KR20190063087A - Apparatus and method for canceling vibration of spindle - Google Patents

Abstract

According to the present invention, a spindle vibration control device includes: a sensor sensing vibrations from a vibrator and delivering a vibration signal; a control part activating and outputting a response signal for offsetting a vibration signal; and an actuator operated in response to the response signal. The vibrator is an air bearing spindle including a shaft and an air bearing, the actuator is a rotary body and the rotary body is rotated in the opposite direction to the rotation of the shaft of the spindle in response to the response signal. Meanwhile, according to a spindle vibration control method by the present invention, a response signal, which is obtained by pre-conducting a vibration analysis test on a vibration signal generated from the air bearing spindle, is set to be outputted, and then, the response signal rotating in the opposite direction to a vibrating direction of the air bearing spindle is outputted to the rotary body, which is the actuator, in response to the input of the vibration signal. According to the present invention, since vibration analysis is pre-conducted, a frequency analyzer in an active damping kit is not necessary, and thus an active damping kit, which is small and low-priced, can be formed, and also, real time responding is possible. Moreover, since the pre-conducted vibration analysis enables a simple and effective response signal for vibration control to be supplied, noise and errors can be minimized, and also, there is no need to respond to every signal, and thus the probability of resonance can be considerably lowered.

Description

[0001] Apparatus and method for canceling vibration of spindle [0002]

The present invention relates to an apparatus and a method for controlling a spindle vibration. More particularly, the present invention relates to a spindle vibration control apparatus and a method for manufacturing a circuit so that an optimum corresponding signal can be supplied through a preceding vibration analysis of a vibrating body, and a vibration is controlled by supplying a corresponding signal to an actuator when a sensor detects a signal .

Vibration control is most effective when the characteristics of the structure are analyzed (experiment and simulation) at the design stage to suppress resonance and transmission of vibration.

1 is an explanatory view showing a structure / equipment stabilization design process and a vibration analysis process.

Referring to FIG. 1, the vibration and the vibration type of the vibrating body (cantilever) are obtained through experiments and simulation, and then the vibration analysis is completed by checking whether the two results coincide with each other.

Damper is most widely used as vibration reducing device, and damper is classified as passive damper and active damper.

Fig. 2 is a configuration diagram of a passive damper, and Fig. 3 is a configuration diagram of an active damper.

2 and 3, the manual damper is a device for absorbing vibration by dissipating internal stress and friction energy of a vibrating object by adding a spring or a vibration absorbing material to the vibrating portion. However, when the passive damper is installed, the rigidity of the structure is lowered, and in some cases, the overall size of the vibration may be larger, so that the reliability of the product quality and durability may be lowered.

Generally, an active damper analyzes a vibration signal by transmitting a sensed vibration signal to an external controller (including a frequency analyzer), generates a corresponding signal capable of suppressing the vibration signal through a signal generator, and transmits the signal to an actuator Thereby reducing vibrations. However, an expensive frequency analyzer (at least 10 million won) is indispensably required to reduce vibration through the process of analyzing a vibration signal using a frequency analyzer, and a high volume external controller, a signal transmission / reception process between the sensor and the actuator There are disadvantages that various parts (antennas, batteries, cables) are required and a signal generator is added to supply an appropriate signal.

In this case, the frequency analyzer is an effective device for obtaining the accurate value of the vibration, but it is expensive, and the calculation process is complicated, so that only the process of analyzing the signal takes 2 to 4 seconds (time to convert the time domain signal into the frequency domain signal ), And the reaction (output of the corresponding signal) becomes possible after several cycles (20 to 40 cycles when the frequency is 10 Hz) after the generation of vibration, real-time vibration control is impossible and the control efficiency is low.

In addition, the active damper can be divided into an active damping kit (kit) and a non-active vibration damping kit.

4 is a block diagram of a control circuit of techniques for performing vibration analysis in an active damper.

Specifically, the left side is a circuit diagram of Japanese Patent No. 5632701, "Active Vibration Isolation Device (Active Vibration Isolation Device)", and the right side is a circuit diagram of US Patent No. 7,047,109, "MACHINERY FOR IMPROVING PERFORMANCE IRREGULARITIES ARISING FROM VIBRATIONS" The operation mechanism of the existing active damper performing the vibration analysis is shown.

Referring to FIG. 4, in these techniques, a vibration signal is analyzed through a control box or other measuring equipment including a frequency analyzer in an active damping kit, and a vibration wave of a reverse phase is transmitted to the signal generator. The mechanism of the active damping system including the frequency analysis process is briefly summarized in the active damping kit used in this conventional technology. The frequency analyzer analyzes the vibration signal measured by the sensor to obtain a finite number of frequency components, The generator supplies the actuator to the opposite phase. Thus, the measured vibration signal and the inverse signal generated by the actuator meet and cancel each other to alleviate the vibration.

