JP2011213138A - Simulated agravic state generating device - Google Patents

Abstract

The present invention provides a pseudo zero gravity generating device that generates a pseudo zero gravity state with one axis.
A pseudo zero gravity generator is disposed in an XYZ orthogonal stationary coordinate system. The inclined crank 10 includes a shaft portion 101 and a shaft portion 102. The shaft portion 101 extends in the X axis direction. The shaft portion 102 is inclined with respect to the shaft portion 101 and connected to the shaft portion 101. The rotating member 11 is attached to the inclined crank 10 so as to be rotatable around the shaft portion 102. The guide member 12 is attached to the rotating member 11. The drive source 13 rotates the inclined crank 10 around the X axis. The guide member 14 is disposed around the rotating member 11 and contacts the guide member 12 to guide the movement of the guide member 12. In the pseudo zero gravity device 1, when the drive source 13 rotates the inclined crank 10, the guide member 14 guides the movement of the guide member 12, whereby the rotating member 11 rotates three-dimensionally.
[Selection] Figure 1

Description

  The present invention relates to a pseudo-weightless generator.

  The pseudo zero gravity generator is also called a three-dimensional clinostat. The pseudo zero gravity generator is equipped with a specimen, and the loaded specimen is rotated three-dimensionally. Since the specimen is rotated three-dimensionally, the direction of gravity applied to the specimen changes before the specimen is stimulated by gravity. In this way, the pseudo zero gravity generator disperses the gravity vector applied to the test material. Then, the time average of gravity acting on each of the three axes in the xyz orthogonal coordinate system fixed to the test material is made substantially zero. In short, the pseudo zero gravity generating device generates a pseudo zero gravity state for the test material.

  JP-A-11-264716 (Patent Document 1), JP-A-2000-79900 (Patent Document 2), JP-A-2003-70456 (Patent Document 3), JP-A-2007-131261 (Patent Document 4) JP, 2007-284006, A (patent documents 5) and JP, 2008-273276, (patent documents 6) disclose a pseudo zero gravity generation device. The pseudo zero gravity generator disclosed in these documents includes a biaxial rotation mechanism. These pseudo-weightless devices rotate the sample material three-dimensionally about two axes.

JP-A-11-264716 JP 2000-79900 A JP 2003-70456 A JP 2007-131261 A JP 2007-284006 A JP 2008-273276 A

  However, the biaxial rotation mechanism has a complicated mechanism. Furthermore, in the case of two axes, the control of the angular velocity of each axis tends to be complicated. Furthermore, when the specimen is rotated three-dimensionally with two axes, the angular velocity during rotation tends to change rapidly and changes discontinuously. Therefore, it is preferable that a pseudo zero gravity state can be provided to the test material on one axis.

  An object of the present invention is to provide a pseudo zero gravity generating device capable of generating a pseudo zero gravity state with one axis.

Means for Solving the Problems and Effects of the Invention

  The pseudo zero gravity generator according to the present invention is arranged in an XYZ orthogonal stationary coordinate system. The pseudo zero gravity apparatus according to the present invention includes an inclined crank, a rotating member, a first guide member, a drive source, and a second guide member. The inclined crank includes a first shaft portion and a second shaft portion. The first shaft portion extends in the X-axis direction. The second shaft portion is inclined with respect to the first shaft portion and connected to the first shaft portion. The rotating member is attached to the inclined crank so as to be rotatable around the second shaft portion. An object is mounted on the rotating member. The first guide member is attached to the rotating member. The drive source rotates the inclined crank around the X axis. The second guide member has a raceway surface. The raceway surface is disposed around the rotating member and contacts the first guide member to guide the movement of the first guide member. In the quasi-gravity device, the second guide member guides the movement of the first guide member when the drive source rotates the inclined crank, so that the rotary member rotates three-dimensionally.

  The weightless generator according to the present invention can generate a pseudo weightless state by rotating the rotating member around one axis.

  Preferably, in the pseudo zero gravity generating device, in the xyz orthogonal motion coordinate system including the x axis extending in the axial direction of the second shaft, the time average of the x axis gravity acceleration, the y axis gravity acceleration, and the z axis gravity acceleration is equal. .

  Preferably, the pseudo-gravity generating device is provided with a raceway shape so that the pitch angle θ, the yaw angle Ψ, and the roll angle φ of the rotating member satisfy the formulas (A) to (C).

