Vibration test system for broadband-large thrust

Abstract

The invention discloses a vibration test system for broadband-large thrust, which relates to the field of vibration test, and comprises a working table, an electro-hydraulic vibration exciter, an electric vibration exciter, an industrial personal computer, a first acquisition piece and a second acquisition piece, and is characterized in that the industrial personal computer is used for generating digital signals required by a vibration excitation system; the signals are divided into high-frequency signals and low-frequency signals by using the signal decomposer by taking 200Hz as a boundary, and when the low-frequency signals are generated, the switch of the servo valve is controlled to achieve the effect of controlling the electro-hydraulic vibration exciter; when the signal is high-frequency, the output of the power amplifier is controlled so as to control the movement of the electric vibration exciter; and meanwhile, closed-loop control is adopted to improve the control precision, and an optimization algorithm is adopted at the low-frequency and high-frequency boundary to enable the control waveform to be continuous. The electro-hydraulic vibration exciter is combined with the electric vibration exciter, so that the requirements of wide-band and high-thrust excitation tests can be met, the excitation test requirements are not limited by the capability of an excitation system, and the electro-hydraulic vibration exciter has the characteristics of high economical efficiency, high operation reliability and excellent performance.

Description

Technical Field

[0001] The invention relates to the field of vibration testing, and in particular to a vibration testing system for wide frequency band and large thrust. Background Art

[0002] As an effective means of testing product reliability and strength, vibration testing has been widely used in product performance assessment and strength identification. Electric exciters and electro-hydraulic exciters are widely used vibration generating devices in vibration testing. They can generate controllable vibration waveforms and are widely used in aviation, aerospace, construction, communications and other fields. They are essential equipment in cutting-edge manufacturing industries.

[0003] Vibration environment tests can be divided into the following types according to the excitation: sine vibration test, impact vibration test, random vibration test, sine plus random vibration test, random plus random vibration test. The vibration tables used for vibration tests are mainly mechanical exciters, electro-hydraulic exciters and electric exciters. With the development of aviation, aerospace and national defense, people have increasingly stringent requirements on the reliability, life and safety of products and components working in various complex environments (especially vibration environments), so the requirements for vibration environment tests are also getting higher and higher. The thrust and vibration frequency range generated by the commonly used exciters can no longer meet people's needs.

[0004] Electric exciters are currently the most widely used vibration test equipment due to their wide frequency band, complete waveform, and easy control. However, their low-frequency characteristics need to be improved, and their lowest frequency can only reach about 5Hz. Electro-hydraulic exciters have large thrust, firm structure, and good low-frequency characteristics, but their upper frequency limit is limited, generally only about 500Hz. Therefore, existing test equipment cannot meet the test needs of the full frequency band. Summary of the invention

[0005] The purpose of the present invention is to design a wide-band and high-thrust vibration test system in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] Vibration test system for wide frequency band and high force, including:

[0008] Work surface; the sample to be tested by vibration is fixedly mounted on the work surface;

[0009] The electro-hydraulic exciter is used to apply thrust to the work surface within the first frequency range, and the electro-hydraulic exciter is fixed to the fixed surface;

[0010] The electric vibrator is used to apply thrust to the work surface in the second frequency range, the first frequency range is different from the second frequency range, and the moving coil frame of the electric vibrator is fixedly connected to the moving part of the hydraulic excitation device;

[0011] Industrial computer; the industrial computer is used to control the working state of the electro-hydraulic vibrator and the electric vibrator, and the control signal output terminal of the industrial computer is connected to the control signal input terminal of the electro-hydraulic vibrator and the electric vibrator respectively;

[0012] The first acquisition component is used to collect the acceleration, displacement and thrust of the power output end of the electro-hydraulic exciter in the first frequency range;

[0013] The second acquisition component is used to collect the acceleration of the power output end of the electric vibrator within the second frequency range, and the data signal output end of the first acquisition component and the data signal output end of the second acquisition component are both connected to the data signal input end of the industrial computer.

