Abstract:
The gravity control apparatus ( 1 ) comprises: a first rotating body ( 10 ) that rotates along a first shaft ( 11   a ) as a result of being driven by a first driving device; a second rotating body ( 20 ) that rotates along a second shaft that is orthogonal to the first shaft ( 11   a ) within the region of rotation of the first rotating body ( 10 ) as a result of being driven by a second driving device; an accelerometer ( 40 ) that is set at any position on the second rotating body ( 20 ) and detects acceleration; and a control device ( 50 ) that controls driving by the first driving device and the second driving device. The control device ( 50 ) controls driving by the first driving device and the second driving device on the basis of acceleration data detected by the accelerometer ( 40 ).

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to a gravity control apparatus. 
       BACKGROUND ART 
       [0002]    In various fields, apparatus capable of controlling gravity are proposed. For example, from cell cultivation experiments and/or the like in space, it is known that growth of living things is greatly influenced by gravity, and apparatus have been proposed that change gravity and generate pseudo-microgravity so as to accomplish experiments on cell cultivation in a zero-gravity environment or a low-gravity environment even on the earth. 
         [0003]    For example, as disclosed in Patent Literature 1, there is an apparatus comprising a first rotating body that rotates around a first rotation shaft, and a second rotating body that rotates around a second rotation shaft that is orthogonal to the first rotation shaft, and causes a culture vessel to rotate three-dimensionally. 
       CITATION LIST 
     Patent Literature 
       [0004]    Patent Literature 1: Unexamined Japanese Patent Application Kokai, Publication No. 2010-193910. 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0005]    In Patent Literature 1, rotation of the first rotating body and the second rotating body is controlled on the basis of complex computation formulas, thus presenting the problem that the manufacturing cost of the apparatus is high. 
         [0006]    In consideration of the foregoing, it is a an objective of the present disclosure to provide a gravity control apparatus for which manufacturing costs can be reduced because it is possible to control rotation of the first rotating body and second rotating body with a simple process. 
       Solution to Problem 
       [0007]    The gravity control apparatus according to the present disclosure comprises: 
         [0008]    a first rotating body that rotates along a first axis as a result of being driven by a first driving device; 
         [0009]    a second rotating body that rotates along a second axis orthogonal to the first axis, within the region of rotation of the first rotating body, as a result of being driven by a second driving device; 
         [0010]    an accelerometer that is positioned at any position on the second rotating body and detects acceleration; and 
         [0011]    a control device that controls driving of the first driving device and the second driving device; 
         [0012]    wherein the control device controls driving by the first driving device and the second driving device on the basis of acceleration data detected by the accelerometer. 
         [0013]    In addition, the gravity control apparatus according to claim  1 , wherein the control device calculates an acceleration vector from Equation 1 below and controls driving by the first driving device and the second driving device so that the integral of the acceleration vector over a prescribed time becomes a prescribed value: 
         [0000]      [Formula 1] 
         [0000]        A=g+rω   2   (Equation 1),
 
         [0014]    where A, g, r, and ω respectively represent an acceleration vector at an arbitrary point P in the second rotating body, a gravitational acceleration vector at the point P, a distance vector from a point of intersection of the first axis and the second axis to the point P, and an angular velocity vector at the point P. 
       Advantageous Effects of Invention 
       [0015]    With the gravity control apparatus according to the present disclosure, it is possible to reduce manufacturing costs because it is possible to control rotation of the first rotating body and second rotating body with a simple process. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is an oblique view showing a state in which a gravity control apparatus is operating; and 
           [0017]      FIG. 2  is a partial cross-sectional view showing an internal structure of a gravity control apparatus. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0018]    Below, a gravity control apparatus according to an exemplary embodiment is described with reference to the drawings. A gravity control apparatus  1  comprises a first rotating body  10 , first shafts  11   a  and  11   b,  a first driving device  12  housed in a first driving device housing unit  32 , a second rotating body  20 , a second shaft  21   a  and  21   b,  a second driving device  22  housed in a second driving device housing unit  33 , a support platform  30 , support members  31   a  and  31   b,  an acceleration detection device  40  and a control device  50 , as shown in  FIG. 1  and  FIG. 2 . 
         [0019]    The support members  31   a  and  31   b  are established opposite each other on the support platform  30 . The first rotating body  10 , the second rotating body  20  and/or the like are supported between the support members  31   a  and  31   b.    
         [0020]    The first rotating body  10  is axially supported on the first shafts  11   a  and  11   b.  The first shafts  11   a  and  11   b  are positioned coaxially. One end of the first shaft  11   a  is connected to the first rotating body  10 , and in addition, the other end is connected to an output shaft  12   a  of the first driving device  12 . The first shaft  11   b  may be in a configuration fixed to the support member  31   a  with the first rotating body  10  in a slidable state, or may be in a configuration fixed to the first rotating body  10  and slidable with respect to the support member  31   a.  With this structure, when the first driving device  12  drives, the first shaft  11   a  connected to the output shaft  12   a  rotates, and the first rotating body  10  rotates around the first shafts  11   a  and  11   b.    