θ = sin ⁻¹ (sin α cos β) (A)
Ψ = tan ⁻¹ (tan αsin β) (B)
φ = β / 2 + f (β) (C)
Here, α is an inclination angle formed by the first shaft portion and the second shaft portion. β is a rotation angle around the X axis of the inclined crank. f (β) is a periodic function with a period π and an odd function.

It is a perspective view of the pseudo zero gravity generation device by this embodiment. It is a schematic diagram of the pseudo zero gravity generation apparatus shown in FIG. In the xyz orthogonal motion coordinate fixed to the rotating member in the pseudo zero gravity generating apparatus shown in FIG. 1, the relationship between the i vector in the x axis direction, the j vector in the y axis direction, and the k vector in the z axis direction will be described. It is a schematic diagram for. It is a schematic diagram which shows the geometric relationship of i vector of the x-axis direction in the xyz orthogonal motion coordinate system, inclination-angle (alpha), and rotation angle (beta). It is a figure which shows the relationship between the Euler angles ((phi), (theta), and (PSI)) calculated based on Formula (5), (6), (7) and (9) in this specification, and the rotation angle (beta). FIG. 6 is a diagram illustrating coordinates on an XYZ orthogonal stationary coordinate of an i vector with respect to a rotation angle β when a roll angle φ, a pitch angle θ, and a yaw angle Ψ are determined as illustrated in FIG. 5. FIG. 6 is a diagram illustrating a trajectory of an i vector in an XYZ orthogonal static coordinate system when a roll angle φ, a pitch angle θ, and a yaw angle Ψ are determined as illustrated in FIG. 5. FIG. 6 is a diagram illustrating coordinates on an XYZ orthogonal stationary coordinate of a j vector with respect to a rotation angle β when a roll angle φ, a pitch angle θ, and a yaw angle Ψ are determined as illustrated in FIG. 5. FIG. 6 is a diagram illustrating a trajectory of a j vector in an XYZ orthogonal stationary coordinate system when a roll angle φ, a pitch angle θ, and a yaw angle Ψ are determined as illustrated in FIG. 5. FIG. 6 is a diagram illustrating coordinates on a XYZ orthogonal stationary coordinate of a unit vector k with respect to a rotation angle β when a roll angle φ, a pitch angle θ, and a yaw angle Ψ are determined as illustrated in FIG. 5. FIG. 6 is a diagram illustrating a locus of a k vector in an XYZ orthogonal static coordinate system when a roll angle φ, a pitch angle θ, and a yaw angle Ψ are determined as illustrated in FIG. 5. Is a diagram illustrating an example of a locus of gravitational acceleration vector g _b represented by the formula (12) in this specification. It is an expanded view of the guide member shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Overall configuration of pseudo zero gravity generator]
FIG. 1 is a perspective view of a pseudo zero gravity generator 1 according to this embodiment. The pseudo zero gravity generator 1 is arranged in an XYZ orthogonal stationary coordinate system. The XYZ orthogonal static coordinate system has an X axis, a Y axis, and a Z axis. The X axis, the Y axis, and the Z axis are orthogonal to each other. The Z axis extends in the vertical direction. The X axis and the Y axis are included in the horizontal plane. The azimuth angles (directions of east, west, north and south) of the X axis and the Y axis are arbitrary.

  The pseudo zero gravity generating device 1 includes an inclined crank 10, a rotating member 11, a guide member 12, a drive source 13, and a guide member 14.

  FIG. 2 is a schematic diagram of the pseudo zero gravity generator 1. With reference to FIGS. 1 and 2, the inclined crank 10 includes a pair of shaft portions 101 and a shaft portion 102. The pair of shaft portions 101 extends in the X-axis direction. The shaft portion 102 is inclined with respect to the shaft portion 101 and connected to the pair of shaft portions 101. More specifically, the shaft portion 102 is disposed between the pair of shaft portions 101. The shaft portion 102 is indirectly connected to the pair of shaft portions 101 via the pair of crank arms 103. As shown in FIG. 2, the angle formed by the shaft portion 101 and the shaft portion 102 is α (deg). Hereinafter, the angle α is referred to as “inclination angle α”. The inclination angle α is constant.

