KR101400137B1 - Microvibration emulator, test device of satellite system including the same, and method of emulating microvibration - Google Patents

Abstract

The micro vibration emulator includes a platform, first through sixth actuators and first through sixth structures. The platform has a cuboidal shape. The first to sixth actuators are attached to the first to sixth surfaces of the platform, respectively, and perform micro-oscillation of the platform based on the drive signal and perform six-axis control on the platform. The first to sixth structures are attached to the first to sixth actuators, respectively.

Description

TECHNICAL FIELD [0001] The present invention relates to a micro vibration emulator, a test apparatus of a satellite system including the micro vibration emulator, and a micro vibration simulation method.

More particularly, the present invention relates to a micro vibration emulator for simulating a micro vibration environment, a test apparatus for a satellite system including the micro vibration emulator, and a micro vibration simulation method.

Recently developed space-based observation satellites are equipped with high-precision optical payloads. These precision observation satellites are required to have a high level of precision and stability of milli-arcseconds. Therefore, in order to improve the image quality of the payload, a jitter analysis for vibration sources in a high frequency region must be preceded.

Among the various actuators, such as reaction wheels, control moment gyros, and cryogenic coolers mounted inside the satellites, the reaction wheel used to control the attitude of the satellite is one of the vibration sources that generate the greatest microvibration. The main causes of the microvibration of the reaction wheel are static and dynamic excitations due to flywheel imbalance and harmonic excitations caused by bearing irregularities. Therefore, the jitter analysis of the reaction wheel is necessary to reduce the vibration of the satellite. However, since the reaction wheel mounted on the satellite is not very easy to obtain because it is a very expensive equipment, the spectrum of the minute vibration generated by the speed, type and size of the wheel is always different, Is required.

It is an object of the present invention to provide a micro vibration emulator which can precisely and efficiently simulate an actual micro vibration environment.

It is another object of the present invention to provide a test apparatus for a satellite system including a micro vibration emulator which can precisely and efficiently simulate an actual micro vibration environment.

It is still another object of the present invention to provide a micro vibration simulation method capable of accurately and effectively simulating an actual micro vibration environment.

In order to accomplish the above object, a micro vibration emulator according to an embodiment of the present invention includes a platform, first through sixth actuators, and first through sixth structures. The platform has a cuboidal shape. The first to sixth actuators are attached to the first to sixth surfaces of the platform, respectively, and perform micro-oscillation of the platform based on the drive signal and perform six-axis control on the platform. The first to sixth structures are attached to the first to sixth actuators, respectively.

In one embodiment, based on a first actuator attached to a first side of the platform and a second actuator attached to a second side of the platform opposite the first side of the platform, And a third actuator attached to a third side of the platform adjacent the first side of the platform and a fourth actuator attached to a fourth side of the platform opposite the third side of the platform, Wherein said platform translates in a second axial direction perpendicular to said first axis and comprises a fifth actuator attached to a fifth side of said platform adjacent said first and third sides of said platform, The platform may translate in a third axial direction perpendicular to the first and second axes based on the sixth actuator attached to a sixth face of the platform opposite the face.

In one embodiment, the platform rotates about the first axis based on the third actuator, the fourth actuator, the fifth actuator, and the sixth actuator, and the first actuator, the second actuator, Based on the fifth actuator and the sixth actuator, the platform rotates about the second axis, and based on the first actuator, the second actuator, the third actuator, and the fourth actuator, And can rotate about the third axis.

In one embodiment, the micro vibration emulator may further include a control unit. The control unit may generate the drive signal based on a predetermined micro-vibration profile.

The control unit may include a processor and a driver. The processor may generate a drive control signal based on the microscopic vibration profile. The driving driver may generate the driving signal based on the driving control signal.

In another embodiment, the micro vibration emulator may further include a sensing unit. The sensing unit may sense the minute vibration of the platform by the first to sixth actuators and generate a sensing signal.

The control unit may include an amplifier, a processor, and a driving driver. The amplifier may amplify the sensing signal and generate a feedback signal. The processor may generate a drive control signal based on the feedback signal and the microvibration profile. The driving driver may generate the driving signal based on the driving control signal.

The micro vibration emulator can simulate micro vibration due to a reaction wheel included in the satellite system. In this case, the micro-vibration profile can be determined based on the driving frequency, harmonic excitation force coefficient, and harmonic number of the reaction wheel obtained through modeling of the reaction wheel.

