JP2022098994A - Excitation force specifying system and excitation force specifying method - Google Patents

Abstract

To provide an excitation force specifying system and an excitation force specifying method with which, even when a rotary apparatus operates with low revolution speed, it is possible to specify the force generated in the rotary apparatus with good accuracy.SOLUTION: With the excitation force specifying system, a transfer function acquisition unit acquires a transfer function that indicates a relationship between an excitation force that serves as input and the strain response of each individual strain gauge, on the basis of an output result from a force sensor and an output result from each individual strain gauge when an excitation device gives an excitation force. Thereafter, an excitation force specifying unit specifies the excitation force generated in the rotary apparatus in operation, on the basis of the output result from each individual strain gauge when the rotary apparatus operates and the transfer function acquired by the transfer function acquisition unit.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an exciting force specifying system and an exciting force specifying method.

Conventionally, it is known to obtain a transfer function of a structure based on a vibration force applied to a structure by a vibration exciter and a response of the structure to which the vibration force is applied. For example, in the sinusoidal sweep vibration method disclosed in Patent Document 1, a load cell and an accelerometer are provided in the structure. The load cell acquires the exciting force applied to the structure by the exciter based on the supplied sinusoidal signal. The accelerometer acquires the acceleration as a response to the structure. The transfer function is obtained from these acquisition results.

Special Fair 3-079658 Gazette

It is conceivable to use a strain gauge instead of an accelerometer to obtain the transfer function of the rotating device as a structure. From the obtained transfer function, the force generated by the rotating device in operation can be specified. In this case, even when the rotating device operates at a low rotation speed, the response of the strain gauge needs to be obtained with high sensitivity, and Patent Document 1 discloses a specific configuration for achieving this. There is no.

An object of the present disclosure is to provide a vibration force specifying system and a vibration force specifying method capable of accurately specifying a force generated by a rotating device even when the rotating device operates at a low rotation speed.

The exciting force specifying system according to at least one embodiment of the present invention is
At least one strain-causing body provided between the rotating device and the foundation,
At least one strain gauge provided on each strain generator,
A vibration device for applying a vibration force to the rotating device based on the input sine sweep signal, and a vibration device.
A force sensor for measuring the vibration force applied from the vibration device, and
Based on the output result from the force sensor and the output result from each of the strain gauges when the vibration device applies the vibration force, the vibration force to be input and each of the strain gauges. A transfer function acquisition unit for acquiring a transfer function showing the relationship with the strain response of
Based on the output result from each strain gauge when the rotating device operates and the transfer function acquired by the transfer function acquisition unit, an addition for specifying the force generated by the rotating device during operation. It is equipped with a vibration force identification unit.

The method for specifying the exciting force according to at least one embodiment of the present invention is
It is a method of specifying the exciting force by the exciting force specifying system.
Vibration to the rotating device based on at least one strain-causing body provided between the rotating device and the foundation, at least one strain gauge provided on each of the strain-causing bodies, and an input sine sweep signal. The output result from the force sensor of the vibration force specifying system including the vibration device for applying the force and the force sensor for measuring the vibration force applied from the vibration device, and the said. A transmission function showing the relationship between the input vibration force and the strain response of each strain gauge based on the output result from each strain gauge when the vibration device applies the vibration force. And the transfer function acquisition process for acquiring
Based on the output result from each strain gauge when the rotating device operates and the transfer function acquired in the transfer function acquisition step, an addition for specifying the force generated by the rotating device during operation. It is equipped with a vibration force identification process.

According to some embodiments, it is possible to provide a vibration force specifying system and a vibration force specifying method that can accurately specify the force generated by the rotating device even when the rotating device operates at a low rotation speed.

It is a front view of the excitation force specifying system which concerns on one Embodiment. It is a top view of the excitation force specifying system which concerns on one Embodiment. It is a perspective view which shows the action point which the exciting force is applied in the rotating apparatus which concerns on one Embodiment. It is a figure which shows the strain response from the strain gauge which concerns on one Embodiment. It is a figure which shows the transfer function acquired from the transfer function acquisition part which concerns on one Embodiment. It is a figure which shows the strain response spectrum at the time of operation of the rotating apparatus which concerns on one Embodiment. It is a figure which shows the result of having specified the force generated during the operation of the rotating apparatus which concerns on one Embodiment. It is a block diagram which shows the function of the excitation force specifying system which concerns on one Embodiment. It is a process drawing which shows the excitation force specifying method which concerns on one Embodiment.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, and are merely explanatory examples.
For example, expressions that represent relative or absolute arrangements such as "in one direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a tolerance or a state of relative displacement at an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, an expression representing a shape such as a square shape or a cylindrical shape not only represents a shape such as a square shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or a chamfering within a range where the same effect can be obtained. It shall also represent the shape including the part and the like.
On the other hand, the expressions "to have", "to have", "to have", "to include", or "to have" one component are not exclusive expressions that exclude the existence of other components.

