Experimental device and experimental method for torsional vibration test of complex shafting

Abstract

The invention discloses an experimental device and an experimental method for testing torsional vibration of a complex shafting. The experimental device comprises a driving motor, a supporting frame, a rotor assembly, an equally-divided structure coded disc, an eddy current sensor, a two-stage transmission gear box, a torsional vibration motor component, a data collector and data analysis software. An output shaft of the driving motor is connected to an input shaft of the two-stage transmission gear box through a rotor assembly, and an output shaft of the two-stage transmission gear box is connected to an output shaft of the torsional vibration motor part through a third coupler; the equant structure code disc is fixed on the rotor assembly. The eddy current sensor is installed at the equally-divided structure code disc and is used for measuring the instantaneous speed of the code disc. The data analysis software measures torsional vibration parameters based on a pulse time sequence counting method. According to the invention, torsional vibration of any frequency can be generated, and research such as rotor torsional vibration simulation and measurement can be carried out, so that real aero-engine complex shafting torsional vibration can be simulated.

Description

Technical Field

[0001] The present invention relates to the technical field of dynamic performance detection of rotating machinery, and particularly relates to an experimental device and an experimental method for torsional vibration testing of a complex shafting system. Background Art

[0002] Torsional vibration is a special form of mechanical vibration that commonly exists in rotating machinery. Since the rotor is not an absolute rigid body but elastic, during the rotation of the rotor, instantaneous speed changes occur at different parts, and torsional movements will occur between the elastic components, just like twisting a "twisted dough stick" back and forth. For large rotating machinery, such as turboprop engines, the entire shafting system consists of multiple segments of rotors, and the structure is more complex. Shafting torsional vibration will cause internal tangential alternating stresses. If the torsional amplitude is too large and the shear exceeds the elastic limit, fatigue loss will occur. If preventive measures cannot be taken in time when the shafting is in a torsional vibration state for a long time, it will affect the stability of the unit at a minimum, and at worst, it may cause fatigue damage to the shafting system or even lead to catastrophic accidents.

[0003] Currently, the commonly used methods for measuring shafting torsional vibration signals are mainly divided into contact measurement methods and non-contact measurement methods. The contact measurement method attaches sensors to the surface of the shafting system, and obtains the shafting torsional vibration state by measuring the dynamic changes of shear stress. This method has high accuracy and a wide frequency response range, but is greatly affected by the working environment and is not easy to install. The non-contact measurement method is the most widely used method at present. By installing sensors at the head or tail of the shafting system and comparing the collected signals, the torsional vibration condition of the shafting system is monitored in real time. Among them, the rotational speed is measured using an optoelectronic sensor. This method can accurately obtain the rotational speed of the shafting system in real time, but is susceptible to interference in a harsh working environment and has a high cost. Therefore, there is an urgent need for a new experimental device to study the torsional vibration of complex shafting systems. Summary of the Invention

[0004] The purpose of the present invention is to provide an experimental device and an experimental method for torsional vibration testing of a complex shafting system, which can generate torsional vibrations of any frequency, conduct research on rotor torsional vibration simulation and measurement, etc., so as to simulate the torsional vibration of the complex shafting system of a real aero-engine, and provide theoretical guidance for the generation and measurement of rotor torsional vibration of an aero-engine.

[0005] To achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0006] In a first aspect, the present invention discloses an experimental device for torsional vibration testing of a complex shafting system. The device includes a driving motor, a support frame, a rotor assembly, an equally divided structure code disk, an eddy current sensor, a two-stage transmission gearbox, a torsional vibration motor component, a data collector, and data analysis software;

[0007] The driving motor is mounted on the support frame. The output shaft of the driving motor is connected to the input shaft of the two-stage transmission gearbox through the rotor assembly. The output shaft of the two-stage transmission gearbox is connected to the output shaft of the torsional vibration motor component through the third coupling. The torsional vibration motor component is used to generate torsional vibration excitation at different frequencies to the rotor assembly.

[0008] The equally divided structure code disk is fixed on the rotor assembly. The eddy current sensor is installed at the equally divided structure code disk. By measuring the pulse signal, the instantaneous speed of the code disk is calculated. The data collector is connected to the eddy current sensor for data acquisition, and the instantaneous speed of the code disk collected is sent to the data analysis software for data analysis. The data analysis software measures the torsional vibration parameters based on the pulse timing counting method.