According to another aspect of the present invention, there is provided a test apparatus for a satellite system including a plurality of emulators and a control circuit. The plurality of emulators simulate the operation of components included in the satellite system. The control circuit controls the plurality of emulators. A first one of the plurality of emulators simulates a micro vibration environment caused by a vibration source among the components. The first emulator includes a platform, first through sixth actuators and first through sixth structures. The platform has a cuboidal shape. The first to sixth actuators are attached to the first to sixth surfaces of the platform, respectively, and perform micro-oscillation of the platform based on the drive signal and perform six-axis control on the platform. The first to sixth structures are attached to the first to sixth actuators, respectively.

In one embodiment, based on a first actuator attached to a first side of the platform and a second actuator attached to a second side of the platform opposite the first side of the platform, And a third actuator attached to a third side of the platform adjacent the first side of the platform and a fourth actuator attached to a fourth side of the platform opposite the third side of the platform, Wherein said platform translates in a second axial direction perpendicular to said first axis and comprises a fifth actuator attached to a fifth side of said platform adjacent said first and third sides of said platform, The platform may translate in a third axial direction perpendicular to the first and second axes based on the sixth actuator attached to a sixth face of the platform opposite the face.

In one embodiment, the platform rotates about the first axis based on the third actuator, the fourth actuator, the fifth actuator, and the sixth actuator, and the first actuator, the second actuator, Based on the fifth actuator and the sixth actuator, the platform rotates about the second axis, and based on the first actuator, the second actuator, the third actuator, and the fourth actuator, And can rotate about the third axis.

The control circuit may include a first control unit that controls the first emulator, and the first control unit may generate the drive signal based on a predetermined micro-vibration profile.

The control unit may include a processor and a driver. The processor may generate a drive control signal based on the microscopic vibration profile. The driving driver may generate the driving signal based on the driving control signal.

The first emulator may further include a sensing unit. The sensing unit may sense the minute vibration of the platform by the first to sixth actuators and generate a sensing signal.

According to another aspect of the present invention, there is provided a micro vibration modeling method for modeling a vibration source to determine a micro vibration profile and driving a micro vibration emulator based on the micro vibration profile. do. The micro vibration emulator includes a platform, first through sixth actuators and first through sixth structures. The platform has a cuboidal shape. The first to sixth actuators are attached to the first to sixth surfaces of the platform, respectively, and perform micro-oscillation of the platform based on the drive signal and perform six-axis control on the platform. The first to sixth structures are attached to the first to sixth actuators, respectively.

In the micro vibration emulator according to the above-described embodiments of the present invention, six actuators are controlled in a cubic shape to generate six-axis force and moment, thereby providing the optimum six-axis control. By actively controlling the force and moment to be accurately generated through the feedback operation using the sensor, the actual micro vibration environment can be accurately and efficiently simulated. Further, by changing the type and / or specification of the actuator, it is possible to simulate a wide variety of vibration environments without increasing the cost.

1 is a diagram illustrating a micro vibration emulator according to an embodiment of the present invention.
2 is a diagram for explaining the operation of the micro vibration emulator of FIG.
FIGS. 3, 4, 5, 6A and 6B are diagrams for explaining a method for determining a micro-vibration profile used in the micro-vibration emulator of FIG.
7 is a diagram illustrating a micro vibration emulator according to another embodiment of the present invention.
8 is a diagram for explaining the operation of the micro vibration emulator of FIG.
9 is a block diagram illustrating a micro vibration simulation method according to an embodiment of the present invention.
10 is a block diagram illustrating a testing apparatus for a satellite system according to an embodiment of the present invention.

For the embodiments of the invention disclosed herein, specific structural and functional descriptions are set forth for the purpose of describing an embodiment of the invention only, and it is to be understood that the embodiments of the invention may be practiced in various forms, The present invention should not be construed as limited to the embodiments described in Figs.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprise", "having", and the like are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be construed as meaning consistent with meaning in the context of the relevant art and are not to be construed as ideal or overly formal in meaning unless expressly defined in the present application .

On the other hand, if an embodiment is otherwise feasible, the functions or operations specified in a particular block may occur differently from the order specified in the flowchart. For example, two consecutive blocks may actually be performed at substantially the same time, and depending on the associated function or operation, the blocks may be performed backwards.

1 is a diagram illustrating a micro vibration emulator according to an embodiment of the present invention. 1 is a perspective view conceptually showing the arrangement of components of the micro vibration emulator 100. As shown in FIG.

1, the micro vibration emulator 100 includes a platform 110, first to sixth actuators 120a, 120b, 120c, 120d, 120e, and 120f, Structures 130a, 130b, 130c, 130d, 130e, 130f. The micro vibration emulator 100 may further include a controller 150.

The platform 110 has a cube shape (i.e., a cube shape). Microvibration may occur in the platform 110 according to the operation of the actuators 120a, 120b, 120c, 120d, 120e, and 120f. In the case where the platform 110 has a cube shape, , It is possible to perform the largest and constant control and perform the vertical and separate control so that the six-axis control can be performed with minimal resources without redundancy.