FIG. 1 is a front view of the exciting force specifying system 1 according to one embodiment, and FIG. 2 is a plan view of the exciting force specifying system 1 according to one embodiment.
The exciting force specifying system 1 of one embodiment is configured to specify the force generated by the rotating device 7. The rotating device 7 of one embodiment includes a rotating shaft 7a and a housing 7b that supports the rotating shaft 7a.
The rotating device 7 of one embodiment is a compressor. As a more specific example, the rotating device 7 is a reciprocating compressor. The rotating device 7 may be, for example, a rotary compressor or the like.

In one embodiment, the exciting force specifying system 1 includes at least one strain-causing body 10 provided between the rotating device 7 and the foundation 6, and at least one strain gauge provided in each strain-causing body 10. 20, a vibration device 30 for applying a vibration force to the rotating device 7, a force sensor 35 for measuring the vibration force, the vibration force as an input, and the strain of each strain gauge 20. A transmission function acquisition unit 40 for acquiring a relationship with a response and a vibration force specifying unit 50 for specifying a force generated by a rotating device 7 in operation are provided.
In FIGS. 1 and 2, in some of the plurality of strain gauges 20 according to the embodiment, the illustration of the connection state with the transfer function acquisition unit 40 is omitted. The number of strain generators 10 and strain gauges 20 may be one each.
An example of a specific configuration of the strain-causing body 10 and the strain gauge 20 will be described later.

In one embodiment, the vibration force applied from the vibration device 30 to the rotation device 7 is based on the sign sweep signal 34 input to the vibration device 30. That is, the period of the exciting force continuously changes according to the input sine sweep signal 34. The vibrating device 30 of one embodiment generates a vibrating force by alternately switching the direction of the force applied to the rotating device 7 between one side and the other side.
Each strain gauge 20 of one embodiment is configured to detect the strain generated by the strain-causing body 10 when the excitation force is applied. When the exciting force is applied, the transfer function acquisition unit 40 acquires the transfer function based on the output result from the strain gauge 20 and the output result from the force sensor 35.
In addition, each strain gauge 20 of one embodiment is also configured to detect the strain generated by the strain-causing body 10 during the operation of the rotating device 7. The exciting force specifying unit 50 specifies the force generated by the rotating device 7 based on the output result from the strain gauge 20 and the acquired transmission function during the operation of the rotating device 7.
In one embodiment, both the vibration exciter 30 and the force sensor 35 are disconnected from the rotating device 7 when the rotating device 7 is operated.

式（２）において、ｎはひずみゲージ２０の個数を示す自然数であり、ｍは回転装置７に付与される加振力の個数（後述の作用点５の個数と一致する）を示す自然数である。
一実施形態では、伝達関数取得部４０は、ひずみゲージ２０の応答スペクトルであるε（ω）と、加振装置３０が作動するときのフォースセンサ３５の出力結果であるＦ（ω）と、式（２）とに基づき、少なくとも一つの伝達関数を取得する（このときの式（２）のωは、加振装置３０から付与される加振力の周波数となる）。
一実施形態では、取得される伝達関数の個数はｎにｍを乗じた値である。一例として、伝達関数の個数は行列としてのＨ（ω）を構成する成分の個数である。
式（１）を変形すると式（３）のようになる。式（３）のＨ_ｉｎｖ（ω）はＨ（ω）の逆行列である。
Ｆ（ω）＝Ｈ_ｉｎｖ（ω）ε（ω）・・・式（３）
加振力特定部５０は、伝達関数取得部４０により取得されたＨ（ω）と、回転装置７が動作するときのひずみゲージ２０の出力結果であるε（ω）と、式（３）とに基づき、Ｆ（ω）を特定する（このときの式（３）のωは回転装置７の回転数を示す）。特定されるＦ（ω）は、加振力が付与される作用点５（後述）で生じている力である。加振装置３０の加振位置から得られる規定の慣性テンソルＩを用いると、回転装置７の中心位置で生じる力Ｆ’は式（４）によって表される。
Ｆ’（ω）＝Ｆ（ω）Ｉ・・・式（４）
加振力特定部５０は、式（４）に基づきＦ’（ω）を特定する。
以上のＦ（ω）又はＦ’（ω）が、加振力特定部５０によって特定される回転装置７で生じる力となる。 The principle that the exciting force specifying unit 50 specifies the exciting force is as follows.
Assuming that the frequency is ω, the response spectrum of the strain gauge 20 is ε, the transfer function (response function matrix) acquired by the transfer function acquisition unit 40 is H, and the excitation force spectrum is F, the following equation (1) is established. ..
ε (ω) = H (ω) F (ω) ・ ・ ・ Equation (1)
When the components of the determinant of the equation (1) are embodied, the equation (2) is obtained.