  Referring to FIG. 1, the rotating member 11 is attached to the inclined crank 10 so as to be rotatable around the shaft portion 102. In other words, the shaft portion 102 is rotatably inserted into the rotating member 11. The rotating member 11 has a through hole into which the shaft portion 102 is inserted. For example, a bearing (not shown) is attached between the through hole of the rotating member 11 and the shaft portion 102. The rotating member 11 rotates around the shaft portion 102.

  An object is mounted on the rotating member 11. The object is, for example, a test material. The test material is, for example, a microorganism or an animal or plant. When the test material is a plant, for example, the growth of the test material under a pseudo-weightless condition is investigated.

  In FIG. 1, the rotating member 11 has a box shape and a rectangular parallelepiped shape. In this case, the test material is stored in the rotating member 11. The shape of the rotating member 11 is not limited to a housing shape. As shown in FIG. 2, the rotating member 11 may be plate-shaped. The plate-like rotating member 11 has a through hole at the center, for example. Then, the shaft portion 102 is inserted into the through hole. The shaft portion 102 extends in the normal direction of the plate-like rotating member 11. In the case of the plate-like rotating member 11, the test material is mounted on the rotating member 11.

The pair of guide members 12 has a rod shape and is attached to the rotating member 11. More specifically, the pair of guide members 12 are arranged on the same virtual line. The guide member 12 is orthogonal to the shaft 102. Preferably, the pair of guide members 12 are arranged on an imaginary line including the center of gravity of the rotating member 11.
The guide member 12 is in contact with the guide member 14. When the inclined crank 10 rotates around the X axis, the guide member 12 slides on the guide member 14 and moves. The rotating member 11 including the guide member 12 rotates around the shaft portion 102 according to the slide of the guide member 12.

  The drive source 13 is connected to the shaft portion 101 of the inclined crank 10. The drive source 13 rotates the inclined crank 10 around the X axis. The drive source 13 is, for example, a known motor. The drive source 13 is mounted on the base 15. The drive source 13 rotates the inclined crank 10 around the X axis at a constant speed.

  The pair of support members 50 are plate-shaped. The pair of support members 50 support the pair of shaft portions 101 of the inclined crank 10 so as to be rotatable in the X-axis direction. The support member 50 is arranged upright on the base 15. The rotating member 11 is disposed between the pair of support members 50. A through hole corresponding to the shaft portion 101 is formed in each of the pair of support members 50. The pair of shaft portions 101 are inserted into the through holes of the pair of support members 50 and are rotatably supported by the support members 50.

  The guide member 14 is disposed around the rotating member 11. In FIG. 1, the guide member 14 has a cylindrical shape having an opening 142 inclined at the upper end. The guide member 14 is disposed on the base 15, and the rotating member 11 is disposed in the inclined opening 142.

  The guide member 14 has a raceway surface 141. The raceway surface 141 corresponds to the periphery of the opening 142 and is disposed at the upper end edge of the cylinder. The raceway surface 141 is disposed around the rotating member 11 and contacts the pair of guide members 12. When the inclined crank 10 rotates, the guide member 12 moves while sliding on the raceway surface 141. That is, the guide member 14 guides the movement of the guide member 12 when the inclined crank 10 rotates.

  As described above, the rotating member 11 rotates around the shaft 102 according to the slide of the guide member 12. Therefore, the rotating member 11 rotates around the shaft 102 according to the shape of the raceway surface 141. In short, the rotation (posture angle) of the rotating member 11 is controlled according to the shapes of the guide member 14 and the raceway surface 141.

  With reference to FIG. 2, an xyz orthogonal motion coordinate system is fixed to the rotating member 11. The xyz orthogonal motion coordinate system is defined as follows. The x axis, the y axis, and the z axis are orthogonal to each other. The x axis extends in the axial direction of the shaft portion 102. The z axis extends in the axial direction of the guide member 12. The guide member 12 is orthogonal to the x axis. In short, the guide member 12 extends in the y-axis or z-axis direction.

[Shape of raceway]
In the pseudo zero gravity generating device 1, when the drive source 13 rotates the inclined crank 10, the guide member 14 guides the movement of the guide member 12, whereby the rotating member 11 rotates three-dimensionally. At this time, the guide member 12 circulates on the raceway surface 141 while being in contact with the raceway surface 141. Therefore, the rotating member 11 rotates three-dimensionally according to the shape of the raceway surface 141. By the above operation, the pseudo zero gravity generating device can generate a pseudo zero gravity state by rotating the rotating member 11 three-dimensionally by rotating one axis (inclined shaft) around the X axis.