[0014] The beneficial effects of the present invention are: using an industrial computer to generate the digital signal required by the excitation system, using a signal decomposer to divide the signal into high-frequency and low-frequency signals with 200Hz as the boundary, when the signal is low-frequency, the switch of the servo valve is controlled to achieve the function of controlling the electro-hydraulic exciter; when the signal is high-frequency, the output of the power amplifier is controlled to control the movement of the electric exciter; at the same time, closed-loop control is used to improve the control accuracy, and an optimization algorithm is used at the boundary between low frequency and high frequency to make the control waveform continuous. By combining the electro-hydraulic exciter with the electric exciter, the needs of wide-band and large-thrust excitation tests can be met, so that the excitation test needs are not limited by the capacity of the excitation system, and it has the characteristics of high economy, high operating reliability and excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The schematic diagram of the vibration test system for wide frequency band and large thrust of the present invention is shown;

[0016] Figure 2 A schematic diagram of the control structure of a wide-band-high-thrust vibration test system according to the present invention;

[0017] Figure 3 It is a schematic diagram of circuit impedance equivalence of an electrodynamic exciter used in a wide-band-large-thrust vibration test system of the present invention;

[0018] The corresponding figures are as follows:

[0019] 1-working table, 2-accumulator, 3-servo valve, 4-upper excitation, 5-moving coil, 6-lower excitation, 7-piston rod, 8-hydraulic cylinder, 9-electric exciter supporting structure. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0024] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] Vibration test system for wide frequency band and high force, including:

[0028] Work surface; the sample to be tested by vibration is fixedly mounted on the work surface;

[0029] Electro-hydraulic exciter; the electro-hydraulic exciter is used to apply thrust to the work surface within the first frequency range, the electro-hydraulic exciter is fixed on the fixed surface, and the first frequency range is 0.1Hz~200Hz;

[0030] Electric vibration exciter; the electric vibration exciter is used to apply thrust to the work surface in the second frequency range, the first frequency range is different from the second frequency range, the moving coil frame of the electric vibration exciter is fixedly connected to the moving part of the hydraulic vibration device, and the second frequency range is 200Hz~2000Hz;

[0031] Industrial computer; the industrial computer is used to control the working state of the electro-hydraulic vibrator and the electric vibrator, and the control signal output terminal of the industrial computer is connected to the control signal input terminal of the electro-hydraulic vibrator and the electric vibrator respectively;

[0032] The first acquisition component is used to collect the acceleration, displacement and thrust of the power output end of the electro-hydraulic exciter within the first frequency range, and the first acquisition component includes a second acceleration sensor, a displacement sensor and a force sensor;

[0033] The second acquisition component is used to collect the acceleration of the power output end of the electric vibrator within the second frequency range. The data signal output end of the first acquisition component and the data signal output end of the second acquisition component are both connected to the data signal input end of the industrial computer. The second acquisition component is the first acceleration sensor.

[0034] The electro-hydraulic exciter is composed of an actuator, a servo valve, a hydraulic source, and a control device. The actuator is composed of a cylinder, a piston rod, a hydrostatic bearing, a work surface, and a displacement sensor. The hydraulic source is composed of a drive motor, a hydraulic pump, a relief valve, a filter, an accumulator, and related valves. The control device is composed of a signal source, a servo amplifier, a modem, an adder, a jitter signal generator, etc. In addition, there are oil source control and measuring instruments.

[0035] The electric vibrator is composed of a table, a signal generator, a power amplifier, a DC excitation power supply, a cooling system, etc. The table part is composed of a motion system, a magnetic circuit system, an elastic support system, a guide mechanism, and a cooling device. It adopts a dual magnetic circuit system, which reduces the volume of the table and the diameter of the moving coil, thereby increasing the working frequency of the moving coil, making the magnetic flux distribution more uniform, improving the waveform, and reducing the magnetic leakage of the work surface; the electric vibrator adopts an induction coil, which increases safety and reliability; the coil winding is optimized to reduce the heating of the moving coil, and water cooling is adopted to improve the heat dissipation efficiency of the moving coil and the excitation; the driving force of the electric vibrator is determined by the alternating force on the moving coil in the constant magnetic field, and the constant magnetic field is determined by the constant DC current passed through the excitation coil.

[0036] For wide-band and high-thrust vibration test systems Figure 1 As shown, the electro-hydraulic exciter is fixed on the foundation, and the dynamic coil frame of the electric exciter is directly connected to the actuator of the electro-hydraulic exciter, eliminating the original airbag structure at the bottom and realizing reliable connection of the system. In this connection method, the low-frequency part of the electro-hydraulic exciter is similar to the common hydraulic exciter, mainly considering that the foundation has a great influence on the performance of the hydraulic exciter. In the high-frequency part, the motion system of the electric exciter and the working table of the electro-hydraulic exciter are fixedly connected to each other to ensure the reliable transmission of the exciting force. Figure 1 Some key structures of the vibration test system are listed, such as the piston rod and hydraulic cylinder of the electro-hydraulic exciter; the upper excitation, dynamic coil, and lower excitation of the electric exciter. The structure is consistent with that of a separate electric excitation system or an electro-hydraulic excitation system, except that the airbag support structure below the dynamic coil is eliminated at the connection between the two, and the bottom of the dynamic coil frame is directly connected to the piston rod.

