JP2013123297A - Magnetic levitation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a magnetic substance to be levitated not only at an equilibrium position but also at a disequilibrium position shifted from the equilibrium position.SOLUTION: A magnetic levitation device comprises: at least a pair of magnets 14 (16); a position detection section 26 which generates location information representing a location of a magnetic substance 12 on an unstable axis; a control coil 22 which generates a magnetic field, by energization, having an inclination along the unstable axis at an equilibrium position 13; and a controller 24 which receives the location information and controls the energization of the control coil 22. The magnetic levitation device also has an acceleration detection section which detects shifting of the magnetic levitation device along the unstable axis and generates acceleration information representing an acceleration of the shifting. The controller 24 controls the energization of the control coil 22 on the basis of the location information as well as the acceleration information.

Description

  The present invention relates to a magnetic levitation device. More specifically, the present invention relates to an improvement in a magnetic levitation device that levitates a magnetic material in the air.

  By detecting that the magnetic body is displaced from the equilibrium position in the static magnetic field generated by the permanent magnet, and controlling the generation of the magnetic field by the electromagnet according to the displacement, the magnetic body is placed at the equilibrium position in the static magnetic field. 2. Description of the Related Art Conventionally, a magnetic levitation device for levitating is known (for example, see Patent Document 1).

Japanese Patent No. 4658449

  However, in the conventional magnetic levitation device, it is not assumed that the entire device moves. For this reason, if the position of the magnet or electromagnet is shifted due to shaking of the entire apparatus, inertia works, and the floating magnetic body cannot stay in the equilibrium position and falls.

  Accordingly, an object of the present invention is to provide a magnetic levitation apparatus that can float a magnetic body not only at a conventional equilibrium position but also at an unbalanced position deviated from the equilibrium position.

In order to solve this problem, the present inventor has made various studies and has obtained knowledge that leads to the solution of the problem. The present invention is based on such knowledge, a magnetic levitation device for levitating a magnetic body in the air,
Arranged to generate a static magnetic field that gives a position-dependent energy that depends on the resultant force of gravity and magnetic force, and makes the magnetic substance unstable at the equilibrium position that the static magnetic field brings. At least a pair of magnets that decrease when moving away from the equilibrium position along an axis and increase when moving away from the balance position along any direction perpendicular to the unstable axis;
A position detector that generates location information indicating the location of the magnetic body on the unstable axis;
An electromagnet that, by energization, generates a magnetic field having a gradient along an unstable axis at an equilibrium position;
A controller that receives location information and controls energization of the electromagnet;
With
An acceleration detector that detects movement along the unstable axis of the magnetic levitation device and generates acceleration information indicating the acceleration of the movement;
The controller controls the energization of the electromagnet based on the location information and the acceleration information.

  When acceleration is generated by moving or shaking the device itself, the magnetic body may be displaced due to the action of inertia and may not be able to stay at the equilibrium position. In this regard, in the magnetic levitation apparatus according to the present invention, when acceleration occurs in the apparatus, the acceleration detection unit detects the movement of the apparatus itself to generate acceleration information, and the acceleration information and the location of the magnetic body The controller controls the energization of the electromagnet on the basis of the location information. According to this, even when the magnetic body deviates from the equilibrium position due to the action of inertia, the magnetic body can be kept in an unbalanced position by adjusting the magnetic force based on each information.

  The magnetic levitation apparatus according to the present invention has a base portion to which a magnet and an electromagnet are fixed, and floats a magnetic body on the base portion.

  A preferred example of the above-described acceleration detection unit is an acceleration sensor that is provided integrally with the base unit and detects acceleration applied to the detection unit itself. Alternatively, the acceleration detection unit may receive the location information and detect the acceleration based on the received change in the location information.

  The magnetic levitation device includes a drive device that drives the base unit based on movement information for moving the base unit to a predetermined position, and the acceleration detection unit detects an acceleration based on the movement information. It is also preferable.