[0009] Further, the rotor assembly includes a first coupling, a rotating shaft, a first rolling bearing, a rotor disk and a second coupling. The rotor assembly is placed horizontally. The output shaft of the motor is connected to one end of the rotating shaft through the first coupling. The first rolling bearing supports the rotating shaft. The rotating shaft is provided with a rotor disk and an equally divided structure code disk. One end of the code disk far from the rotor disk is connected to the second rolling bearing. The second rolling bearing is connected to the input shaft of the two-stage transmission gearbox through the second coupling. The eddy current sensor is fixed at the code disk through a bracket.

[0010] Further, the tooth pitch size of the equally divided structure code disk is larger than the diameter of the eddy current sensor.

[0011] Further, the data collector uses a BNC male wiring terminal to connect to the eddy current sensor.

[0012] Further, the eddy current sensor is mounted at the equally divided structure code disk in a bracket type.

[0013] Further, the equally divided structure code disk is fixed on the rotor assembly through a locking device.

[0014] The locking device is divided into a first locking fitting, a second locking fitting and a plurality of bolts. The conical surface of the first locking fitting cooperates with the code disk. The other side is cooperated with the second locking fitting through threads, and the rotating shaft and the code disk are locked through a plurality of bolts.

[0015] Further, the two-stage transmission gearbox includes an input shaft, an intermediate shaft, an output shaft and gears. The transmission ratio of the two-stage transmission gearbox is 4.97:1 and is composed of two stages of gears. The number of teeth of each stage of gears is 58:25 and 60:28 respectively. The two-stage transmission gearbox slides the gear along the intermediate shaft. The first gear on the intermediate shaft meshes with the gear on the input shaft, and the second gear on the intermediate shaft meshes with the gear on the output shaft.

[0016] Further, the torsional vibration motor component includes a torsional vibration motor, a signal generator, a power amplifier, and a DC power supply; the torsional vibration motor is an AC motor, and the frequency modulation signal generating device provides an alternating signal to the power amplifier. The alternating signal is amplified by the power amplifier and then transmitted to the torsional vibration motor to provide an alternating current for the excitation winding of the torsional vibration motor; the frequency and amplitude of the torsional vibration output by the torsional vibration motor are respectively adjusted by the signal generator and the DC power supply.

[0017] Further, the data analysis software includes an angular displacement calculation module, a pulse width value acquisition module, a shaft average speed calculation module, an instantaneous angular velocity calculation module, and a torsional angular displacement calculation module;

[0018] The angular displacement calculation module is used to calculate the angular displacement θ(t) at time t according to the average angular velocity ω of the rotating shaft A and the torsional vibration angular velocity ω T :

[0019]

[0020] In the formula, is the phase angle of torsional vibration;

[0021] The pulse width value acquisition module is used to obtain the arrival time sequence {t k} of n encoder pulses, and calculate n pulse width values {Δt k}, where Δt k =t k -t k-1 ;

[0022] The shaft average speed calculation module calculates the shaft average speed according to the encoder tooth number N and n pulse width values {Δt k} as:

[0023]

[0024] The instantaneous angular velocity calculation module is used to calculate the instantaneous angular velocity according to the following formula:

[0025]

[0026] The torsional angular displacement calculation module is used to calculate the torsional angular displacement at the end of the kth pulse:

[0027]

[0028] In a second aspect, the present invention discloses an experimental method for testing torsional vibration of a complex shafting system, and the method is executed based on the experimental device as described above; the method includes the following steps:

[0029] The armature of the torsion motor is powered by a DC power supply. By setting the signal frequency of the signal generator and using a power amplifier to supply power to the excitation coil, torsional vibration excitation at different frequencies is generated.

[0030] Each time the rotor disc rotates a preset angle, a pulse is generated. The corresponding pulse signal is measured by an eddy current sensor, and the average width of multiple adjacent pulses is calculated.

[0031] The angular displacement θ(t) of the code disk at time t is calculated as follows:

[0032]

[0033] The angular displacement of the measurement axis corresponding to a single pulse is calculated as:

[0034]

[0035] In the formula, N is the number of teeth of the code disk;

[0036] By comparing the angular displacement θ(t) of the code disk and the angular displacement θ of the measurement axis G , it is judged whether torsional vibration occurs;

[0037] If torsional vibration occurs, let the time when the k-th pulse arrives be t k , then the angular displacement at this time is Assume is 0, then there is:

[0038]

[0039] In the formula, k = 1, 2......n;

[0040] The arrival time sequence {t k} of n code disk pulses is obtained, and n pulse width values {Δt k} are calculated, where Δt k = t k - t k-1 ; According to the number of teeth N of the code disk and the n pulse width values {Δt k}, the average speed of the rotating shaft is calculated as:

[0041]

[0042] The instantaneous angular velocity is calculated as:

[0043]

[0044] In the formula, ω T (k) is the instantaneous angular velocity of torsional vibration at the current moment, and ω(k) is the total angular velocity at the current moment;

[0045] At the end of the k-th pulse, the calculated torsional angular displacement is as follows:

[0046]

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] The experimental device and experimental method for torsional vibration testing of a complex shafting system of the present invention can generate torsional vibrations of any frequency, conduct research on rotor torsional vibration simulation and measurement, etc., so as to simulate the torsional vibration of a real aero-engine complex shafting system, and provide theoretical guidance for the generation and measurement of rotor torsional vibration of an aero-engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a schematic structural diagram of the experimental device for torsional vibration testing of a complex shafting system of the present invention;

[0050] Figure 2 is a schematic diagram of a torsional vibration motor control device;

[0051] Figure 3 is a control logic diagram of a torsional vibration motor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] The following further describes the embodiments of the present invention in detail with reference to the accompanying drawings.

[0053] The present invention provides an experimental device for torsional vibration testing of a complex shafting system, including a driving motor, a support frame, a rotor assembly, an equally divided structural code disk, an eddy current sensor, a two-stage transmission gearbox, a torsional vibration motor component, a data collector, and data analysis software; the driving motor is installed on the support frame, and the output shaft of the driving motor is connected to the input shaft of the two-stage transmission gearbox through the rotor assembly, and the output shaft of the two-stage transmission gearbox is connected to the output shaft of the torsional vibration motor component through a third coupling; the torsional vibration motor component is used to generate torsional vibration excitations at different frequencies to the rotor assembly; the equally divided structural code disk is fixed on the rotor assembly; the eddy current sensor is installed at the equally divided structural code disk, and the instantaneous speed of the code disk is calculated by measuring a pulse signal; the data collector is connected to the eddy current sensor for data collection, and the collected instantaneous speed of the code disk is sent to the data analysis software for data analysis, and the torsional vibration parameters are measured by the data analysis software based on the pulse timing counting method.

[0054] See Figure 1, the experimental device of the present invention includes: a driving motor, a coupling, an experimental shaft end, a two-stage transmission gearbox, a gear disc, a torsional vibration motor, a support, and an eddy current sensor. The driving motor is fixed on a support frame, connected to a rolling bearing through a coupling. The rolling bearing supports the rotor disc. The eddy current sensor is fixed on the support frame at the code disc. The code disc is further connected to the rolling bearing, and the rolling bearing is connected to the input shaft of the two-stage transmission gearbox. The transmission ratio of the two standard gearboxes of the transmission gearbox is 4.97:1 and is composed of two stages of gears. By sliding the gear along the intermediate shaft, the normal gear on the intermediate shaft can mesh with the gear on the input shaft, and another gear on the intermediate shaft can also mesh with the gear on the output shaft, thus achieving the transmission effect. The main device for measuring torsional vibration in the present invention is the equally divided structure code disc installed on the rotating shaft. The equally divided structure code disc is used to measure the instantaneous speed of the rotating shaft, and the measured instantaneous speed is converted to achieve the effect of measuring torsional vibration.

[0055] The measurement component of the present invention includes: a support frame, an equally divided structure code disc, an eddy current sensor, a 16-channel data collector, and data analysis software; the code disc is fixed on the experimental shaft end through a locking device. The eddy current sensor is installed in a bracket type at the equally divided structure code disc for measuring the instantaneous speed of the code disc. The 16-channel data collector uses BNC male wiring terminals to connect to the eddy current sensor for data collection, and accesses the data analysis software through a gigabit network port for data analysis;

[0056] The rotor component of the present invention includes a first coupling, a rotating shaft, a first rolling bearing, a rotor disc, an equally divided structure code disc, and a second coupling; the rotor component is placed horizontally. The motor is arranged at the head of the support frame. The output shaft of the motor is connected to one end of the rotating shaft through the first coupling. The first rolling bearing supports the rotating shaft. The rotating shaft is provided with a rotor disc and an equally divided structure code disc. The code disc is further connected to the second rolling bearing, and the rolling bearing is connected to the input shaft of the two-stage transmission gearbox through the second coupling. The eddy current sensor is fixed at the code disc through a bracket; the shaft of the entire experimental shaft section is made of stainless steel material, with two specifications for the length: long rotor / short rotor, and two specifications for the diameter: diameter: 10mm, 30mm.