The operation mechanism of this method can be summarized into four steps as shown in FIG. 5 below.

FIG. 5 is an explanatory view showing an operation mechanism of a conventional active damper by a waveform, and the following operation is performed in each step.

- Step 1: Measure the vibration on the sensor.

- Step 2: The time domain signal measured by the sensor is input to the frequency analyzer in the active damping kit and converted to the frequency domain signal. In this case, it takes about 2 to 4 seconds because it takes a complicated process requiring mathematical operation. On the other hand, vibration generally consists of infinite number of frequency components. Looking at the graph in the frequency domain, there are several peaks, the frequencies of which constitute one vibration.

- Step 3: Generate a vibration signal for each analyzed finite frequency component in the signal generator, generate a reverse signal with the opposite polarity, and supply the reverse signal to the actuator.

- Step 4: Activate the actuator with the supplied reverse signal.

However, as described above, when the frequency analysis process is performed in the active damping kit, it takes a long time to analyze the vibration, accurately analyze the waveforms of the plurality of frequency components, The price of the active damper is very high and the price of the frequency analyzer to be included in the active damping kit is high (Table 1; price of the frequency analyzer).

In addition, when a signal is transmitted from a sensor to a frequency analyzer, a frequency analyzer analyzes the frequency, amplitude, and period of the signal, and then a wire or an antenna or a battery Further, the active damping kit is bulky due to the inconvenience of battery and antenna installation, which makes it difficult to construct an integral active damper.

Fig. 6 is a block diagram of a control circuit of a technique in which vibration analysis is not performed in an active damper.

Specifically, this is a circuit diagram of Japanese Unexamined Patent Application Publication No. 2009-114821, "Building damping device (building drainage device)".

Referring to FIG. 6, in this technique, the entire phase of the measured vibration signal is directly inverted to correspond to the vibration signal. A brief description of the mechanism of the active damping system which does not include the frequency analysis process in the active damping kit used in this conventional technique is that the signal from the sensor 1 passes through the phase inverters 31 and 32 and the actuator 2 To control the vibration of the vibrating body (4).

However, since this technique corresponds to the entire signal of the vibrating body, the corresponding signal must be moved in the opposite direction to the vibration of the vibrating body, so the actuator must be attached to the vibrating body.

When this method is used, since the corresponding signal is the opposite signal to the vibration signal, the operating speed of the actuator becomes equal to the natural frequency of the vibrating body. Therefore, resonance occurs between the actuator and the vibrating body. In addition, in the process of generating a signal corresponding to the vibration of a complex signal having an infinite number of frequency components in order to correspond to the entire signal, noise and errors are very likely to occur. In general, signal processing is an operation on an input signal. The more complex the signal, the more time it takes to process the signal. Therefore, when the vibration signal is complicated, the delay time becomes longer and accurate control becomes difficult in real time.

FIG. 7 is a waveform diagram for explaining a problem that may occur due to a delay time in an active damping method for generating an inverse signal with respect to the entire vibration signal.

Referring to FIG. 7, the influence of the delay time generated in the process of applying the reverse signal to the vibrator by the actuator of the active damping system on the low frequency and the high frequency will be described. FIG. 7 (a) (A) of FIG. 7 is reversed and a delay time of 0.005 seconds is generated to be shown in FIG. 7 (b). Since 0.005 second is 1/2 cycle based on 100 Hz frequency, 100 Hz frequency becomes the same phase after 0.005 second, and 10 Hz vibration signal has very short delay time (1/20 cycle). Signal is supplied. As a result of the sum of the two signals, the low frequency (10 Hz) component disappears as a reversed phase, but the high frequency component (100 Hz) becomes in phase and the two signals are combined so that the vibration does not disappear as shown in FIG. 7 (c).

On the other hand, another problem corresponding to the entire vibration signal will be described.

8 is a waveform diagram showing the original vibration signal and a signal passed through a PCB (Printed Circuit Board) or an FPCB (Flexible Printed Circuit Board).

FIG. 8A is a waveform diagram of a vibration signal, and FIG. 8B is a waveform diagram of a noise generating signal after passing through a PCB.

Referring to FIG. 8, it can be seen that noise occurs in the signal due to the interface problem between the sensor, the PCB, and the actuator after the vibration signal (impulse vibration) passes through the PCB. This means that the more frequency components of the signal, the higher the probability of occurrence. Because of this noise, the actuator responds to a small signal, causing errors in the process of generating a corresponding signal, and the efficiency is lowered.

When the LPF (Low Pass Filter) is used to reduce such noise, the phenomenon shown in FIG. 9 occurs.

9 (a) is a waveform diagram showing a PCB signal and an LPF pass signal. 9 (a) is a signal passed through the PCB, and the lower signal is a signal passed through an LPF (Low Pass Filter) to remove noise. 9 (b) is an enlarged view of the LPF passing signal.