  Preferably, the shape of the raceway surface 141 is provided so that the posture angles (pitch angle θ, yaw angle Ψ, and roll angle φ) of the rotating member 11 satisfy the expressions (A) to (C).

θ = sin ⁻¹ (sin α cos β) (A)
Ψ = tan ⁻¹ (tan αsin β) (B)
φ = β / 2 + f (β) (C)
Here, the roll angle φ indicates the rotation angle around the x-axis of the rotating member 11, the pitch angle θ indicates the angle formed by the x-axis and the horizontal plane, and the yaw angle Ψ is the rotation angle of the x-axis projected on the horizontal plane. Indicates. A more precise definition is as follows. First, the rotating member 11 (xyz orthogonal motion coordinate system) is matched with the XYZ orthogonal static coordinate system. As the first rotation, the angle obtained by rotating the rotating member 11 (xyz orthogonal motion coordinate system) around the + Z axis (in this stage, the + Z axis and the + z axis coincide with each other) with the clockwise rotation as positive is the yaw angle ψ ( deg). As the second rotation, an angle obtained by rotating the rotating member 11 (xyz orthogonal motion coordinate system) around the + y axis after the first rotation with the clockwise rotation as positive is defined as a pitch angle θ (deg). As the third rotation, an angle obtained by rotating the rotation member 11 (xyz orthogonal motion coordinate system) around the + x axis after the second rotation with the clockwise rotation as positive is defined as a roll angle φ (deg).

  Further, as shown in FIG. 2, the inclination angle α (deg) is an angle formed by the shaft portion 101 and the shaft portion 102. The inclination angle α (deg) is constant. The rotation angle β (deg) is a rotation angle around the X axis of the inclined crank 10 and is positive in the clockwise direction toward the + X axis direction.

If the pitch angle θ, the yaw angle Ψ, and the roll angle φ of the rotating member 11 satisfy the above-described formulas (A) to (C), the pseudo zero gravity state generated by the pseudo zero gravity generation device 1 further approaches the zero gravity state. In other words, the pseudo zero gravity generating device has the orbital surface 141 provided so as to satisfy the expressions (A) to (C), so that the time of the gravitational acceleration component g _x of the x axis in the xyz orthogonal motion coordinate system. the average _{g Xave,} and time average _{g Yave} of gravitational acceleration component _{g y} of y-axis, can be substantially equal to the time average _{g Zave} of gravitational acceleration component _{g z} of the z-axis, both can be zero. Hereinafter, this point will be described in detail.

  As shown in FIG. 3, an x-axis unit vector is defined as an i vector in the xyz orthogonal motion coordinate system. The j vector is defined as the unit vector of the y axis. A z-axis unit vector is defined as a k vector.

  The coordinates of the i vector, j vector, and z vector in the XYZ orthogonal static coordinate system are defined by equation (1).

Here, i _X , j _X and k _X are the _X coordinates of the i vector, j vector and k vector in the XYZ orthogonal stationary coordinate system. Similarly, i _Y , j _Y and k _Y are the _Y coordinates of the i vector, j vector and k vector in the XYZ orthogonal stationary coordinate system. i _Z , j _Z and k _Z are the _Z coordinates of the i vector, j vector and k vector in the XYZ orthogonal stationary coordinate system.
A coordinate transformation matrix (direction cosine matrix) C ⁿ _b from the xyz orthogonal moving coordinate system to the XYZ orthogonal static coordinate system is defined by Expression (2).

Conversely, a coordinate conversion matrix (direction cosine matrix) C ^b _n from the XYZ orthogonal static coordinate system to the xyz orthogonal motion coordinate system is defined by Expression (3).

A matrix C ^b _n represented by Expression (3) is an inverse matrix of the matrix C ⁿ _b represented by Expression (2). In the coordinate transformation matrix, the inverse matrix matches the transpose matrix.

FIG. 4 is a schematic diagram showing a geometric relationship among the i vector, the inclination angle α, and the rotation angle β in the XYZ orthogonal static coordinate system. Referring to FIG. 4, the coordinates (i _X , i _Y , i _Z ) of the i vector in the XYZ orthogonal static coordinate system are defined by Expression (4).

  If Expressions (2) to (4) are used, the pitch angle θ and the yaw angle Ψ are expressed as a function of the rotation angle β. Specifically, the pitch angle θ is represented by Expression (5), and the yaw angle Ψ is represented by Expression (6).