[0057] The equally divided structure code disc component of the present invention includes an equally divided structure code disc and a locking device; the requirements for the tooth space size of the equally divided structure code disc: for the convenience of accurately measuring the instantaneous speed by the eddy current sensor, the tooth space size of the equally divided structure code disc shall not be less than the diameter of the eddy current sensor. Considering that the diameter of the eddy current sensor is 8mm and the convenience of measuring data, the tooth space size of the equally divided structure code disc is taken as 10mm, and the entire code disc is equally divided; the locking device is divided into locking fitting a and locking fitting b, and the two fittings are fitted together through threads. The conical surface of fitting a cooperates with the code disc, and the other side is assembled with locking fitting b through threads. After assembly, it can lock the rotating shaft and the code disc through 6 bolts.

[0058] The two-stage transmission gearbox of the present invention includes an input shaft, an intermediate shaft, an output shaft and gears; the transmission ratio of the standard gearbox is 4.97:1, which is composed of two stages of gears. The number of teeth of each stage of gears is 58:25 and 60:28 respectively. The two-stage transmission gearbox can achieve the transmission effect by sliding the gears along the intermediate shaft. The normal gear on the intermediate shaft can be engaged with the gear on the input shaft, and the other gear on the intermediate shaft can also be engaged with the gear on the output shaft. The gearbox is also equipped with an intermediate shaft bracket, which can adjust the backlash arbitrarily.

[0059] In the present invention, the most important torsional vibration motor components for generating torsional vibration include a torsional vibration motor, a signal generator, a power amplifier and a DC power supply. Figure 2 It is a schematic diagram of the torsional vibration motor control device. Among them, (a) is the power amplifier, (b) is the signal generator, and (c) is the DC power supply. The torsional vibration motor is a special AC motor. The frequency modulation signal generating device provides an alternating signal to the power amplifier. The signal is amplified by the power amplifier and then sent to the torsional vibration motor to provide an alternating current for the excitation winding of the torsional vibration motor. The frequency and amplitude of the torsional vibration output by the torsional vibration motor can be adjusted by the signal generator and the DC power supply respectively. Figure 3 It is the control logic diagram of the torsional vibration motor.

[0060] Example

[0061] The entire shafting of the torsional vibration test bench consists of the following:

[0062] (1) Driving motor. This system adopts the ABB three-phase asynchronous driving motor scheme. The motor shaft directly drives the load through a coupling. When the rated current of the motor is 380V, it is 4.58A, or when it is 220V, it is 7.93A. The maximum output power is 2.2KW. The power supply system directly supplies 220 / 380V AC voltage to the motor, and adjusts the operating frequency of the motor through a frequency converter, so as to achieve stepless speed regulation of the motor within the range of 0 to 10,000 rpm.

[0063] (2) Test shaft section. The shaft of the entire test shaft section is made of stainless steel, with two specifications of length: long rotor / short rotor, and two specifications of diameter: 10mm and 30mm.

[0064] (3) Gear disk. There is a 160×10mm steel gear disk on the test shaft section. The number of teeth of the gear is 30. The gear disk is fixed on the rotating shaft by a nut fixing method, which can be conveniently installed and disassembled.

[0065] (4) Support bearing. The bearing unit assembly consists of two bearing seats and a 30mm shaft. The installed bearing type is the conventional model of the rolling bearing UPH206, and the inner diameter is 30mm.

[0066] (5) Gearbox: Oil-immersed lubrication, two-stage transmission, reduction ratio: 1:4.97 (1st stage: 25 / 58, 2nd stage: 28 / 60).

[0067] (6) Torsional vibration motor. The torsional vibration motor is a special DC excitation motor that is connected to the test shaft section with a rigid coupling to provide torsional vibration torque to the test shaft system.

[0068] The torsional vibration measurement method of this embodiment operates as follows: Torsional vibration is measured using a pulse sequence counting method. A code disk mounted on the shaft generates a corresponding pulse signal via a non-contact eddy current sensor. Each time the rotor disk rotates a certain angle, a pulse is generated. The average width of multiple adjacent pulses is measured to determine the average angular velocity of the rotating shaft. The width of a single pulse is measured to determine the instantaneous angular velocity of the rotating shaft, thereby obtaining the angular velocity difference and the angular displacement of the torsional angle.

