Vibration analyzer and vibration analysis method

Abstract

To estimate with good accuracy a load applied to an object of vibration analysis when the load cannot be measured directly.SOLUTION: Provided is a vibration analyzer for a structure in which structural bodies are connected by fastening parts, the vibration analyzer comprising: an exciting force application unit for generating an exciting force or an exciting moment (exciting force or the like); a force measurement unit for measuring the exciting force or the like; a fastening part load estimation unit for estimating the center load of a fastening part to which the exciting force or the like is applied; and a structure analysis unit for analyzing the vibration characteristic of the structure. The fastening part load estimation unit conducts vibration analysis of the exciting force application unit and the force measurement unit by using measurement results of the force measurement unit in a first measurement state where edges of the force measurement unit are secured to a stool and a first vibration measurement unit is installed to the exciting force application unit, and of the first vibration measurement unit, and obtains a response magnification of the center load of the fastening part with respect to the exciting force or the like. The structure analysis unit analyzes measurement results of the force measurement unit in a second measurement state where edges of the force measurement unit are secured to the fastening part and a second vibration measurement unit is installed to the structure, and of the second vibration measurement unit and the response magnification.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vibration analysis apparatus and a vibration analysis method.

Background Art

[0002] There is known a technique for grasping the vibration characteristics of an object to be vibration-analyzed vibrated by a vibration exciter by calculating a transfer function. As such a technique, for example, Patent Document 1 is known.

[0003] In Patent Document 1, paragraphs 0018 and FIG. 2 describe that "a flange portion 18 protruding radially outward is formed on the upper side of the bearing housing 17, and a measuring device 20 for measuring the characteristics of the tire T is provided between the flange portion 18 and the upper portion of the spindle base 16." Paragraph 0020 describes that "a vibration exciter 50 for forcibly vibrating the spindle shaft 3 by varying the position of the spindle shaft 3 with respect to the magnetic bearing 23 is provided on the upper side of the spindle shaft 3, that is, on the end side of the spindle shaft 3 to which the rim is attached."

[0004] In Patent Document 1, paragraph 0026 states that "an output signal S1 of a predetermined frequency is generated by the signal transmitter 42, and the spindle shaft 3 is vibrated at a predetermined frequency. Then, the radial load of the tire T in a state where the spindle shaft 3 is vibrating in the radial direction is measured by the measuring device 20. The measured value measured by the measuring device 20 in a state where the spindle shaft 3 is vibrating is used as the response value. Further, the excitation force applied to the spindle shaft 3 is used as the reference value." Further, paragraph 0028 states that "as shown in FIG. 5, with the vibration frequency when the spindle shaft 3 is vibrated taken as the horizontal axis and the value obtained by dividing the radial load (response value) for each vibration frequency by the reference value (amplitude of the transfer function) taken as the vertical axis, each data measured by the measuring device 20 is plotted to create a frequency response curve (transfer function). At the same time, using the same data, as shown in FIG. 6, a curve of the time delay of the radial load measured by the measuring device 20 in the frequency response may be created. In this case, the vertical axis of the figure represents the value indicating the time delay (phase of the transfer function). "

Prior Art Document

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When the load applied to the object of vibration analysis (the tire in Patent Document 1) can be directly measured as in Patent Document 1, that is, when the measured value of the load measuring device can be regarded as the load, the transfer function can be accurately calculated from the measured value. On the other hand, when the load applied to the object of vibration analysis cannot be directly measured, that is, when there is a deviation between the measured value of the load measuring device and the actual load applied to the object, the accuracy of the transfer function deteriorates when the measured value of the load measuring device is regarded as the load applied to the object and the transfer function is calculated.

[0007] Therefore, an object of the present invention is to provide a vibration analysis apparatus and a vibration analysis method that can accurately estimate even when the load applied to the object of vibration analysis cannot be directly measured.