Furthermore, the present invention is a magnetic levitation device for levitating a magnetic material in the air,
Arranged to generate a static magnetic field that gives a position-dependent energy that depends on the resultant force of gravity and magnetic force, and makes the magnetic substance unstable at the equilibrium position that the static magnetic field brings. At least a pair of magnets that decrease when moving away from the equilibrium position along an axis and increase when moving away from the balance position along any direction perpendicular to the unstable axis;
A position detector that generates location information indicating the location of the magnetic body on the unstable axis;
An electromagnet that, by energization, generates a magnetic field having a gradient along an unstable axis at an equilibrium position;
A controller that receives location information and controls energization of the electromagnet;
With
A target position control unit for generating target position information indicating a target position away from the equilibrium position;
The controller calculates the moving direction and moving speed of the magnetic body from the deviation information indicating the deviation from the target position information, and generates an intensity compensation information for canceling the direction, the target position information and the location information. A magnetic force intensity information determination unit for adding magnetic force intensity information generated by each of the inertia compensation control unit and the movement control unit, a movement control unit for generating magnetic force intensity information for causing the magnetic body to reach a target position from It is characterized by having.

  In this magnetic levitation device, magnetic force intensity information for causing the magnetic body to reach the target position is generated based on the target position information and the location information indicating the location of the magnetic body, and based on these information, the controller supplies the electromagnet to the electromagnet. Control energization. According to this, the magnetic body can be moved to a target position away from the equilibrium position or can be retained. Further, by changing the target position every moment, it is possible to move the magnetic body constantly or to move it so as to shake.

  According to the present invention, the magnetic material can be levitated not only at the conventional equilibrium position but also at an unbalanced position deviating from the equilibrium position.

1 is a partial schematic diagram of a magnetic levitation system in one form of a magnetic levitation device. 3 is a partial schematic view of a magnetic air levitation system in another form of magnetic levitation device. FIG. 5 is a partial schematic diagram of a magnetic levitation system according to yet another form of magnetic levitation device. It is a plot which shows the fluctuation | variation of the position-dependent magnetic energy accompanying the movement from the equilibrium position of the magnetic body levitated along each of the x-axis, y-axis, and z-axis of the magnetic levitation system shown in FIG. It is a plot which shows the fluctuation | variation of the position-dependent magnetic energy accompanying the movement from the equilibrium position of the magnetic body levitated along each of the x-axis, y-axis, and z-axis of the magnetic levitation system shown in FIG. It is a plot which shows the fluctuation | variation of the position-dependent magnetic energy accompanying the movement from the equilibrium position of the magnetic body levitated along each of the x-axis, y-axis, and z-axis of the magnetic levitation system shown in FIG. 1 is a plan view of a magnetic levitation system having a control coil arranged to generate a quadrupole magnetic field in an equilibrium position. FIG. 1 is a plan view of a magnetic levitation system having magnets to improve the stability of a levitated magnetic body against rotation. FIG. 1 is a side view of a magnetic levitation system having a movable platform that supports a magnetic body near an equilibrium position. FIG. Illustrates a mechanism for illuminating and activating floating objects. FIG. 3 is a cross-sectional view about an xz plane through a control coil in one form of a magnetic levitation system. It is a figure which shows the coil shape by another form of a magnetic levitation system. It is a figure which shows the coil shape by another form of a magnetic levitation system. 1 is a partial schematic diagram of a magnetic levitation system of a magnetic levitation apparatus in an embodiment of the present invention. It is a figure which shows an example of the relationship between the location along the x-axis of a magnetic body (levitation magnet), and position-dependent energy, and is a thing when a magnetic body exists in an equilibrium position. It is a figure which shows an example of the relationship between the location along the x-axis of a magnetic body (levitation magnet), and position-dependent energy, and is a thing in the case where a magnetic body exists in the unbalanced position shifted | deviated from the equilibrium position. It is a figure which shows an example of the relationship between the location along the x-axis of a magnetic body (levitation magnet), and position-dependent energy, and is a thing in the case where the magnetic body exists in another unbalanced position shifted from the equilibrium position. In one Embodiment of this invention, it is a control block diagram showing the mechanism which continues maintaining stability, when the base apparatus of a magnetic levitation apparatus moves. In one Embodiment of this invention, it is a control block diagram showing the mechanism in the case of moving the magnetic body (levitation magnet) which floated stably.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  The form of the magnetic levitation apparatus concerning this invention is shown in FIGS. The magnetic levitation device 1 according to the present invention is a device that levitates a magnetic body (magnetic element) 12 in the air, and includes a magnet, a position detection unit, an electromagnet, a controller, and the like.

  FIG. 1 shows an example of a magnetic levitation system 10 in the magnetic levitation apparatus 1. In FIG. 1, the two orthogonal axes in the horizontal plane are the x-axis and the y-axis, and the vertical direction is the z-axis.

