KR20210079793A - Apparatus for simulating micogravity and a control method of the same - Google Patents

Abstract

The present invention relates to a device for simulating microgravity, and a method for controlling the same. According to one embodiment of the present invention, a microgravity simulation device comprises: an outer frame; a first rotating unit for rotating the outer frame; an inner frame positioned inside the outer frame; a second rotating unit configured to rotate the inner frame; a mounting unit which is provided to rotate integrally with the second rotating unit and to which a container in which an object is received is mounted; and a control unit for controlling an angular speed of the second rotating unit so that a conversion speed in the direction of a gravity vector is changed as a micro-region in which a gravity vector generated by the rotation of the first rotating unit and the second rotating unit stays becomes narrower. A gravity vector can be more uniformly distributed.

Description

Apparatus for simulating microgravity and a control method of the same}

The present invention relates to a device for simulating microgravity and a method for controlling the same.

Recently, interest in space exploration is increasing in Korea and abroad, and interest in space life sciences including manned space exploration is also increasing. In this case, simulating a gravitational environment in space, for example, a microgravity environment or a partial gravity environment, is essential for examining the effects of space exploration and space medicine to be promoted in the future.

Specifically, in experiments with cells in the field of space medicine and biomedical life, an environment that can simulate microgravity is created to conduct comparison experiments with the gravity of 1 g on Earth, and to examine the effects of changes in cell characteristics and death of cancer cells. Many attempts are being made.

For space medicine, it is important to observe changes in cells that occur in the space environment. Compared to normal cells, research results have been reported that cancer cells grow slower in weightless or microgravity environments or are sensitive to anticancer drugs. Therefore, it is expected that the use of microgravity to kill cancer cells and decrease cancer cell growth will create new fields in the field of biomedical science in the future.

Experiments in space are expensive and time consuming. Therefore, attempts to simulate the microgravity environment on the ground are continuously being made. In order to simulate the microgravity environment on the ground, a clinostat or a random positioning machine (RPM) has been mainly used. Basically, in order to simulate microgravity, an algorithm that approaches the average value of the gravity vector felt by the cell or test sample to 0 in the coordinate system of the cell or test sample has been used. To this end, it is important to uniformly distribute the direction of the gravity vector. This is because, in the case of a non-uniform distribution, the effect as an error on an object such as a cell may be increased due to the non-uniformity of the gravity vector.

However, the uniform distribution of the gravitational bump that can be obtained through the conventional microgravity simulating device and control method has certain limitations. In particular, there is a problem in that it is difficult to disperse the concentration of gravity vectors at the poles. In other words, there is a certain limit in obtaining a uniform distribution of the gravity vector by intensively gathering the gravity vector at the pole.

Therefore, there is a need to provide an apparatus and a control method capable of simulating microgravity by more effectively generating a gravity vector having a uniform distribution.

An object of the present invention is to solve the problems of the conventional gravity simulating apparatus and its control method.

Through an embodiment of the present invention, an object of the present invention is to provide a microgravity simulating device and a control method thereof in which a gravity vector can be more uniformly distributed.

Through an embodiment of the present invention, it is an object to provide a microgravity simulating apparatus and a control method thereof that can effectively reduce the concentration of the gravity vector at the pole position.

An object of the present invention is to provide an apparatus for simulating microgravity that can effectively reduce the position error of the pole over time and a method for controlling the same.

An object of the present invention is to provide an apparatus for simulating microgravity and a method for controlling the same, in which an average gravity vector that can be received by a cell or an experimental sample converges to zero in a very short time.

In order to achieve the above object, according to an embodiment of the present invention, the first rotating portion for rotating the outer frame and the outer frame; an inner frame positioned inside the outer frame and a second rotating part for rotating the inner frame; a mounting unit provided to rotate integrally with the second rotating unit and to which a container in which an object is accommodated; and a control unit for controlling the angular velocity of the second rotating unit so that the micro-region in which the gravity vector generated by the rotation of the first rotating unit and the second rotating unit stays becomes narrower, so that the conversion speed in the direction of the gravitational vector is varied. A gravity simulator may be provided.

