotes a signal amplifier, 14 denotes an auxiliary function generator (slave or frequency multiplier), and 18 denotes a four-multiplier divider. (Divider), 19 denotes a high speed counter / timer, and in the signal input / output in the following configuration, 101 denotes a main function generator signal output, 102 denotes a main function generator synchronization signal, and 103 denotes a phase synchronization signal. Reference signal, 104 is auxiliary function generator (or frequency multiplier) output, 107 is low speed interface bus, 108 is high speed interface bus, 109 is power amplifier output signal, 112 is A / B phase encoder output signal, and 113 is increase / decrease Indicates an up / down counter signal.

Currently, high precision linear encoders of about several tens of [nm] are commercially available, and the amplitude measurement of vibration displacement using them can also be realized with high precision [Jung Wan-seop, Yong-bong Lee, Doo-hee Lee, “ A Study on High Precision Measurement Technique, ”Proceedings of the Korean Society for Noise and Vibration Engineering Conference, ISSN 1598-2548, 685-688, 2004].

Figure 4 shows the configuration of an isometric signal collection device for the calibration vibration period using a high precision displacement measuring device using such linear and rotary encoder (encoder).

The output signal 112 of the linear encoder for length measurement or the rotary encoder for angle measurement consists mainly of two quadrature signals of phase A and phase B, and these two signals have a 90 ° phase difference from each other. Therefore, by using the change in the relative phase difference characteristics of the two signals, an up / down counter signal 113 of a four-fold multiple, that is, a four-times divided signal can be made.

The four times divided up / down counter signal 113 is input to a high-speed counter / timer 19, and during forward movement, a counter register The value increases and the counter register decreases during reverse movement. The value of this increment decrement counter corresponds to a vibration amplitude measurement that is proportional to the amplitude of the vibration.

In this method, an external trigger signal used to store the contents of the up / down counter register of the high-speed counter / timer 19 containing the vibration amplitude information in the position information register is stored in the auxiliary function generator ( A method of controlling with the output signal 104 of 14 is proposed.

That is, the auxiliary function generator 14 in phase synchronization with the synchronizing signal 102 of the main function generator 1 as mentioned in the previous section 1.2 divides one period of the frequency by equal intervals, i.e., the phase of one period. Stores the contents of the up / down counter of the high-speed counter / timer 19 as a location information register according to an isometric signal acquisition control signal that divides 360 degrees into equal intervals. Way. Therefore, the high-speed counter / timer 19 for measuring the length or the rotation angle can implement the ESM isoelectric vibration amplitude signal collection technique (EASM), which is equal to the M cycle at an interval.

And phase synchronization digital to synchronize the first conversion time with the sine wave output signal 101 of the main function generator 1 after the high speed counter / timer 19 for displacement measurement using an encoder is ready. The output signal 102 is input to the high speed counter / timer 19 as an external trigger signal. The time synchronization of the initial digital conversion using the phase synchronizing digital output signal 102 of the main signal generator 1 as the external trigger input signal 102 of the high speed counter / timer 19 is used to measure the phase of the periodic function. It is an effective way to increase precision.

The isometric signal acquisition technique (EASM), which is applied to encoder-based vibration displacement measurement, collects vibration measurement signals for M isometric phases that are constant in one period at all times even if the excitation frequency changes. It offers the advantage of being able to. This isometric signal collection technique has the advantage that the uncertainty of amplitude and phase measurement can be kept constant because it estimates the amplitude and phase of the vibration signal measured from a constant M digital values over a period even if the excitation frequency changes. Will be provided.

2. How to measure amplitude and phase of vibration signal

As shown in Figs. 2, 3 and 4, the output signal measurement of the vibration sensor for calibration using an analog-to-digital converter, the vibration amplitude measurement using a laser, and the vibration amplitude measurement method using linear and rotary encoders Is the M digital measurement {x _n ; n = 1, 2,... , M}.

Thus, for an excitation frequency f ₀ [Hz], the number of digital signals measured during one second is N _T = M × f ₀ . In this way, the total number of digital vibration signals collected at equal angles during the period of the constant K is N _K = M × K.