  The magnetic levitation system 10 is provided with at least a pair of magnets. In FIG. 1, a first pair of magnets 14 (the respective magnets are indicated by reference numerals 14A and 14B) arranged along the x-axis and a second pair of magnets 16 arranged along the y-axis. (The respective magnets are indicated by reference numerals 16A and 16B).

  The magnets 14 and 16 are arranged so as to generate a static magnetic field that provides position-dependent energy depending on the resultant force of gravity and magnetic force with respect to the magnetic body 12. The magnets 14 and 16 reduce the position-dependent energy at the equilibrium position 13 caused by the static magnetic field when the magnetic body 12 is moved away from the equilibrium position 13 along the unstable axis, and the magnetic body is unstable. It increases when it leaves | separates from the equilibrium position 13 along all the directions orthogonal to.

  For example, in the present embodiment, in the magnetic levitation system 10 shown in FIG. 1, the second pair of magnets arranged along the y-axis rather than the first pair of magnets 14A and 14B arranged along the x-axis. 16A and 16B are assumed to have a stronger magnetic force. Therefore, in this magnetic levitation system 10, the magnetic body 12 is stable and hardly shakes in the direction along the y-axis, and easily shakes in the direction along the x-axis. For this reason, in this case, the x-axis becomes an “unstable axis”.

  More specifically, in the present embodiment, the first pair of magnets 14 (14A, 14B) are disposed apart from each other by a distance D1, and the second pair of magnets 16 (16A, 16B) are disposed by a distance D2. They are spaced apart (see FIG. 1) and D2> D1. A suitable ratio of D2 to D1 is, for example, in the range of 1.5: 1 to 2: 1.

  Further, the magnet 16 arranged further away from the magnet 14 (D2> D1) has a magnetic force that is greater than or equal to that of the magnet 14. The magnetic force of the magnet 16 is large enough to substantially prevent the undesired curvature of the field lines of the magnetic field present in the absence of the magnet 16 but is steep due to the proximity of the equilibrium position 13 that the weaker magnet 14 produces. It is preferably not so great as to interfere with a gradient magnetic field. The magnets 14A and 14B preferably have the same magnetic strength, and the magnets 16A and 16B preferably have the same magnetic strength. The strength M14 of the magnet 14 may be less than the strength M16 of the magnet 16 or may be equal to the strength M16 of the magnet 16. A suitable range for the ratio of M16 to M14 is, for example, in the range of 1: 1 to 2: 1.

  In this embodiment, magnets 14A and 14B are arranged along the x axis, and magnets 16A and 16B are arranged along the y axis. Further, the magnets 14 and 16 are all arranged so as to be close to the plane 18. A Cartesian coordinate system having an x-axis and y-axis orthogonal to the plane 18 and a z-axis perpendicular to the plane 18 has an origin at which the magnets 14A and 14B and the magnets 16A and 16B are positioned symmetrically. ing. The z axis of the coordinate system of the illustrated magnetic levitation system 10 forms an axis of symmetry of the magnetic levitation system 10 (see FIG. 1). In FIG. 1 and the like, a distance (vertical direction distance) from the plane 18 to the equilibrium position 13 along the z-axis is indicated as D3.

  The magnets 14 and 16 are smaller in size than the distance between the magnets 14 and 16 and the equilibrium position 13 where the magnetic body 12 can be levitated in the air by the magnetic levitation system 10. Preferably there is. Each of the magnets 14, 16 generates a magnetic field at the equilibrium position 13, the strength of which is approximately the same as the strength of the magnetic field generated by a single magnet at the location of the magnet 14, or magnet 16.

  Further, in this embodiment, the magnetic poles of the magnets 14 and 16 are all parallel to the z axis. FIG. 2 shows a partial schematic diagram of the magnetic levitation system 10, where each of the magnets 14 is tilted toward the z-axis at an angle φ1 and each of the magnets 16 is at an angle φ2. It is inclined toward the z-axis. φ1 = φ2 can also be set. As shown in FIG. 2, tilting one or both of the magnets 14 and 16 toward the z-axis is a magnetic material for motion in one direction, at the expense of reduced stability in the other direction. It may lead to gaining stiffness in 12 air levitations.

  In addition, the magnets 14 and 16 are opposed to a first polarity pole (for example, N) oriented in a first direction (for example, + z direction) and a first direction (for example, -z direction). And a second polarity pole (eg, S) oriented in a second direction.