Referring to FIG. 9, since the frequencies of vibrations generated in the interlayer noise, snoring, etc. are mostly low frequencies less than 10 Hz, high frequency noise can be removed only by passing the LPF through low frequencies.

However, when the signal is enlarged, the noise component of the PCB signal is partially removed, but the delay time (about 50 ms, in the case of a 10 Hz signal) occurs due to the passage of the LPF. And resonance may occur.

Therefore, there is a need to overcome problems such as price problems, problems that can not be controlled in real time, problems of increasing volume (integrally attaching an actuator to a vibrating body), problems corresponding to the entire vibration signal (error occurrence, delay time) .

Document 1: Japanese Patent No. 5632701, "Active vibration isolation device (active vibration isolation device)" US Patent No. 7,047,109, "MACHINERY FOR IMPROVING PERFORMANCE IRREGULARITIES ARISING FROM VIBRATIONS" Document 3: Japanese Unexamined Patent Application Publication No. 2009-114821, "Building Damping Device

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a circuit capable of supplying an optimum response signal through a preliminary analysis of a vibrating body, To the actuator so as to control the vibration of the spindle.

According to an aspect of the present invention, there is provided a spindle vibration control apparatus comprising: a sensor for sensing vibration from a vibrating body to transmit a vibration signal; A control unit for activating and outputting a corresponding signal canceling the vibration signal; And an actuator that is driven in response to the corresponding signal, wherein the vibrator is an air bearing spindle including a shaft and an air bearing, the actuator is a rotator, and the rotator corresponds to the corresponding signal, In the direction opposite to the shaft rotation direction of the shaft.

In addition, the spindle vibration control device of the present invention includes: a sensor that detects vibration from a vibrating body and transmits a vibration signal; A control unit for activating and outputting a corresponding signal canceling the vibration signal; And an actuator that is driven in response to the corresponding signal, wherein the vibrator is an air bearing spindle including a shaft and an air bearing, the actuator is a rotator, and the rotator corresponds to the corresponding signal, In the direction opposite to the shaft rotation direction of the shaft.

At this time, the rotating body may be a motor, and the motor is preferably positioned at a selected position through a preliminary vibration analysis.

The rotating body may be a motor, and the motor may be installed inside or outside the housing along the circumferential direction of the housing of the air bearing spindle.

The corresponding signal may be generated by generating a corresponding signal only in a set number of frequency component vibration signals in the order of the largest amplitude among the vibration signals of the infinite frequency components, It is possible to generate a corresponding signal only.

Meanwhile, the spindle vibration control method of the present invention includes: obtaining a main vibration frequency generated from an air bearing spindle from a sensor; Determining a vibration direction from the main vibration frequency; And generating a corresponding signal rotating in a vibration direction opposite to the vibration direction and outputting the corresponding signal to the rotating body as an actuator.

The method of controlling a spindle vibration according to the present invention is a method for controlling a spindle vibration of an air bearing spindle in response to input of a vibration signal in a state in which a corresponding signal obtained by preceding vibration analysis experiment of a vibration signal generated in an air bearing spindle is output, And outputs the corresponding signal, which rotates in the vibration direction opposite to the vibration direction, to the rotating body as an actuator.

At this time, the corresponding signals can be generated only in the frequency components of the set number of frequency components in the order of the greatest amplitude among the vibration signals of the infinite frequency components. The frequency component of the set number can be set in a range of 1 to N (where N is a natural number of 2 or more).

Further, a corresponding signal can be generated only for the (+) direction signal or the (-) direction signal of the vibration signal.

Then, a corresponding signal can be generated only for a part of the period of the vibration signal. At this time, the partial period is 1 / N period (where N is a positive integer).

As described above, according to the apparatus and method for controlling the spindle vibration according to the present invention, since the preceding vibration analysis is performed, a frequency analyzer in the active damping kit is not required, so that an active damping kit having a small volume and low cost can be constructed, Since the frequency analysis is not performed in the active damping kit, real-time response to vibration is possible.

In addition, since the preceding vibration analysis is performed, the corresponding signal of the active damper including the damper installation position, corresponding signal size, frequency, supply time (1/2 or 1/4 period), supply frequency, , And can be applied to all kinds of environments.

By performing the preceding vibration analysis so as to correspond only to a finite number of frequency components having the largest vibration, circuit / actuator configuration and operation can be simplified, and control accuracy and efficiency improvement and error / delay time suppression can be achieved . That is, since the signal to be processed is simple, the error / delay time can be reduced during the process, and accurate response in real time is possible.

On the other hand, by designing the actuator to be isolated from the vibrating body and to isolate the vibration between the actuator driving part and the active damping kit, the possibility of resonance can be prevented in advance and precise vibration control can be achieved.