The first to sixth actuators 120a, 120b, 120c, 120d, 120e and 120f are respectively attached to the first to sixth surfaces 112a, 112b, 112c, 112d, 112e and 112f of the platform 110. [ For example, the first actuator 120a may be attached to a first side (e.g., the right side) 112a of the platform 110. For example, The second actuator 120b may be attached to a second side (e.g., the left side) 112b of the platform 110 that faces the first side 112a of the platform 110. [ The third actuator 120c may be attached to a third side (e.g., lower surface) 112c of the platform 110 adjacent the first side 112a of the platform 110. The fourth actuator 120d may be attached to a fourth side (e.g., top side) 112d of the platform 110 opposite the third side 112c of the platform 110. [ The fifth actuator 120e may be attached to a first side 112a of the platform 110 and a fifth side (e.g., a front side) 112e of the platform 110 adjacent the third side 112c have. The sixth actuator 120f may be attached to a sixth side (e.g., the back side) 112f of the platform 110 opposite the fifth side 112e of the platform 110. [

The first to sixth actuators 120a, 120b, 120c, 120d, 120e and 120f micro-oscillate the platform 110 based on the drive signals and perform six-axis control on the platform 110. [ For example, the platform 110 may translate in the first axial direction based on the first actuator 120a and the second actuator 120b. Based on the third actuator 120c and the fourth actuator 120d, the platform 110 may translate in a second axial direction perpendicular to the first axis. Based on the fifth actuator 120e and the sixth actuator 120f, the platform 110 may translate in a third axial direction perpendicular to the first and second axes. The platform 110 can be rotated about the first axis based on the third actuator 120c, the fourth actuator 120d, the fifth actuator 120e and the sixth actuator 120f. The platform 110 can be rotated about the second axis based on the first actuator 120a, the second actuator 120b, the fifth actuator 120e and the sixth actuator 120f. The platform 110 can be rotated about the third axis based on the first actuator 120a, the second actuator 120b, the third actuator 120c and the fourth actuator 120d.

In one embodiment, the first to sixth actuators 120a, 120b, 120c, 120d, 120e and 120f may be piezoelectric actuators, voice coil actuators, proof-mass actuators actuator, and the like. The first and second actuators 120a and 120b may be attached so as to be opposite to each other and parallel to the first axis. The third and fourth actuators 120c and 120d may be attached so as to be opposite to each other and parallel to the second axis. The fifth and sixth actuators 120e and 120f may be attached so as to face in opposite directions and parallel to the third axis.

The first to sixth structures 130a to 130f are attached to the first to sixth actuators 120a to 120f respectively. For example, the first structure 130a is attached to the first actuator 120a, the second structure 130b is attached to the second actuator 120b, and the third structure 130c is attached to the third actuator 120c The fourth structure 130d is attached to the fourth actuator 120d and the fifth structure 130e is attached to the fifth actuator 120e and the sixth structure 130f is attached to the sixth actuator 130e 120f. On the other hand, the structures 130a, 130b, 130c, 130d, 130e, and 130f may not be directly attached to the platform 110. [ The structures 130a, 130b, 130c, 130d, 130e and 130f may be any object having a mass and the actuators 120a, 120b, 120c, 120d, 120e, , 130d, 130e, and 130f are transmitted to the platform 110, so that minute vibration may be generated in the platform 110. [

The control unit 150 may generate the drive signal based on a predetermined micro-vibration profile. 1, the controller 150 is disposed outside the platform 110. However, the controller 150 may be disposed inside the platform 110 according to an embodiment of the present invention.

2 is a diagram for explaining the operation of the micro vibration emulator of FIG. 2 is a block diagram conceptually showing the flow of data and / or signals for driving the micro vibration emulator 100 of FIG.

Referring to FIGS. 1 and 2, the controller 150 may include a processor 152 and a driving driver 154. Meanwhile, although not shown, the controller 150 may further include a power supply block.

The processor 152 may generate the drive control signal DCON based on the microvibration profile 153. [ The processor 152 may be a microprocessor, a digital signal processor (DSP), or a central processing unit (CPU). The microvibration profile 153 may correspond to the actual disturbance force generated in the microvibration source that generates the microvibration that the microvibration emulator 100 wants to simulate and performs modeling on the vibration source May be determined based on the obtained parameters (PARA). However, since it is difficult to accurately model the disturbance force of the vibration source, the micro vibration profile 153 can be determined based on the transfer force, by obtaining a transmitted force corresponding to the disturbance force through experiments. A specific method of determining the micro vibration profile 153 will be described later with reference to Figs. 3, 4, 5, 6A and 6B.