         [0021]    The first rotating body  10  here is a rectangular frame, and the second rotating body  20  is placed within and has space to rotate in the inside region of the rotation region of the first rotating body  10 . 
         [0022]    The second shafts  21   a  and  21   b  are respectively attached to facing frames of the first rotating body  10 . The second shafts  21   a  and  21   b  are positioned coaxially. The second rotating body  20  is attached to the second shafts  21   a  and  21   b.    
         [0023]    One end of the second shaft  21   a  is connected to the second rotating body  20 , and in addition, the other end is connected to a bevel gear  28 . When the bevel gear  28  rotates, the second rotating body  20  rotates in the inside region of the first rotating body  10 . One end of the second shaft  21   b  is connected to the second rotating body  20 , and the other end is slidably attached to the first rotating body  10 . 
         [0024]    The second rotating body  20  is a place to which various objects to be placed in various gravitational environments, such as microgravity environments or supergravity environments, can be attached. For example, a sealed culture vessel for cell cultivation can be attached to the second rotating body  20 , and it is possible to accomplish cell culturing experiments under various gravitational environments, such as microgravity environments or supergravity environments. Attachment of the culture vessel to the second rotating body  20  is fixed using a cord, rubber, fixing hardware and/or the like to an arbitrary location on the second rotating body  20 . In addition, an attachment unit for attaching a cell vessel may be formed in the second rotating body  20 . 
         [0025]    The second driving device  22  is installed on the support member  31   a.  An output shaft  22   a  of the second driving device  22  is installed parallel to the first shafts  11   a  and  11   b,  and a gear  23  is installed on the output shaft  22   a.  The gear  23  is installed so as to engage with a gear  24  slidably attached to the first shaft  11   b.    
         [0026]    The gear  24  is formed integrally with a bevel gear  25  positioned inside the first rotating body  10 . The first shaft  11   b  penetrates the gear  24  and the bevel gear  25 , and the gear  24  and the bevel gear  25  are slidably configured with respect to the first shaft  11   b.    
         [0027]    Inside the first rotating body  10 , rotational power transfer members  26  and  27  that transfer drive power from the second driving device  22  to the second shaft  21   a  are positioned. 
         [0028]    The rotational power transfer member  26  comprises bevel gears  26   a  and  26   c  respectively attached to the two ends of a shaft  26   b.  The shaft  26   b  is slidably positioned in the first rotating body  10 , and is positioned orthogonal to the first shaft  11   a  (parallel to the second shafts  21   a  and  21   b ). 
         [0029]    On the other hand, the rotational power transfer member  27  comprises bevel gears  27   a  and  27   c  respectively attached to the two ends of a shaft  27   b.  The shaft  27   b  is slidably positioned in the first rotating body  10  and is positioned parallel to the first shaft  11   a  (orthogonal to the second shafts  21   a  and  21   b ). 
         [0030]    The bevel gear  26   c  of the rotational power transfer member  26  engages with the bevel gear  25  attached to the first shaft  11   b.  In addition, the bevel gear  26   a  engages with the bevel gear  27   a  of the rotational power transfer member  27 . In addition, the bevel gear  27   c  engages with the bevel gear  28  attached to the second shaft  21   a  connected to the second rotating body  20 . 
         [0031]    For the first driving device  12  and the second driving device  22 , electric driving devices capable of supplying rotational power to the first rotating body  10  and the second rotating body  20 , and for example a motor such as a servo motor, a stepping motor and/or the like capable of controlling with high precision rotation of the output shafts  12   a  and  22   a  is used. 
         [0032]    The acceleration detection device  40  is positioned at an arbitrary position on the second rotating body  20 , and detects acceleration of the arbitrary position of the second rotating body  20 . As the acceleration detection device  40 , a three-axis detection sensor capable of detecting acceleration in the x-axis, y-axis and z-axis directions is used. 
         [0033]    The control device  50  controls the number of rotations of the first driving device  12  and the second driving device  22 , and controls the number of rotations of the first rotating body  10  and the second rotating body  20 . 
         [0034]    The control device  50  controls driving of the first driving device  12  and the second driving device  22  on the basis of acceleration data detected by the acceleration detection device  40 . 
         [0035]    The acceleration detection device  40  and the control device  50  preferably have a configuration capable of communicating acceleration data wirelessly. In this case, the acceleration detection device  40  comprises a wireless transmitter, while the control device  50  comprises a wireless receiver. 
         [0036]    In addition, the acceleration detection device  40  preferably has a configuration that comprises an internal storage battery, receives power transmission wirelessly from the outside, and accomplishes detection of acceleration and sending to the control device  50 . In this case, the support platform  30  and the support members  31   a,    31   b  and/or the like comprise devices capable of accomplishing power transmission to the acceleration detection device  40  at an arbitrary position. As a method of transmitting power, a commonly known method such as a radio wave method, an electromagnetic induction method, an electromagnetic field resonance method and/or the like can be used. 