1 is an explanatory view showing a structure / equipment stabilization design process and a vibration analysis process.
2 is a configuration diagram of a passive damper.
3 is a configuration diagram of an active damper.
4 is a block diagram of a control circuit of techniques for performing vibration analysis in an active damper.
5 is an explanatory view showing an operation mechanism of a conventional active damper in waveform.
Fig. 6 is a block diagram of a control circuit of a technique in which vibration analysis is not performed in an active damper.
FIG. 7 is a waveform diagram for explaining a problem that may occur due to a delay time in an active damping method for generating an inverse signal with respect to the entire vibration signal.
8 is a waveform diagram showing an original vibration signal and a signal passed through the PCB.
9 is a waveform diagram and an enlarged view showing a PCB signal and an LPF pass signal.
10 is a configuration diagram of a vibration control apparatus according to the first embodiment of the present invention.
11 is a conceptual diagram of an operation mechanism of the vibration control apparatus according to the first embodiment of the present invention.
12 is a photograph of a PCB according to the first embodiment of the present invention.
13 is a conceptual diagram showing the effect of frequency component-based vibration and finite number of corresponding signal subtraction effects.
14 is a waveform diagram showing an impulse oscillation type.
Fig. 15 is a waveform diagram in the case of corresponding to the entire vibration signal.
16 is a waveform diagram in the case where only the signal in the (+) direction of the vibration signal corresponds.
Figs. 17 and 18 are waveform diagrams when only signals of 1/2 cycle and 1/4 cycle are supported.
Fig. 19 is an analysis waveform diagram of vibration due to harmonic force. Fig.
20 is a waveform diagram showing the result of removing the largest frequency.
21 is a configuration diagram of a conventional spindle.
22 is a configuration diagram of an air bearing spindle according to an embodiment of the present invention.
23 is a flowchart illustrating a process of controlling an air bearing spindle according to an embodiment of the present invention.
FIG. 24 is a graph showing a result of measurement of the magnitude of vibration of the spindle by operating speed.
25 is a flowchart illustrating a process of controlling an air bearing spindle according to another embodiment of the present invention.
FIG. 26 is a waveform diagram illustrating 10 periods of impulse oscillations generated for 1 second.
27 is a conceptual diagram of the shaft vibration control.
28 is a state diagram in which a damper is attached to a fixing jig to perform shaft vibration control.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in detail with reference to preferred embodiments of the present invention and accompanying drawings, wherein like reference numerals refer to like elements.

It is to be understood that when an element is referred to as being "comprising" another element in the description of the invention or in the claims, it is not to be construed as being limited to only that element, And the like.

Also, in the description of the invention or the claims, the components named as "means", "parts", "modules", "blocks" refer to units that process at least one function or operation, Each of which may be implemented by software or hardware, or a combination thereof.

In the present invention, before the vibration control device (active damper) is designed, the vibration analysis experiment of the vibration control object (vibrating body) is preceded and the characteristics of the vibration (frequency, vibration size, cycle, (Programming) in advance so that a corresponding signal that is optimal for vibration control is supplied. Since vibration analysis is performed in advance, it is not necessary to install an expensive frequency analyzer in the active damping kit, and it is possible to construct an active damping kit having a small volume and a low cost. That is, it means that the signal analysis process is not necessary in the active damping kit.

On the other hand, as a method of suppressing the vibration, a method of directly transmitting to the actuator by using the signal sensed by the sensor and a method of responding only to signals of one direction ((+) direction or (-) direction) It is possible to use a method of controlling the vibration corresponding to only two or four periods of the signal. Since all of these methods precede vibration analysis, it is possible to control the vibration in real time.

Hereinafter, an embodiment in which the vibration control apparatus and method of the present invention are implemented will be described with reference to specific embodiments.

10 is a configuration diagram of a vibration control apparatus according to the first embodiment of the present invention.

10, the vibration control apparatus of the present invention includes a sensor 100 for sensing a vibration from a vibrating body and transmitting a vibration signal, a control unit 200 for activating and outputting a corresponding signal for canceling the vibration signal, And an actuator 300 that is driven in response to the corresponding signal.

At this time, the control unit 200 is designed (programmed) in advance so that a corresponding signal acquired by preceding vibration analysis of the vibration signal is outputted.

In the present embodiment, the actuator 300 is coupled to the vibrating body. However, the actuator 300 may be installed separately from the vibrating body.

11 is a conceptual diagram of an operation mechanism of the vibration control apparatus according to the first embodiment of the present invention.

Referring to FIG. 11, the operation mechanism of the vibration control apparatus of the present invention can be roughly divided into the following three stages.

- Step 1: Precede the vibration analysis for the vibrating body. (1 to 3) frequency components having the greatest amplitude among the vibration amplitude, the cycle, the degree of attenuation of the amplitude, and the infinite number of frequency component vibrations, or signal filtering (PCB circuit (control unit 200) (1 to 3) frequency components (1 to 3) are selected through the filtering of the low frequency components by computer programming of the frequency domain. Although the case of selecting one to three frequency components of the present embodiment is described, N frequency components can be arbitrarily selected. Here, N is a natural number of 1 or more.