In the formula (2), n is a natural number indicating the number of strain gauges 20, and m is a natural number indicating the number of exciting forces applied to the rotating device 7 (corresponding to the number of action points 5 described later). ..
In one embodiment, the transfer function acquisition unit 40 has an equation of ε (ω), which is the response spectrum of the strain gauge 20, and F (ω), which is the output result of the force sensor 35 when the vibration exciter 30 operates. Based on (2), at least one transfer function is acquired (at this time, ω in the equation (2) is the frequency of the exciting force applied by the exciting device 30).
In one embodiment, the number of transfer functions acquired is n multiplied by m. As an example, the number of transfer functions is the number of components constituting H (ω) as a matrix.
When the equation (1) is modified, it becomes the equation (3). H _inv (ω) in equation (3) is the inverse matrix of H (ω).
F (ω) = H _inv (ω) ε (ω) ・ ・ ・ Equation (3)
The exciting force specifying unit 50 includes H (ω) acquired by the transmission function acquisition unit 40, ε (ω) which is the output result of the strain gauge 20 when the rotating device 7 operates, and equation (3). F (ω) is specified based on (ω in the equation (3) at this time indicates the number of rotations of the rotating device 7). The specified F (ω) is the force generated at the point of action 5 (described later) to which the exciting force is applied. Using the specified moment of inertia tensor I obtained from the vibration position of the vibration device 30, the force F'generated at the center position of the rotation device 7 is expressed by the equation (4).
F'(ω) = F (ω) I ... Equation (4)
The exciting force specifying unit 50 specifies F'(ω) based on the equation (4).
The above F (ω) or F'(ω) is the force generated by the rotating device 7 specified by the exciting force specifying unit 50.

A plurality of strain generating bodies 10 according to one embodiment are provided. The shape of the strain-causing body 10 can be freely designed according to the vibration force specifying system 1. Further, the number of strain generating bodies 10 can be freely adjusted. The number of strain generating bodies 10 is 4 as an example. The number may be 1, 2, 3, or 5 or more.
Each straining element 10 according to an embodiment includes straining bodies 10a and 10b different from each other.
The strain-causing body 10a of one embodiment is fixed to the foundation 6. As an example, the strain-causing body 10a is provided at a position avoiding the housing 7b of the rotating device 7 in a plan view. For example, the strain-causing body 10a may be provided at a position displaced from the housing 7b on the outer side in the radial direction of the rotation shaft 7a. Alternatively, the strain-causing body 10a may be provided at a position displaced from the housing 7b on the outer side of the rotating device 7 in the axial direction.
The strain-causing body 10a of one embodiment extends in the vertical direction. More specifically, the strain-causing body 10a is rod-shaped. The strain-causing body 10a has an upper end portion 11a, a lower end portion 11b, and a central portion 11c. The upper end portion 11a and the lower end portion 11b have the same diameter, while the central portion 11c has a smaller diameter than the upper end portion 11a and the lower end portion 11b. In this case, the central portion 11c is more flexible than the upper end portion 11a and the lower end portion 11b. The upper end portion 11a, the lower end portion 11b, and the central portion 11c may be separate members from each other, or may be formed by a single member. Further, the strain-causing body 10a may have a columnar shape having the same outer diameter in the vertical direction, or may have a prismatic shape instead of the columnar shape.
The strain-causing body 10b of one embodiment connects the strain-causing body 10a and the rotating device 7. The strain-causing body 10b of one embodiment has a plate shape extending in the horizontal direction. In this case, the strain-causing body 10b tends to bend in the vertical direction. The strain-causing body 10b of one embodiment has one end fixed to the strain-causing body 10a and the other end to which the rotating device 7 is fixed.
In another embodiment, the strain-causing body 10 may be a single member.

