Pseudo-low gravity generation device, pseudo-low gravity generation method, and program

Abstract

The specified pseudo-low gravity is generated for the test specimen. [Solution] The pseudo-low gravity generating device 100 comprises a clinostat 10 capable of realizing pseudo-weightlessness on a test specimen by rotating a first rotation axis of the outer frame and a second rotation axis of the inner frame, and a control unit 30 that controls the rotation of the first rotation axis and the second rotation axis. The first rotation axis is defined as the Y axis and the second rotation axis as the X axis. A coordinate system is defined for the rotation angles from a reference angle of the first drive source that rotates the first rotation axis and the second drive source that rotates the second rotation axis. The trajectory is defined as the path of the tip of the Z2 axis vector of the coordinate system fixed to the inner frame. Based on the first trajectory that realizes pseudo-weightlessness, the control unit 30 derives a second trajectory such that the magnitude of low gravity specified by the integral effect of gravity applied to the test specimen remains in the Z-axis direction of the specimen. The control unit 30 generates pseudo-low gravity on the test specimen by controlling the rotation of the first rotation axis and the second rotation axis so that the velocity of a part of the second trajectory changes from the velocity of the other part.

Description

[Technical Field]

[0001] The present invention relates to a pseudo-low gravity generation device, a pseudo-low gravity generation method, and a program. [Background technology]

[0002] A clinostat is a device that provides a simulated weightless environment to a test specimen by rotating it around two orthogonal axes. Patent Document 1 describes a simulated weightlessness generation device that prevents rapid changes in the rotational angular velocity of a gimbal by utilizing Fourier series and orthogonality. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 4719066 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, while conventional pseudo-zero-gravity environment generators enable testing in a pseudo-zero-gravity environment, in recent years there has been a demand for testing in pseudo-low gravity environments, such as 1 / 6 gravity or 1 / 3 gravity.

[0005] This disclosure aims to solve the aforementioned problems and to provide a pseudo-low gravity generation device, a pseudo-low gravity generation method, and a program capable of generating a specified pseudo-low gravity on a test specimen. [Means for solving the problem]

[0006] To solve the above-mentioned problems and achieve the objective, the pseudo-low gravity generating device according to this disclosure comprises a clinostat capable of realizing pseudo-weightlessness on a test specimen by rotating the outer frame around a first rotation axis and the inner frame around a second rotation axis, respectively, and a control unit that controls the rotation of the first rotation axis and the second rotation axis. The first rotation axis is defined as the Y axis and the second rotation axis as the X axis, a coordinate system of rotation angles from a reference angle of the first drive source that rotates around the first rotation axis and the second drive source that rotates around the second rotation axis is defined, and the trajectory is defined as the path of the tip of the Z2 axis vector of the coordinate system fixed to the inner frame. The control unit derives a second trajectory based on the first trajectory that realizes pseudo-weightlessness, such that the magnitude of low gravity specified by the integral effect of gravity in all directions applied to the test specimen remains in the Z-axis direction of the specimen, and generates pseudo-low gravity on the test specimen by controlling the rotation of the first rotation axis and the second rotation axis so that the velocity of a part of the second trajectory changes from the velocity of a part of the trajectory.

[0007] To solve the above-mentioned problems and achieve the objective, the pseudo-low gravity generation method according to the present disclosure includes a clinostat capable of realizing pseudo-weightlessness on a test specimen by rotating the outer frame around a first rotation axis and the inner frame around a second rotation axis, respectively, and a pseudo-low gravity generation method for a pseudo-low gravity generation device that controls the rotation of the first rotation axis and the second rotation axis, comprising the steps of defining a coordinate system of rotation angles from a reference angle of a first drive source that rotates around the first rotation axis and a second drive source that rotates around the second rotation axis, with the first rotation axis as the Y axis and the second rotation axis as the X axis, defining the trajectory of the movement of the tip of the Z2 axis vector of the coordinate system fixed to the inner frame as the trajectory, deriving a second trajectory based on the first trajectory that realizes the pseudo-weightlessness, such that the magnitude of low gravity specified by the integral effect of gravity in all directions applied to the test specimen remains in the Z-axis direction of the specimen, and controlling the rotation of the first rotation axis and the second rotation axis in a part of the derived second trajectory so as to change from the velocity at which the other part of the second trajectory moves.

[0008] To solve the above-mentioned problems and achieve the objective, the program relating to this disclosure includes a clinostat capable of realizing pseudo-weightlessness on a test specimen by rotating the outer frame around a first rotation axis and the inner frame around a second rotation axis, respectively, and a pseudo-low gravity generating device that controls the rotation of the first and second rotation axes. The program causes the clinostat to perform the following steps: define a coordinate system of rotation angles from a reference angle of a first drive source that rotates around the first rotation axis and a second drive source that rotates around the second rotation axis, with the first rotation axis as the Y axis and the second rotation axis as the X axis, define the trajectory of the movement of the tip of the Z2 axis vector of the coordinate system fixed to the inner frame, derive a second trajectory based on the first trajectory that realizes the pseudo-weightlessness, such that the magnitude of low gravity specified by the integral effect of gravity in all directions applied to the test specimen remains in the Z-axis direction of the specimen; and control the rotation of the first and second rotation axes in a part of the derived second trajectory so as to change from the velocity at which the other part of the second trajectory moves. [Effects of the Invention]

[0009] According to this disclosure, a specified pseudo-low gravity can be generated for the test specimen. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 shows an example of a pseudo-low gravity generation device according to an embodiment. [Figure 2] Figure 2 is a diagram illustrating the coordinate system defined for the pseudo-low gravity generator. [Figure 3] Figure 3 is a diagram illustrating the definition of Partial G. [Figure 4] Figure 4 shows an example of a pseudo-zero-gravity orbit. [Figure 5] Figure 5 illustrates the vertical component of the Z-axis of the specimen. [Figure 6] Figure 6 illustrates the motion of an artificial potential field. [Figure 7] Figure 7 illustrates the velocity of passage through an artificial potential field. [Figure 8] Figure 8 is a table showing the variables used in the trajectory vector calculation. [Figure 9] Figure 9 is a flowchart showing an example of the calculation procedure for the pG orbital. [Figure 10] Figure 10 is a flowchart showing the processing procedure for calculating the orbit of a pseudo-low gravity generator. [Figure 11] Figure 11 shows the pG orbital and its characteristics with a bias of g / 3. [Figure 12] Figure 12 shows the pG orbital and its characteristics with a bias of g / 6. [Figure 13] Figure 13 is a table illustrating an example of a potential model. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. However, the present invention is not limited to these embodiments, and if there are multiple embodiments, they may be constructed by combining these embodiments.