The driving driver 154 may generate the driving signal DRV based on the driving control signal DCON. The driving signal DRV may be an electrical signal such as a voltage signal or a current signal. For example, in the case of attempting to translate the platform 110 in the first axial direction, the drive driver 154 may drive only the first and second actuators 120a, 120b based on the drive signal DRV And the drive driver 154 drives only the third to sixth actuators 120c, 120d, 120e, and 120f based on the drive signal DRV when the platform 110 is to be rotated about the first axis .

According to the embodiment, the micro vibration emulator 100 can simulate micro vibration by the reaction wheel assembly (RWA) included in the satellite system. That is, the vibration source that generates the micro vibration to be simulated by the micro vibration emulator 100 may be a reaction wheel included in the satellite system. In this case, the parameters PARA may include the driving frequency, harmonic excitation force coefficient and harmonic number of the reaction wheel obtained through modeling for the reaction wheel, and the driving frequency of the reaction wheel, The microvibration profile 153 can be determined based on the number.

Hereinafter, a method of determining a micro-vibration profile in a micro-vibration emulator according to an embodiment of the present invention will be described in detail with reference to an example of modeling of a reaction wheel.

FIGS. 3, 4, 5, 6A and 6B are diagrams for explaining a method for determining a micro-vibration profile used in the micro-vibration emulator of FIG.

3 is a view showing an apparatus for measuring a transfer force generated by a reaction wheel. FIG. 4 is a graph showing frequency distribution of the transmission force measured by the apparatus of FIG. 3; FIG. 5 is a diagram showing a modeling result for a reaction wheel. 6A and 6B are graphs showing the microvibration profile for the force and moment generated by the reaction wheel.

The reaction wheel used in the satellite system is an important driver for controlling the attitude of the satellite using the rotation of the flywheel. In order to maintain the posture, the reaction wheel is operated on the principle of accelerating or decelerating the rotation speed when rotating the flywheel at a constant speed and changing the posture. At this time, Can act as a constant source of energy. The disturbance forces generated by the driving of the reaction wheel are largely affected by the fundamental harmonic due to static imbalance and dynamic imbalance, the wear of the bearing, the high frequency disturbance caused by the torque ripple and cogging of the motor, imbalance). Disturbances due to static and dynamic imbalances are easy to model mathematically, but high frequency disturbances are not easily mathematically modeled and can be determined empirically by experimental data. Thus, analytical modeling related to disturbances due to static and dynamic imbalances, and empirical modeling related to high frequency disturbances can be performed, and the two models can be integrated to determine the microvibration profile.

3 and 4, the calendar force measuring apparatus 10 may include a reaction wheel 20, a calendar force measuring unit 30, a support unit 40, and a data processing unit 50. The calendar calibrator 10 may be implemented in the form of a Kistler table.

The reaction wheel 20 may be driven based on the command signal CMD. For example, the reaction wheel 20 may be an Ithaco B type reaction wheel. The calendar calibrator 30 may generate an output signal FOUT including information on the calorific power corresponding to the disturbance force by the driving of the reaction wheel 20. [ For example, the calendar measuring unit 30 may be a Kistler force platform. The supporting part 40 supports the conveying force measuring part 30 and may include a marble 42, an insulator 44 and a seismic floor 46. The data processing section 50 may provide a command signal CMD and process the output signal FOUT and perform a feedback operation on the reaction wheel 20 based on the output signal FOUT.

The six-axis transmission force can be obtained in the time domain based on the output signal FOUT output from the transmission power measurer 30, and the frequency domain waterfall as shown in FIG. 4, You can draw a graph.

The disturbance due to the high frequency disturbance has a characteristic proportional to the square of the rotational speed of the wheel (that is, the driving frequency of the wheel), but since it appears as an integral multiple or an integer multiple of the rotational speed of the wheel, It is difficult to do. The magnitude of the disturbance force due to the high frequency disturbance (i.e., the disturbance force and the moment) can be expressed by the following equation (1).

[Equation 1]

In the above equation (1), m (t) denotes a disturbance force (or disturbance torque) according to time t, n denotes the number of harmonic numbers, C _i denotes i Th harmonic excitation coefficient, h _i represents the i-th harmonic number, and? Represents the driving frequency of the wheel.

In the above equation (1), the harmonic excitation force coefficient C _i and the harmonic number h _i have different values for each type of reaction wheel, and it is difficult to perform analytical modeling so that they are determined empirically by experimental data. The harmonic excitation force coefficient and harmonic number for the B type reaction wheel of Ithaco Co. can be obtained as shown in [Table 1] through experiments using the transfer force measuring device 10 of FIG.