  Here, consider a case where the roll angle φ is defined by equation (7).

The function f (β) in Equation (7) is an odd function and a periodic function with a period π. In other words, the function f (β) is defined by equation (8).
f (β) = − f (−β)
f (β + π) = f (β) (8)

The function f (β) is arbitrary as long as Expression (8) is satisfied.
The above equation (5) corresponds to the equation (A), and the equation (6) corresponds to the equation (B). Expression (7) corresponds to Expression (C). By forming the raceway surface 141 so as to satisfy these formulas (A) to (C), the simulated weightless state generated by the simulated weightless generation device 1 further approaches the weightless state.
Hereinafter, as an example of the function f (β), the operation of the pseudo zero gravity generating device 1 when the function f (β) is represented by Expression (9) will be described.
f (β) = a × sin (2β) (9)
Here, a is an arbitrary constant.

  Based on the equations (5), (6), (7) and the equation (9), the Euler angles (φ, θ and ψ) at the rotation angle β are determined. FIG. 5 shows the relationship between the posture angle (φ, θ and Ψ) (deg) and the rotation angle β (deg) calculated based on the equations (5), (6), (7), and (9). FIG. A curve L1 in the figure indicates the roll angle φ. A curve L2 indicates the pitch angle θ. A curve L3 indicates the yaw angle ψ. The roll angle φ is generally defined in the range of the rotation angle β = ± 180 deg. However, the roll angle φ in FIG. 5 is continuously plotted based on Equation (7). Referring to FIG. 5, when the rotation angle β is rotated by 720 degrees, the roll angle φ is rotated by 360 °. That is, in this example, when the rotation angle β is rotated by 720 degrees, the rotating member 11 makes one rotation around the x axis.

If the roll angle φ, the pitch angle θ, and the yaw angle ψ are determined, the i-vector, j-vector, and k-vector of the rotation angle β in the xyz orthogonal motion coordinate system based on the equation (2) or the equation (3). Coordinates are determined. For example, when the roll angle φ, the pitch angle θ, and the yaw angle Ψ are determined as shown in FIG. 5, the coordinates on the XYZ orthogonal stationary coordinates of the i vector with respect to the rotation angle β are as shown in FIG. A curve LiX in the figure indicates the X coordinate (i _X ) of the i vector. A curve LiY indicates the Y coordinate (i _Y ) of the i vector. A curve LiZ indicates the Z coordinate (i _Z ) of the i vector.
7A to 7C show trajectories of the i vector in the XYZ orthogonal stationary coordinate system in the case of the roll angle φ, the pitch angle θ, and the yaw angle ψ shown in FIG. FIG. 7A shows the trajectory of the i vector on the XZ plane. FIG. 7B shows the locus of the i vector on the YZ plane. FIG. 7C shows the locus of the i vector on the XY plane.

When the roll angle φ, the pitch angle θ, and the yaw angle Ψ are determined as shown in FIG. 5, the coordinates of the j vector with respect to the rotation angle β on the XYZ orthogonal stationary coordinate system are as shown in FIG. A curve LjX in FIG. 8 indicates the X coordinate (j _X ) of the j vector. A curve LjY indicates the Y coordinate (j _Y ) of the j vector, and a curve LjZ indicates the Z coordinate (j _Z ) of the j vector. Further, FIGS. 9A to 9C show trajectories of the j vector in the XYZ orthogonal stationary coordinate system in the case of the roll angle φ, the pitch angle θ, and the yaw angle ψ shown in FIG. FIG. 9A shows the trajectory of the j vector on the XZ plane. FIG. 9B shows the trajectory of the j vector on the YZ plane. FIG. 9C shows the trajectory of the j vector on the XY plane.
Further, in the case of the roll angle φ, the pitch angle θ, and the yaw angle ψ shown in FIG. 5, the coordinates of the k vector with respect to the rotation angle β on the XYZ orthogonal stationary coordinate system are as shown in FIG. The curve LkX in FIG. 8 indicates the X coordinate (k _X ) of the k vector, the curve LkY indicates the Y coordinate (k _Y ) of the k vector, and the curve LkZ indicates the Z coordinate (k _Z ) of the k vector. Show. FIGS. 11A to 11C show the locus of the k vector in the XYZ orthogonal stationary coordinate system. 11A shows the locus of the k vector on the XZ plane, FIG. 11B shows the locus of the k vector on the YZ plane, and FIG. 11C shows the k vector on the XY plane. Shows the trajectory.