The control unit may control the angular speed of the second rotation unit so that as the microregion becomes narrower, the conversion speed in the direction of the gravity vector increases.

The controller may control the angular velocity of the second rotation unit to increase as the microregion becomes narrower.

Preferably, the control unit controls the angular velocity of the second rotating unit to be less than or equal to a preset maximum value.

The control unit, the angular velocity of the second rotation unit <Equation 1>

is calculated through

Here, θ is the value of the latitude of the microregion ds, ω(θ) is the angular velocity of the second rotating part 6, and k and ω _max are preferably constant values that can be changed according to experimental conditions.

A sensor for sensing an angle of the second rotation unit may be further included. The sensor may be a Hall sensor.

In order to reduce the occurrence of a cumulative error over time with respect to the width position of the gravity vector, a feedback controller may further include a feedback controller for controlling the angular velocity of the second rotation unit based on the angular value sensed by the constant sensor have.

The feedback controller may be included in the control unit.

The control unit may include a first motor control device and a second motor control device for respectively controlling the rotation of the first rotating unit and the second rotating unit.

When the control unit provides the command angular velocity to each motor control device, the motor control device may control the first rotation unit and the second rotation unit to rotate by following the command angular velocity.

The feedback controller may include a proportional unit that receives an angle error value calculated through an angle value sensed by the sensor.

The feedback controller may include a differentiator that receives a difference value between the angular error values in the current step and the previous step.

Preferably, the control unit determines the angular velocity of the final second rotating unit by comparing the angular velocity of the second rotating unit corrected through the feedback controller with Equation (1).

In order to achieve the above object, according to an embodiment of the present invention, a first rotating part for rotating the outer frame and the outer frame, the inner frame located inside the outer frame, and a second rotating part for rotating the inner frame And, in the control method of a microgravity simulating apparatus comprising a mounting part which is provided to rotate integrally with the second rotating part and to which the container in which the object is accommodated, the microgravity is simulated by rotating the first rotating part and the second rotating part. In the step of simulating the microgravity, as the microregion in which the gravity vector generated by the rotation of the first and second rotation parts stays becomes narrower, the conversion speed in the direction of the gravity vector is variable. The control method of the microgravity simulating device, characterized in that it comprises the step of variably controlling the angular speed of the second rotating part can be provided.

The step of simulating the microgravity may include controlling the first rotating part at a preset angular velocity.

The variable control of the angular velocity of the second rotating part is preferably performed so that the conversion speed in the direction of the gravity vector increases as the microregion becomes narrower.

The variable control of the angular velocity of the second rotation unit is preferably performed so that the angular velocity of the second rotation unit increases as the micro region becomes narrower.

The variable control of the angular velocity of the second rotation unit is preferably controlled so that the angular velocity of the second rotation unit is equal to or less than a preset maximum value.

According to the microgravity simulating apparatus and its control method, it is possible to obtain a gravity vector distribution having a more uniform distribution. In addition, it is possible to significantly reduce the concentration of the gravity vector at the pole position. In addition, it is possible to significantly reduce the occurrence of an error in the pole position.

Through an embodiment of the present invention, it is possible to provide a microgravity simulating device and a control method thereof in which the gravity vector can be more uniformly distributed.

Through an embodiment of the present invention, it is possible to provide a microgravity simulating device and a control method thereof that can effectively reduce the concentration of the gravity vector at the pole position.

Through one embodiment of the present invention, it is possible to provide a microgravity simulating device and a control method thereof that can effectively reduce the position error of the pole over time.

According to an embodiment of the present invention, it is possible to provide a microgravity simulating device and a method for controlling the same, in which the average gravity vector that a cell or an experimental sample can receive can converge to zero in a very short time.