  Any suitable magnet may be used as the magnets 14 and 16 in the magnetic levitation system 10 of the magnetic levitation device 1. The magnets 14 and 16 may be permanent magnets, for example, or may be equipped with an electromagnet that generates a magnetic field equivalent to the permanent magnets. When the magnetic levitation system 10 is powered by a battery or another power supply limited by total capacity or peak power, or to minimize the power consumption of the magnetic levitation system 10. If preferred, the magnets 14 and 16 are preferably permanent magnets. Further, the magnets 14 and 16 may include NdFeB magnets, barium ferrite magnets, samarium cobalt (Samarium Cobalta) magnets, or AlNiCo magnets. The magnets 14 and 16 can each be an array of a plurality of magnets.

  In the illustrated form, the poles of the magnets 14, 16 closest to the equilibrium position 13 are in the same plane, and all are located in close proximity to the plane 18. The magnets 14 and 16 of this embodiment can be mounted on the base device (base portion) 110 of the magnetic levitation system 10 (see FIGS. 3, 9 and 10). The magnets 14 and 16 and the base device 110 have a thin structure in the z direction. Base device 110 may be less than D3 in thickness, and as an example, base device 110 may be ½ × D3 or less in thickness.

  The magnets 14 and 16 generate a static magnetic field that supports the magnetic body 12 in a floating state at the equilibrium position 13. The static magnetic field has a gradient, and the position-dependent energy due to the magnetic force acting between the magnetic body 12 levitated in the air and the static magnetic field causes the levitated magnetic body 12 to become a stable plane 20 (the yz plane in FIG. 1). It increases if it is moved slightly in a direction parallel to (shown).

  In the present embodiment, the ideal case where the magnets 14 and 16 are positioned on the orthogonal axes (x axis, y axis) is illustrated (see FIG. 1). Within the scope of In this embodiment, the magnets 14 and 16 are arranged at the apexes of the rhombus. The Cartesian coordinate system is established only for convenience in explaining the shape of the illustrated apparatus. Other coordinate systems can be used.

  The magnetic body 12 includes one magnet or an array of a plurality of magnets. The magnetic body 12 may be configured to include a permanent magnet attached to a lightweight main body that floats in the air.

  Here, FIGS. 4, 5, and 6 show fluctuations in the magnetic energy U depending on the position of the magnetic body 12 when moving along the x-axis, y-axis, and z-axis, respectively. The position-dependent magnetic energy U increases when the magnetic body 12 moves away from the equilibrium position 13 along either the y-axis or the z-axis (see FIGS. 5 and 6). That is, the magnetic body 12 is stable with respect to movement along these axes (y-axis and z-axis) (the magnetic body 12 is not easily separated in these axial directions). On the other hand, the position-dependent magnetic energy U decreases when the magnetic body 12 moves away from the equilibrium position 13 along the x axis (see FIG. 4). That is, the magnetic body 12 is unstable with respect to the movement from the equilibrium position 13 along the x-axis (the magnetic body 12 is easily separated from the equilibrium position 13 in the direction along the x-axis).

  The magnetic levitation system 10 includes control coils 22 (individually 22A and 22B) that generate variable magnetic fields under the control of a controller 24 (see FIG. 1). As the levitated magnetic body 12 moves away from the equilibrium position 13, the controller 24 adjusts one or more flows of current in the control coil 22, resulting in the control coil 22 applying a force applied to the magnetic body 12. To generate a magnetic field. The force acts to move the magnetic body 12 in any selected direction along an unstable axis (x-axis in this embodiment). The variable magnetic field generated by the passage of current in the control coil 22 stabilizes the magnetic body 12 against movement in the x-axis direction. In this embodiment, the control coils 22A and 22B are close to each other and arranged along the x axis (see FIG. 1). The control coil 22A is wound around the magnet 14A, and the control coil 22B is wound around the magnet 14B. When energized, the control coil 22 generates a magnetic field having a gradient along an unstable axis at the equilibrium position 13.