When the pseudo zero gravity generator 1 operates, if the pitch angle θ, the yaw angle Ψ, and the roll angle φ of the rotating member 11 satisfy the expressions (A) to (C), the i vector, the j vector, and the rotating member 11 The k vector indicates the locus shown in FIGS. 6 to 11 with respect to the rotation of the inclined crank 10. Here, FIGS. 6, 8 and 10 show the coordinates of each unit vector with respect to the rotation angle β. The drive source 13 rotates the tilt shaft 10 around the X axis at a constant speed. Therefore, the horizontal axis (rotation angle β) in FIGS. 6, 8, and 10 corresponds to the time axis.
Next, the trajectory of the gravitational acceleration vector of the rotating member 11 having the i vector, the j vector, and the k vector that describe the trajectory will be described.

The direction of gravity is the vertical direction and the + Z-axis direction. Accordingly, the gravitational acceleration vector _{g n} in the XYZ orthogonal coordinate system at rest, the gravitational acceleration of magnitude 1G a (= 9.80665 m / ^{s 2)} as one unit, is defined by equation (10).

gravitational acceleration vector _{g b} in xyz orthogonal movement coordinate system, the matrix ^C _{b n} of formula (3), the product of the gravitational acceleration vector _{g n} of the formula (10), formula (11).

Here, g _x , g _y and g _z are gravity acceleration components of the x-axis, y-axis and z-axis of the gravity acceleration vector g _b in the xyz orthogonal motion coordinate system.

Substituting Equation (5) and Equation (7) into Equation (11), the gravitational acceleration components g _x , _gy and g _z are represented by the inclination angle α and the rotation angle β as shown in Equation (12). It is.

As described above, the inclination angle α is constant. Therefore, the only independent variable of the gravitational acceleration components g _x , g _y and g _z shown in Expression (12) is the rotation angle β. The gravitational acceleration components g _x , g _y and g _z are all periodic functions. Referring to Expression (12), the period of the gravitational acceleration component g _x is 2π. The periods of the gravitational acceleration components g _y and g _z are both π. This can be understood with reference to the curves LiZ, LjZ, and LkZ in FIGS.

FIGS. 12A and 12B are diagrams illustrating an example of the locus of the gravitational acceleration vector g _b represented by Expression (12). Figure 12 (a) and 12 (b) shows the locus of gravitational acceleration vector _{g b} in the case where the inclination angle α = 54.7deg. 12 (a) shows the locus of gravitational acceleration vector _{g b} in the xz plane of the xyz orthogonal moving coordinate system. Figure 12 (b) shows the locus of gravitational acceleration vector _{g b} on yz plane of the xyz orthogonal moving coordinate system.

The raceway surface 141 has a shape that satisfies the expressions (A) to (C). Therefore, the gravitational acceleration vector _{g b} applied to the rotating member 11 becomes as Equation (12). At this time, it will be described below that the gravitational acceleration components g _x , g _y and g _z of the gravitational acceleration vector g _b have the same time average and become zero.

From equation (12), the gravitational acceleration component g _x in the x-axis direction of the gravitational acceleration vector g _b is a periodic function having a period of 2π. Therefore, the time average of the gravitational acceleration _{g x,} the rotation angle β is equal to the average of the gravitational acceleration _{g x} in the range of 0Rad～2pai. Therefore, the time average g _xave of the gravitational acceleration component g _x is expressed by Expression (13).

Next, the time average g _yave of the gravitational acceleration component g _{y in} the y-axis direction will be examined. As shown in Expression (12), the gravitational acceleration component g _y (also referred to as g _y (β)) is a periodic function having a period π. Therefore, the time average _{g Yave} is the rotation angle β is equal to the average of the gravitational acceleration component _{g y} in the range of -π / 2~π / 2. From the above, the time average g _yave is _expressed by the equation (14).

The integrand g _y (β) is a periodic function with a period π and an odd function, as shown in Expression (12). Therefore, as shown in the equation (14), the time average g _yave is 0.

Next, the time average g _zave of the gravitational acceleration component g _z (also referred to as gz (β)) in the z-axis direction will be examined. As shown in Expression (12), the gravitational acceleration g _z (β) is a periodic function having a period π. Substitute β + π for the gravitational acceleration g _z (β). At this time, the gravitational acceleration g _z (β + π) is expressed by Expression (15).