1 shows an example of a microgravity simulating device that can be applied to the present invention,
Figure 2 shows the gravity vector distribution through the conventional micro-gravity simulating device,
3 shows the relationship between latitude, microregion, and gravity vector in the three-dimensional coordinate system of the inner frame;
Figure 4 shows the control configuration of the microgravity simulating device according to an embodiment of the present invention.
Figure 5 shows the gravity vector distribution through the microgravity simulating device according to an embodiment of the present invention,
Figure 6 shows a feedback control state applied to the microgravity simulating device according to an embodiment of the present invention,
Figure 7 shows the decrease trend of the average gravity vector through the conventional micro-gravity simulating device,
Figure 8 shows the decrease trend of the average gravity vector through the microgravity simulating device according to an embodiment of the present invention,
9 shows a control method of a microgravity simulating device according to an embodiment of the present invention.

Hereinafter, an apparatus for simulating microgravity and a method for controlling the same according to an embodiment of the present invention will be described in detail with reference to the drawings.

First, the microgravity simulating device will be described in detail.

1 is a perspective view of a copying device that can be applied to an embodiment of the present invention.

Referring to FIG. 1 , the copying device 10 includes an outer frame 1 that rotates about a first axis of rotation 4a and an inner frame that rotates about a second axis of rotation 6a from the inside of the outer frame 1 . (7) may be included.

The copying device 10 rotates in association with the inner frame 7 and may include a mounting part 2 in which an object is accommodated. A microorganism, a cell, or a tissue, which is an object, may be mounted on the mounting unit together with the medium. That is, the mounting part 2 may be provided so that the medium container is mounted. Accordingly, the mounting unit may be referred to as a medium mounting unit or a medium container mounting unit.

The inner frame 7 may be positioned inside the outer frame 1 , and the mounting part 2 may be positioned inside the inner frame 7 .

A first rotating part 4 for rotating the outer frame 1 may be provided, and a second rotating part 6 may be provided for rotating the inner frame 7 . The first rotation part 4 may be provided to have a coaxial axis with the first rotation shaft 4a, and the second rotation part 6 may be provided to have a coaxial axis with the second rotation shaft 6a.

The copying device 10 may include a base 3 and a pair of support bars 3a and 3b extending vertically from the base 3 . An outer frame 1 rotatably provided between the pair of support bars 3a and 3b may be provided.

As shown, the first rotating shaft 4a and the second rotating shaft 4b are formed to be orthogonal to each other, and the rotational driving of the first rotating unit 4 and the second rotating unit 6 is controlled through the control unit 20 . can be

An object such as a cell is mounted on the mounting unit 2 in a state accommodated in the medium container, and the first rotating unit 4 and the second rotating unit 6 are controlled by the control unit 20 to the outer frame (1) And the inner frame 7 is rotated. That is, as the outer frame 1 and the inner frame 7 rotate through the first rotating part 4 and the second rotating part 6 , the mounting part 2 is connected to the first rotating shaft 4a and the second rotating part 6 . It rotates about the rotating shaft 6a, whereby an acceleration acts on the object to simulate a desired level of gravity.

However, the conventional copying apparatus and its control method were merely controlling the first rotating part 4 and the second rotating part 6 to rotate at separate angular speeds, respectively. In other words, the outer frame 1 and the inner frame 7 were rotated in accordance with each preset angular velocity to simulate a preset gravity level for the object accommodated in the medium.

2 shows the distribution of gravity vectors in the conventional microgravity simulation algorithm.

As shown, it can be observed that the gravity vector is concentrated at the pole position, that is, (0, 1, 0) coordinates and (0, -1, 0) in the xyz three-dimensional coordinates. In other words, it can be seen that the density increases as the gravity vector is concentrated at the two pole positions.

Therefore, since the gravity vector is concentrated at the pole position, a certain limit inevitably follows in obtaining a gravity vector having a uniform distribution.

FIG. 3 shows a gravitational vector and a microregion ds where the gravitational vector stays when the gravitational vector and the gravitational vector affect a cell or an experimental sample in the xyz three-dimensional coordinate system for the inner frame 7 .

If the value of the latitude of the microregion ds is θ, the angular velocity of the second rotating unit 6 when it corresponds to the microregion is ω(θ). And it can be said that the microregion ds is 2πr ^{2 cosθdθ.}

Therefore, it can be seen that the microregion changes as the latitude θ value changes. That is, it can be seen that the area or width of the microregion changes as the latitude θ value changes.