Fourier transform, (User's Guide for Signal Processing Toolbox, Mathworks Co., 1996; JS Bendat and AG Piersol, Random Data: Analysis and Measurement Procedures, John Wiley & Sons, Newyork: USA, 1986)] applies (M × K) / 2 + 1 frequency components, i.e. {(k / (M × K)) × f ₀ ; k = 0, 1, 2, 3,... , (M × K) / 2}. Therefore, M / 2-1 higher harmonic components, i.e., {k × f ₀ : k = 2, 3,... , M / 2} as well as the K-1 sub-harmonic components, i.e., the frequency component {(k / K) × f ₀ : k = 1, 2,... , (K-1)} can also be measured. Therefore, the precision spectrum analysis comprehensively analyzes the frequency characteristics of the calibrated vibration sensor using the frequency f ₀ [Hz] component and the total K + M / 2-1 frequency components corresponding to the lower and upper harmonic components. can do.

If the cosine components corresponding to the excitation frequency components and the lower and upper harmonic components are C _k and the sine component is S _k , these cosine and sine components can be calculated from the Fourier transform as follows.

Here, the subscript k denotes the indices for the lower and upper harmonic components in addition to the excitation frequency components, and the corresponding frequencies are {k × f ₀ : k = 1 / K, 2 / K,... , (K-1) / K, 1, 2,... , M / 2}.

Digital vibration signal collected during constant K periods depending on the equiangular angle {x _n ; n = 1, 2,... , M × K} include not only the sensor of the calibration vibration sensor and the electrical noise signal of the signal amplifier, but also the quantization error of the digital conversion process of the analog signal. These electrical noise and discretization error components have cosine and sine components of frequency and lower and upper harmonic components {C _k , S _k : k = 1 / K, 2 / K,. , (K-1) / K, 1, 2,... In this case, statistical characterization of the estimated cosine and sine components must be performed.

First, the estimates of the cosine and sine components, respectively, are obtained by repeatedly collecting the digital vibration signal collected during the constant K period according to the equiangular angle. If the number of repetitive collections of the digital vibration signal is J, an estimate of cosine and sine components for each collection number {C _k (j), S _k (j): k = 1 / K, 2 / K,. , (K-1) / K, 1, 2,... , M / 2; j = 1, 2,... , J} to calculate the mean value, standard deviation, and normalized standard error.

Where j represents the index of the number of repeated collections, and the symbols μ, σ, and ε represent the mean, standard deviation and normal standard error of the cosine and sine components obtained repeatedly.

On the other hand, the normal standard error (ε) in the above equation is a statistical characteristic analysis of the estimated cosine and sine components [J.S. Bendat and A.G. Piersol, Random Data: Analysis and Measurement Procedures, John Wiley & Sons, Newyork: USA, 1986], as well as directly assessing the uncertainty of vibration amplitude and phase measurements for the frequencies and lower and upper harmonics that have excitation.

And, the frequencies of the lower and upper harmonic components as well as the excitation frequency {k × f ₀ : k = 1 / K, 2 / K,... , (K-1) / K, 1, 2,... From the mean value of cosine and sine components (μ) corresponding to, M / 2}, convert the vibration amplitude and phase measurements as follows.

Where k is the index of the frequencies of the lower and upper harmonic components as well as the excited frequencies, and the Arctan function represents the tangent arc-tangent for calculating the phase using the mean cosine and sine components. Since the amplitude A _k square corresponding to the frequency in the above equation is expressed as the sum of the squares of the cosine and sine components, the vibration amplitude estimation is estimated according to the chi-square distribution statistical characteristics when the normal normal error value is small. It is possible.

As a result, the present invention estimates cosine and sine components corresponding to frequencies of lower and upper harmonic components as well as frequencies with Fourier transform from digital vibration signals collected according to isoangles during the period of integer K. In this paper, a method of measuring the vibration amplitude and phase from the average value of the cosine and sine components obtained by converting the average of cosine and sine components obtained by repeating this estimation several times is proposed. The vibration amplitude measurement value of the excitation frequency component is obtained when the normalized standard error is converted using the cosine and sine components of the excitation frequency component obtained from the repeatedly collected digital vibration signal, and the converted normal standard error is small (for example, 0.05 or less). The final reliability verification using the chi-square distribution, i.e. the measurement uncertainty evaluation, is performed.