In short, g _z (β) is equal to the phase of g _y (β) shifted by π. Therefore, the time average g _{zave is} also 0 as with the time average g _yave as shown in the equation (16).

g _zave = 0 (16)
From the above, if the shape of the raceway surface 141 is provided so as to satisfy the expressions (A) to (C), the three axes (x in the rotating member 11 (xyz orthogonal motion coordinate system)) as shown in the expression (17). The time averages g _xave , g _yave, and g _zave of the gravitational acceleration components of the axis, y axis, and z axis are all equal to zero.

g _xave = g _yave = g _zave = 0 (17)
An example of a developed view of the raceway surface 141 is shown in FIG. FIG. 13 is a diagram in which the guide member 14 and the raceway surface 141 are developed around the Z axis, and corresponds to a development view of the peripheral surface of the guide member 14.
The shape of the track surface 141 is obtained by projecting the curve LkZ (Z coordinate (k _Z ) of k vector) shown in FIG. 10 onto the peripheral wall of the cylindrical guide 14. In short, the developed view of the raceway surface 141 is a projection of the Z coordinate locus on the guide member 14 with respect to the rotation angle β of the unit vector (here k vector) of the axis (here z axis) on which the guide member 12 is arranged. Have the same shape.
[The mean square of gravitational acceleration in the dynamic coordinate system]
In the pseudo zero gravity generating device 1, it is preferable that the mean squares of the gravitational acceleration components g _xave , g _yave, and g _zave are equal. When the mean square of the three-axis gravity acceleration is equal, the gravity acceleration component acting on the test material is dispersed substantially uniformly. Therefore, the influence of the gravity acceleration components g _x , g _y and g _{z on} the test material can be made substantially uniform.

When the inclination angle α is 45 to 65 deg, the root mean squares of the triaxial gravitational acceleration components g _x , g _y, and g _z approach each other. The preferable inclination angle α is 50 to 60 deg, and more preferably 54.7 ± 2 deg. The more preferable inclination angle α is 54.7 deg. Most preferably, the inclination angle α satisfies the formula (D).

α = sin ⁻¹ ((2/3) ^1/2 ) (D)
If the inclination angle α satisfies the equation (D), the mean squares of the gravitational acceleration components g _x , g _y, and g _z coincide with each other. Hereinafter, this point will be described in detail.

The root mean square g _xave ² of the gravitational acceleration gx is expressed by Expression (18).

The root mean square g _yave ² of the gravitational acceleration gy is expressed by Expression (19).

When β + π is substituted into g _y (β) represented by Expression (12), g _y (β + π) is represented by Expression (20).

Based on Expression (20), the integrand g _y (β) ² + g _y (β + π) ² in Expression (19) is expressed by Expression (21).

Substituting Equation (21) into Equation (20), the root mean square g _yave ² is expressed by Equation (22).

Next, the root mean square g _zave ² of the gravitational acceleration g _z will be examined. From the equations (12) and (15), the gravitational acceleration g _z (β) is equal to the gravity acceleration g _y (β) shifted by π. Therefore, the root mean square g _zave ² is _expressed by the equation (23).
g _zave ² = g _yave ² = 1 / 2−sin ² α / 4 (23)

From the above, the root mean square g _xave ² , g _yave ^2, and g _zave ² are expressed by Expression (24).
g _xave ² = sin ² α / 2
g _zave ² = g _yave ² = 1 / 2−sin ² α / 4 (24)

The inclination angle α when the gravitational accelerations of the three axes (x axis, y axis, and z axis) of the xyz orthogonal motion coordinate system are equal to each other is obtained. From the equation (24), when g _xave ² = g _yave ² is established, the equation (25) is established.

From Equation (25), the most preferable inclination angle α is given by Equation (26).
α = sin ⁻¹ ((2/3) ^1/2 ) (26)
Expression (26) corresponds to Expression (D). Therefore, when the inclination angle α satisfies the equation (D), the mean squares of the gravitational acceleration components g _x , _gy and g _{z in} the xyz orthogonal motion coordinate system are equal to each other, and the gravitational acceleration components applied to the rotating member 11 are It becomes equal in three axes (x axis, y axis, and z axis).
As described above, if the inclination angle α is 45Deg～65deg, gravitational acceleration component _g x of the three axes, the root mean square of _{g y} and _{g z} close to each other. Therefore, the gravitational acceleration component applied to the rotating member 11 is substantially uniform.