Means for Solving the Problems

[0008] In order to solve the above problems, a vibration analysis apparatus of the present invention is, for example, a vibration analysis apparatus that performs vibration analysis of a structure in which structures are coupled to each other by fastening portions, and includes a vibration force application unit that generates a vibration force or a vibration moment that is a moment of the vibration force, a force measurement unit that is installed in the vibration force application unit and measures the vibration force or the vibration moment, a fastening portion load estimation unit that estimates a load applied to the center of the fastening portion when the vibration force or the vibration moment is applied to the fastening portion by the vibration force application unit, and a structure analysis unit that analyzes vibration characteristics of the structure. The fastening portion load estimation unit performs vibration analysis related to the vibration force application unit and the force measurement unit using measurement results of the force measurement unit and the first vibration measurement unit in a first measurement state in which an end of the force measurement unit is fixed to a surface plate and the first vibration measurement unit that measures vibration of the vibration force application unit is installed in the vibration force application unit, obtains a response magnification of the load applied to the center of the fastening portion with respect to the vibration force or the vibration moment generated by the vibration force application unit, and the structure analysis unit analyzes the vibration characteristics of the structure using the measurement results of the force measurement unit and the second vibration measurement unit and the response magnification in a second measurement state in which an end of the force measurement unit is fixed to the fastening portion and the second vibration measurement unit that measures vibration of the structure is installed in the structure.

[0009] Further, the vibration analysis method of the present invention is, for example, a vibration analysis method for performing vibration analysis of a structure in which structures are coupled to each other by fastening portions, and in a first measurement state where the end of a force measurement unit installed in a vibration force application unit is fixed to a surface plate, a first vibration force application step of generating a vibration force or a vibration moment that is the moment of the vibration force by the vibration force application unit; a first force measurement step of measuring the vibration force or the vibration moment generated in the first vibration force application step; a first vibration measurement step of measuring the vibration of the vibration force application unit; a vibration analysis regarding the vibration force application unit and the force measurement unit is performed using the measurement results in the first force measurement step and the first vibration measurement step, and a fastening portion load estimation step of obtaining a response magnification of the load applied to the center of the fastening portion with respect to the vibration force or the vibration moment when the vibration force or the vibration moment is applied to the fastening portion; in a second measurement state where the end of the force measurement unit is fixed to the fastening portion, a second vibration force application step of generating the vibration force or the vibration moment by the vibration force application unit; a second force measurement step of measuring the vibration force or the vibration moment generated in the second vibration force application step; a second vibration measurement step of measuring the vibration of the structure; and a structure analysis step of analyzing the vibration characteristics of the structure using the measurement results of the second force measurement step and the second vibration measurement step and the response magnification.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a vibration analysis device and a vibration analysis method that can accurately estimate even when the load applied to the object of vibration analysis cannot be directly measured. Other problems and novel features will become apparent from the description of this specification and the attached drawings.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below. This embodiment is merely an example, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. Also, in each of the drawings used in the following description, the same reference numerals are assigned to common devices and equipment, and the description of devices, equipment, and operations already described may be omitted.

[0013] FIG. 1 is a diagram showing an example of a vibration analysis device 10 in a state where the end of the force measurement unit 12 is fixed to the surface plate 20. The vibration analysis device 10 mainly includes a vibration force application unit 11, a force measurement unit 12, a vibration measurement unit, and an arithmetic processing device 14. The vibration force generated by the vibration force application unit 11 is applied to the structure as a load by bringing the end of the force measurement unit 12 into contact with the structure. The vibration force generated by the vibration force application unit 11 involves multi-degree-of-freedom vibration, and it is difficult to directly measure the load applied to the structure. Therefore, the vibration analysis device 10 has a function of measuring the force measured by the force measurement unit 12 and the vibration measured by the vibration measurement unit arranged in the measurement system, and estimating the load applied to the structure. In the example of FIG. 1, as the vibration measurement unit, a first vibration measurement unit 13 is provided in the vibration force application unit 11, and as a functional unit for estimating the load applied to the structure, a fastening part load estimation unit 14A is provided.

[0014] The arithmetic processing unit 14 is a computer including, for example, a processor and a memory. The processor functions as a functional unit that provides a predetermined function by executing processing according to a program loaded in the memory. In the case of FIG. 1, the arithmetic processing unit 14 functions as a fastening part load estimation unit 14A by executing a fastening part load estimation program.