[0012] [First Embodiment] (Pseudo-low gravity generator) Figure 1 shows an example of a pseudo-low gravity generating device according to an embodiment. As shown in Figure 1, the pseudo-low gravity generating device 100 comprises a clinostat 10 and a control unit 30. The pseudo-low gravity generating device 100 controls the rotation of the clinostat 10, which is a three-dimensional rotating device, using the control unit 30.

[0013] The clinostat 10 has a two-axis gimbal, and a test specimen can be placed in the center of the gimbal. The test specimen is a component used for testing. In this embodiment, the clinostat 10 comprises a holding part 13, an inner frame 14, an outer frame 15, leg parts 16, a first motor 17, and a second motor 18.

[0014] The holding section 13 holds the test specimen or the container containing the test specimen in a fixed state. The holding section 13 is formed in a box shape and comprises a pair of opposing holding plates 13a and a plurality of connecting sections 13b. The pair of holding plates 13a are each flat plates and are positioned facing each other with the inner frame 14 in between. One end of the connecting section 13b is connected to the inner frame 14, and the other end is connected to one of the holding plates 13a. The connecting section 13b is connected to one of the four corners of the holding plate 13a. In this embodiment, the connecting section 13b is fixed to the holding plate 13a with screws. Each of the four corners of the holding plate 13a is connected to a connecting section 13b. The holding plate 13a is fixed to the inner frame 14 by the connecting sections 13b. The holding section 13 fixes the two holding plates 13a to the inner frame 14 by the plurality of connecting sections 13b.

[0015] The inner frame 14 is a rectangular frame. The inner frame 14 holds the test specimen via the holding portion 13. The inner frame 14 rotates around the second rotation axis β, which is the inner axis. In this embodiment, the second rotation axis β is the axis passing through the rotation axis of the second motor 18. The rotation direction of the inner frame 14 may be either clockwise or counterclockwise.

[0016] The outer frame 15 is a rectangular frame composed of four sides 15a, with the holding part 13 and the inner frame 14 arranged inside the frame. Of the four sides 15a of the outer frame 15, a pair of opposing sides 15a hold the inner frame 14 so that it can rotate around the second rotation axis β. Of the four sides 15a of the outer frame 15, another pair of opposing sides 15a are held by the legs 16 so that the outer frame 15 can rotate around the first rotation axis α, which is the outer axis. The first rotation axis α is an axis perpendicular to the second rotation axis β. The rotation direction of the outer frame 15 can be either clockwise or counterclockwise.

[0017] The legs 16 hold the outer frame 15 so that it can rotate around the first rotation axis α. The legs 16 are fixed to the base 19. The second motor 18 rotates the inner frame 14 around the second rotation axis β.

[0018] The second motor 18 is located on the outside of one of the pair of side portions 15a. The second motor 18 rotates the inner frame 14 around the second rotation axis β via a power transmission mechanism such as gears or a belt. The second motor 18 is an example of a second drive source.

[0019] The first motor 17 is mounted on one of the pair of legs 16. The first motor 17 rotates the outer frame 15 around a first rotation axis α via a power transmission mechanism such as gears or a belt. The first motor 17 is an example of a first drive source.

[0020] In this embodiment, the clinostat 10 is configured such that the first rotation axis α and the second rotation axis β are substantially orthogonal to each other. The inner frame 14, outer frame 15, and leg portion 16 constitute a gimbal mechanism that can tilt in any direction by combining the orthogonal first rotation axis α and the second rotation axis β. Note that the first rotation axis α and the second rotation axis β are not limited to being orthogonal to each other, and may be configured to have a predetermined angle between them.

[0021] The clinostat 10 rotates the specimen in two axes by using a first motor 17 to rotate the outer frame 15 around a first rotation axis α and a second motor 18 to rotate the inner frame 14 around a second rotation axis β. By combining the first rotation axis α and the second rotation axis β, the clinostat 10 can generate a pseudo-weightless state by rotating the specimen in three dimensions. A pseudo-weightless state is achieved by controlling the rotation speeds of two mutually orthogonal axes, so that the time average of the gravity vector acting at the specimen placement position is 1 × 10⁻⁶. -3This refers to a state of pseudo-zero gravity (microgravity) of approximately G. In contrast, the pseudo-low gravity in this embodiment is a different type of gravity from pseudo-zero gravity (microgravity), where the time-averaged value of the gravity vector acting at the sample placement position is greater than 0 and less than g / 2 relative to gravity g.

[0022] (Coordinate system of the pseudo-low gravity generator) Figure 2 is a diagram illustrating the coordinate system defined for the pseudo-low gravity generator. In Figure 2, the first rotation axis α corresponds to the Y0 axis, and the second rotation axis β corresponds to the X1 axis. In this embodiment, a fixed reference coordinate system {P0,X0,Y0,Z0} is defined, which is fixed to the frame 19. In addition, a coordinate system {P1,X1,Y1,Z1} is defined, which is fixed to the outer frame 15, and a coordinate system {P2,X2,Y2,Z2} is defined, which is fixed to the inner frame 14. The origins of each coordinate system coincide, so P0=P1=P2. The X0 and Y0 axes are oriented horizontally, and the Z0 axis is vertically downward.

[0023] In this disclosure, "trajectory" is defined as follows: As shown in Figures 1 and 2, the trajectory is the trajectory traced on the reference coordinate system by the tip position {P2,0,0,1} of the unit vector in the Z2 direction of the X2-Y2-Z2 coordinate system fixed to the inner frame, as the frame rotates. This is defined by taking the first rotation axis α of the outer first motor 17 as the Y axis and the second rotation axis β of the inner second motor 18 as the X axis, and defining a coordinate system where the rotation displacement angles from the reference angle of the outer first motor 17 and the inner second motor 18 are φ and θ.

[0024] (Control unit for the pseudo-low gravity generator) As shown in Figure 1, the control unit 30 generates conditions such as pseudo-zero gravity and pseudo-low gravity for the test specimen by controlling the rotation of the clinostat 10. The control unit 30 includes a rotation angle detector 31, a rotation angle detector 32, a motor control unit (motor controller) 33, a trajectory generation unit 34, and a memory unit 35.

[0025] The rotation angle detector 31 detects the rotation angle θ of the outer frame 15 around the Y0 axis relative to the base 19, and the detected rotation angle θS to the motor control unit 33 as . The rotation angle detector 32 detects the rotation angle φ of the inner frame 14 about the X1 axis relative to the outer frame 15, and outputs the detected rotation angle φ S to the motor control unit 33 as . The trajectory generating unit 34 generates the rotation angle command θ * and the rotation angle command φ * and outputs them to the motor control unit 33. The motor control unit 33 performs control such that the detected rotation angle θ S matches the rotation angle command θ * , and generates the torque command τ θ * and outputs the torque command τ to the outer first motor 17, and the detected rotation angle φ S is made to match the rotation angle command φ * , and the torque command τ φ * is output to the inner second motor 18. Accordingly, the outer first motor 17 operates in accordance with the torque command τ θ * to rotate the outer frame 15 about the Y0 axis. The inner second motor 18 operates in accordance with the torque command τ φ * to rotate the inner frame 14 about the X1 axis.