[Table 1]

Referring to FIG. 5, the reaction wheel is symmetric with respect to the rotational axis of the flywheel 21 therein. The reaction wheel is located at the center of gravity and has three translations and three rotations based on the rotational axis fixed coordinate parallel to the rotational axis. The degree of freedom can be modeled as a kinetic model. To simplify the equation, the reaction wheel modeling for 4 degrees of freedom is performed except for the translational degree of freedom (z) and the degree of freedom of rotation (Ω). The mass by the static imbalance 23 and the mass by the dynamic imbalance 25a and 25b are modeled to be located at the edge of the flywheel 21. [

The kinetic model of the reaction wheel considering the static and dynamic imbalances can be expressed as the following equations (2) and (3) as the translational and rotational equations for the x and y axes using the energy method , And some coefficients shown in the following equations (2) and (3) are expressed by the following equations (4) and (5). (6) and (7) can be satisfied.

&Quot; (2) "

&Quot; (3) "

&Quot; (4) "

&Quot; (5) "

&Quot; (6) "

&Quot; (7) "

In the above equations (2) to (7), M represents the mass of the flywheel 21, m _s represents the mass by the static imbalance 23, m _d represents the dynamic imbalance Wherein r _s and r _d respectively represent the radius of the flywheel 21 and I _rr and I _zz represent the inertia of the flywheel 21, k denotes a coefficient of the spring (SP), the d _k denotes the distance of the flywheel 21 and the spring (SP), wherein c represents the coefficient of the damper (DP), wherein d _c is the flywheel (21 ) And the damper (DP).

By integrating the experimental modeling described with reference to FIGS. 3 and 4 and the analytical modeling described with reference to FIG. 5, the kinetic equations of the reaction wheel can be solved and the transfer force by the structural response of the reaction wheel can be calculated. The transfer force due to the structural response of the reaction wheel may be expressed as Equation (8) below, and this force may be the force that must ultimately be generated in the micro vibration emulator (100).

&Quot; (8) "

Referring to FIGS. 6A and 6B, the micro-oscillation profile can be determined based on the above-mentioned equation (8). Figure 6a shows the profile for force and Figure 6b shows the profile for torque. 120b, 120c, 120d, 120e, 120f so as to correspond to the micro-vibration profile as described above, and sets the actuators 120a, 120b, 120c, 120d, 120e, 120f based on the set drive frequency and drive voltage, 120c, 120d, 120e, and 120f to micro-vibrate the platform 110. FIG.

7 is a diagram illustrating a micro vibration emulator according to another embodiment of the present invention. 7 is a perspective view conceptually showing the arrangement of components of the micro vibration emulator 100a.

7, the micro vibration emulator 100a includes a platform 110, first to sixth actuators 120a, 120b, 120c, 120d, 120e, and 120f, and first to sixth Structures 130a, 130b, 130c, 130d, 130e, 130f. The micro vibration emulator 100a may further include a sensing unit 140 and a control unit 150a.

Compared with the micro vibration emulator 100 of FIG. 1, the micro vibration emulator 100a of FIG. 7 further includes a sensing unit 140, whereby the configuration of the control unit 150a can be changed. The platform 110, the first to sixth actuators 120a, 120b, 120c, 120d, 120e and 120f and the first to sixth structures 130a, 130b, and 120c included in the micro vibration emulator 100a of FIG. The configuration and operation of the micro vibration emulator 100 of FIG. 1 include the platform 110, the first to sixth actuators 120a, 120b, 120c, 120d, 120e, and 120f, And the first to sixth structures 130a, 130b, 130c, 130d, 130e, and 130f.

The sensing unit 140 may sense a minute vibration of the platform 110 by the first to sixth actuators 120a, 120b, 120c, 120d, 120e, and 120f to generate a sensing signal. According to an embodiment, the sensing unit 140 may be implemented with at least two sensors such as a three-axis acceleration sensor and a three-axis gyro sensor, or may be implemented with one sensor such as a six-axis force sensor .

The controller 150a may generate a drive signal for driving the actuators 120a, 120b, 120c, 120d, 120e, and 120f based on the sensing signal and the predetermined micro-vibration profile. That is, the controller 150a of FIG. 7 may further perform a feedback operation on the actuators 120a, 120b, 120c, 120d, 120e, and 120f based on the sensing signal.

8 is a diagram for explaining the operation of the micro vibration emulator of FIG. 8 is a block diagram conceptually showing the flow of data and / or signals for driving the micro vibration emulator 100a of FIG.