The fixed structures of the foundation 6, the strain generating bodies 10a and 10b, and the rotating device 7 in one embodiment are as follows.
A male screw is formed on the lower end portion 11b of the strain-causing body 10a, and a nut (not shown) is fixed to the foundation 6. The strain generating body 10a is fixed to the foundation 6 by screwing the lower end portion 11b into the nut.
A male screw is also formed on the upper end portion 11a of the strain-causing body 10a, and a nut (not shown) is screwed. A hole formed at one end of the strain-causing body 10b is inserted into the upper end portion 11a, and the strain-causing body 10b hits the nut from above. After that, another nut is screwed into the upper end portion 11a and tightened until it is pressed against the strain generating body 10b from above. As a result, the upper end portion 11a is fixed to one end of the strain generating body 10b.
Holes (not shown) are formed in each of the other end of the strain-causing body 10b and the housing 7b of the rotating device 7. After the arrangement of the rotating device 7 is adjusted so that the positions of these holes overlap each other, bolts (not shown) are inserted into these holes. After that, the nut is screwed into the shaft portion of the bolt and tightened until it is pressed against either the strain generating body 10b or the rotating device 7. As a result, the rotating device 7 is fixed to the strain-causing body 10b.
In one embodiment, the fixed positions of the strain-causing body 10a and the strain-causing body 10b and the fixed positions of the strain-causing body 10b and the rotating device 7 may be arranged along the axial direction of the rotating device 7 or the rotating shaft. It may be arranged along the radial direction of 7a.

A plurality of strain gauges 20 according to one embodiment are provided. In one embodiment, all of these strain gauges 20 are provided outside the housing 7b in the radial direction with respect to the rotation shaft 7a of the rotation device 7 (on the arrow T side in FIG. 2). In addition, at least one strain gauge 20 may be provided at a position overlapping with the housing 7b in a plan view.
At least one strain gauge 20 according to an embodiment includes strain gauges 20a, 20b, 20c. For example, when the strain gauge 20 is provided with four strain gauges 10, four sets of strain gauges 20a, 20b, and 20c (12 in total) are provided.
In one embodiment, the strain gauges 20a and 20b are provided on the strain-causing body 10a, and the strain gauge 20c is provided on the strain-causing body 10c. More specifically, as an example, the strain gauges 20a and 20b are provided in the central portion 11c of the strain-causing body 10a. Further, the strain gauge 20c is provided between one end and the other end of the strain-causing body 10c extending in the horizontal direction.
In one embodiment, in each strain-causing body 10a, the strain gauges 20a and 20b are provided at positions offset from each other by 90 degrees (or 270 degrees) around the axis of the strain-causing body 10a. In one embodiment, the strain gauges 20a and 20b are located at the same height as each other, but may be located at different heights from each other.
In one embodiment, the strain gauges 20a and 20b and the strain gauges 20c extend in a direction intersecting each other. More specifically, as an example, the strain gauges 20a and 20b extend in the vertical direction, and the strain gauges 20c extend in the horizontal direction.
In another embodiment, the strain gauge 20c may extend at an angle with respect to the horizontal direction and the vertical direction. Even in this case, the extending direction of the strain gauge 20c intersects with the extending direction of the strain gauges 20a and 20b. Further, the extending directions of the strain gauges 20a and 20b may intersect each other.
In one embodiment, the thickness directions of the strain gauges 20a, 20b, 20c intersect each other. That is, the flexible directions of the strain gauges 20a, 20b, and 20c intersect each other. In one embodiment, the three thickness directions are orthogonal to each other.
In another embodiment, each strain generating body 10a may be provided with only one of the strain gauges 20a and 20b. Alternatively, in another embodiment, the strain gauge 20 may not include the strain gauge 20c.

In the following description, the X, Y, and Z directions that are orthogonal to each other may be used. In one embodiment, the X and Y directions are horizontal directions, and the Z direction is parallel to the vertical direction. In one embodiment, the Y direction is parallel to the axial direction of the rotating device 7.
In one embodiment, the thickness directions of the strain gauges 20a, 20b, and 20c are parallel to the X, Y, and Z directions, respectively.
When the vibrating device 30 applies a vibrating force to the rotating device 7, or when the rotating device 7 operates, a force and a moment are generated in the rotating device 7. Each of these forces and moments has a vector component in at least one of the X, Y, or Z directions. Each straining body 10 according to one embodiment is distorted by the combined action of the force and the moment, and the combined action is reflected in the output result of the strain gauge 20.

FIG. 3 shows an action point 5 in which a vibrating force is applied from the vibrating device 30 in the rotating device 7 according to the embodiment. In FIG. 3, the rotation axis 7a is illustrated by a two-dot chain line. Further, in FIG. 3, the strain-causing body 10 and the strain gauge 20 are shown in a simplified manner (the same applies to FIGS. 4 and 5).