[0026] Here, P0, X0, Y0, Z0 are expressed by Formula (Equation 1): [Formula] Here, the superscript "T" means "transpose".

[0027] The coordinate system {X1, Y1, Z1} when the outer frame 15 rotates by the rotation angle θ about the Y0 axis is expressed by Formula (Equation 2): [Formula]

[0028] The coordinate system {X2, Y2, Z2} when the inner frame 14 rotates by the rotation angle φ about the X1 axis is expressed by Formula (Equation 3): ​

number

[0029] Here, R Y This is a coordinate transformation matrix representing rotation around the Y0 axis, and is given by equation (Equation 4):

number

number

[0030] From the above equation, the tip position of the unit vector in the Z2 direction as seen from a coordinate system fixed to the inner frame 14 is given by equation (Equation 6) when viewed from the fixed coordinate system:

number

[0031] If we let ω1 be the angular velocity vector of the outer frame 15 and ω2 be the angular velocity vector of the inner frame 14, then equation (Equation 7):

number

number

[0032] Therefore, the angular acceleration α2 of the inner frame 14 is given by equation (Equation 9):

number

[0033] Therefore, the magnitude of the angular acceleration α2 of the inner frame 14 to which the specimen is fixed is given by equation (Equation 10):

number

[0034] The orbit generation unit 34 generates rotation angle commands θ(t) and φ(t), respectively. * and rotation angle command φ * The following is output to the motor control unit 33. θ(t) and φ(t) are time t, a predetermined period T, and predetermined coefficients b1 and b 2k+1 For given positive integers k, M, and N, the formula (Equation 11) is:

number

[0035] Here, M and N are given by equation (Equation 12) for any positive integer M:

number

number

[0036] When the pseudo-low gravity generator 100 is controlled based on equation (Equation 11), the time average of the gravity vector acting on the test specimen becomes zero at period T, and the gravitational effect acting on the specimen is evenly distributed across three mutually orthogonal axes, creating a pseudo-weightless state. During the time leading up to period T, gravity is biased towards the positive or negative side, but at T, the integral values ​​of gravity cancel each other out and become zero. As time increases to 2T, 3T, etc., the gravitational biases along the way are also affected by the cumulative effect of the previous integrals, so the fluctuations become smaller.

[0037] In equation (Equation 11), the rotational angular acceleration d around the X1 axis is given by 2 φ / dt 2 Since it is zero, as is clear from equation (Equation 10), the magnitude of the angular acceleration α2 of the inner frame 14 becomes small.

[0038] Furthermore, since the orbit defined by equation (Equation 11) is expressed using analytical equations, it is easy to predict how the orbit will change when parameters such as M and N are modified.

[0039] Furthermore, since the orbit defined by equation (Equation 11) has periodicity, it becomes easier to set the operating conditions of the pseudo-low gravity generator 100 when conducting experiments in a pseudo-zero-gravity state. For example, the experimenter can determine the period T such that the experiment time is a positive integer multiple of the period T, and then determine the parameters M and N by how many rotations are made around the Y0 axis and the X1 axis, respectively, during period T.

[0040] Furthermore, in the trajectory defined by equation (Equation 11), the infinitely advanced differential function at any time t is continuous, thus preventing abrupt changes in the rotation angle, rotational velocity, and rotational acceleration around the Y0 axis and X1 axis. Consequently, vibrations are prevented when the pseudo-low gravity generator 100 is in operation.

[0041] The components of gravitational acceleration g shown in equation (Equation 6) along the three axes of the coordinate system {P2, X2, Y2, Z2} X , g Y , g ZFor it to cancel out over time and become zero, in each interval of period T represented by (n-1)T≦t≦nT (n=1, 2, ...), equation (Equation 14):

number

[0042] Furthermore, in order for the gravitational effect acting on the specimen to be evenly distributed across three mutually orthogonal axes, equation (Equation 15) is required:

number

[0043] The memory unit 35 is a memory that stores various information such as the calculation contents and programs of the control unit 30, and includes at least one of the following: RAM (Random Access Memory), main memory such as ROM (Read Only Memory), and external memory such as HDD (Hard Disk Drive). The memory unit 35 can store a program that causes the control unit 30, which is a computer, to execute the pseudo-low gravity generation method of the pseudo-low gravity generation device 100. The memory unit 35 can store orbital information 35A that indicates orbits such as pseudo-zero gravity orbits and partial gravity orbits. The orbital information 35A contains information for controlling the rotation of the rotation axis according to the orbit. In the following description, pseudo-zero gravity includes microgravity.

[0044] (Requests regarding a pseudo-low gravity generator) The conditions in equations (Equation 14) and (Equation 15) are intended for simulated weightlessness, but in recent years, there has been a demand for testing simulated low gravity (simulated partial gravity). Simulated low gravity is generated by partially changing simulated microgravity. Simulated low gravity precisely applies a bias in gravity to one axis (Z axis) to which the target gravity g (e.g., g / 6, g / 3, etc.) is applied, while the other axes are made almost zero. Furthermore, in simulated partial gravity, the distribution of gravity is not extremely biased towards one axis, g X 2 , g Y 2, g Z 2 Give it a certain size, g Z 2 It is necessary to create an orbit that maximizes the effect. In this embodiment, the pseudo-low gravity generator 100 provides a technology for generating a specified pseudo-low gravity on a test specimen in an orbit that realizes pseudo-weightlessness.

[0045] (Definition of the orbit of a pseudo-low gravity generator) The following explains the definition of the Partial G (hereinafter also referred to as "pG") orbit in the pseudo-low gravity generator 100. The pG orbit is an example of a second orbit, which is a partial gravity orbit.

[0046] The pseudo-low gravity generator 100, as defined (1), uses a two-axis clinostat 10 and applies gravity in all directions to a test specimen placed in the center of a gimbal by statically rotating two orthogonal axes. The integral effect of this rotation generates a three-dimensional trajectory such that a specified magnitude of gravity remains only in the Z2 direction of the test specimen.