7 and 8, the control unit 150a may include an amplifier 151, a processor 152, and a driving driver 154. [

The amplifier 151 amplifies the sensing signal SS generated by the sensing unit 140 to generate the feedback signal FS. The feedback signal FS may include information related to the current driving state of the actuators 120a, 120b, 120c, 120d, 120e, 120f.

The processor 152 may generate the drive control signal DCON based on the feedback signal FS and the microscopic vibration profile 153. [ The driving driver 154 may generate the driving signal DRV based on the driving control signal DCON. That is, the processor 152 and the drive driver 154 generate a drive signal DRV such that the actuators 120a, 120b, 120c, 120d, 120e, and 120f operate in accordance with the microscopic vibration profile 153, 120b, 120c, 120d, 120e, and 120f are compared with the micro vibration profile 153 by comparing the current driving state of the actuator 120a, 120b, 120c, 120d, 120e, 120b, 120c, 120d, 120e, 120f can operate in accordance with the micro-oscillation profile 153 in the case of different operation.

9 is a block diagram illustrating a micro vibration simulation method according to an embodiment of the present invention.

Referring to FIG. 9, in the micro vibration modeling method according to the embodiment of the present invention, the micro vibration profile is determined by modeling the vibration source (step S100). For example, the oscillation source may be a reaction wheel included in the satellite system. The microvibration profile may be obtained by performing experimental modeling on the vibrating source (e.g., a reaction wheel) to obtain high frequency perturbation characteristics as described with reference to Figures 3, 4, 5, 6a and 6b, The disturbance characteristic due to dynamic and static imbalance is obtained by performing analytical modeling on the response wheel, and the propagation force due to the structural response of the reaction wheel is integrated by integrating the results of the experimental modeling and the analytical modeling, The microvibration profile can be determined.

The micro vibration emulator is driven based on the micro vibration profile (step S200). The micro vibration emulator 100 may be the micro vibration emulator 100 of FIG. 1 or the micro vibration emulator 100a of FIG. That is, the micro vibration emulator includes a cube-shaped platform, first to sixth actuators attached to the platform to micro-vibrate the platform and perform six-axis control on the platform, and first to sixth actuators The first to sixth structures respectively attached to the first to sixth structures.

In driving the micro vibration emulator, a drive signal may be generated based on the micro vibration profile (step S210). For example, it is possible to generate a drive control signal based on the microscopic vibration profile, and generate the drive signal based on the drive control signal. According to an embodiment, when the micro vibration emulator further includes a sensing unit, a drive control signal may be generated based on the sensing signal and the microscopic vibration profile provided by the sensing unit.

The platform may be micro-vibrated by driving at least one of the first to sixth actuators based on the drive signal (step S220). For example, two of the first through sixth actuators may be driven to translate the platform in a first axis, a second axis, or a third axis, and two of the first through sixth actuators The platform can be rotated about the first axis, the second axis, or the third axis by driving the dog.

10 is a block diagram illustrating a testing apparatus for a satellite system according to an embodiment of the present invention.

Referring to FIG. 10, a test apparatus 200 of a satellite system includes a plurality of emulators 212a, 212b,..., 212n and a control circuit 220.

The plurality of emulators 212a, 212b, ..., 212n simulate the operation of the components included in the satellite system. The plurality of emulators 212a, 212b, ..., 212n may constitute a simulation unit 210. [

The first emulator 212a of the plurality of emulators 212a, 212b, ..., 212n simulates a micro vibration environment caused by a vibration source among the components included in the satellite system. For example, the first emulator 212a may be one of the micro vibration emulators 100, 100a of FIGS. 1 and 7. The vibration source may be a reaction wheel.

The control circuit 220 controls the plurality of emulators 212a, 212b, ..., 212n. The control circuit 220 may include a plurality of controllers 222a, 222b, ..., 222n. The first controller 222a may control the first emulator 212a.

According to the embodiment, the first emulator 212a and the first controller 222a may be implemented as separate elements or as one element.

11 to 16 are diagrams for explaining a specific implementation example of a micro vibration emulator according to the embodiments of the present invention.

11, the micro vibration emulator of the present invention can be implemented by using the platform 6, the actuator 2, the structure 1, the spring 4, and the damper 5. The actuator 2 is a voice coil actuator, and the micro vibration emulator of FIG. 11 is one-dimensionally implemented for convenience.

The voice coil actuator can generate a magnetic force according to the Faraday's law. The external force corresponding to the magnetic force of the voice coil actuator can be expressed as the following equation (9) as a force generated in order to cancel the change of the magnetic field.

&Quot; (9) "

In Equation (9), f represents an external force corresponding to the magnetic force of the voice coil actuator, i represents a current flowing in the coil of the voice coil actuator, and 2nr represents a current of the coil exposed to the magnetic flux B represents the magnetic flux density, and T represents the force constant of the voice coil actuator.

