RU2029255C1 - Device for diagnosis of cyclic-action mechanisms - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: device has series-connected vibration transducer 1, amplifier 2, unit 3 for processing vibroacoustic signals and recording device 4. Unit 3 in turn has analogue-to-digital converter 5 connected to the output of amplifier 2, digital-to-analog converter 6 connected to recording unit 4, series connected two-input adder 7, digital multiplier 8 and controllable delay line 9 the output of which is connected to the first input of adder 7 the second input of which is connected to the output of analogue-to-digital converter 5. The output of digital multiplier 8 is connected to the input of digital-to-analogue converter 6 and control input of delay line 9 through series-connected digital frequency multiplier 10 and pulse shaper 11 is connected to cycle phase sensor 12. EFFECT: enhanced reliability. 1 dwg

Description

 The invention relates to measuring technique, and more specifically to the diagnosis of cyclic mechanisms (gears, pumps, turbines, electric motors, internal combustion engines, etc.), and can be used to balance rotors, study the dynamics of mechanisms when creating low-noise equipment in sonar.

 The vibroacoustic signals of the mechanisms of cyclic action have periodic (cyclic) components hidden in the noise and carrying exhaustive information about the dynamics of the mechanisms, therefore, for the purpose of diagnosis, they must be distinguished from the total noise.

 A known device for vibration control of a turbine unit [1], which allows you to measure the values of n-harmonics of the cyclic components of the vibration of the mechanism using n-servo filters controlled from a speed sensor and a frequency multiplier.

 However, this device when measuring loses the phase of the harmonic components, therefore, it is impossible to use it to evaluate the shape of the cyclic component of the vibroacoustic signal, which reduces the accuracy of the control of defects in the mechanism. In addition, the bulkiness and complexity of the device greatly increases with the number of harmonics, the values of which must be measured using this device. So, in order to provide control of the state of gears with a large number of teeth (up to 128), 512 analog-to-digital converters and servo filters should be introduced into the device.

 Thus, this device does not provide accuracy with its significant complication for a certain range of diagnosed mechanisms.

 Closest to the technical nature of the invention is a device that implements a method of vibroacoustic diagnostics of cyclic mechanisms [2] and containing a series-connected vibrator, amplifier, processing unit vibroacoustic signal and a recording device. The vibro-acoustic signal processing unit includes a multiplier, a probe pulse shaper, a probe pulse delay line, a temporary control device, and an integrator.

 The device extracts a periodic (cyclic) component from the vibroacoustic signal, the shape of which rather closely reflects the nature of the dynamic processes in the node, with the movement of which the sequence of probe pulses is synchronized, and therefore carries reliable information about the technical condition of the node. However, due to the fact that the measurement of signal values in certain phases of the cycle is performed in the strobe with a finite duration, there is some error due to smoothing of the signal in the strobe (coarsening of the shape of the cyclic component) and, therefore, the measurement accuracy decreases. In addition, integration (smoothing) in the strobe is carried out by an analog integrator, which also reduces the accuracy of measurements. This device allows you to view the cyclic component by a sequential supply of probing pulses, which increases the diagnostic time.

 The objective of the invention is to develop a device for the diagnosis of mechanisms of cyclic action, which would reduce the time and improve the accuracy of diagnosis of the mechanism.

 This is achieved by the fact that in a device for diagnosing a cyclic action mechanism, including a series-connected vibration transducer, amplifier, vibroacoustic signal processing unit and a recording device, according to the invention, the vibroacoustic signal processing unit comprises an analog-to-digital converter (ADC) connected to the amplifier output, a recirculator and a digital-to-analog converter (DAC) connected to a recording device, while the recirculator consists of series-connected vuhvhodovogo adder, the multiplier and the digital controlled delay line, which signal output is connected to the ADC output, the digital output of the multiplier is connected to the input of the DAC, and the control input of the delay line connected in series through a digital frequency multiplier and a pulse generator - the sensor cycle phase.