[0047] In the pseudo-low gravity generator 100, the orbital period is T, and the gravity component of the fixed coordinates of the test specimen is g. X ,g Y ,g Z The coefficient of pG is K PG Therefore, the pG orbital is given by equation (Equation 16):

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[0048] Figure 3 is a diagram illustrating the definition of Partial G. As shown in scene C1 of Figure 3, the pseudo-low gravity generator 100 defines gravity g as the magnitude of gravity in the Z-axis direction of the pG orbit before the test. Then, as shown in scene C2 of Figure 3, the pseudo-low gravity generator 100 defines gravity g / K as the magnitude of gravity in the Z-axis direction of the pG orbit after the test. PG This is how it is defined.

[0049] (Assumption of a pseudo-low gravity generator) The pseudo-low gravity generator 100 is assumed to consider only gravity, without considering the effects of centrifugal force, tangential acceleration, etc. In other words, the pseudo-low gravity generator 100 considers static movement. Furthermore, the pseudo-low gravity generator 100 is assumed to place the test specimen in the center of the inner frame 14 so as not to generate an unbalanced moment.

[0050] (An approach to creating a bias in gravity) Figure 4 shows an example of a pseudo-zero-gravity orbit. In the following explanation, the pseudo-zero-gravity orbit will also be referred to as a "μG orbit." The pseudo-zero-gravity orbit shown in Figure 4 is obtained by operating the rotation angle θ of the pitch angle and the rotation angle φ of the roll angle according to equation (Equation 11). In the example shown in Figure 4, the integer k is set to 1. The μG orbit has a gravity mean of zero across the three axes and the variance is uniform.

[0051] Figure 5 illustrates the vertical component of the Z-axis of the specimen. In Figure 5, the coordinate system of the specimen and the vertical component of the Z2 axis that it references are shown. p (t) is shown. The sphere shown in Figure 5 is an example of a unit sphere defined by a pG orbit, and is defined for the Northern and Southern Hemispheres with respect to the equator.

[0052] As shown in Figure 5, the pseudo-low gravity generator 100 has the test specimen fixed to the coordinate system {X2, Y2, Z2} of the inner frame 14 (inner gimbal), so it is sufficient for a gravity bias to occur in the Z-axis component of this coordinate system. In this embodiment, as an approach, the tip of the Z2 axis vector moves along a pseudo-zero gravity orbit generated in all directions of the sphere, and velocity control is performed to reduce the velocity in the southern hemisphere, thereby generating a gravity bias g through velocity change.

[0053] This approach, based on the known μG orbit, allows for a gravity bias by having the Z2-axis component pass through at a faster speed on the northern hemisphere side and at a slower speed on the southern hemisphere side, thus enabling simple control. In a μG orbit, the gravitational mean of the three axes is zero and the variance is uniform, so it is sufficient to add a gravity bias in the Z-axis direction.

[0054] (Velocity control on a pseudo-zero-gravity orbit) For the pseudo-low gravity generator 100, velocity control on a pseudo-zero gravity orbit can be achieved by decelerating the Z2 axis vector as it moves towards the Southern Hemisphere, thereby increasing the time it is subjected to gravity. For example, the Z-axis component, which is the vertical component of the Z2 axis as shown in Figure 5, is Z p Let (t), then Z p (t) is equation (Equation 17):

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[0055] In controlling the speed of the pseudo-low gravity generator 100, Z p Based on the value of (t), the speed is reduced in the Southern Hemisphere and increased in the Northern Hemisphere.

[0056] Figure 6 illustrates the motion of the artificial potential field. As shown in Figure 6, in the pG orbit created by moving along the μG orbit with velocity control, it is desirable that the period does not extend significantly compared to the μG orbit and that the acceleration is kept to a minimum. Therefore, the pseudo-low gravity generator 100 performs control to decelerate in the southern hemisphere and accelerate in the northern hemisphere so that the time for one rotation does not change significantly. Because the velocity is changed according to the position in the northern and southern hemispheres, the test specimen is subjected to an inertial force due to acceleration.

[0057] To minimize this acceleration, we focus on a potential field where the difference between potential energy and kinetic energy is always minimal (0) and energy exchange occurs. As a velocity control law, we can virtually introduce an artificial potential field and change the velocity so that the potential energy and kinetic energy of the point mass at the tip of the Z-axis component are exchanged. Since the characteristics of the artificial potential field can be freely set, we can create a potential field with a structure that allows adjustment of its directivity towards gravity. The potential coefficient is ε, and the bias is Z. aIf we define a potential that is sensitive downwards (opposite to Earth's gravitational field) with a unit mass of a point mass, then from the law of conservation of energy, we get equation (Equation 18):

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[0058] From equation (Equation 18), velocity v ap To find the velocity v, ap This is equation (Equation 19):

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[0059] Figure 7 illustrates the velocity of the artificial potential field. As shown in Figure 7, the velocity v when crossing the equator can be seen from equation (Equation 19). E To find the velocity v, E This is equation (Equation 20):

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[0060] From equation (Equation 19), the velocity v when passing the South Pole S To find the velocity v, S Equation (Equation 21):

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[0061] From equation (Equation 19), the velocity v when crossing the Arctic N To find the velocity v, N This is equation (Equation 22):

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[0062] Next, the superposition of velocities is explained below. The velocity of the μG orbital is v m Then, velocity v m This is equation (Equation 23):

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[0063] At this time, the velocity v of the pG orbital p (θ,φ) is the velocity v when crossing the equator. E Based on this, equation (Equation 24):

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[0064] The orbit generation unit 34 of the control unit 30 has the function of calculating a μG orbit (first orbit) based on parameters, and if the target gravity is not zero, calculating a pG orbit (second orbit) based on parameters.

[0065] (Calculation of pG orbitals) The pG orbital is derived from the time, gimbal angle, and μG velocity of the μG orbital using Equation (Equation 25):

number

[0066] FIG. 8 is a table showing variables for orbit vector calculation. As shown in FIG. 8, θ m is a vector representing a temporal change in the gimbal pitch angle of the μG orbit. The variable θ m =[θ m1 ,θ m2 ,…,θ mn T holds. φ m is a vector representing a temporal change in the gimbal roll angle of the μG orbit. φ m =[φ m1 ,φ m2 ,…,φ mn T holds. v m is a vector representing a temporal change in the movement velocity of the μG orbit. v m =[v m1 ,v m2 ,…,v mn T holds. v p is a vector representing a temporal change in the movement velocity of the pG orbit. v p =[v p1 ,v p2 ,…,v pn T holds. θ p is a vector representing a temporal change in the gimbal pitch angle of the pG orbit. θ p =[θ p1 ,θ p2 ,…,θ pn T holds. φ p is a vector representing a temporal change in the gimbal roll angle of the μG orbit. φ p =[φ p1 ,φ p2 ,…,φ pn T holds.