The micro-vibration emulator of Fig. 11 can be modeled as a spring-damper system. In this case, the equation of motion for the micro vibration emulator of FIG. 11 can be expressed as the following equation (10), which can be expressed by the following equation (11).

&Quot; (10) "

&Quot; (11) "

In the above equations (10) and (11), m represents the mass of the structure (1), c represents the coefficient of the damper (5), and k represents the constant of the spring .

The total force transmitted to the platform 6 of the micro vibration emulator is equal in magnitude to the force transmitted to the structure 1 and is opposite in direction. That is, the total force transmitted to the platform 6 can be expressed by Equation (12) below, and the transfer function between the current flowing in the voice coil actuator and the total force can be expressed by Equation Can be expressed as shown in Equation 13 below.

&Quot; (12) "

&Quot; (13) "

In the above equations (12) and (13), F represents the total force transmitted to the platform (6).

The voltage-current equation for the micro-oscillation emulator of FIG. 11 can be expressed as Equation (14) below, and the transfer function between the voltage of the voice coil actuator and the total force can be expressed by the following equation Can be expressed as: " (15) "

&Quot; (14) "

&Quot; (15) "

V denotes the voltage of the voice coil actuator, L denotes the inductance of the voice coil actuator, R denotes the resistance value of the voice coil actuator, and V denotes the inductance of the voice coil actuator. In the equations (14) and (15) .

12, a frequency sweep (e.g., about 0 to about 100 mV) is applied to various input voltages (e.g., about 10 to 100 mV) to obtain a transfer function between voltage (V) ~ 200 Hz). As shown in FIG. 12, transfer functions for all input voltages are plotted, and on this basis, the linearity of the microvibration emulator system of FIG. 11 can be confirmed.

Referring to FIG. 13, curve fitting is performed to mathematically model the transfer function of the micro vibration emulator system of FIG.

Based on Equation (15), the mathematical modeling result of the transfer function between voltage and force can be expressed as Equation (16) below.

&Quot; (16) "

In the above equation (16), TF (f) represents a transfer function between the voltage and the force, and the gain represents a gain value determined on the micro vibration emulator system.

For example, when the force constant T of the voice coil actuator is determined to be about 6.9 N / A, the resistance value R of the voice coil actuator is determined to be about 1.7 ?, and the inductance L of the voice coil actuator ) Is determined to be about 0.6 mH, and the mass of the structure (1) can be determined to be about 730 g. In this case, the gain on the micro vibration emulator system is determined to be about 10.92, the constant k of the spring 4 is determined to be about 9481 N / m, and the damper 5) can be determined to be about 1.571.

Referring to Fig. 14, the input voltage profile of the micro vibration emulator is determined based on the determined transfer function between the voltage and the force and the determined micro-vibration profile (i.e., the profile for the force and moment), as shown in Figs. 6A and 6B do.

Specifically, first, the magnitude of disturbance force measured from the reaction wheel in the time domain is measured as shown in FIGS. 6A and 6B. Next, the input voltage to be applied to the emulator in the time domain can be obtained by dividing the force by the transfer function. However, since the transfer function is a frequency function, the disturbance force of the time domain measured in FIGS. And is transformed through a Fast Fourier Transform (FFT) process. After converting to the frequency domain, the input voltage profile of the emulator in the frequency domain can be obtained by dividing it by the transfer function. Finally, if the input voltage profile is changed from the frequency domain to the time domain through an inverse fast Fourier transform (FFT) process, the input voltage profile of the emulator in the time domain can be obtained.

Referring to FIG. 15, when the input voltage profile obtained as described above is input to the emulator, it is possible to compare disturbance forces between the reaction wheel and the emulator in the time domain and frequency domain measured by the sensor. The target at the top right of FIG. 15 is the waterfall graph of the reaction wheel, and the waveform at the bottom right is the waterfall graph of the micro vibration emulator of FIG. As shown in FIG. 15, it can be confirmed that the magnitude of the disturbance force generated is substantially the same as the actual disturbance force of the reaction wheel.

Referring to FIG. 16, three micro vibration emulators of FIG. 11 are three-dimensionally combined to realize a micro vibration emulator. The three-dimensionally implemented micro vibration emulator can more effectively simulate the actual micro vibration environment.

The micro vibration emulator according to the embodiments of the present invention can be used for developing a micro vibration isolation device capable of reducing a vibration level generated in a vibration source by simulating and analyzing a micro vibration environment by a vibration source.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It will be understood.