[0015] In the following description, when explaining the processing by a program, the program, functional units, etc. may be mainly explained. However, the main body of the hardware for them is a processor or an arithmetic processing unit (computer) configured to include the processor or the like. The arithmetic processing unit executes processing according to a program read onto the memory while appropriately using resources such as a memory and a communication interface by the processor. In addition to a CPU (Central Processing Unit), a GPU (Graphical Processing Unit) or the like may be used for the processor. Also, the processing for realizing a function is not limited to software program processing and can also be implemented by a dedicated circuit. For the dedicated circuit, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), etc. are applicable.

[0016] In FIG. 1, since the end of the force measurement unit 12 is fixed to the surface plate 20, the vibration force application unit 11 is fixed to the surface plate 20, and the first vibration measurement unit 13 is installed in the vibration force application unit 11. This state is called the first measurement state. The first measurement state is a state when the vibration analysis device 10 performs measurement for estimating what kind of load is actually applied to the structure by the vibration force generated by the vibration force application unit 11. For this reason, the end of the force measurement unit 12 is in contact with the surface plate 20 instead of the structure to be analyzed.

[0017] The vibration force applying unit 11 includes a vibrator 11A and a moment generating body 11B. The vibrator 11A generates a vibration force. The moment generating body 11B converts the vibration force applied by the vibration force applying unit 11 into a vibration moment (moment of the vibration force) based on the coordinate deviation between the force point to which the vibration force from the vibrator 11A is applied and the action point to which the vibration force or vibration moment from the moment generating body 11B is applied to the structure (surface plate 20 in the example of FIG. 1). With such a configuration, the simple vibration generated by the vibrator 11A can be converted into a complex vibration with multiple degrees of freedom.

[0018] The moment generating body 11B can be configured as a columnar member, and fixing parts such as screw holes for connecting the vibrator 11A are provided on its side surface, and the vibrator 11A is fixed with screws at the fixing parts. The fixing parts are provided on different surfaces of the moment generating body 11B, and by varying the side surfaces of the moment generating body 11B to which the vibrator 11A is fixed, the vibration force from the vibrator 11A can act on the moment generating body 11B at six or more points. FIG. 1 shows an example in which the moment generating body 11B is a columnar member extending in the X-axis direction. In this case, assuming that the vibrator 11A generates a vibration that displaces in a uniaxial direction, when a vibration force in the X-axis direction is applied to the moment generating body 11B, the vibration force in the X-axis direction acts directly on the action point, while when a vibration force other than the X-axis direction is applied, it is converted into a vibration moment and acts on the action point. In the example of FIG. 1, since the vibration force from the vibrator 11A is applied in the Z-axis direction, the converted vibration moment is applied to the action point. Note that the moment generating body 11B preferably has high rigidity without a resonance frequency in the frequency band of the vibration force, but several resonance frequencies may exist.

[0019] The force measurement unit 12 includes a force sensor 12A and an adapter 12B. The force sensor 12A measures the vibration force and vibration moment generated by the vibration force application unit 11. The force sensor 12A includes, for example, a strain body and a strain gauge. When a vibration force or vibration moment is applied, the strain body deforms, causing the strain gauge to be strained. The relationship between the amount of strain of the strain gauge and the forces in each direction is calibrated and obtained in advance. The force sensor 12A includes an arithmetic circuit that performs arithmetic processing, and based on the relational expression, outputs the forces of each component from the measured amount of strain of the strain gauge. Note that the force sensor 12A outputs the amount of strain of the strain gauge, and the arithmetic processing for obtaining the force from the amount of strain may be performed by a device external to the force sensor 12A, for example, the fastening part load estimation unit 14A. Note that the configuration of the force sensor 12A is not limited to the configuration using a strain gauge. Any device that can measure not only the vibration force that causes displacement in the linear direction but also the vibration moment that causes displacement in the rotational direction may be used. The adapter 12B is for fixing the end to an object, for example, the fastening part 22 (see FIG. 3) of the surface plate 20 or the structure 21 described later. When the force measurement unit 12 can be directly fixed to the surface plate 20 or the fastening part 22, the force measurement unit 12 can omit the adapter 12B.