[0067] ​​​​​​Next, an example of the procedure for calculating the gimbal angle of the pG orbit is described below. Figure 9 is a flowchart showing an example of the pG orbit calculation procedure. The calculation procedure shown in Figure 9 is executed by a computer, such as the control unit 30 of the pseudo-low gravity generator 100 or a computer. The calculation procedure shown in Figure 9 includes steps P1 to P8 for calculating the gimbal angle of the pG orbit. Note that the variable i is 0 ≤ i ≤ n.

[0068] In step P1, the gimbal angle vector θ of the μG orbit is used. m ,φ m Numerically differentiate the expression to obtain equation (Equation 25). Specifically, the numerical derivative value θ with respect to θm and φm is obtained. m(i) * ,φ m(i) * The array is put into place, and the second iteration of the calculation is θ. p(i) ,φ p(i) The velocity is estimated from the value of .

[0069] In step P2, the velocity vector v on the μG orbit is m(i) Calculate the following. For details, see formula (Equation 26):

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[0070] In step P3, the parameter ξ (i) Set the corrected velocity vector v of the μG orbital. p(i) Calculate the following. For details, see formula (Equation 27):

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[0071] In step P4, the corrected velocity vector v p(i) and velocity vector v m(i) Velocity ratio η (i) Calculate the following. For details, see formula (Equation 28):

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[0072] Since the pG orbital moves along the μG orbital, in step P5, the velocity ratio η (i) This is then decomposed into two-axis angular velocities. For details, see equation (Equation 29):

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[0073] In step P6, the gimbal angular velocity vector θ of the obtained pG trajectory is calculated. p(i+1) ,φ p(i+1) By integrating and repeating this n times, we obtain the gimbal angular velocity vector for the entire trajectory. For details, see Equation (Equation 30):

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[0074] In step P7, the overall average gravity G z(k) and gravity error dG (k) Calculate the following. For details, see formula (Equation 31):

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[0075] In step P8, the gravity error dG (k) The convergence condition dG cc Determine whether it falls within the specified range. In step P8, the gravity error dG (k) The convergence condition dG ccIf it does not fall within the range, that is, equation (Equation 33):

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[0076] Also, in step 8, the gravity error dG (k) The convergence condition dG cc If it is within the specified time, complete the procedure shown in Figure 9.

[0077] (Parameters) An example of parameters to be set during testing of the simulated low gravity generator 100 is described below.

[0078] Target G(G) of the pseudo-low gravity generator 100 ref ) sets the target low gravity value of pG. In this embodiment, g / 2 is the maximum. The algorithm controls the acceleration to be minimized, and if the value is greater than g / 2, the acceleration will not be minimized and the problem cannot be solved. If the value is greater than g / 2, the acceleration will increase, but it is possible to consider algorithms that allow this.

[0079] Average time per rotation of the gimbal (T rev The "Gravity Change Guideline" setting (short for faster gravity changes, long for very slow changes) can be adjusted by setting a shorter time. While it's possible to set an extremely long time of 24 hours, this requires a significant amount of time for orbital calculations.

[0080] The gimbal rotation speed, M, sets the number of rotations within one cycle. This setting determines the rotation speed of the first rotation axis α, which is the outer gimbal, and the rotation speed N of the second rotation axis β, which is the inner gimbal, is given by N = M + 1. The goal is to minimize the difference in rotation speeds between the two axes to make the spatial density as uniform as possible. Furthermore, M and N are given as relatively prime values.

[0081] Tolerance: eG ccThis is fixed at the time of shipment and sets the tolerance for the target gravity in the pG orbit.

[0082] Adjustment parameter: X i This parameter is fixed at the time of shipment and is a velocity adjustment parameter used when generating pG orbitals.

[0083] (Trajectory calculation) Figure 10 is a flowchart showing the processing procedure for the orbital calculation of the pseudo-low gravity generator 100. The processing procedure shown in Figure 10 is realized when the control unit 30 of the pseudo-low gravity generator 100 executes a program.

[0084] As shown in Figure 10, the control unit 30 of the pseudo-low gravity generator 100 acquires the set parameters (step S101). For example, the control unit 30 acquires the target G (e.g., 0 to g / 2), the average time for one rotation of the gimbal (gravity change rate), the rotation speed of the gimbal (e.g., M: rotation speed of the outer axis, N: rotation speed of the inner axis), etc. The acquisition method is, for example, acquisition via an input screen or acquisition from a pre-set storage location. For example, the control unit 30 defines one period as the average time for one rotation of the gimbal multiplied by the rotation speed. When the processing in step S101 is completed, the control unit 30 proceeds to step S102.

[0085] The control unit 30 calculates the μG trajectory (step S102). For example, the control unit 30 defines the μG trajectory according to equation (equation 11) by calculating according to the setting parameters obtained in step S101. The control unit 30 stores the trajectory information 35A of the μG trajectory, which can identify, for example, the calculated gimbal angle and the μG movement speed, in the storage unit 35, and when the processing in step S102 is completed, the processing proceeds to step S103.

[0086] The control unit 30 determines whether the target G obtained in step S101 is zero (step S103). When the processing in step S101 is completed, the control unit 30 proceeds to step S102. If the control unit 30 determines that the target G is zero (step S103; Yes), there is no need to bias the gravity, so it terminates the processing procedure shown in Figure 10.

[0087] Furthermore, if the control unit 30 determines in step S103 that the target G is not zero (step S103; No), it proceeds to step S104. The control unit 30 calculates the pG trajectory (step S104). For example, the control unit 30 performs the pG trajectory calculation described above to determine the pG velocity from the time, gimbal angle, and μG velocity of the μG trajectory and equation (equation 25), and calculates the gimbal angle of the pG trajectory from the conditions that constrain movement on the μG trajectory. The control unit 30 stores the trajectory information 35A of the pG trajectory, which can identify the calculated gimbal angle, pG velocity, etc., in the storage unit 35, and when the processing in step S104 is completed, it proceeds to step S105.

[0088] The control unit 30 determines whether the pG target value is within ±δ (step S105). For example, the control unit 30 calculates the error relative to the pG target value and determines whether the error is within the allowable error ±δ. Parameter adjustment is performed, for example, using the Newton-Raphson method, with an allowable error of 1 mg. If the control unit 30 determines that the pG target value is not within ±δ (step S105; No), i.e., it is not within the allowable error, it performs parameter adjustment, returns the process to step S104 as described earlier, and repeats the process. As a result, the control unit 30 modifies the parameters so that the value falls within the target value and recalculates the pG orbital.

[0089] Furthermore, if the control unit 30 determines that the pG target value is within ±δ (step S105; Yes), the error in the pG target value is within the allowable error ±δ, so it terminates the calculation of the pG orbit and proceeds to step S106.