In addition, the present invention provides a method for examining the effective bit resolution of the digital conversion step from the amplitude A _k measured in addition to the reliability test of the measurement result in order to improve the reliability of the measurement result, and the amplitude and phase measurement This is called the 'first-order reliability test step'. The reliability verification step includes the digital vibration signal {x _n ; n = 1, 2,... , MxK} is performed directly from the cosine and sine components of the Fourier transform result, which is performed before the reliability verification of the amplitude and phase final measurements described above.

Effective bit resolution R _k as follows using voltage values {V _{C, k} , V _{S, k} : k = 1} of cosine and sine component values {C _k , S _k : k = 1} corresponding to excitation frequencies Calculate

Where R _AD is the number of bits of the analog-to-digital converter used to collect the vibration signal, and F _V is the full-scale input voltage of the analog-to-digital converter. Indicates. For example, if a 1 V oscillation amplitude signal is input to a 16-bit analog-to-digital converter with a set input voltage of 10 V, the effective bit resolution R _k is 12.67 bits [R _k = 16 + log ₂ (0.1). )]. That is, even if a 16-bit analog-to-digital converter is used, only the effective bit resolution improved over the 12-bit analog-to-digital converter can be obtained.

This effective bit resolution is a factor that directly affects the amplitude and phase measurements of the vibration signal. In addition, the number of divisions M dividing one period by an equal angle also affects the amplitude and phase measurement of the vibration signal.

Therefore, the effect of the actual effective bit resolution used for the actual amplitude measurement and the number of divisions that divide one period into equal angles together will be described in the amplitude and phase estimation.

5 is a graph showing the characteristics of the amplitude estimation error according to the period division number (M) and the resolution of the analog-to-digital converter under ideal conditions without electrical noise, and FIG. M) and a graph showing the characteristics of the phase estimation error according to the resolution of the analog-digital converter.

That is, FIGS. 5 and 6 show that when the ideal periodic signal without electrical noise is input at 100% of the full-scale input voltage of the analog-to-digital converter, that is, the set input voltage in Equation (4). When the relationship between the voltage values of the cosine and sine components is F _v ² = V _{C, k} ² + V _{S, k} ² , the division number M and the resolution of the analog-to-digital converter, i.e., bit ) Shows the relative estimation errors of the amplitude and phase of the periodic function, respectively.

The results of FIGS. 5 and 6 show an estimation error analysis result of amplitude and phase using 2,000 kinds of periodic functions whose initial phase is uniformly distributed in the range of 0 to 360 °.

First, as shown in FIG. 5 in the amplitude estimation error, it was confirmed that an amplitude estimation error of 0.1% or less cannot be obtained when the number of bits, which are analog-digital converter resolutions, is 5 or 6. When the number of bits is 7, it is confirmed that an amplitude estimation error of 0.1% can be obtained at the period division number M = 160 or more, and when the number of bits is 8, the period division number M = 30 or more. It was also confirmed that when the number of bits is 8, the amplitude estimation error of 0.05% can be improved by increasing the period division number M = 100. When the number of bits is 9, the amplitude estimation error of about 0.05% can be reduced only when the period division number M = 20 or more and when the number of bits is 10, the period division number M = 10 or more. Even in the case of the period division number M = 10, it was confirmed from the graph results that the amplitude estimation error could be improved to 0.02% and 0.01%, respectively, when the number of bits was increased to 11 or 12.