The present inventor found that when the gravity vector affects cells or test samples, if the microregion (ds) where the gravity vector stays becomes narrower, the concentration of the gravity vector at the pole can be alleviated by allowing the gravitational vector to get out of the narrowed microregion more quickly. could pay attention to

In other words, by changing the direction of the gravity vector faster when the microregion is narrowed, the concentration of the gravity vector at the pole can be relaxed.

In order to change the direction of the gravitational vector, an increase or decrease in the angular velocity can be considered.

Due to the characteristics of the cosine function, as latitude θ approaches π/2 and 3π/2, it gradually decreases and converges to 0. That is, as the latitude θ approaches π/2 and 3π/2, the microregion ds gradually becomes narrower. This is because the microregion is proportional to cosθ.

The inventors of the present invention can change ω(θ) as the microregion ds becomes narrower so that the concentration of the gravity vector at the pole is relaxed. More specifically, by increasing ω(θ), the concentration of gravity vectors at the poles could be relaxed.

Specifically, the absolute value of the reciprocal (1/cosθ) of the cosine function gradually increases as latitude θ approaches π/2 and 3π/2. And when latitude θ is π/2 and 3π/2, the absolute value of the reciprocal of the cosine function (1/cosθ) is infinite.

Therefore, the angular velocity ω(θ) can be increased as the microregion ds becomes narrower by using the cosine function and the reciprocal of the cosine function. On the other hand, since ω(θ) cannot be infinitely increased, the maximum value of the angular velocity ω(θ) may be preset. In other words, as the microregion ds becomes narrower, the angular velocity ω(θ) may be increased, but only up to a preset maximum angular velocity.

Reflecting the above-described relationship, the angular velocity ω (θ) of the second rotating part 6 can be expressed by Equation 1 as follows.

<Equation 1>

That is, as the microregion ds becomes narrower, the angular velocity ω(θ) increases, but the expression limiting the maximum angular velocity up to the _{maximum value ω max can be completed.}

The microregion is proportional to cosθ. On the other hand, the angular velocity ω(θ) is proportional to the absolute value of the reciprocal of cosθ. Therefore, it can be said that the microregion and the angular velocity have opposite tendencies. That is, as the microregion decreases, the angular velocity increases.

Since the angular velocity cannot be infinitely increased, the angular velocity increases as the micro-region decreases, but the maximum value is limited.

Here, k and ω _max are constant values that can be adjusted according to experimental conditions. As an example, the value of k may be 0.119834 rad/s and ω _max may be 1.19834 rad/s.

Therefore, according to an embodiment of the present invention, the angular velocity of the second rotation unit 6 is not controlled to follow a preset value, but may be controlled to follow a value calculated through Equation 1, for example.

Figure 4 shows the control configuration of the microgravity simulating device according to an embodiment of the present invention.

The first rotation unit 4 and the second rotation unit 6 may include a motor, and rotation may be controlled through the first motor control unit 4b and the second motor control unit 6b, respectively.

When the control unit 30 commands each motor control device an angular velocity value, the motor control device may control the rotating parts to rotate according to the commanded angular velocity value.

As described above, in the present embodiment, variable control is performed in which the angular velocity of the second rotation unit is varied according to a condition other than a preset angular velocity. In addition, feedback control may be performed through the feedback controller 16 in order to reduce the accumulated error of the pole position.

To this end, a sensor 15 for detecting the rotation angle of the second rotating part may be provided. The sensor may include a Hall sensor.

The rotation angle sensed by the Hall sensor is input to the feedback controller 16 and/or the control unit 20 so that the angular speed of the second rotation unit is variably controlled through the second motor control device 6b, and error correction is also performed. can

Microgravity simulator may include a UI (17). That is, it may include a user interface. The experimenter may manipulate the UI to make the microgravity simulator work, and it may be possible to change the gravity level to be simulated.

5 shows the distribution of gravity vectors in the microgravity simulation algorithm according to an embodiment of the present invention.

Comparing with the conventional gravity vector distribution shown in FIG. 2 , it can be seen that the gravity vector can be uniformly distributed in a highly improved form. In other words, it can be seen that the portion where the density of the gravity vector is concentrated is significantly reduced, and the concentration of the gravity vector in the pole portion is significantly reduced.