[0090] The control unit 30 evaluates the pG orbit (step S106). For example, the control unit 30 evaluates the magnitude of the gravitational mean, gravitational dispersion, and disturbance acceleration of the finally obtained pG orbit. The control unit 30 stores evaluation information that can be displayed as a bar graph in the storage unit 35. When the processing in step S106 is completed, the control unit 30 proceeds to step S107.

[0091] The control unit 30 stores the pG orbital information in the storage unit 35 (step S107). For example, the control unit 30 creates orbital information for controlling the clinostat 10 in the pG orbit based on conditions that constrain movement on the μG orbit and stores it in the storage unit 35. When the processing in step S107 is completed, the control unit 30 terminates the processing procedure shown in Figure 10.

[0092] In the case of pseudo-zero gravity where the target G is zero, the control unit 30 issues a rotation angle command θ based on the μG orbit information indicated by the orbit information 35A in the memory unit 35. * and rotation angle command φ * This is output to the motor control unit 33. As a result, the pseudo-low gravity generator 100 generates pseudo-weightlessness on the test specimen by statically rotating two orthogonal axes.

[0093] Furthermore, in the case of pseudo-low gravity (pseudo-partial gravity) where the target G is g / 3 or g / 6, the control unit 30 issues a rotation angle command θ based on the pG orbit information indicated by the orbit information 35A in the memory unit 35. * and rotation angle command φ * This is output to the motor control unit 33. As a result, the pseudo-low gravity generator 100 can change the speed at which it moves in a part of the pG orbit, so that the gravity in the X and Y components of the test specimen becomes zero in that part, and a bias is introduced only in the Z component. As a result, the pseudo-low gravity generator 100 can realize a pG orbit with minimal bias from a μG orbit with uniform dispersion.

[0094] (Characteristics of the trajectory to be evaluated) If the test time is long, the two selected orbitals will be used repeatedly for many cycles, so the error when solving in convergence calculations will accumulate. In this embodiment, in order to make the error of the pG orbital that occurs in one cycle extremely small, the convergence error is set to the μG orbital and the orbitals are solved.

[0095] Figure 11 shows the pG orbital and its characteristics with a bias of g / 3. Figure 12 shows the pG orbital and its characteristics with a bias of g / 6. Figures 11 and 12 show the three-axis components of the gravitational mean (g) and the three-axis components of the gravitational dispersion (g) of the pG orbital and its characteristics. 2 ) indicates that the gravity average is the component g of the three axes. X , g Y , g Z This shows that the gravitational dispersion is represented by the three-axis component g X 2 , g Y 2 , g Z 2 This shows that, as shown in Figure 11, the pG orbital with a bias of g / 3 has a gravity-averaged component g X , g Y The value becomes zero, and component g Z Only the gravitational component is present, and the gravitational average component g of the gravitational dispersion X , g Y For comparison, the gravity-averaged component g Z This value is approximately double. And, as shown in Figure 12, the pG orbital with a bias of g / 6 has a gravity-averaged component g X , g Y The value becomes zero, and component g Z Only the gravitational component is present, and the gravitational average component g of the gravitational dispersion X , g Y is ingredient g Z The value is slightly less than that.

[0096] Thus, the pseudo-low gravity generator 100 controls the rotation of the first rotation axis α and the second rotation axis β so that, in the μG orbit (first orbit) where the control unit 30 realizes pseudo-weightlessness, the magnitude of low gravity specified by the integral effect of gravity in all directions applied to the test specimen remains in the Z-axis direction of the test specimen, and in a part of the second orbit derived in this manner, the velocity changes from that of the other part of the second orbit.

[0097] In other words, the pseudo-low gravity generator 100 comprises a clinostat 10 capable of realizing pseudo-weightlessness on a test specimen by rotating a first rotation axis α and a second rotation axis β, and a control unit 30 that controls the rotation of the first rotation axis α and the second rotation axis β. The control unit 30 generates pseudo-low gravity on the test specimen by controlling the rotation of the first rotation axis α and the second rotation axis β so that in a part of the second orbit (pG orbit) derived from the integral effect of gravity applied to the test specimen in the first orbit (μG orbit) that realizes pseudo-weightlessness, the velocity at which the test specimen moves in that part changes from the velocity at which it moves in the other part of the second orbit. As a result, the pseudo-low gravity generator 100 can change the velocity at which it moves in a part of the second orbit (pG orbit) so that gravity becomes zero in the X and Y components of the test specimen in that part, and a gravity bias is applied only to the Z component. As a result, the pseudo-low gravity generator 100 can generate a specified pseudo-low gravity for the test specimen by controlling the rotation of the clinostat 10.

[0098] In this embodiment, the pseudo-low gravity generator 100 is described as a device capable of generating pseudo-microgravity and pseudo-low gravity, but it is not limited to this. For example, the pseudo-low gravity generator 100 may be configured to generate only pseudo-low gravity and not pseudo-microgravity.

[0099] (Second Embodiment) Next, a second embodiment will be described. When the clinostat 10 rotates, angular acceleration is inevitably generated due to the nature of the trajectory. At that time, the specimen placed on the clinostat 10 is subjected to the acceleration generated when it rotates, which becomes a disturbance. Therefore, the clinostat 10 needs to rotate smoothly with the smallest possible acceleration, and in order to achieve this, an artificial potential model is introduced in the second embodiment. This model ensures that the acceleration when rotating is determined by the exchange of potential energy and kinetic energy, and the trajectory created under these conditions will have the minimum angular acceleration.

[0100] The pseudo-low gravity generator 100 according to the second embodiment uses a potential field with enhanced gravity directivity. Figure 13 is a table illustrating an example of a potential model. In Figure 13, potential model PM1 is the artificial potential of the first embodiment, but with the direction of the potential reversed. The artificial potential can be freely set according to the purpose. For example, potential models PM2 and PM3 can increase the magnitude of partial gravity while smoothing the acceleration. Although the generated acceleration increases, the target G can be expanded to g / 2 or more. Potential model PM2 is an artificial potential with the direction of the potential reversed and gravity directivity squared. Potential model PM3 is an artificial potential with the direction of the potential reversed and gravity directivity cubed.