Next, as an analysis result of the phase estimation error, as shown in FIG. 6, when the number of bits is 5, an estimated error of about 0.1 ° may be obtained when the number of period divisions M = 400 or more, and when the number of bits is 6, the period division number It was confirmed that an estimated error of about 0.1 ° was obtained above M = 120. If the number of bits is 7, an estimated error of about 0.1 ° can be obtained when the number of period divisions M = 50 or more. If the number of period divisions M = 500 increases, the phase estimation error can be reduced to 0.05 °. When the number of bits is 8, it is confirmed that the estimated error of 0.1 ° or less can be obtained at the period division number M = 10, and can be reduced to 0.05 ° when increasing to the period division number M = 40 or more. In addition, when the number of bits is increased to 9, 10, and 11, it is confirmed that estimated errors of 0.04 °, 0.02 °, and 0.01 ° can be obtained at the period division number M = 10, respectively.

These facts show that the vibration amplitude and phase estimation error can be reduced by properly selecting the resolution of the analog-to-digital converter and the period division number (M).

3. Example

This embodiment introduces the experimental results obtained using the Equi-Angle Angle Sampling Method (EASM).

On the other hand, Fig. 7 (a) shows a low frequency excitation generator for generating a large amplitude rotational vibration of less than 10 Hz and Fig. 7 (b) shows an excitation generator for generating a high frequency of 10 Hz or more [Chang Wan-seop, Lee Yong-bong, Lee Doo-hee, " A Study on the High Precision Measuring Technique for the Implementation of the Rotation Vibration Correction System, ”Proceedings of the Korean Society for Noise and Vibration Engineering Conference, ISSN 1598-2548, 685-688, 2004].

The low frequency exciter adopts a commercially available high precision servo motor to minimize the manufacturing cost and utilizes the existing control technology.The high frequency exciter minimizes the frictional force generated during the rotary motion and the electromagnetic part to generate the rotating force. Specially designed air bearings were used. The characteristics of these two devices have already been discussed in Korean academic conferences [Jung Wan-seop, Yong-bong Lee, Doo-hee Lee, “A Study on the High-precision Measuring Technique for Implementing the Rotation Vibration Calibration Device,” Proceedings of the Korean Society for Noise and Vibration Engineering Conference, ISSN 1598-2548, 685 -688, 2004].

FIG. 8 shows a measuring device constructed to precisely measure rotational vibration amplitude using an isometric vibration amplitude signal collection technique.

First, the rotational vibration sensor (ATA Dyna-ILC) and the frequency analyzer (HP 35660A) were used to analyze the general characteristics of the periodic vibration signal generated by the rotational exciter.

A dotted line in FIG. 8 is a key element of the rotation angle measuring device, which is a frequency-equal equi-angle sampling (EAS) device having a shaping circuit portion of an oscillating rotation encoder output signal. Consists of. Rotation angle measurements are made for the positive-going and negative-going conditions of quadrature signal A, the output signal of the rotary encoder, and the positive- for quadrature signal B. By adding a circuit that generates separate pulses in positive-going and negative-going conditions, we can change the state transition pulses of two quadratic signals A and B {φ _A , φ _B } We added an electronic circuit that can be counted together. This pulse generating circuit is called a pulse “shaping circuit” and the output signal of this circuit is input to a general purpose counter HP 53131A as shown in Fig. 8. This shaping circuit of the rotary encoder signal is It was developed to realize 1.333μrad (4,712,388 pulses / revolution), which is the maximum rotation angle resolution of rotary encoder.

As previously discussed, conventional methods for measuring vibration amplitude [ISO 16062-11, Methods for the calibration of vibration and shock transducers-Part 11: Primary vibration calibration by laser interferometry, International Organization for Standards, 1999; A. Link and H.-J. von Martens, "Amplitude and phase measurement of sinusoidal vibration in the nanometer range using laser interferomrtry," Measurement, 24, pp 55-67, 1998; H.-J. von Martens, "Current state and trends of ensuring traceability for vibration and shock measurements," Metrologia, 36, pp 267-373, 1999; H.-J. von Martens, et al, "Traceability of vibration and chock measurements by laser interferometry," Measurement, 28, pp. 3-20, 2000; User's Guide for Signal Processing Toolbox, Mathworks Co., 1996] used a fringe-counting method for the pulse of the light detector output of a laser interferometer for a certain period of time. Thus, in the prior art, much larger values than the ideal measurement uncertainty standard error 2ΔΦ {ΔΦ: encoder resolution, rad / pulse} of the fringe-counting method have been observed.