         [0037]    Next, rotational control of the first rotating body  10  and the second rotating body  20  by the control device  50  is described. 
         [0038]    While the first driving device  12  and the second driving device  22  drive and the first rotating body  10  and the second rotating body  20  respectively rotate, the acceleration detection device  40  continuously detects acceleration in the three axial directions. 
         [0039]    The acceleration data thus detected is sent to the control device  50 . With the control device  50 , an acceleration vector is calculated using Equation 1, on the basis of the acceleration data sent. When the location where the acceleration detection device  40  is positioned is point P, the symbols A, g, r and ω in Equation 1 respectively indicate an acceleration vector at point P, a gravitational acceleration vector at point P, a distance vector from the center of the second rotating body (the point of intersection of the first shafts  11   a  and  11   b  and the second shafts  21   a  and  21   b ) to point P, and an angular velocity vector at point P. 
         [0000]      [Formula 2] 
         [0000]        A=g+r ω 2   (Equation 1)
 
         [0040]    With the acceleration detection device  40 , acceleration data in each of the three axial directions is obtained, and in the control device  50 , an angular velocity vector (ω 1 ) around the first shafts  11   a  and  11   b  at the point P, an angular velocity vector (ω 2 ) around the second shafts  21   a  and  21   b  and a gravitational acceleration vector (g) undergo component analysis from the acceleration data respectively obtained. In addition, an angular acceleration vector (ω) at the point P is analyzed from the angular velocity vector (ω 1 ) around the first shafts  11   a  and  11   b  at the point P, the angular velocity vector (ω 2 ) around the second shafts  21   a  and  21   b,  and an acceleration vector at the point P is calculated on the basis of Equation 1. The aforementioned analysis can be accomplished by an arbitrary method. In addition, an angular velocity vector (ω 1 )around the first shafts  11   a  and  11   b  at an arbitrary point and an angular velocity vector ( 0 ) 2 ) around the second shafts  21   a  and  21   b  may have a configuration based on detection number-of-revolutions detection device, or may have a configuration in which the calculation is from the number of rotations of the first driving device  12  and the second driving device  22 . 
         [0041]    Furthermore, the acceleration vector at the point P is computed continually while the first rotating body  10  and the second rotating body  20  are rotating and is fed back, and driving of the first driving device  12  and the second driving device  22  is controlled so that the integral of the acceleration vector over a prescribed time (for example, 10 minutes) becomes a pseudo-zero-gravity state (around 1/1000 G). Through this, a pseudo-microgravity environment is created. For example, it would be fine to control the first driving device  12  and the second driving device  22  so that the first rotating body  10  and the second rotating body  20  are each caused to rotate at constant angular velocities with the ratio of the angular velocity of the first rotating body  10  to the angular velocity of the second rotating body  20  a prescribed ratio. 
         [0042]    In addition, by the control device  50  controlling the respective rotations of the first rotating body  10  and the second rotating body  20  so that the integral of the acceleration vector at the point P over a prescribed time becomes ⅙ G, it is possible to reproduce the gravitational environment on the moon, and it is possible to virtually reproduce various gravitational environments, such as supergravity environments exceeding 1 G, such as 2 G, 3 G and/or the like. 
         [0043]    In this manner, with the gravity control apparatus  1  according to the exemplary embodiment, it is possible to create a microgravity environment in a space inside the second rotating body  20  with an easy process and to create various gravitational environments, and it is possible to reduce the cost of the gravity control apparatus  1 . 
         [0044]    Above, the explanation used an example in which the second driving device  22  is positioned external to the first rotating body  10 , but it is similarly possible to accomplish control even with a configuration in which the second driving device  22  is installed on the first rotating body  10  and the second driving device  22  is driven by supplying electric power by a contract-type power supply mechanism such as a coupling comprising a slip ring and a brush, and/or the like. 
         [0045]    The foregoing describes some example embodiments for explanatory purposes. Although the foregoing discussion has presented specific embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of the invention is defined only by the included claims, along with the full range of equivalents to which such claims are entitled. 
         [0046]    This application claims the benefit of Japanese Patent Application No. 2013-124777, filed on Jun. 13, 2013, the entire disclosure of which is incorporated by reference herein. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  Gravity control apparatus 
           10  First rotating body 
           11   a,    11   b  First shaft 
           12  First driving device 
           12   a  Output shaft 
           20  Second rotating body 
           21   a,    21   b  Second shaft 
           22  Second driving device 
           22   a  Output shaft 
           23  Gear 
           24  Gear 
           25  Bevel gear 
           26  Rotational power transfer member 
           26   a  Bevel gear 
           26   b  Shaft 
           26   c  Bevel gear 
           27  Rotational power transfer member 
           27   a  Bevel gear 
           27   b  Shaft 
           27   c  Bevel gear 
           28  Bevel gear 
           30  Support platform 
           31   a,    31   b  Support member 
           32  First driving device housing unit 
           33  Second driving device housing unit 
           40  Acceleration detection device 
           50  Control device