In one embodiment, there are a plurality of action points 5 in which the exciting force is applied to the rotating device 7.
The plurality of points of action 5 of one embodiment include a plurality of points of action 5X, a plurality of points of action 5Y, and a plurality of points of action 5Z. In one embodiment, a vibrating force parallel to the X-axis is applied at each point of action 5X. Similarly, a vibration force parallel to the Y-axis direction is applied at each action point 5Y, and a vibration force parallel to the Z-axis direction is applied at each action point 5Z.
The total number of action points 5 in one embodiment is the same as the number of strain gauges 20. In one embodiment, the total number of action points 5X, 5Y, and 5Z is 12, which is the same as the total number of strain gauges 20a, 20b, and 20c.
In another embodiment, the point of action 5 may include at least one of the points of action 5X, 5Y, 5Z. Further, at the point of action 5X, a vibrating force inclined in the X direction and the Z direction or a vibrating force inclined in the X direction and the Y direction may be applied. Further, the number of action points 5 may be different from the number of strain gauges 20.
In one embodiment, the number of action points 5 is the number of vibration forces applied to the rotating device 7 by the vibration device 30. The transfer function acquisition unit 40 acquires a plurality of transfer functions for each of the plurality of action points 5 to which the exciting force is applied.

In one embodiment, the action point 5, the force sensor 35, and the vibration device 30 connection structure are as follows. A screw hole is formed in a portion of the housing 7b corresponding to each action point 5, and one end of a rod-shaped force sensor 35 is screwed into the screw hole. Further, the rod-shaped actuating portion provided in the vibration exciter 30 is screwed into the screw hole formed at the other end of the force sensor 35. As a result, at each point of action 5, the rod-shaped operating portion is coaxially fixed to the force sensor 35, and the vibration exciter 30 is connected to the rotating device 7 via the force sensor 35. In this case, since the force sensor 35 is directly connected to the housing 7b and the rotating device 7, the exciting force applied from the vibration device 30 to the rotating device 7 can be directly measured. Therefore, the exciting force is measured with high accuracy.
The number of "each point of action 5" means one or more, but the number of points of action 5 is preferably three or more, and more preferably at least one of the points of action 5X, 5Y, and 5Z, respectively. It is preferable that each of them is contained in the point of action 5.
In one embodiment, the vibration exciter 30 is supported by another member during operation.

FIG. 4 shows the strain response output from each strain gauge 20 when an exciting force is applied at each action point 5. Although detailed illustration is omitted, the strain response according to the embodiment can be represented by a graph with time as the horizontal axis and strain amount as the vertical axis.
In one embodiment, when four sets of strain gauges 20a, 20b, and 20c (12 in total) are provided, a total of 12 strain responses are applied each time a vibrating force is applied at any of a plurality of points of action 5. Is output. For example, when the number of action points 5 is 12 (4 action points 5X, 5Y, 5Z each), a total of 144 strain responses are output. At this time, the output result from the force sensor 35 is 12, which is the same as the number of action points 5. When the above formula (2) is applied to this embodiment, m is 12 because there are four points of action 5X, 5Y, and 5Z. That is, FX _-1 , FX _-2 , FX _-3 , FX _-4 , _FY-1 , ..., _FZ-4 indicating the output result of the force sensor 35 are on the right side of the equation (2). It is the matrix component of the second term. When there are 4 sets of strain gauges 20a, 20b, and 20c (12 in total), n in the equation (2) is 12. That is, ε _1-1 , ε _1-2 , ε _1-3 , ε _2-1 and ... ε _4-3 showing the output result of the strain gauge 20 are the matrix components on the left side of the equation (2). At this time, the number of transfer functions acquired based on the equation (2) is 144.

FIG. 5 shows a graph of the transfer function acquired by the transfer function acquisition unit 40 according to the embodiment. In the illustrated graph of FIG. 5, the horizontal axis shows the frequency of the exciting force, and the vertical axis shows the strain response per unit force of the strain gauge 20.
In the example of FIG. 5, graphs of transfer functions corresponding to each of the four sets of strain gauges 20a, 20b, and 20c (12 in total) are obtained for each of the four points of action 5Y. “1-a”, “1-b”, and “1-c” in FIG. 5 correspond to any of four sets of strain gauges 20a, 20b, and 20c, and the transfer acquired at each point of action 5Y. The number of functions is twelve.
Although detailed illustration is omitted, a transfer function is obtained in the same manner for each of the points of action 5X and 5Y.

FIG. 6 shows the strain response of the strain gauge 20 when the rotating device 7 operates in one embodiment. “1-a”, “1-b”, and “1-c” in FIG. 6 correspond to any of four sets of strain gauges 20a, 20b, and 20c.
In one embodiment, data in which time and strain amount are associated are acquired from each strain gauge 20, and this data is subjected to FFT processing (fast Fourier transform processing) to obtain the strain response spectrum of FIG. To be acquired. In the foremost graph in FIG. 6, as an example, it is shown that there are two resonance frequencies in which the amount of strain increases.