[0037] The vibration test system also includes a signal decomposer. The digital signal decomposer is used to divide the control signal into a high-frequency signal and a low-frequency signal. The high-frequency signal is located in the second frequency range, and the low-frequency signal is located in the first frequency range. When divided into a high-frequency signal, the control signal is transmitted to the electric vibration exciter through the power amplifier, the electric vibration exciter is in a working state, and a thrust is applied to the work surface, and the electro-hydraulic vibration exciter is in a closed state; when divided into a low-frequency signal, the control signal is transmitted to the servo valve, the electro-hydraulic vibration exciter is controlled to be in a working state, and a thrust is applied to the work surface, and the electric vibration exciter is in a closed state.

[0038] The digital signal required by the vibration test system is generated by an industrial computer. The signal is divided into high-frequency and low-frequency signals by a signal decomposer with 200Hz as the boundary. When the signal is low-frequency, the switch of the servo valve is controlled to control the electro-hydraulic exciter; when the signal is high-frequency, the output of the power amplifier is controlled to control the movement of the electric exciter; at the same time, closed-loop control is used to improve the control accuracy, and an optimization algorithm is used at the boundary between low and high frequencies to make the control waveform continuous. The combination of the electro-hydraulic exciter and the electric exciter can meet the needs of wide-band and high-thrust excitation tests, so that the excitation test needs are not limited by the capacity of the vibration test system, and it has the characteristics of high economy, high operational reliability and superior performance.

[0039] The overall control framework of the vibration test system is as follows: Figure 2As shown, the control signal in the industrial computer is converted into a digital signal through analog / digital conversion. The digital signal is divided into high-frequency signal and low-frequency signal according to the frequency through the signal decomposer, where the frequency separation boundary of the signal decomposer is based on 200Hz. The frequency range of the low-frequency signal is 0.1~200Hz, and the frequency range of the high-frequency signal is 200Hz~2000Hz. The electric vibrator or electro-hydraulic vibrator is controlled within the respective frequency bands to obtain the required output response. The actual response can be measured by the sensor on the workbench, and the data is converted into a digital signal through an analog-to-digital converter. The digital signal is input into the industrial computer and compared with the standard output spectrum to obtain the updated control signal.

[0040] The impedance characteristics of the dynamic coil of the electric exciter determine its vibration output response. The vibration test system also includes two short-circuit rings, which are installed on the inner and outer sides of the dynamic coil frame respectively. The installation of two short-circuit rings on both sides of the dynamic coil increases the driving force and expands the frequency range, and can reduce the equivalent impedance dominated by inductance in certain areas of medium and high frequencies. Figure 3 As shown, R1 and L1 are the resistance and inductance of the moving coil; R2 and L2 are the resistance and inductance of the inner short-circuit ring; R3 and L3 are the resistance and inductance of the outer short-circuit ring; M1 and M3 are the mutual inductance between the driving coil and the inner and outer short-circuit rings respectively; M2 is the mutual inductance between the two short-circuit rings. By solving the relevant equations, the current load required by the moving coil at different frequencies can be obtained.

[0041] The current in the moving coil is determined by the output of the power amplifier. Assuming the current i is a sinusoidal signal, that is, , the driving force can be expressed as follows: ; Where: B is the magnetic induction intensity in the air gap around the moving coil (Wb / m 2 ), L is the effective length of the moving coil winding (m), I is the current in the moving coil (A). Generally speaking, the magnetic induction intensity and the length of the moving coil winding are constants, so the driving force F mainly depends on the change of the current in the moving coil.

[0042] The impedance of the motion system of the electric exciter also has a great influence on the driving force, and matching with the power amplifier is also crucial. Generally speaking, the impedance of the drive coil input end is composed of two parts. The first is the circuit impedance, that is, the impedance in the short-circuit loop, which is mainly determined by its own circuit parameters, and the second is the motion impedance, that is, the impedance shown by the motion system generating back electromotive force in the moving coil.