Claims (15)

A platform having a cube shape;
First to sixth actuators attached to first to sixth surfaces of the platform, respectively, for micro-oscillating the platform based on a drive signal and performing six-axis control on the platform;
First to sixth structures respectively attached to the first to sixth actuators; And
And a sensing unit for sensing a minute vibration of the platform by the first to sixth actuators and generating a sensing signal. The method according to claim 1,
The platform translates in a first axial direction based on a first actuator attached to a first side of the platform and a second actuator attached to a second side of the platform opposite the first side of the platform, Based on a third actuator attached to a third side of the platform adjacent a first side of the platform and a fourth actuator attached to a fourth side of the platform opposite the third side of the platform, A fifth actuator that translates in a second axial direction perpendicular to the first axis and is attached to a fifth side of the platform adjacent to the first and third sides of the platform and a second actuator that is opposite to the fifth side of the platform Wherein said platform translates in a third axial direction perpendicular to said first and second axes based on said sixth actuator attached to a sixth side of the platform. 3. The method of claim 2,
Wherein the platform rotates about the first axis based on the third actuator, the fourth actuator, the fifth actuator, and the sixth actuator, and the first actuator, the second actuator, the fifth actuator, Wherein the platform rotates relative to the second axis based on the sixth actuator and the platform is positioned on the third axis based on the first actuator, the second actuator, the third actuator, and the fourth actuator, Wherein the rotating body is rotated with respect to the body. delete The method according to claim 1,
Further comprising a control section for generating said drive signal based on a predetermined microscopic vibration profile,
Wherein,
A processor for generating a drive control signal based on the microscopic vibration profile; And
And a drive driver for generating the drive signal based on the drive control signal. delete The method according to claim 1,
Further comprising a control section for generating said drive signal based on a predetermined microscopic vibration profile,
Wherein,
An amplifier for amplifying the sensing signal to generate a feedback signal;
A processor for generating a drive control signal based on the feedback signal and the microvibration profile; And
And a drive driver for generating the drive signal based on the drive control signal. 8. The method of claim 7,
The micro-vibration emulator simulates micro-vibrations by a reaction wheel included in a satellite system,
Wherein the microscopic vibration profile is determined based on the driving frequency, the harmonic excitation force coefficient, and the harmonic number of the reaction wheel obtained through modeling of the reaction wheel. A plurality of emulators for simulating the operation of components included in the satellite system; And
And a control circuit for controlling the plurality of emulators,
Wherein the first emulator of the plurality of emulators simulates a micro vibration environment by a vibration source of the components,
A platform having a cube shape;
First to sixth actuators attached to first to sixth surfaces of the platform, respectively, for micro-oscillating the platform based on a drive signal and performing six-axis control on the platform; And
Wherein the first to sixth actuators are attached to the first to sixth actuators, respectively. 10. The method of claim 9,
The platform translates in a first axial direction based on a first actuator attached to a first side of the platform and a second actuator attached to a second side of the platform opposite the first side of the platform, Based on a third actuator attached to a third side of the platform adjacent a first side of the platform and a fourth actuator attached to a fourth side of the platform opposite the third side of the platform, A fifth actuator that translates in a second axial direction perpendicular to the first axis and is attached to a fifth side of the platform adjacent to the first and third sides of the platform and a second actuator that is opposite to the fifth side of the platform Wherein the platform translates in a third axial direction perpendicular to the first and second axes based on the sixth actuator attached to a sixth side of the platform. 11. The method of claim 10,
Wherein the platform rotates about the first axis based on the third actuator, the fourth actuator, the fifth actuator, and the sixth actuator, and the first actuator, the second actuator, the fifth actuator, Wherein the platform rotates relative to the second axis based on the sixth actuator and the platform is positioned on the third axis based on the first actuator, the second actuator, the third actuator, and the fourth actuator, Wherein the rotating body is rotated with respect to the ground. 10. The method of claim 9,
Wherein the control circuit includes a first control unit for controlling the first emulator, and the first control unit generates the drive signal based on a predetermined microscopic profile. 13. The apparatus according to claim 12,
A processor for generating a drive control signal based on the microscopic vibration profile; And
And a drive driver for generating the drive signal based on the drive control signal. 13. The apparatus of claim 12, wherein the first emulator comprises:
Further comprising a sensing unit for sensing a minute vibration of the platform by the first to sixth actuators and generating a sensing signal. Performing modeling on the vibration source to determine a microvibration profile; And
And driving the micro vibration emulator based on the micro vibration profile,
In the micro vibration emulator,
A platform having a cube shape;
And first to sixth actuators attached to the first to sixth surfaces of the platform, respectively, for micro-oscillating the platform based on a drive signal corresponding to the micro-vibration profile and performing six- )field; And
Wherein the first to sixth actuators are attached to the first to sixth actuators, respectively.

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