On the other hand, the present inventors have noted that, in the case of the pole position, a cumulative error occurs over time, which may hinder the convergence of the accurate gravity vector. Therefore, an attempt was made to correct the angular velocity and the angular error caused by the angular velocity accumulation.

Specifically, the feedback controller shown in FIG. 6 may be mounted to correct the angular velocity and the angle error due to the angular velocity accumulation.

When the actual angle value of the n-th step is input through the sensor 16, the angular velocity may be calculated by comparing it with the angle in the previous step (step n-1). Then, the difference between the angular velocity in the current stage and the angular velocity in the previous stage may be calculated.

Accordingly, the current angular velocity actually input may be corrected by comparing it with the angular velocity to be reached in the previous stage (the angular velocity in the previous stage actually input). That is, the actual input current angular velocity may be finally determined through Equation 1 above.

Specifically, the feedback controller calculates an angle error from an actual angle value sensed through the sensor 16 (eg, a Hall sensor). The current angular error is used for angular velocity correction through a proportional device. In addition, the difference between the current angle error and the angle error in the previous step is used for angular velocity correction through a differentiator.

The current angular velocity can be calculated through the angular velocity in the previous step, the component input from the proportional unit, and the component input from the differentiator. The calculated current angular velocity is input to Equation 1, and finally the current angular velocity is input. In other words, the rotation of the second rotation unit 6 is controlled to follow the finally input angular velocity.

As described above, it has been explained that the average gravity vector should converge to zero in microgravity simulation. Here, the time it takes for the average gravity vector to converge to zero is important. In other words, the shorter the time taken for zero convergence of the average gravity vector, the more effective microgravity simulation can be performed.

7 shows the change of the average gravity vector and the change of the average gravity vector sum on the x, y, and z axes in the conventional microgravity simulating device.

7 shows the change of the average gravity vector and the change of the average gravity vector sum on the x, y, and z axes in the microgravity simulating device according to an embodiment of the present invention.

Comparing the graphs shown in FIG. 7 and FIG. 8 , it can be seen that the time until reaching 0 convergence of the average gravity vector component of each of the x, y, and z axes and 0 convergence of the average gravity vector sum is significantly different. That is, it can be seen that the time required to reach zero convergence is significantly reduced through an embodiment of the present invention.

Therefore, according to an embodiment of the present invention, it can be seen that the distribution of the gravity vector can be generated more uniformly, and the average gravity vector can be converged to 0 in a faster time.

Hereinafter, with reference to FIG. 9, a control method of the microgravity simulating apparatus according to an embodiment of the present invention will be described in detail.

When the user manipulates the microgravity simulating device to be driven through the UI, the microgravity simulation step (S10) is performed. The microgravity simulation step may be performed for a preset time. Of course, the user may forcibly stop the microgravity simulation step before the lapse of a preset time.

The microgravity simulation step ( S10 ) may include a first rotating part rotating step ( S11 ) and a second rotating part rotating step ( S12 ). These steps may start at the same time and end at the same time.

The first rotating part rotating step (S11) may be performed to follow a preset angular velocity. That is, the preset angular velocity may not be changed during the microgravity simulation step.

On the other hand, the second rotating part rotating step (S12) may be performed to follow the variable angular velocity. That is, the second rotating part angular velocity variable control step (S13) may be performed.

Here, the angular velocity of the second rotation unit may be calculated through Equation 1 described above. That is, as the microregion becomes narrower, the angular velocity of the second rotation unit can be calculated to be larger. As the angular velocity of the second rotating part increases, a more uniform distribution of the gravity vector can be expected.

Pole positions may not be fixed over time due to error accumulation. Therefore, it is necessary to fix the pole position by minimizing the accumulation of errors.

To this end, the feedback control (S14) may be performed by sensing the rotation angle of the second rotation unit. The angular velocity of the second rotation unit calculated through the feedback control S14 may be reflected in Equation 1 to calculate the final command angular velocity.