[0020] The first vibration measurement unit 13 measures the vibration of the vibration force application unit 11. For the first vibration measurement unit 13, a six-axis sensor (for example, a MEMS (Micro Electro Mechanical Systems) type sensor) that can measure the acceleration in the X-axis, Y-axis, and Z-axis (hereinafter referred to as "three axes") directions and the angular velocity around the three axes, or two sensors that can measure the vibration of the three axes and are respectively installed on two orthogonal surfaces can be used. In the latter case, the angular velocity around the three axes is estimated from the vibrations measured by each of the two sensors.

[0021] The fastening part load estimation unit 14A uses the measurement results of the force measurement unit 12 and the first vibration measurement unit 13 in the first measurement state to perform vibration analysis on the vibration force application unit 11 and the force measurement unit 12, and estimates the load applied to the center 22a of the fastening part when a vibration force or vibration moment is applied to the fastening part 22 shown in FIG. 3 described later.

[0022] FIG. 2A is an example of a flowchart of the load estimation process by the vibration analysis device 10.

[0023] In step S101, in the first measurement state, the excitation force application unit 11 generates an excitation force or an excitation moment, and the force measurement unit 12 and the first vibration measurement unit 13 perform measurements. At this time, the excitation force or the excitation moment is generated by changing the fixed portion of the moment generating body 11B to which the vibrator 11A is connected, and measurements are performed for each case. In the first measurement state, since the end of the force measurement unit 12 is fixed to the surface plate 20, it is in a non-vibrating state. Therefore, it is desirable that the surface plate 20 has high rigidity so as not to affect the vibration characteristics of the force measurement unit 12 and the first vibration measurement unit 13.

[0024] In step S102, the fastening portion load estimation unit 14A performs FFT processing on the measurement results of the force measurement unit 12 and the first vibration measurement unit 13 in the first measurement state, that is, the excitation force and the excitation moment measured by the force measurement unit 12 in the first measurement state, and the acceleration measured by the first vibration measurement unit 13 in the first measurement state, to calculate the accelerance. For the FFT processing and the method of deriving the accelerance, generally used methods are utilized. Then, from the calculated accelerance, the natural modes of the excitation force application unit 11 and the force measurement unit 12 and the modal damping ratio of each natural mode are calculated by curve fitting processing. The curve fitting processing utilizes generally used methods.

[0025] In step S103, the fastening portion load estimation unit 14A performs a vibration analysis simulation by setting the calculated modal damping ratio for the model representing the excitation force application unit 11 and the force measurement unit 12 in the first measurement state. Thereby, the load applied to the end of the force measurement unit 12 is calculated.

[0026] In step S104, the fastening part load estimation unit 14A calculates the response magnification of the load applied to the end of the force measurement unit 12 with respect to the measurement result of the force measurement unit 12 as the response magnification of the load applied to the center 22a of the fastening part 22 (see FIG. 3) with respect to the measurement result of the force measurement unit 12. Here, the response magnification of the load applied to the end of the force measurement unit 12 with respect to the measurement result of the force measurement unit 12 is, for each frequency, the load applied to the end of the force measurement unit 12 divided by the measurement result (excitation force or excitation moment) of the force measurement unit 12, and is complex number data having an amplitude (magnification) and a phase. An example of the response magnification table obtained in step S104 is shown in FIG. 2B. For the excitation forces F and excitation moments F M in different directions, the magnification and phase (a, θ) of the response magnification are registered for each frequency f. The response magnification table is registered in the storage unit of the arithmetic processing unit.

[0027] By multiplying the thus calculated response magnification by the measurement result of the force measurement unit 12, it becomes possible to obtain the load applied to the center 22a of the fastening part 22 (see FIG. 3).