Thus, the control unit does not require a frequency analysis function and can be manufactured at a low cost. Simplification is performed so that the control unit 200 corresponds only to the frequency components of the finite elements (1 to 3). In addition, since the time for the actuator 300 to react in advance can be designed and limited, the signal corresponding to the entire signal is not supplied, so that the possibility of resonance can be excluded. Since the control unit processes a simple signal, it is possible to minimize noise, signal processing time, and actuator response time.

- Step 2: The vibration generated by the vibrating body is detected by the sensor 100 and input to the controller.

Step 3: When the vibration signal is input to the control unit 200, the actuator 300 is driven by outputting a preset corresponding signal.

12 is a photograph of a control unit (PCB) according to the first embodiment of the present invention.

12, the control unit 200 of the present invention includes an input unit 1 for receiving a vibration signal, a control unit 200 for controlling the operation of the control unit 200 according to the corresponding signaling method, the number of times of supplying the corresponding signal, A corresponding signal activating unit 2 that is designed (programmed), and an output unit 3 that outputs a corresponding signal to the actuator 300. [

Here, it may further include a current output regulating device 4 for regulating an amount of actuator driving current.

The controller 200 configured as described above inputs and outputs signals in the vibration control device (active damper) and serves as an interface between the sensor 100 and the actuator 300. That is, when a vibration signal is detected by the sensor 100, the corresponding signal activating unit 2 generates a corresponding signal and supplies the corresponding signal to the actuator 300.

Meanwhile, the vibration generated in the second step of FIG. 11 consists of infinite number of frequency components. Of these, about 1 to 3 frequencies have 80 to 90% energy of vibration, and it is most effective to remove 1 to 3 major frequency components. In the present invention, it is possible to effectively eliminate the vibration by removing only a finite number of frequency components by classifying the vibration according to the frequency component through the preceding frequency analysis.

13 is a conceptual diagram showing the effect of frequency component-based vibration and finite number of corresponding signal subtraction effects.

Referring to FIG. 13, it is possible to obtain the vibration components (1) to (5) in advance by performing the frequency analysis, and as an example, it is possible to eliminate the major vibration components (1) and (2) to achieve efficient vibration extinction. In other words, the left vibration signal is a picture of vibration consisting of five frequency components ① ~ ⑤. If two signals with the largest amplitude (① and ②) are removed, 80% of the vibration will disappear Can be confirmed. In this case, it can be seen that the delay time and error can be greatly reduced compared with the case where the signals are corresponding to the five signals (generally, infinite). This can be achieved by designing (programming) to generate the optimum corresponding signal for controlling the main vibration signal in the corresponding signal activating part 2 of the control unit for which the basic design is designed. By using the corresponding signals for one to three frequency components that are previously grasped in this way, the probability of noise generation can be lowered (since it is a very simple signal processing), and the control unit 200 can respond in real time . Further, since the actuator 300 is a simple type signal to be implemented, the reaction time is short and mechanical malfunction can be minimized.

On the other hand, aspects of vibration generally include vibration caused by impact (vibration due to interlayer noise, snoring, momentary deceleration acceleration), vibration due to harmonic force (vibration generated from the centrifugal force of a rotating body such as a motor shaft) Earthquake). Hereinafter, the vibration suppression method corresponding to each vibration mode will be described.

14 is a waveform diagram showing an impulse (vibration by impact) oscillation type.

Referring to FIG. 14, impulse means 'shock', and examples of impulse vibration include snoring, children's footsteps, hammer sounds, and object dropping sounds. That is, the impulse vibration means short and large impact vibration. Here, as an example, a method for suppressing impulse vibration will be described.

Fig. 15 is a waveform diagram in the case of corresponding to the entire vibration signal.

Referring to FIG. 15, as an example of a method corresponding to the entire vibration signal, a signal detected by the sensor 100 is used to directly transmit an opposite signal to the actuator 300. Since this method needs to supply the entire opposite signal of the vibration signal, the vibration control device (active damper) of the present invention must be combined with the vibrating body. Since the frequency of the active damper for supplying the inverse vibration in the coupled state between the active damper and the vibrating body is equal to the frequency of the vibrating body, as described in the above-mentioned prior art, this method has a very high possibility of resonance. In the present invention, in order to prevent the possibility of resonance, which is a problem of the existing technology, it is preferable that a passive damper is installed in the actuator driving part and the active damper coupling part to isolate the vibration.

On the other hand, as another vibration control method, there may be a method corresponding only to signals of one direction ((+) direction signal and (-) direction signal) according to the vibration characteristics of the structure.

16 is a waveform diagram in the case where only the signal in the (+) direction of the vibration signal corresponds.