FIG. 7 graphically shows the force specified by the exciting force specifying unit 50 based on the output result of the strain gauge 20 when the rotating device 7 operates in one embodiment. In one embodiment, a graph is generated by extracting and plotting the operating order component of F'(ω) in equation (4). In one embodiment, a graph is shown in which a rotation primary component and a rotation secondary component are extracted in each of the X direction, the Y direction, and the Z direction. In another embodiment, a graph may be created by extracting rotation components of order 3 or higher.
Although detailed illustration is omitted, in one embodiment, the moment acting on the rotating device 7 may be specified based on the specified F'(ω). In one embodiment, the moment may be determined for each of the primary and secondary rotation components in the X, Y and Z directions. The moment may be obtained for each rotation component of the third order or higher.

FIG. 8 is a block diagram showing a function of the excitation force specifying system 1 according to the embodiment.
The vibration force specifying system 1 of one embodiment includes a control unit 70, a vibration system 80 that operates in response to a command from the control unit 70, and a measurement target system 90.

The control unit 70 of one embodiment is a device including a processor unit. The processor included in the processor unit is configured to load the read program into memory and execute the instructions contained in the loaded program. The processor is, for example, a CPU, a GPU, an MPU, a DSP, various arithmetic units other than these, or a combination thereof. The processor may be realized by integrated circuits such as PLD, ASIC, FPGA, and MCU.
The control unit 70 includes a command unit 71 that sends an operation start command to the vibration system 80, a data logger 75 that records the output results of the force sensor 35 and the strain generator 10, and a transfer function acquisition unit 40. It is provided with a vibration force specifying unit 50.

The vibration system 80 of one embodiment adds a signal generator 81 that generates a signal in response to receiving a command from the command unit 71, and a sign sweep signal 34 that amplifies the signal generated by the signal generator 81. It includes an amplifier 82 for input to the vibration device 30, a vibration device 30, and a force sensor 35. The output result of the force sensor 35 is output to the data logger 75.

The measurement target system 90 includes a rotating device 7, at least one strain-causing body 10, and a drive motor 88. The drive motor 88 of one embodiment is connected to the rotating device 7 when operating the rotating device 7. The drive motor 88 is driven by the electric power supplied from the inverter 94. The rotating device 7 that obtains the driving force from the driving motor 88 operates while changing the rotation speed. When the rotating device 7 of one embodiment is a compressor, the rotating device 7 operates with the suction port and the discharging port of the rotating device 7 opened. As a result, it is possible to suppress the pressure of the gas inside the rotating device 7 from affecting the output result of the strain gauge 20.

FIG. 9 shows a process diagram of a vibration force specifying method by the vibration force specifying system 1 according to the embodiment.
First, in the transfer function acquisition step (S11), based on the output result from the force sensor 35 and the output result from each strain gauge 20 when the vibration device 30 applies the vibration force to the rotation device 7. The transfer function acquisition unit 40 acquires the transfer function. In one embodiment, when there are a plurality of action points 5, the vibrating device 30 sequentially applies a vibrating force to each of the action points 5.
In the subsequent vibration force specifying step (S13), the rotation during operation is based on the output result from each strain gauge 20 when the rotating device 7 is operated and the transmission function acquired by the transmission function acquisition unit 40. The exciting force specifying unit 50 specifies the force generated by the device.
By the above steps, the force generated by the rotating device 7 is specified.

Hereinafter, the vibration force specifying system 1 and the method for specifying the vibration force according to some embodiments will be outlined.

(1) The exciting force specifying system 1 according to at least one embodiment of the present invention is
At least one strain-causing body 10 provided between the rotating device 7 and the foundation 6 and
At least one strain gauge 20 provided on each strain-causing body 10 and
A vibration device 30 for applying a vibration force to the rotation device 7 based on the input sign sweep signal 34, and a vibration device 30.
A force sensor 35 for measuring the vibration force applied from the vibration device 30 and a force sensor 35.
Based on the output result from the force sensor 35 and the output result from each of the strain gauges 20 when the vibration device 30 applies the vibration force, the vibration force to be input and each of them. A transfer function acquisition unit 40 for acquiring a transfer function showing the relationship with the strain response of the strain gauge 20 and
Based on the output result from each strain gauge 20 when the rotating device 7 operates and the transfer function acquired by the transfer function acquisition unit 40, the force generated by the rotating device 7 during operation is specified. It is provided with a vibration force specifying unit 50 for performing the vibration.
The number of the above-mentioned "each strain generating body 10" and "each strain gauge 20" refers to one or more.