In order to approach this problem systematically, we devised a method of subdividing and measuring the change in amplitude over a period, and attempted to measure the rotation angle corresponding to each time by dividing the period by hundreds or thousands. This method is the Equi-Angle Sampling Method (EASM) of the vibration amplitude described above.

As shown in FIG. 8, the exciter drive signal having the calibration vibration frequency f [Hz] is exciter by a first signal generator having a time stabilization function (signal generator 1: HP33120A, time safety 1.0 ppm). And a synchronizing clock of the first signal generator is a device that generates an isometric signal acquisition frequency M × f [Hz] (M = isometric partition number), that is, a second signal generator (signal generator 2). : HP33120A, time safety 1.0 ppm) for phase synchronization.

A sampling clock with frequency M × f [Hz] synchronized with the exciter drive signal is input to an external sampling clock signal from a counter / timer (NI-PCI 6602). Therefore, the isometric signal collection for each calibration frequency was implemented. As the rotation angle measuring device constructed in this embodiment, a counter (NI, model PCI-6602) having a speed of 80 MHz and a register capacity of 32-bit was used.

Directly inputs the A-phase B-phase signal of the encoder to the 32-bit counter for rotation angle measurement, and manufactures a signal shaping function circuit that provides four times the resolution using the A-phase B-phase signal. The maximum rotation angle resolution of 1.333 μrad of the measuring encoder was obtained.

Distinguish the positive and reverse direction of the displacement from the relative phase information of the A-phase and B-phase signals of the encoder. Perform down-counting. The contents of the 32-bit up / down counter are stored in auxiliary memory (FIFO) at every equi-angle sampling cycle, and the contents of the auxiliary memory are stored on the PCI bus. Is transmitted to the computer in real time. The program to perform the rotation angle measurement was written using NI's LABVIEW software.

The most important task in the rotary vibration calibration is the precise measurement of vibration amplitude. In this embodiment, the rotation vibration amplitude measurement is a fringe-counting method that accumulatively counts signals of an encoder pulse (A phase or B phase) and a newly devised equi-angle sampling method. The rotation angle measurement was attempted using the technique. Table 1 shows the measured amplitude and standard deviation for one cycle.The average pulse number of the rotation angles performed 20 times using the low frequency calibrator is shown as the average value and standard deviation measured for each frequency band. Is 1.333 μrad and the values in parentheses indicate the relative standard deviation.

As shown in Table 1, it was confirmed that the standard deviation of the measurement angle by the fringe-counting method exceeds the ideal amplitude measurement standard error 2ΔΦ at all frequencies.

On the other hand, the amplitude estimation result of rotational vibration obtained by using the equi-angle sampling method is also shown in the right part of Table 1. As can be seen from these results, the standard deviation obtained for rotational vibrations of 10 Hz or less was close to the ideal amplitude measurement standard error 2ΔΦ (2 pulses). On the other hand, the increased standard deviation at 12.5 [Hz] and 16 [Hz] was caused by the harmonic distortion of the low frequency exciter. It was confirmed that caused.

The amplitude measurement values described in Table 1 are measured in multiples of the angular resolution (ΔΦ = 1.333 μrad), i.e. the number of resolutions. In order to convert these measurements into the number of equivalent bits (denoted as "NEB"), the equivalent number of bits can be converted as follows.

Where _k is the number of measured amplitudes, or angular resolutions. Applying Equation (5) to the average measured amplitude values in Table 1, the number of equivalent bits is 19.9 bits at 0.5 [Hz], the number of equivalent bits is 16.1 bits at 10 [Hz], and the number of equivalent bits is 16 [Hz]. Verified with 15.1 bits. Therefore, it is confirmed that the measurement results shown in Table 1 provide the digital conversion results with the resolution of at least 15 bits, and these measurement results prove that the amplitude measurement error can be realized with high precision of 0.01% or less.