Referring to FIG. 16, the magnitude of the vibration is sensed, and the operation of the actuator 300 corresponds to a certain number of times. This is because, in the impulse vibration, after the initial vibration response, the vibration is insignificant and it is not necessary to respond.

At this time, it is preferable to separate the vibrator and the actuator 300 from each other in order to block the possibility of resonance in the vibration control method of Fig.

As another vibration control method, it is also possible to cope with only a part of the cycle of the vibration signal.

Figs. 17 and 18 are waveform diagrams when only signals of 1/2 cycle and 1/4 cycle are supported.

Referring to FIGS. 17 and 18, one corresponding signal is generated for 1/2 period or one corresponding signal is generated for 1/4 period.

In this way, it is possible to control the vibration without the possibility of resonance by supplying signals only for a predetermined time (or a number of times) in correspondence with signals of 1/2 cycle or 1/4 cycle. Since all of the above four methods precede vibration analysis, effective vibration control is possible by supplying an optimum corresponding signal in real time. Experimental results show that the oscillation of the vibrating body can be eliminated by more than 80%. On the other hand, in the present embodiment, only the case of 1/2 period or 1/4 period signal is explained, but it can correspond to 1 / N (where N is a positive integer) period.

15 to 18, the operation of the actuator 300 according to the shape of the graph presented by the vibration control method corresponding to the impulse vibration is performed by the actuator 300 corresponding to the (+) direction signal and the (- Front and rear movement of the vehicle. Since the actuator 300 and the vibrating body are facing each other, when the vibrating body moves toward the positive direction signal, the actuator 300 moves toward the negative direction signal having the same energy magnitude and collides with each other, It will disappear. For example, as an approach to solve the interlayer noise problem, it is possible to disassemble the lamp in the living room ceiling and attach the active damping kit assembled on the steel plate to the ceiling. Regardless of where the impact occurs, the largest amplitude occurs at a specific location (near the center of the living room) for each apartment, and the closest match to this position is the center position 19). By controlling the vibration of this place, vibration and noise of the whole apartment will be extinguished by 90% or more, and very noisy 70dB noise can be reduced to less than 40dB.

On the other hand, as a mode of vibration, a vibration suppression method corresponding to an aspect of vibration due to a harmonic force (periodic vibration, rotating vibration, vibration generated from the centrifugal force of a rotating body such as a motor shaft) will be described.

Fig. 19 is an analysis waveform diagram of vibration due to harmonic force. Fig.

Referring to FIG. 19, harmonic vibration occurs from a centrifugal force generated by rotation of a rotating body, and vibrations (machine tools, helicopter blades, ship propellers, monitors, screws, engine vibrations ) Is repeated.

Vibration by harmonic forces also has several frequency components and occurs repeatedly. In the present embodiment, four frequency components are exemplified with respect to a vibration signal by a harmonic force through vibration analysis.

In this case, when the largest frequency shown at the top is removed, as shown in the left side of FIG. 20, and when the two largest frequencies are reduced, the right side is as shown in FIG. 20, and the vibration is reduced by 80% or more in all cases.

On the other hand, in order to extinguish the vibration, a corresponding signal may be supplied at a plurality of positions in the case of a rotating body such as an axis (see Fig. 27), or a corresponding signal may be supplied at both sides in the vibration direction of the vibrating body. In addition, based on the preceding vibration analysis, it is also possible to supply a corresponding signal only to a finite number of main frequency components, thereby extinguishing the vibration.

Here, spindles will be described as an example of controlling the vibration due to the harmonic force.

The spindle is a part of a machine tool such as a lathe and a drilling machine, and is composed of a shaft and a bearing, and is a device used in the rotary processing field. That is, a cutting tool or the like is attached to the shaft end of the spindle, and grinding or cutting can be performed.

As shown in FIG. 21, the conventional spindle uses a ball bearing 222 that is in direct contact with the shaft 221, but recently, a non-contact type air bearing is used due to the limitation of friction and high speed rotation. In other words, the spindle with an air bearing can be machined at extremely high speed and with high precision.

However, since the air bearing is not in contact with the shaft, eccentricity of the shaft may occur, which may cause vibration of the entire spindle as well as vibration of the shaft itself. The vibration of the spindle produces not only defective products, but also wears the tool connected to the spindle. Thus, the vibration of the spindle makes high-precision machining of the workpiece impossible. Therefore, controlling the vibration of the spindle is a very important task.

On the other hand, a method of minimizing the centrifugal force (f ₀ ) for controlling the vibration of the air bearing spindle has been proposed.

Where m is the mass, e is the eccentricity (the difference between the center of rotation and the center of mass), and w is the rotational velocity.

However, existing devices for vibration control of air bearing spindles have limitations in minimizing centrifugal force.

Herein, the present invention proposes a method for controlling the vibration due to the harmonic force including the air bearing spindle.