[0028] FIG. 3 is a diagram showing an example of the vibration analysis device 10 in a state where the force measurement unit 12 is fixed by the fastening part 22 of the structure 21. The structure 21 is an object of vibration analysis and has a structure in which the structure body 25A and the structure body 25B are joined by the fastening part 22. In the vibration analysis device 10 shown in FIG. 3, since the end of the force measurement unit 12 is fixed to the fastening part 22, the excitation force application unit 11 is fixed to the structure 21, and the second vibration measurement unit 15 is installed on the structure body 25A of the structure 21. This state is called the second measurement state. Note that the fastening part 22 refers to a part that fastens the structure bodies 25 together with bolts or the like. Also, the center 22a of the fastening part 22 is on the central axis of the bolt and on the boundary plane between the structure bodies 25.

[0029] In the second measurement state, in the vibration analysis device 10, as a vibration measurement unit, the second vibration measurement unit 15 is provided on the structure 21 (structure body 25A in the example of FIG. 3), and the arithmetic processing unit 14 has a structure analysis unit 14B which is a functional unit for performing vibration analysis of the structure 21.

[0030] The second vibration measurement unit 15 measures the vibration of the structure 21 caused by the application of a vibration force or a vibration moment from the vibration force application unit 11 to the fastening part 22. The same sensors as those of the first vibration measurement unit 13 can be used for the second vibration measurement unit 15. Also, although the installation position of the second vibration measurement unit 15 on the structure 25A is not limited, it is preferably installed at a position where the natural mode shape (a combination of nodes and bellies) of the structure 21 can be understood.

[0031] The structure analysis unit 14B analyzes the vibration characteristics of the structure using the measurement results of the force measurement unit 12 and the second vibration measurement unit 15 in the second measurement state. That is, the structure analysis unit 14B obtains a transfer function with the measurement result (vibration force or vibration moment) of the force measurement unit 12 in the second measurement state as the input and the measurement result of the second vibration measurement unit 15 in the second measurement state as the output, thereby analyzing the vibration characteristics of the structure 21. At this time, the structure analysis unit 14B applies a response magnification factor table to the measurement result of the force measurement unit 12 to obtain a transfer function between the load applied to the center 22a of the fastening part 22 and the vibration measured by the second vibration measurement unit 15.

[0032] Thus, according to the present embodiment, even when the load applied to the object of vibration analysis cannot be directly measured, the transfer function can be accurately calculated.

[0033] Structures such as machines often have a structure in which structures are joined by bolts or the like. When the structure has a vibration source such as a motor, it becomes possible to optimize the design by modeling how the vibration generated in one structure is transmitted to another structure joined by a fastening part. Therefore, the arithmetic processing unit 14 may have a functional unit that generates a model of the structure 21 in which the vibration characteristics of the structure are represented by using the above-described vibration analysis.

[0034] FIG. 4 is a diagram for explaining the modeling of the structure 21 shown in FIG. 3. For example, as shown in FIG. 4, the arithmetic processing unit 14 represents the model of the structure 25A by the fastening part center point P0 and the vibration measurement point P1, and the transfer function TF1 from the fastening part center point P0 to the vibration measurement point P1, and represents the model of the structure 25B by the fastening part center point P0 and the vibration measurement point P2, and the transfer function TF2 from the fastening part center point P0 to the vibration measurement point P2. The vibration measurement point P1 is the part where the second vibration measurement unit 15 is installed, and the transfer function TF1 uses the one obtained by the structure analysis unit 14B. The transfer function TF2 represents the vibration characteristics of the structure 25B obtained by similarly analyzing the structure 25B by the structure analysis unit 14B with the second vibration measurement unit 15 installed at the position of the vibration measurement point P2 of the structure 25B.

[0035] By generating such a model, the vibration characteristics of the structure 21 can be visualized. For example, when the vibration measurement point P1 of the structure 25A is excited, the vibration transmitted to the vibration measurement point P2 of the structure 25B via the fastening part 22 can be grasped. Note that the model generation may be performed by a device different from the arithmetic processing unit 14.