Table 2 shows the average values and standard deviations measured for each frequency band of the average number of pulses of the rotation angle where 20 times of high frequency rotation vibration amplitude measurements are performed using the high frequency rotation vibration generator shown in FIG. 7 (b). . That is, Table 2 relates to the comparison of the estimates of the vibration amplitudes measured in the high frequency region, where the angular resolution ΔΦ is 1.333 μrad, and the values in parentheses indicate the relative standard deviations.

For high frequency rotational vibrations with relatively small amplitudes, it was confirmed that the amplitude estimates of the rotational vibrations by the isometric signal collection technique provided lower standard deviations. In particular, it can be seen that the amplitude standard deviation of the isometric collection method proposed at this high frequency of 100 Hz provides about 10 times higher measurement accuracy than the result of the conventional fringe-counting method. Applying these high frequency vibration amplitude measurements to Equation (5), 12.4 bits at 20 [Hz], 10.4 bits at 40 [Hz], 9.8 bits at 50 [Hz], and 7.9 bits at 100 [Hz], respectively. Corresponding. Although the number of equivalent bits (NEB) per frequency band was 8 to 12 bits, the actual standard deviation of the amplitude measurement was all higher than 0.1%. Therefore, it can be confirmed that the vibration amplitude of the current high frequency exciter should be increased to reduce the standard deviation to 0.1% or less.

Three types of device configuration that can implement the isometric signal collection method according to the present invention, that is, for measuring the output signal of the vibration sensor, vibration amplitude measurement using a laser interferometer, and vibration amplitude measurement using a linear or rotary encoder (encoder) According to the apparatus configuration method and the method of accurately estimating the amplitude and phase corresponding to the calibration frequency from the measurement vibration signal obtained in the isometric measurement device configuration of these vibration amplitudes, it is possible to reduce the computation time and the computer memory load. It can create an effect that can provide improved measurement accuracy than the fringe-counting method, which is a precision vibration measurement method.

Claims (12)