22 is a configuration diagram of an air bearing spindle according to an embodiment of the present invention.

22, the air bearing spindle 23 includes a shaft 231 provided with a tool holder on which a tool is mounted at the front end thereof, and an air bearing spindle 233 formed on the outer peripheral surface of the shaft 231 in the axial direction along the shaft 231 An air bearing 232, a housing 233 containing a shaft 231 and an air bearing 232, and a vibration cancellation device 234 for canceling vibration of the shaft 231.

The vibration canceling apparatus 234 includes a sensor for sensing the vibration of the shaft 231, a control unit for generating a control signal corresponding to the vibration of the shaft 231, And an actuator that rotates in the opposite direction.

The vibration cancellation device 234 may be formed on the inside or outside of the housing 233 or may be formed on a third body connected to the spindle. It is preferable that the rotating body is located at the position where the vibration of the vibrating body is greatest for the efficiency of vibration control.

In addition, the vibration cancellation device 234 may modularize the sensor, the control unit, and the rotating body integrally, or they may be separated from each other and installed at different positions. For example, the sensor may be installed near the tool holder, and the rotating body may be installed at any position where the shaft 231 is formed, and the control unit may be installed outside the air bearing spindle 23 through the wiring have.

On the other hand, the rotating body uses a motor and can be arranged in a plurality of radial directions along the circumferential direction of the housing 233.

Hereinafter, the control process of the air bearing spindle 23 of the present invention will be described.

23 is a flowchart illustrating a process of controlling an air bearing spindle according to an embodiment of the present invention.

Referring to FIG. 23, first, the main vibration frequency generated in the air bearing spindle 23 is measured (S241).

In general, the air bearing spindle 23 oscillates most at the operating speed (spindle rotational speed). That is, the largest influence on the vibration of the air bearing spindle 23 is the centrifugal force due to the eccentricity generated when the air bearing spindle 23 rotates.

24 is a result of measuring the vibration magnitude of the air bearing spindle 23 at each operating speed (acceleration sensor), and it can be seen that the vibration is greatest at the operating speed. In this case, the vibration amplitude can be measured using an acceleration sensor, a displacement sensor, an encoder, or the like.

Next, the direction of vibration generated in the air bearing spindle 23 is determined (S242). The vibration direction of the air bearing spindle 23 coincides with the direction in which the center of mass moves. The vibration direction can be determined based on the peak point of the vibration graph measured by the sensor. At this time, the vibration direction can be determined using an acceleration sensor, a displacement sensor, or the like.

As a final step, the rotating body is rotated in the direction opposite to the rotating direction of the shaft 231 of the air bearing spindle 23 (S243). That is, the vibration direction of the rotating body is opposite to the vibration direction of the air bearing spindle 23 so that the vibration is canceled. Here, the rotating body, the air bearing spindle 23 and the rotating body are controlled so that the center of mass is symmetrical. On the other hand, when the rotating body is provided in the housing 233 in a radial manner, more precise vibration cancellation can be achieved through combination control of these rotating bodies.

25 is a flowchart illustrating a process of controlling an air bearing spindle according to another embodiment of the present invention.

Referring to FIG. 25, the corresponding signal is acquired by preceding the vibration analysis experiment of the vibration signal generated in the air bearing spindle 23 (S261). That is, the air bearing spindle 23 sets the corresponding signal obtained through the vibration analysis experiment to be outputted when the vibration is generated.

Thereafter, in response to the occurrence of vibration in the air bearing spindle 23, a corresponding signal is applied to the rotating body so that the rotating body is rotated in the vibration direction opposite to the vibration direction of the air bearing spindle 23 (S262).

At this time, although the corresponding signals shown in FIGS. 23 and 25 can be output corresponding to the entire vibration signal, only the corresponding signals of the set number of frequency component vibration signals in the order of the greatest amplitude among the vibration signals of the infinite frequency components . That is, the frequency component of the set number can be set in the range of 1 to N (N is a natural number of 2 or more).

It is also possible to generate a corresponding signal only for the (+) direction signal or the (-) direction signal of the vibration signal shown in FIGS. 23 and 25, or to generate the corresponding signal only for a part of the period of the vibration signal. Here, some periods are 1 / N (N is a positive integer) period.

As described above, in the case of a damper having a frequency analysis process in the active damping kit (see FIG. 5), a delay time (2 to 4 seconds) occurs in the frequency analysis process in the damper, and real time control is impossible. As shown in FIG. 26, in the case of vibration having a frequency component of 10 Hz, even if analysis time (delay time) has elapsed for only 1 second, large vibration acts for 10 cycles. In addition, there is a problem that the price of the active damper is expensive due to the necessity of a frequency analyzer (see Table 1).