[0101] The three potential models shown in Figure 13 assume the same velocity when the sphere passes through the equator, North Pole, and South Pole; the difference lies in the acceleration generated in the orbit between these two points. In one example shown in Figure 13, the acceleration increases in the order of potential models PM1, PM2, and PM3. Velocity v of the pG orbit p When (θ,φ) is expressed in the potential model, it is given by equation (Equation 34):

number

[0102] The control unit 30 controls the rotation of the first rotation axis α and the second rotation axis β so as to bias the specimen in the Z-axis direction with the velocity of the second orbit calculated using a potential model with enhanced gravity directivity. The control unit 30 obtains the pG orbit by applying equation (Equation 34) to the calculation of the pG orbit in the first embodiment, and in the case of pseudo-weightlessness where the target G is zero, it issues a rotation angle command θ based on the μG orbit information shown in the orbital information 35A of the memory unit 35. * and rotation angle command φ * This is output to the motor control unit 33. As a result, the pseudo-low gravity generator 100 can suppress the effects of acceleration generated when the test specimen installed on the clinostat 10 rotates.

[0103] (effect) A pseudo-low gravity generating device 100 according to a first aspect of this disclosure comprises a clinostat 10 capable of realizing pseudo-weightlessness in a test specimen by rotating the outer frame 15 around a first rotation axis α and the inner frame 14 around a second rotation axis β, respectively, and a control unit 30 that controls the rotation of the first rotation axis α and the second rotation axis β, wherein the first rotation axis α is defined as the Y axis and the second rotation axis β as the X axis, and a coordinate system is defined for the rotation angles from a reference angle of the first drive source that rotates around the first rotation axis α and the second drive source that rotates around the second rotation axis β. The control unit 30 uses the trajectory of the tip of the Z2 axis vector of the coordinate system fixed to the inner frame as the orbit, and based on the first orbit (μG orbit) that realizes pseudo-zero gravity, it derives a second orbit (pG orbit) such that the magnitude of the specified low gravity remains in the Z-axis direction of the test object due to the integral effect of gravity in all directions applied to the test object. By controlling the rotation of the first rotation axis α and the second rotation axis β so that the speed at which the second orbit moves changes from that at which the other parts move, the pseudo-low gravity generator 100 can change the speed at which the second orbit moves, so that gravity becomes zero in the X-axis and Y-axis components of the test object in that part, and a gravity bias is applied only to the Z-axis component. As a result, the pseudo-low gravity generator 100 can generate the specified pseudo-low gravity for the test object.

[0104] In the pseudo-low gravity generating device 100 according to a second aspect of this disclosure, the control unit 30 controls the rotation of the first rotation axis α and the second rotation axis β so as to make the components of the test specimen in the X0 axis direction and Y0 axis direction zero and impart a gravity bias in the Z0 axis direction, by generating a second orbit based on the first orbit (μG orbit) without weighting in the X and Y directions and decreasing velocity as it approaches the vertical direction. As a result, the pseudo-low gravity generating device 100 can impart a gravity bias to the Z-axis component of the test specimen by decreasing velocity according to the magnitude of the gravity of the target to which the bias is to be applied.

[0105] The pseudo-low gravity generator 100 according to a third aspect of this disclosure has a second orbit that moves along the surface of a unit sphere having a northern hemisphere and a southern hemisphere, and the control unit 30 controls the rotation of the first rotation axis α and the second rotation axis β such that the velocity of the tip of the Z2 axis vector moving along the second orbit is a first velocity in the northern hemisphere and a second velocity slower than the first velocity in the southern hemisphere. As a result, the pseudo-low gravity generator 100 can impart a gravity bias to the Z-axis component of the specimen by performing simple velocity control.

[0106] The pseudo-low gravity generating device 100 according to the fourth aspect of this disclosure is a gimbal mechanism in which the clinostat 10 can tilt the specimen in any direction by combining a first rotation axis α and a second rotation axis β. The control unit 30 determines the speed of movement in the first orbit based on the time, gimbal angle and velocity of the first orbit, and controls the rotation of the first rotation axis α and the second rotation axis β based on the gimbal angle of the second orbit determined from the conditions constraining the movement of the first orbit. As a result, the pseudo-low gravity generating device 100 can appropriately control the rotation of the first rotation axis α and the second rotation axis β by determining the gimbal angle of the second orbit determined using the state variables of the orbital vector.

[0107] The pseudo-low gravity generator 100 according to the fifth aspect of this disclosure has a control unit 30 which has an orbit generation unit 34 that calculates a first orbit based on parameters and calculates a second orbit based on the parameters if the target gravity is not zero. The orbit generation unit 34 terminates the calculation of the second orbit when the error with respect to the target gravity is within an acceptable range, and performs the calculation of the second orbit based on the corrected parameters when the error with respect to the target gravity is within an acceptable range. As a result, the pseudo-low gravity generator 100 can accurately calculate the control angle of the second orbit and improve the accuracy of the control of the rotation of the first rotation axis α and the second rotation axis β, thereby more accurately applying a gravity bias to the Z-axis component of the specimen.

[0108] In the pseudo-low gravity generator 100 according to the sixth aspect of this disclosure, the control unit 30 controls the rotation of the first rotation axis α and the second rotation axis β so as to impart a bias in the Z-axis direction to the velocity of the second orbit calculated using a potential model with enhanced gravity directivity. As a result, the pseudo-low gravity generator 100 can determine the exchange of potential energy and kinetic energy when the clinostat 10 rotates using a potential model, and can minimize the angular acceleration of the orbit created under these conditions.

[0109] A pseudo-low gravity generation method according to a seventh aspect of this disclosure is a pseudo-low gravity generation method for a pseudo-low gravity generation device 100 comprising a clinostat 10 capable of realizing pseudo-weightlessness in a test specimen by rotating the outer frame 15 around a first rotation axis α and the inner frame 14 around a second rotation axis β, respectively, and a control unit 30 that controls the rotation of the first rotation axis α and the second rotation axis β, wherein the first rotation axis α is the Y axis and the second rotation axis β is the X axis, and the reference angles of the first drive source that rotates around the first rotation axis α and the second drive source that rotates around the second rotation axis β are The method includes the steps of defining a coordinate system for the rotation angles, defining the trajectory of the tip of the Z2 axis vector of the coordinate system fixed to the inner frame as the orbit, deriving a second orbit (pG orbit) based on a first orbit (μG orbit) that realizes pseudo-weightlessness, such that the magnitude of the specified low gravity remains in the Z-axis direction of the test specimen due to the integral effect of gravity in all directions applied to the test specimen, and controlling the rotation of the first rotation axis α and the second rotation axis β such that the velocity of a portion of the derived second orbit changes from the velocity of the other portion of the second orbit. As a result, the pseudo-low gravity generation method can change the velocity of a portion of the second orbit so that gravity becomes zero in the X-axis and Y-axis components of the test specimen in that portion, and a gravity bias is applied only to the Z-axis component.