 The use of a recirculator with a delay line controlled by the cycle phase sensor at each moment of time ensures that the delay time and the duration of the cycle of the mechanism are exactly equal, as a result of which the recirculator is precisely tuned to the frequency of rotation of the mechanism in the tracking mode of the recirculator This allows the in-phase accumulation of the useful periodic component of the vibration signal of the mechanism and filter it from noise and powerful non-synchronous periodic vibrations of neighboring nodes and mechanisms, fully preserving the shape, which increases the accuracy of diagnostics.

 The equality of the delay time and the period of the cyclic component allows using the recirculator to simultaneously receive and output to the recording device all the values of the useful signal, which speeds up the diagnostic time. In addition, the execution of the processing unit of the vibro-acoustic signal allows you to organize the operation of the entire device so that the signal is processed at a digital level, which also improves the accuracy of diagnostics.

 The drawing shows a functional diagram of a diagnostic device.

 The device contains a series-connected vibration transducer 1, an amplifier 2, a vibroacoustic signal processing unit 3 and a recording device 4. The vibroacoustic signal processing unit includes an ADC 5 connected to the output of an amplifier 2, a DAC 6 connected to a recording device 4.

 The vibro-acoustic signal processing unit consists of a two-input adder 7 connected in series, a digital multiplier 8 with a multiplication factor β <1 and a controlled delay line 9, the output of which is connected to the first input of the adder 7, the second input of which is connected to the output of the ADC 5. The output of the digital multiplier 8 is connected with the input of the DAC 6, and the control input of the delay line 9 through a series-connected digital frequency multiplier 10 and a pulse shaper 11 is connected to the sensor 12 of the phase of the cycle.

 The device operates as follows. The signal generated by the cyclic action mechanism from the vibration transducer 1 after amplification in the amplifier 2 and conversion to the ADC 5 enters the processing unit of the vibroacoustic signal. Having passed through the adder 7, the signal is attenuated in the digital multiplier 8 with a multiplication factor β <1.

 The coefficient sets a certain time constant of the signal recirculation for the implementation of the exponential mode of accumulation of the useful signal.

 The attenuated signal from the digital multiplier 8 enters the DAC 6 and the delay line 9, from where, after a delay for a time equal to the duration of the cycle of the mechanism, it arrives at the first input of the adder 7, where the common mode values of the useful signal are delayed for a time equal to the cycle time the useful signal received by the ADC 5. In this case, the phase-matching of the values of the useful signal coming from the ADC 5 and the signal coming from the delay line 9 is provided by the control signal from the mechanism cycle phase sensor.

 The control signal from the sensor 12 is generated in the pulse shaper 11 and then fed to a digital frequency multiplier 10, in which the frequency of the generated phase signal of the cycle is multiplied by a number that determines the number of signal values during the period required for accurate measurement of the cyclic component.

 The signal from the multiplied frequency is fed to the control input of the delay line 9 and records the values of the useful vibroacoustic signal in the delay line and their reading is equal after a period of rotation of the mechanism. This ensures a constant (tracking) equality of the period of rotation of the mechanism and the delay time. Moreover, the exponential accumulation of the useful signal in the adder 7 while fully maintaining the shape of the cyclic component, which increases the accuracy of the measurements. The signal accumulated in the adder 7 through the digital multiplier 8 is continuously fed to the DAC 6 and after formation in analog form - to the recording device. At the same time, all values of the useful signal are output to the recording device 4 at the same time, which speeds up the diagnostic time.

Claims (1)

 DEVICE FOR DIAGNOSTIC OF MECHANISMS OF CYCLIC ACTION, containing serially connected vibration transducer, amplifier, processing unit of vibroacoustic signal and recording unit, characterized in that the processing unit of vibroacoustic signal is made in the form of series-connected analog-to-digital converter, two-input adder, digital multiplier, digital-to-digital connected cycle phase sensor, pulse shaper and digital frequency multiplier, a delay line, the first input of which is connected to the output of the digital multiplier, the second input - with the output of the digital frequency multiplier, and the output - with the second input of the two-input adder, the input of the analog-to-digital converter is the input of the vibroacoustic signal processing unit, the output of the digital-to-analog converter is the output of the processing unit vibroacoustic signal.