Description of Signs

[0036] 10: Vibration analysis device 11: Excitation force application part 11A: Vibration exciter 11B: Moment generator 12: Force measurement part 12A: Force sensor 12B: Adapter 13: First vibration measurement unit 14: Arithmetic processing unit 14A: Fastening part load estimation unit 14B: Structure analysis unit 15: Second vibration measurement unit 20: Surface plate 21: Structure 22: Fastening part 22a: Center of the fastening part 25: Structure

Claims

1. A vibration analysis device for performing vibration analysis of a structure in which structures are coupled to each other by fastening parts, comprising: a vibration force application unit that generates a vibration force or a vibration moment that is a moment of the vibration force; a force measurement unit that is installed in the vibration force application unit and measures the vibration force or the vibration moment; a fastening part load estimation unit that estimates a load applied to the center of the fastening part when the vibration force or the vibration moment is applied to the fastening part by the vibration force application unit; a structure analysis unit that analyzes the vibration characteristics of the structure, wherein the fastening part load estimation unit performs vibration analysis regarding the vibration force application unit and the force measurement unit by using measurement results of the force measurement unit and a first vibration measurement unit in a first measurement state in which an end of the force measurement unit is fixed to a surface plate and the first vibration measurement unit that measures vibration of the vibration force application unit is installed in the vibration force application unit, obtains a response magnification of the load applied to the center of the fastening part with respect to the vibration force or the vibration moment generated by the vibration force application unit, and the structure analysis unit analyzes the vibration characteristics of the structure by using the measurement results of the force measurement unit and a second vibration measurement unit and the response magnification in a second measurement state in which an end of the force measurement unit is fixed to the fastening part and the second vibration measurement unit that measures vibration of the structure is installed in the structure. A vibration analysis device characterized by the above.

2. The vibration analysis device according to claim 1, wherein the fastening part load estimation unit calculates a mode damping ratio of the vibration force application unit and the force measurement unit based on the measurement results of the force measurement unit and the first vibration measurement unit in the first measurement state, sets the mode damping ratio for a model representing the vibration force application unit and the force measurement unit in the first measurement state, and performs simulation of the vibration analysis to calculate a load applied to an end of the force measurement unit in the first measurement state, and calculates a response magnification of the load applied to the end of the force measurement unit with respect to the measurement result of the force measurement unit as a response magnification of the load applied to the center of the fastening part with respect to the vibration force or the vibration moment generated by the vibration force application unit. A vibration analysis device characterized by the above.

3. A vibration analysis method for performing vibration analysis of a structure in which structures are coupled to each other by fastening parts, comprising: In a first measurement state where an end of a force measurement unit installed in a vibration force application unit is fixed to a surface plate, a first vibration force application step of generating a vibration force or a vibration moment that is a moment of the vibration force by the vibration force application unit; A first force measurement step of measuring the vibration force or the vibration moment generated in the first vibration force application step; A first vibration measurement step of measuring the vibration of the vibration force application unit; Using the measurement results in the first force measurement step and the first vibration measurement step, performing a vibration analysis on the vibration force application unit and the force measurement unit, and obtaining a response magnification of the load applied to the center of the fastening part with respect to the vibration force or the vibration moment when the vibration force or the vibration moment is applied to the fastening part. A fastening part load estimation step; In a second measurement state where an end of the force measurement unit is fixed to the fastening part, a second vibration force application step of generating the vibration force or the vibration moment by the vibration force application unit; A second force measurement step of measuring the vibration force or the vibration moment generated in the second vibration force application step; A second vibration measurement step of measuring the vibration of the structure; A structure analysis step of analyzing the vibration characteristics of the structure using the measurement results of the second force measurement step and the second vibration measurement step and the response magnification. A vibration analysis method characterized by the above.

4. The vibration analysis method according to claim 3, In the fastening part load estimation step, based on the measurement results of the first force measurement step and the first vibration measurement step, calculate the mode damping ratio of the vibration force application unit and the force measurement unit, and set the mode damping ratio for the model representing the vibration force application unit and the force measurement unit in the first measurement state to perform the simulation of the vibration analysis. Calculate the load applied to the end of the force measurement unit, and calculate the response magnification of the load applied to the end of the force measurement unit with respect to the measurement result of the first force measurement step as the response magnification of the load applied to the center of the fastening part with respect to the vibration force or the vibration moment generated by the vibration force application unit. A vibration analysis method characterized by the above.

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