[0110] The program according to the eighth aspect of this disclosure is a pseudo-low gravity generating device 100 comprising a clinostat 10 capable of realizing pseudo-weightlessness in a test specimen by rotating the outer frame 15 around a first rotation axis α and the inner frame 14 around a second rotation axis β, respectively, and a control unit 30 that controls the rotation of the first rotation axis α and the second rotation axis β, wherein the first rotation axis α is the Y axis and the second rotation axis β is the X axis, and the coordinate system of the rotation angles from the reference angle of the first drive source that rotates around the first rotation axis α and the second drive source that rotates around the second rotation axis β The program defines a first orbit (μG orbit) that realizes pseudo-weightlessness, and derives a second orbit (pG orbit) based on the first orbit (μG orbit) that realizes pseudo-weightlessness, such that the magnitude of the specified low gravity remains in the Z-axis direction of the test object due to the integral effect of gravity in all directions applied to the test object; and controls the rotation of the first rotation axis α and the second rotation axis β so that the velocity at which the derived second orbit moves differs from the velocity at which the other part of the second orbit moves. As a result, the program can change the velocity at which the pseudo-low gravity generator 100 moves in a part of the second orbit, so that gravity becomes zero in the X-axis and Y-axis components of the test object in that part, and a bias is applied only to the Z-axis component.

[0111] Although embodiments of the present invention have been described above, the embodiments are not limited to those described herein. Furthermore, the aforementioned components include those that can be easily conceived by those skilled in the art, those that are substantially the same, and those that fall within the so-called equivalent range. Moreover, the aforementioned components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the embodiments described above. [Explanation of Symbols]

[0112] 10. Clinostat 13 Holding part 13a Holding plate 13b Connection part 14 Inner frame 15 Outer frame 15a Edge 16 Legs 17 First Motor 18. Second motor 19. Stand 30 Control Unit 31,32 Rotation angle detector 33 Motor Control Unit (Motor Controller) 34 Trajectory generation part 35 Storage section 35A orbit information 100 Pseudo-low gravity generator

Claims

1. A clinostat capable of creating a pseudo-weightless environment in a test specimen by rotating the outer frame around its first rotation axis and the inner frame around its second rotation axis, A control unit that controls the rotation of the first rotation axis and the second rotation axis, Equipped with, The first rotation axis is defined as the Y-axis and the second rotation axis as the X-axis. A coordinate system is defined for the rotation angles from a reference angle of the first drive source that rotates around the first rotation axis and the second drive source that rotates around the second rotation axis, and the Z coordinate system is fixed to the inner frame. ２ The trajectory is defined as the path of the tip of the axis vector as it moves. The control unit derives a second orbit based on the first orbit that realizes the pseudo-zero gravity, such that the magnitude of low gravity specified by the integral effect of gravity applied to the test specimen in all directions remains in the Z-axis direction of the test specimen, and controls the rotation of the first and second rotation axes so that the velocity of a part of the second orbit changes from the velocity of the other part, thereby generating pseudo-low gravity for the test specimen.

2. The control unit generates a second trajectory based on the first trajectory, without weighting in the X and Y directions, and with the velocity decreasing as it approaches the vertical direction, thereby controlling the X of the test specimen. ０ Axial direction and Y ０ Set the axial component to 0, Z ０ The pseudo-low gravity generating device according to claim 1, wherein the rotation of the first rotation axis and the second rotation axis is controlled so as to impart a gravity bias in the axial direction.

3. The second orbit is an orbit that moves across the surface of a unit sphere having the Northern and Southern Hemispheres, The control unit controls the Z moving along the second trajectory. ２ The pseudo-low gravity generating device according to claim 2, wherein the rotation of the first rotation axis and the second rotation axis is controlled such that the velocity of the tip of the axis vector moves at a first velocity in the northern hemisphere and at a second velocity slower than the first velocity in the southern hemisphere.

4. The clinostat is a gimbal mechanism that can tilt the specimen in any direction by combining the first rotation axis and the second rotation axis. The pseudo-low gravity generating device according to any one of claims 1 to 3, wherein the control unit determines the speed of movement along the first orbit based on the time, gimbal angle and velocity of the first orbit, and controls the rotation of the first rotation axis and the second rotation axis based on the gimbal angle of the second orbit determined from the conditions constraining the movement of the first orbit.

5. The control unit has a trajectory generation unit that calculates the first trajectory based on parameters and, if the target gravity is not zero, calculates the second trajectory based on the parameters. The pseudo-low gravity generating device according to claim 4, wherein the orbit generation unit terminates the calculation of the second orbit when the error with respect to the target gravity is within an acceptable range, and performs the calculation of the second orbit based on the corrected parameters when the error with respect to the target gravity is within an acceptable range.

6. The pseudo-low gravity generating device according to claim 1, wherein the control unit controls the rotation of the first rotation axis and the second rotation axis so as to impose a bias in the Z-axis direction with the velocity of the second orbit calculated using a potential model with enhanced gravity directivity.

7. A clinostat capable of realizing pseudo-weightlessness in a test specimen by rotating the outer frame around a first rotation axis and the inner frame around a second rotation axis, respectively, and a pseudo-low gravity generation device for controlling the rotation of the first and second rotation axes, wherein The first rotation axis is defined as the Y-axis and the second rotation axis as the X-axis. A coordinate system is defined for the rotation angles from a reference angle of the first drive source that rotates around the first rotation axis and the second drive source that rotates around the second rotation axis, and the Z coordinate system is fixed to the inner frame. ２ The trajectory is defined as the path of the tip of the axis vector as it moves. Based on the first orbit that realizes the aforementioned pseudo-weightlessness, a second orbit is derived such that the magnitude of low gravity specified by the integral effect of gravity in all directions applied to the test specimen remains in the Z-axis direction of the specimen. A step of controlling the rotation of the first and second rotation axes such that a portion of the derived second orbit is different from the speed at which the other portion of the second orbit moves, A method for generating pseudo-low gravity, including [the specified method].

8. A clinostat capable of realizing pseudo-weightlessness in a test specimen by rotating the outer frame around a first rotation axis and the inner frame around a second rotation axis, respectively, and a pseudo-low gravity generating device that controls the rotation of the first and second rotation axes, The first rotation axis is defined as the Y-axis and the second rotation axis as the X-axis. A coordinate system is defined for the rotation angles from a reference angle of the first drive source that rotates around the first rotation axis and the second drive source that rotates around the second rotation axis, and the Z coordinate system is fixed to the inner frame. ２ The trajectory is defined as the path of the tip of the axis vector as it moves. The first orbit that realizes the aforementioned pseudo-weightlessness, the second orbit is derived such that the magnitude of the low gravity specified by the integral effect of gravity applied to the test specimen in all directions remains in the Z-axis direction of the test specimen, A step of controlling the rotation of the first and second rotation axes such that a portion of the derived second orbit is different from the speed at which the other portion of the second orbit moves, A program that executes something.

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