According to an embodiment of the present invention, it can be seen that a microgravity environment that is as close as possible to the microgravity environment of the real universe can be created in various biomedical science experiments through the microgravity environment simulation.

One… outer frame
2… (Medium container) Mounting part
3… Base
4… 1st rotation part
6… 2nd rotating part
7… inner frame
10… rotator
15… sensor
16… feedback controller
17… UI
20… control

Claims (15)

a first rotating part for rotating the outer frame and the outer frame;
an inner frame positioned inside the outer frame and a second rotating part for rotating the inner frame;
a mounting unit provided to rotate integrally with the second rotating unit and to which a container in which an object is accommodated is mounted; And
Microgravity including a control unit for controlling the angular velocity of the second rotating unit so that the micro-region in which the gravity vector generated by the rotation of the first rotating unit and the second rotating unit stays becomes narrower, so that the conversion speed in the direction of the gravitational vector is changed imitation device. The method of claim 1,
The control unit, micro-gravity simulating device, characterized in that for controlling the angular speed of the second rotation unit so that the conversion speed in the direction of the gravity vector increases as the micro region becomes narrower. 3. The method of claim 2,
The control unit, Microgravity simulating device, characterized in that the control so that the angular velocity of the second rotation unit increases as the microregion becomes narrower. 4. The method of claim 3,
The control unit, Microgravity simulating device, characterized in that the control so that the angular velocity of the second rotating part is less than or equal to a preset maximum value. 5. The method of claim 4,
The control unit, the angular velocity of the second rotation unit <Equation 1>

is calculated through
Here, θ is the value of latitude of the microregion ds, ω(θ) is the angular velocity of the second rotating part 6, and k and ω _max are constant values that can be changed according to experimental conditions. imitation device. 6. The method of claim 5,
Microgravity simulating device, characterized in that it further comprises a sensor for sensing the angle of the second rotating part. 7. The method of claim 6,
In order to reduce the occurrence of a cumulative error over time with respect to the width position of the gravity vector, a feedback controller for controlling the angular velocity of the second rotating part based on the angular value detected by the constant sensor is further included A microgravity simulator characterized by. 8. The method of claim 7,
The feedback controller, Microgravity simulating device, characterized in that it comprises a proportional unit receiving an angular error value calculated through the angular value detected by the sensor. 9. The method of claim 8,
The feedback controller, Microgravity simulating device, characterized in that it comprises a differentiator that receives the difference value for the angle error value in the current step and the previous step. 10. The method of claim 9,
The control unit, Microgravity simulating device, characterized in that for determining the angular velocity of the final second rotating part by comparing the angular velocity of the second rotating part corrected through the feedback controller with Equation (1). A first rotator for rotating the outer frame and the outer frame, a second rotator for rotating the inner frame and the inner frame positioned inside the outer frame, and the second rotator are provided to rotate integrally with the object. In the control method of a microgravity simulating device comprising a mounting part to which the container is mounted,
Comprising the step of simulating microgravity by rotating the first and second rotation parts,
The step of simulating the microgravity is,
Variably controlling the angular speed of the second rotating unit so that the micro-region in which the gravity vector generated by the rotation of the first rotating unit and the second rotating unit stays becomes narrower, so that the conversion speed in the direction of the gravitational vector is varied. Control method of microgravity simulating device, characterized in that. 12. The method of claim 11,
The step of simulating the microgravity is,
Control method of a microgravity simulating device, characterized in that it comprises the step of controlling the first rotation unit at a preset angular velocity. 12. The method of claim 11,
The control method of the microgravity simulating apparatus, characterized in that the variable control of the angular speed of the second rotating part is performed so that the conversion speed in the direction of the gravity vector increases as the microregion becomes narrower. 13. The method of claim 12,
The control method of the microgravity simulating apparatus, characterized in that the variable control of the angular velocity of the second rotating part is performed so that the angular velocity of the second rotating part is increased as the microregion becomes narrower. 15. The method of claim 14,
The control method of the microgravity simulating apparatus, characterized in that the angular velocity variable control of the second rotating part is controlled so that the angular velocity of the second rotating part is less than or equal to a preset maximum value.

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