According to the configuration of (1) above, each strain gauge 20 is provided on the strain generating body 10 between the rotating device 7 and the foundation 6. As a result, the strain-causing body 10 can be distorted with high sensitivity even when the frequency band of the vibration force applied by the vibration device 30 is low. Therefore, the strain gauge 20 can react with high sensitivity, and the transfer function acquisition unit 40 can acquire a highly reliable transfer function. Therefore, even when the rotating device 7 operates at a low rotation speed, the force generated by the rotating device 7 during operation can be accurately specified.
By accurately specifying the force generated when the rotating device 7 operates, resonance does not occur in the structure including the rotating device 7 and the foundation 6 at the time of designing the foundation 6 for installing the rotating device 7, for example. The shape and material of the foundation 6 can be adopted, and a vibration-proof design can be applied.
Here, a method of performing impulse vibration instead of sweep vibration and specifying the force in the rotating device 7 based on the output result of the acceleration pickup instead of the strain gauge 20 can be considered. More specifically, as an example, a method of specifying the response when the impact excitation using the impulse hammer is applied to the rotating device 7 based on the output result of the acceleration pickup and obtaining the transfer function based on the output result can be considered. However, the inventor has confirmed by experiment that the value of the coherence function of the transfer function obtained by the above method does not approach 1 in a relatively low frequency band. That is, the lower the frequency band of the applied force, the lower the reliability of the acquired transfer function, and the lower the accuracy of the force specified by the exciting force specifying unit 50. It is considered that this problem is partly due to restrictions on the measurement characteristics and mounting method of commercially available acceleration pickups. In this regard, according to the configuration of (1) above, for the reason described above, a transfer function with higher reliability than in the past can be obtained, and various forces can be specified with high accuracy. The coherence function is a variable of 0 or more and 1 or less indicating the reliability of the transfer function, and the closer the value is to 1, the higher the reliability of the transfer function.
Further, since the shape of the strain-causing body 10 related to one embodiment can be freely designed, the shape, material, arrangement position, etc. of the strain-causing body 10 so that distortion is generated with high sensitivity while ensuring the required strength, etc. Can be adopted. Therefore, even when the frequency band of the exciting force and the rotation speed of the rotating device 7 are low, the strain-causing body 10 can react with high sensitivity, so that various forces generated by the rotating device 7 can be accurately specified.

(2) In some embodiments, in the configuration of (1) above,
The at least one strain gauge 20 includes a plurality of strain gauges 20.
The transfer function acquisition unit 40 is configured to acquire a plurality of transfer functions corresponding to each of the plurality of strain gauges 20.

According to the configuration of (2) above, the exciting force specifying unit 50 specifies the force generated by the rotating device 7 based on the plurality of transfer functions corresponding to the plurality of strain gauges 20. Therefore, the force generated by the rotating device 7 during operation can be accurately specified.

(3) In some embodiments, in the configuration of (2) above,
The at least one strain gauge 20 includes two strain gauges 20a and 20c each extending in a direction intersecting each other.

According to the configuration of (3) above, even when the force generated by the rotating device 7 has components in a plurality of directions, at least one of the strain gauges 20a and 20c can react to this force with high sensitivity. Therefore, the exciting force specifying unit 50 can accurately specify the force generated by the rotating device 7 during operation.

(4) In some embodiments, in any of the configurations (1) to (3) above,
Each of the strain gauges 20 is provided outside the housing 7b of the rotating device 7 in a radial direction with respect to the rotating shaft 7a of the rotating device 7 in a plan view.

According to the configuration of (4) above, since the strain generating body 10 provided with the strain gauge 20 is separated from the center of gravity of the rotating device 7, the strain generating body 10 is distorted with high sensitivity according to various forces generated by the rotating device 7. Can be done. As a result, the exciting force specifying unit 50 can accurately specify the force generated by the rotating device 7 during operation.

(5) In some embodiments, in any of the configurations (1) to (4) above,
The transfer function acquisition unit 40 is configured to acquire a plurality of the transfer functions for each of the plurality of action points 5 to which the excitation force is applied in the rotation device 7.

According to the configuration of (5) above, the exciting force specifying unit 50 specifies the force generated by the rotating device 7 based on a plurality of transfer functions for each of the plurality of action points 5 to which the exciting force is applied. Therefore, the force generated by the rotating device 7 during operation can be accurately specified.

(6) In some embodiments, in the configuration of (5) above,
The at least one strain gauge 20 includes a plurality of strain gauges 20.
The transfer function acquisition unit 40 is configured to acquire a plurality of transfer functions for each of the plurality of action points 5 to which the excitation force is applied in the rotation device 7.
The number of the strain gauges 20 and the number of the points of action are the same.