[0069] When the rotating shaft is rotating at a constant speed without torsional vibration, the pulse signal intervals generated are uniform. The instantaneous speed of the rotating shaft is equal to its average speed. Let the angular velocity of the rotating shaft be ω A , if there is no torsional vibration, the angular displacement at time t is ω A t. If there is torsional vibration, and the average angular velocity of the rotating axis is ω A , the torsional angular velocity is ω T , then the angular displacement at time t is:

[0070]

[0071] Assuming there are N teeth on the code disk, the angular displacement corresponding to a single pulse is:

[0072]

[0073] Assuming that the time when the kth pulse arrives is tk, the angular displacement at this time is Assumptions If is 0, then:

[0074]

[0075] By solving the nonlinear equation, we can obtain the arrival time sequence of n code disk pulses: {t k ,k=1,2…n}

[0076]

[0077] Alternatively, the axial vibration motion can be regarded as the involved motion, and the approximate arrival time sequence of the code disk pulse can also be generated.

[0078] {t k ,k=1,2…n}

[0079] Select an NI data acquisition card and use its DI counter channel to continuously collect pulse signals from the code disk, and the arrival times of n code disk pulses can be obtained as {t k , k = 1, 2…n}.

[0080] The known conditions include: the number of teeth N of the code disk, and n pulse width values {Δt k , k = 1, 2…n}. From this, it can be obtained that:

[0081] Average speed of the rotating shaft:

[0082]

[0083] Instantaneous angular velocity (assuming the angular velocity remains unchanged within the current k-th pulse width time):

[0084]

[0085] At the end of the k-th pulse, the torsional angular displacement can be obtained:

[0086]

[0087] Since it is difficult for the tester to generate torsional vibration by itself, and the amplitude of the torsional vibration is small and easily annihilated in the noise. Therefore, the present invention provides a torsional vibration motor to provide torsional vibration excitation, increase the torsional vibration phenomenon of the tester, so that the measurement results are more obvious.

[0088] The entire test method includes three parts:

[0089] (1) Torsional vibration excitation: Supply power to the armature of the torsional vibration motor with a DC power supply, set the signal frequency of the signal generator, and supply power to the excitation coil using a power amplifier to achieve torsional vibration excitation at different frequencies. As Figure 3 shown.

[0090] (2) Signal acquisition: Use the code disk structure installed on the shaft to generate corresponding pulse signals through a non-contact eddy current sensor, transmit the signals, and use a digital acquisition card to perform signal acquisition.

[0091] (3) Signal analysis: The signals collected by the digital acquisition card are uploaded to the computer processor, and the specific results of the torsion can be displayed on the interface through corresponding algorithms, and it supports simultaneously displaying the displacement changes and their spectra of the torsional vibration.

[0092] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0093] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these modifications and variations.

Claims

1. An experimental device for torsional vibration testing of a complex shafting system, characterized in that, The device includes a driving motor, a support frame, a rotor assembly, an equally divided structure code disk, an eddy current sensor, a two-stage transmission gearbox, a torsional vibration motor component, a data collector, and a data analysis software; The driving motor is installed on the support frame. The output shaft of the driving motor is connected to the input shaft of the two-stage transmission gearbox through the rotor assembly. The output shaft of the two-stage transmission gearbox is connected to the output shaft of the torsional vibration motor component through a third coupling. The torsional vibration motor component is used to generate torsional vibration excitations at different frequencies to the rotor assembly; The equally divided structure code disk is fixed on the rotor assembly. The eddy current sensor is installed at the equally divided structure code disk. By measuring the pulse signal, the instantaneous speed of the code disk is calculated. The data collector is connected to the eddy current sensor for data collection, and the instantaneous speed of the code disk collected is sent to the data analysis software for data analysis. The data analysis software measures the torsional vibration parameters based on the pulse timing counting method.

2. The experimental device for torsional vibration testing of a complex shafting system according to claim 1, wherein The rotor assembly includes a first coupling, a rotating shaft, a first rolling bearing, a rotor disk, and a second coupling. The rotor assembly is placed horizontally. The output shaft of the motor is connected to one end of the rotating shaft through the first coupling. The first rolling bearing supports the rotating shaft. The rotating shaft is provided with a rotor disk and an equally divided structure code disk. One end of the code disk far from the rotor disk is connected to the second rolling bearing. The second rolling bearing is connected to the input shaft of the two-stage transmission gearbox through the second coupling. The eddy current sensor is fixed at the code disk through a bracket.

3. The experimental device for torsional vibration testing of a complex shafting system according to claim 1, wherein The tooth space size of the equally divided structure code disk is larger than the diameter of the eddy current sensor.