Note that the root mean square g _xave ² , g _yave ^2, and g _zave ^{2 at} this time are represented by Expression (27).
g _xave ² = g _yave ² = g _zave ² = 1/3 (27)

The rms values (root mean squares) g _{x, rms} , g _{y, rms} , g _{z, rms} of the gravitational acceleration components g _x , g _y, and g _z are expressed by Expression (28).

  In the present embodiment, the guide member 14 has a cylindrical shape having an inclined opening at the upper end. However, the shape of the guide member 14 is not limited to this. The shape of the raceway surface 141 should just be set so that the above-mentioned Formula (A)-Formula (C) may be satisfy | filled. For example, the guide member 14 may be a spherical or rectangular parallelepiped housing that houses the rotating body 11 and may have a slit on the side surface where the raceway surface 141 is formed. In this case, the number of guide members 12 may be one.

The guide member 14 may be a rail disposed around the rotating member 11. In this case, the raceway surface 141 is formed on the surface of the rail. In short, the raceway surface 141 is formed around the rotary member 11, and the developed view of the raceway surface 141 is arranged so that the attitude angle of the rotary member 11 satisfies the equations (A) to (C). It is only necessary to have a shape in which the locus of the Z coordinate with respect to the rotation angle β of the axis unit vector is projected. In other words, the shape of the raceway surface 141 is such that the posture angle of the rotating member 11 satisfies the formulas (A) to (C), and the Z coordinate with respect to the rotation angle β of the unit vector of the axis on which the guide member 12 is arranged. Corresponds to the trajectory.
In the present embodiment, the guide member 12 has a rod shape. However, the shape of the guide member 12 is not limited to a rod shape. The guide member 12 may be, for example, a plate shape or another shape. In short, the shape of the guide member 12 is not particularly limited as long as it can move on the raceway surface 141 while being in contact with the raceway surface 141 of the guide member 14.

  While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately modifying the above-described embodiment without departing from the spirit thereof.

DESCRIPTION OF SYMBOLS 1 Pseudo zero gravity production | generation apparatus 10 Inclination crank 11 Rotating members 12, 14 Guide member 13 Drive source 15 Base 50 Support members 101, 102 Shaft part 141 Track surface 142 Opening

Claims (5)

A pseudo zero gravity generator arranged in an XYZ orthogonal stationary coordinate system,
An inclined crank including a first shaft portion extending in the X-axis direction and a second shaft portion that is inclined with respect to the first shaft portion and connected to the first shaft portion;
A rotating member that is attached to the inclined crank so as to be rotatable around the second shaft portion and on which an object is mounted;
A first guide member attached to the rotating member;
A drive source for rotating the inclined crank around the X axis;
A second guide member disposed around the rotating member and having a raceway surface that contacts the first guide member and guides the movement of the first guide member;
The pseudo zero gravity generating device, wherein when the driving source rotates the inclined crank, the second guide member guides the movement of the first guide member, whereby the rotating member rotates three-dimensionally. The pseudo zero gravity generator according to claim 1,
In the xyz orthogonal motion coordinate system including the x axis extending in the axial direction of the second shaft, the pseudo zero gravity generating device in which the time average of the gravitational acceleration of the x axis, the gravitational acceleration of the y axis, and the gravitational acceleration of the z axis is equal . The pseudo zero gravity generating device according to claim 2,
The shape of the raceway surface is a pseudo zero gravity generating device in which the pitch angle θ, the yaw angle Ψ, and the roll angle φ of the rotating member are set so as to satisfy the expressions (A) to (C).
θ = sin ⁻¹ (sin α cos β) (A)
Ψ = tan ⁻¹ (tan αsin β) (B)
φ = β / 2 + f (β) (C)
Here, α is an angle formed by the first shaft portion and the second shaft portion. Β is a rotation angle of the inclined crank around the X axis. The f (β) is a periodic function with a period π and an odd function. The pseudo zero gravity generator according to claim 1,
The first guide member is a pseudo zero gravity generator perpendicular to the x-axis. The pseudo zero gravity generating device according to claim 3,
The pseudo-gravity generating device, wherein the angle α is 45 to 65 deg.

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