In the case of a conventional damper (see FIG. 7) in which the frequency analysis is not performed in the active damping kit, since there is no frequency analysis process in the active damping kit, the response time is short. . In addition, since the actuator 300 and the vibrating body must be attached to correspond to all vibration directions (+, -), there is a problem that resonance is likely to occur.

Fig. 27 is a conceptual diagram of shaft vibration control, and Fig. 28 is a conceptual diagram in which vibration control is performed by attaching an active damper to a fixing jig.

27 and 28, the vibration control apparatus (active damper) proposed in the present invention is a damping unit constructed by a sensor 100, a control unit (PCB or FPCB) 200, and an actuator 300 And the damping unit is assembled to a plate member (rigid body or flexible plate member) to complete the integral damping kit 10.

The completed integral damping kit 10 may be installed to be coupled to the vibrating body or may be installed separately from the vibrating body.

In the case where the integral active damping kit 10 is installed to be coupled to the vibrating body, vibration is interposed between the damping unit (the actuator 300) and the plate material, It is possible to prevent the resonance from being transmitted to the sieve.

When the integral active damping kit 10 is installed separately from the vibrating body, at least one integral damping kit 10 is provided in correspondence to the vibration direction using the fixing jig 20. At this time, it is preferable that the fixing jig 20 is fixed to an area other than the vibrating body.

According to the present invention, first, a damper is designed to correspond only to a finite number of modes having a maximum vibration based on the preceding vibration analysis, and the vibration is eliminated by a simple operation. Therefore, the delay time, noise, and error It is not necessary to install the actuator 300 in a plurality of places in order to cope with a complicated mode. Third, the actuator 300 is separated from the vibrating body, the vibration is isolated between the actuator driving part and the active damping kit, So that the possibility of resonance can be blocked.

The technical idea of the present invention has been described through several embodiments.

It will be apparent to those skilled in the art that various changes and modifications may be made to the embodiments described above from the description of the present invention. Further, although not explicitly shown or described, those skilled in the art can make various modifications including the technical idea of the present invention from the description of the present invention Which is still within the scope of the present invention. The above-described embodiments described with reference to the accompanying drawings are intended to illustrate the present invention and the scope of the present invention is not limited to these embodiments.

1: Input
2:
3: Output section
4: Current output regulator

Claims (12)

A sensor for sensing the vibration from the vibrating body and transmitting the vibration signal;
A control unit for activating and outputting a corresponding signal canceling the vibration signal; And
And an actuator which is driven in response to the corresponding signal,
The vibrating body is an air bearing spindle including a shaft and an air bearing,
The actuator is a rotating body,
Wherein the rotating body rotates in a direction opposite to a shaft rotating direction of the spindle corresponding to the corresponding signal.
A sensor for sensing the vibration from the vibrating body and transmitting the vibration signal;
A control unit for activating and outputting a corresponding signal canceling the vibration signal; And
And an actuator which is driven in response to the corresponding signal,
The vibrating body is an air bearing spindle including a shaft and an air bearing,
The actuator is a rotating body,
Wherein the rotating body rotates in a direction opposite to a shaft rotating direction of the spindle corresponding to the corresponding signal.
3. The method of claim 2,
The rotating body is a motor,
Wherein the motor is positioned at a selected portion through a preceding vibration analysis.
3. The method according to claim 1 or 2,
The rotating body is a motor,
Wherein the plurality of motors are installed inside or outside the housing along the circumferential direction of the housing of the air bearing spindle.
3. The method according to claim 1 or 2,
The corresponding signal is generated only for the (+) direction signal or the (-) direction signal of the vibration signal by generating a corresponding signal only in the set number of frequency component vibration signals in the order of the greatest amplitude among the vibration signals for every infinite number of frequency components And generates a signal.
Obtaining a main vibration frequency generated from an air bearing spindle from a sensor;
Determining a vibration direction from the main vibration frequency; And
Generating a corresponding signal rotating in a vibration direction opposite to the vibration direction and outputting the corresponding signal to a rotating body as an actuator.
In a state in which a corresponding signal obtained by preceding the vibration analysis experiment of the vibration signal generated in the air bearing spindle is set to be outputted, the rotation in the vibration direction opposite to the vibration direction of the air bearing spindle in response to the input of the vibration signal And outputting the corresponding signal to a rotating body as an actuator.
8. The method according to claim 6 or 7,
And generating a corresponding signal only in a frequency component vibration signal of the set number of the largest amplitude order among the vibration signals of the infinite frequency components.
9. The method of claim 8,
Wherein the frequency component of the set number is set in a range of 1 to N.
(Where N is a natural number of 2 or more)
8. The method according to claim 6 or 7,
And generating a corresponding signal only for a (+) direction signal or a (-) direction signal of the vibration signal.
8. The method according to claim 6 or 7,
And generating a corresponding signal only for a part of the period of the vibration signal.
12. The method of claim 11,
Wherein the partial period is a 1 / N period.
(Where N is a positive integer)

Images