[0043] Taking the double short-circuit ring structure as an example, according to the circuit principle, the equation of its equivalent circuit structure can be obtained:

[0044] ;

[0045] Where: Ri is the resistance of the three circuits (i=1,2,3); are the currents of the three circuits (i=1,2,3); (i=1,2,3); is the current of the three circuits (i=1,2,3); w is the frequency; is the mutual inductance between the three loops (i=1,2,3); is the inductance of the three loops (i=1,2,3);

[0046] According to the above equation, the input impedance of the circuit can be solved as:

[0047] ;

[0048] Where: Z 11 is the self-impedance of the primary circuit (moving coil); Z 1f The equivalent impedance added by the secondary circuit (double short-circuit ring) in the primary circuit; R 1f X is the resistance introduced by the secondary (double short-circuit ring) to the primary (moving coil); 1f It is the reactance introduced by the secondary (double short-circuit ring) to the primary (moving coil).

[0049] The introduction resistance R of the secondary circuit 1f and introduce reactance X 1f They are:

[0050] ; ;

[0051] At high frequencies: ;

[0052] The input impedance is:

[0053] ;

[0054] The motion system and suspension device can be regarded as a single-degree-of-freedom vibration system. The equation of the system can be obtained from the dynamic coil current and driving force, which is expressed as:

[0055] ;

[0056] Where: M e is the effective mass of the moving parts; K s is the dynamic stiffness of the suspension; is the viscous damping coefficient of the system structure and material; x is the displacement;

[0057] Through Laplace transformation and the law of electromagnetic induction, the electromotive force generated at both ends of the moving coil can be obtained:

[0058] ;

[0059] Where: B is the magnetic induction intensity; l is the effective length of the moving coil; is the moving coil speed;

[0060] Then the complex form of the motion impedance of the moving coil is obtained as:

[0061] ;

[0062] The total impedance of the moving coil is the sum of the circuit impedance and the motion impedance of the moving coil. The voltage value required for the moving coil to output the corresponding thrust can be obtained by calculating the impedance. The thrust of the electro-hydraulic exciter is relatively large, and the upper limit of the thrust of the vibration test system depends on the output thrust of the electric exciter. Therefore, only the equation related to the impedance of the electric exciter is explained.

[0063] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A wide-band and high-thrust vibration test system, characterized in that: include: Work surface; the sample to be tested by vibration is fixedly mounted on the work surface; Electro-hydraulic exciter; The electro-hydraulic vibrator is used to apply thrust to the work surface within the first frequency range, and the electro-hydraulic vibrator is fixed to the fixed surface; The electric vibrator is used to apply thrust to the work surface in the second frequency range, the first frequency range is different from the second frequency range, and the moving coil frame of the electric vibrator is fixedly connected to the moving part of the hydraulic excitation device; Industrial computer; the industrial computer is used to control the working state of the electro-hydraulic vibrator and the electric vibrator, and the control signal output terminal of the industrial computer is connected to the control signal input terminal of the electro-hydraulic vibrator and the electric vibrator respectively; The first acquisition component is used to collect the acceleration, displacement and thrust of the power output end of the electro-hydraulic exciter in the first frequency range; The second collection piece; The second acquisition component is used to collect the acceleration of the power output end of the electric vibrator within the second frequency range. The data signal output end of the first acquisition component and the data signal output end of the second acquisition component are both connected to the data signal input end of the industrial computer.

2. The wide-band and high-thrust vibration test system according to claim 1, characterized in that: The vibration test system also includes a signal decomposer, which is used to divide the control signal into a high-frequency signal and a low-frequency signal. The high-frequency signal is located in the second frequency range, and the low-frequency signal is located in the first frequency range. When divided into a high-frequency signal, the control signal is transmitted to the electric vibration exciter through the power amplifier, the electric vibration exciter is in a working state, and a thrust is applied to the work surface, and the electro-hydraulic vibration exciter is in a closed state; when divided into a low-frequency signal, the control signal is transmitted to the servo valve, the electro-hydraulic vibration exciter is controlled to be in a working state, and a thrust is applied to the work surface, and the electric vibration exciter is in a closed state.

3. The wide-band-high-thrust vibration test system according to claim 1, characterized in that: The vibration test system also includes two short-circuit rings, which are respectively installed on the inner side and the outer side of the dynamic coil frame.

4. The wide-band and high-thrust vibration test system according to claim 1, characterized in that: The first acquisition component includes a second acceleration sensor, a displacement sensor and a force sensor.

5. The wide-band-high-thrust vibration test system according to claim 1, characterized in that: The second acquisition component is a first acceleration sensor.

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