4. The experimental device for torsional vibration testing of a complex shafting system according to claim 1, characterized in that, The data collector uses a BNC male wiring terminal to connect to the eddy current sensor.

5. The experimental device for torsional vibration testing of a complex shafting system according to claim 1, characterized in that, The eddy current sensor is installed at the equally divided structure code disk in a bracket type.

6. The experimental device for torsional vibration testing of a complex shafting system according to claim 1, characterized in that, The equally divided structure code disk is fixed on the rotor assembly through a locking device; The locking device is divided into a first locking fitting, a second locking fitting, and a plurality of bolts. The conical surface of the first locking fitting cooperates with the code disk, and the other side is cooperated with the second locking fitting through threads, and the rotating shaft and the code disk are locked through a plurality of bolts.

7. The experimental device for torsional vibration testing of a complex shafting system according to claim 1, characterized in that, The two-stage transmission gearbox includes an input shaft, an intermediate shaft, an output shaft, and gears. The transmission ratio of the two-stage transmission gearbox is 4.97:1 and is composed of two stages of gears. The number of teeth of each stage of gears is 58:25 and 60:28 respectively. The two-stage transmission gearbox slides the gear along the intermediate shaft. The first gear on the intermediate shaft meshes with the gear on the input shaft, and the second gear on the intermediate shaft meshes with the gear on the output shaft.

8. The experimental device for torsional vibration testing of a complex shafting system according to claim 1, characterized in that, The torsional vibration motor component includes a torsional vibration motor, a signal generator, a power amplifier, and a DC power supply. The torsional vibration motor is an AC motor. The frequency modulation signal generating device provides an alternating signal to the power amplifier. The alternating signal is amplified by the power amplifier and then sent to the torsional vibration motor to provide an alternating current for the excitation winding of the torsional vibration motor. The frequency and amplitude of the torsional vibration output by the torsional vibration motor are adjusted by the signal generator and the DC power supply respectively.

9. The experimental device for torsional vibration testing of a complex shafting system according to claim 1, characterized in that, The data analysis software includes an angular displacement calculation module, a pulse width value acquisition module, a rotating shaft average speed calculation module, an instantaneous angular velocity calculation module, and a torsional angular displacement calculation module; The angular displacement calculation module is used to calculate the angular displacement θ(t) at time t according to the average angular velocity ω of the rotating shaft A and the torsional vibration angular velocity ω T : wherein, is the phase angle of torsional vibration; The pulse width value acquisition module is used to obtain the arrival time sequence {t k} of n encoder pulses, and calculate n pulse width values {Δt k}, where Δt k = t k - t k-1 ; The average shaft speed calculation module calculates the average shaft speed based on the number of teeth N of the code disk and n pulse width values {Δt k}, and the result is as follows: The instantaneous angular velocity calculation module is used to calculate the instantaneous angular velocity according to the following formula: The torsional angular displacement calculation module is used to calculate the torsional angular displacement at the end of the k-th pulse:

10. An experimental method for torsional vibration testing of a complex shafting system, characterized in that, The method is executed based on the experimental device described in claim 2; the method includes the following steps: Power the armature of the torsion motor with a DC power supply, set the signal frequency of the signal generator, and supply power to the excitation coil using a power amplifier to generate torsional vibrations at different frequencies; Each time the rotor disc rotates a preset angle, a pulse is generated. Measure the corresponding pulse signal through an eddy current sensor and calculate the average width of multiple adjacent pulses; Calculate the encoder disk angular displacement θ(t) at time t: Calculate the angular displacement of the measurement axis corresponding to a single pulse as: In the formula, N is the number of teeth of the encoder disk; By comparing the angular displacement θ(t) of the code disk and the angular displacement θ of the measuring axis G , it is determined whether torsional vibration occurs; If torsional vibration occurs, let the time when the k-th pulse arrives be t k , then the angular displacement at this time is Assume is 0, then there is: In the formula, k = 1, 2......n; Obtain the arrival time sequence {t k} of n encoder pulses, and calculate n pulse width values {Δt k}, where Δt k = t k - t k-1 ; According to the number of teeth N of the code disk and n pulse width values {Δt k}, the average speed of the rotating shaft is calculated as follows: Calculate the instantaneous angular velocity as: where ω T (k) is the instantaneous angular velocity of torsional vibration at the current moment, and ω(k) is the total angular velocity at the current moment; At the end of the k-th pulse, calculate the torsional angular displacement as:

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