According to the configuration of the above (6), in the equation (2), it is not necessary to add a dummy component to the matrix of the first term on the left side or the second term on the right side to execute the arithmetic processing, so that the load of the arithmetic processing is reduced. do. Therefore, the process of acquiring the transfer function by the transfer function acquisition unit 40 is speeded up.

(7) In some embodiments, in any of the configurations (1) to (6) above.
The strain-causing body 10 is provided between the reciprocating compressor, which is the rotating device 7, and the foundation 6.

According to the configuration of (7) above, the exciting force specifying unit 50 can accurately specify the force generated during the operation of the reciprocating compressor, which tends to have a relatively low rotation speed.

(8) The vibration force specifying method according to at least one embodiment of the present invention is
It is a method of specifying the exciting force by the exciting force specifying system.
Based on at least one straining body 10 provided between the rotating device 7 and the foundation 6, at least one strain gauge 20 provided on each straining body 10, and an input sine sweep signal 34. The vibration force specifying system 1 including a vibration device 30 for applying a vibration force to the rotating device 7 and a force sensor 35 for measuring the vibration force applied from the vibration device 30. Based on the output result from the force sensor 35 and the output result from each strain gauge 20 when the vibration device 30 applies the vibration force, the vibration force to be input and each of them. In the transfer function acquisition step (S11) for acquiring a transfer function showing the relationship with the strain response of the strain gauge 20 of the above,
Based on the output result from each strain gauge 20 when the rotating device 7 operates and the transfer function acquired in the transfer function acquisition step, the force generated by the rotating device 7 during operation is specified. It is equipped with a vibration force specifying process for this purpose.

According to the configuration of the above (8), for the same reason as the above (1), even when the rotating device 7 operates at a low rotation speed, the force generated by the operating rotating device 7 can be accurately specified. ..

1: Excitation force identification system 5, 5X, 5Y, 5Z: Action point 6: Foundation 7: Rotating device 7a: Rotating shaft 7b: Housing 10, 10a, 10b, 10c: Distortion body 20, 20a, 20b, 20c: Gauge 30: Excitation device 34: Sign sweep signal 35: Force sensor 40: Transmission function acquisition unit 50: Excitation force identification unit

Claims (8)

At least one strain-causing body provided between the rotating device and the foundation,
At least one strain gauge provided on each strain generator,
A vibration device for applying a vibration force to the rotating device based on the input sine sweep signal, and a vibration device.
A force sensor for measuring the vibration force applied from the vibration device, and
Based on the output result from the force sensor and the output result from each of the strain gauges when the vibration device applies the vibration force, the vibration force to be input and each of the strain gauges. A transfer function acquisition unit for acquiring a transfer function showing the relationship with the strain response of
Based on the output result from each strain gauge when the rotating device operates and the transfer function acquired by the transfer function acquisition unit, an addition for specifying the force generated by the rotating device during operation. A vibration force identification system equipped with a vibration force identification unit. The at least one strain gauge includes a plurality of strain gauges.
The vibration force specifying system according to claim 1, wherein the transfer function acquisition unit is configured to acquire a plurality of transfer functions corresponding to each of the plurality of strain gauges. The exciting force specifying system according to claim 2, wherein the at least one strain gauge includes two strain gauges each extending in a direction intersecting each other. The excitation force specification according to any one of claims 1 to 3, wherein each strain gauge is provided outside the housing of the rotating device in a plan view in the radial direction with respect to the rotating axis of the rotating device. system. 6. Excitation force identification system. The at least one strain gauge includes a plurality of strain gauges.
The transfer function acquisition unit is configured to acquire a plurality of transfer functions for each of the plurality of action points to which the vibration force is applied in the rotating device.
The exciting force specifying system according to claim 5, wherein the number of strain gauges and the number of points of action are the same. The excitation force specifying system according to any one of claims 1 to 6, wherein the strain-causing body is provided between the reciprocating compressor, which is the rotating device, and the foundation. It is a method of specifying the exciting force by the exciting force specifying system.
Vibration is applied to the rotating device based on at least one strain-causing body provided between the rotating device and the foundation, at least one strain gauge provided on each of the strain-causing bodies, and an input sine sweep signal. The output result from the force sensor of the vibration force specifying system including the vibration device for applying the force and the force sensor for measuring the vibration force applied from the vibration device, and the said. A transmission function showing the relationship between the input vibration force and the strain response of each strain gauge based on the output result from each strain gauge when the vibration device applies the vibration force. And the transfer function acquisition process for acquiring
Based on the output result from each of the strain gauges when the rotating device operates and the transfer function acquired in the transfer function acquisition step, an addition for specifying the force generated by the rotating device during operation. A vibration force identification method including a vibration force identification process.

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