In the isometric signal collection device of the sensor output signal to be calibrated using an analog-to-digital converter, A main function generator for outputting an exciter driving signal having an oscillation frequency f ₀ for supplying to the exciter and a phase synchronizing synchronization signal in phase with the exciter driving signal; The phase synchronizing synchronization signal is input, and in order to synchronize the phase with the synchronizing signal, an equal angle collection having a frequency of M × f ₀ is obtained by dividing phase 360 ° of one period of the frequency of the excitation drive signal at equal intervals by M. An auxiliary function generator for outputting a control signal; And A high precision analog-to-digital converter that implements digital conversion according to an isometric acquisition control signal of the auxiliary function generator and uses a phase synchronization synchronization signal of the main function generator as an external trigger input signal; Isometric signal acquisition device for precise measurement of the amplitude and phase components comprising a. In the isometric signal collection device of vibration displacement signal using a laser interferometer, A main function generator for outputting an exciter driving signal having an oscillation frequency f ₀ for supplying to the exciter and a phase synchronizing synchronization signal in phase with the exciter driving signal; The phase synchronizing synchronization signal is input, and in order to synchronize the phase with the synchronizing signal, an equal angle collection having a frequency of M × f ₀ is obtained by dividing phase 360 ° of one period of the frequency of the excitation drive signal at equal intervals by M. An auxiliary function generator for outputting a control signal; And According to the isometric collection control signal of the auxiliary function generator, the contents of the up / down counter are stored in the position information register, and the laser using the phase synchronization synchronization signal of the main function generator as an external trigger input signal. Interferometer displacement measuring board; Isometric signal acquisition device for precise measurement of the amplitude and phase components comprising a. In the isometric signal collecting device of vibration displacement signal using an encoder, A main function generator for outputting an exciter driving signal having an oscillation frequency f ₀ for supplying to the exciter and a phase synchronizing synchronization signal in phase with the exciter driving signal; The phase synchronizing synchronization signal is input, and in order to synchronize the phase with the synchronizing signal, an equal angle collection having a frequency of M × f ₀ is obtained by dividing phase 360 ° of one period of the frequency of the excitation drive signal at equal intervals by M. An auxiliary function generator for outputting a control signal; And A high speed that stores contents of an up / down counter in a position information register according to an isometric acquisition control signal of the auxiliary function generator, and uses a phase synchronization synchronization signal of the main function generator as an external trigger input signal; Counter / timers; Isometric signal acquisition device for precise measurement of the amplitude and phase components comprising a. The method according to any one of claims 1 to 3, And the main function generator outputs a reference clock signal for phase synchronization and frequency stabilization of an auxiliary function generator. The method according to any one of claims 1 to 3, An isometric signal collection device for precise measurement of amplitude and phase components, characterized in that the frequency of the excitation drive signal of the main function generator is set through an interface connected to an external calibration computer. The method according to any one of claims 1 to 3, The isometric dividing number M is set by a user through an interface connected to an external computer, and when the dividing number M value is received by the auxiliary function generator, the synchronization signal of the main function generator and phase synchronization are performed. Isometric signal collector for precise measurement of amplitude and phase components. In the isometric signal collection method of the sensor output signal to be calibrated using an analog-to-digital converter, Outputs an excitation drive signal having a vibration frequency f ₀ for supplying to the excitation device by the main function generator, and a phase synchronization synchronization signal in phase with the excitation drive signal, The output phase synchronization synchronization signal is input to an auxiliary function generator, and the auxiliary function generator equally spaces a phase 360 ° of one period of the excitation drive signal frequency for phase synchronization with the phase synchronization synchronization signal. Dividing into M to output an isometric acquisition control signal having a frequency of M × f ₀ , A digital conversion is implemented in a high precision analog-to-digital converter according to an isometric acquisition control signal of the auxiliary function generator, and a phase synchronization synchronization signal of the main function generator is used as an external trigger input signal of the high precision analog-to-digital converter. An isometric signal collection method for precise measurement of amplitude and phase components. In the isometric signal collection method of vibration displacement signal using a laser interferometer, Outputting an exciter driving signal having a vibration frequency f ₀ for supplying to the exciter by a main function generator, and a phase synchronizing synchronization signal in phase with the exciter driving signal, The output phase synchronization synchronization signal is input to an auxiliary function generator, and the auxiliary function generator equally spaces a phase 360 ° of one period of the excitation drive signal frequency for phase synchronization with the phase synchronization synchronization signal. Dividing into M to output an isometric acquisition control signal having a frequency of M × f ₀ , According to the isometric collection control signal of the auxiliary function generator, the contents of the up / down counter provided in the laser interferometer displacement measuring board are stored in the position information register, and the phase synchronization of the main function generator is performed. An isometric signal collection method for precise measurement of amplitude and phase components, characterized in that a synchronization signal is used as an external trigger input signal of the laser interferometer displacement measuring board. In the isometric signal collection method of vibration displacement signal using an encoder, Outputting an exciter driving signal having a vibration frequency f ₀ for supplying to the exciter by a main function generator, and a phase synchronizing synchronization signal in phase with the exciter driving signal, The output phase synchronization synchronization signal is input to an auxiliary function generator, and the auxiliary function generator equally spaces a phase 360 ° of one period of the excitation drive signal frequency for phase synchronization with the phase synchronization synchronization signal. Dividing into M to output an isometric acquisition control signal having a frequency of M × f ₀ , The contents of the up / down counter included in the high-speed counter / timer are stored in the position information register according to the isometric collection control signal of the auxiliary function generator, and the phase synchronization synchronization signal of the main function generator is stored. Isometric signal collection method for precise measurement of amplitude and phase components, characterized in that used as an external trigger input signal of the high-speed counter / timer. The method according to any one of claims 7 to 9, And the main function generator outputs a reference clock signal for phase synchronization and frequency stabilization of an auxiliary function generator. The method according to any one of claims 7 to 9, The isometric signal collection method for the precise measurement of the amplitude and phase components, characterized in that the frequency of the excitation drive signal of the main function generator is set through an interface connected to an external calibration computer. The method according to any one of claims 7 to 9, The isometric dividing number M is set by a user through an interface connected to an external computer, and when the dividing number M value is received by the auxiliary function generator, the synchronization signal of the main function generator and phase synchronization are performed. An isometric signal acquisition method for precise measurement of amplitude and phase components.

Images