  The position sensor 26 functions as a position detection unit that generates location information indicating the location of the magnetic body 12 on an unstable axis (in this embodiment, the x-axis). A signal (location information) representing the movement of the magnetic body 12 relatively moved along the axis) is supplied. In this embodiment, the position sensor 26 is disposed at the center portion of the magnetic levitation system 10 that is directly below the equilibrium position 13 in the vertical direction. The position sensor 26 may include a Hall effect sensor, for example. The Hall effect sensor can be oriented to detect the strength of the magnetic field from the levitated magnetic body 12 in a direction parallel to the x-axis. When the magnetic body 12 is located at the equilibrium position 13, the magnetic poles of the magnetic body 12 are aligned with the direction of the static magnetic field and parallel to the z-axis. The magnetic field created by the magnetic poles of the magnetic body 12 does not have a component in the direction parallel to the x-axis at the position of the position sensor 26. When the magnetic body 12 moves in any direction along the unstable x-axis, the magnetic field detected by the position sensor 26 has a non-zero component in the x-axis direction, and the magnetic body 12 is in the equilibrium position 13. It increases as you move away from it. Therefore, the signal output by the Hall effect sensor 26 can be used as feedback information on the position of the magnetic body 12 along the unstable x-axis in the controller 24.

  The controller 24 adjusts the current supplied to the control coil 22 in order to maintain the magnetic body 12 at the equilibrium position 13 at the equilibrium position 13 or at an unbalanced position shifted from the equilibrium position 13. The controller 24 comprises any suitable control technology including a computer, a programmable controller, or a digital signal processor, or a suitably programmed data processor such as a suitable analog or digital feedback control circuit. The controller 24 of this embodiment receives location information indicating the location of the magnetic body 12 and controls energization to the control coil 22.

  The distance D3 between the equilibrium position 13 where the magnetic body 12 is stably levitated in the air and the plane 18 close to the magnets 14 and 16 adjusts the distance D1 between the magnets 14A and 14B. Can be changed. By slightly decreasing the distance D1 while the magnetic body 12 is levitating in the air, the distance D3 is decreased and at the same time from the equilibrium position 13 in the stable plane 20 (ie, the yz plane in FIG. 1). The stability of the magnetic body 12 can be increased with respect to movement. Further, if the distance D1 is slightly increased while the magnetic body 12 is levitated in the air, the distance D3 is increased, and at the same time, the stability of the magnetic body 12 is decreased with respect to the movement from the equilibrium position 13 on the stable plane 20. To do.

  The equilibrium position 13 is set so that the static magnetic field of the magnets 14 and 16 exerts a force to hold the magnetic body 12 at the equilibrium position 13 against gravity when there is no current flowing in the control coil 22. Has been. As described above, in this embodiment, the magnetic body 12 is unstable in the x direction, and the control coil 22 is operated so as to prevent any movement in the x direction of the magnetic body 12 away from the equilibrium position 13. When the magnetic body 12 moves away from the equilibrium position 13 or moves, the magnetic body 12 is stabilized at the equilibrium position 13 by causing a current to flow in the control coil 22.

  Here, the control coil 22 is arranged so that a magnetic field gradient (dBz / dx) sufficient to control the positioning of the unstable magnetic body 12 in the x-axis direction can be provided in the vicinity of the equilibrium position 13. Yes. The size and location of the control coil 22 are preferably set such that the magnitude of the magnetic field generated by the control coil 22 is very small near the equilibrium position 13. In such a case, the magnetic body 12 can be stabilized without generating a magnetic field component that may cause the magnetic body 12 to rotate due to the strong magnetic field component in the lateral direction at the position of the magnetic body 12. In practice, the x-, y-, and z-direction components of the magnetic field generated by the control coil 22 are as small as possible, and a large gradient (dBz / dx) sufficient to control the positioning of the x-axis magnetic body 12 is set in the x-direction. Having it is preferred.

  FIG. 7 shows a magnetic levitation system 10 </ b> A that minimizes the magnetic field from the control coil 22 in the vicinity of the equilibrium position 13. The same reference numerals as in the embodiments described so far are used to indicate parts of the magnetic levitation system 10A. The magnetic levitation system 10A has four control coils 22, that is, control coils 22A, 22B, 22C, and 22D. The control coils 22A to 22D are rectangular coils arranged in parallel to the plane 18 and in parallel to each other. The long side surfaces of the control coils 22A to 22D extend so as to be parallel to the y-axis and perpendicular to the unstable x-axis. The control coils 22A to 22D are arranged symmetrically along the x axis. Magnets 14A and 14B are in control coils 22A and 22B, respectively. The control coils 22A to 22D are arranged symmetrically with respect to the yz stable plane. Ideally, the control coils 22A and 22B are close to each other, the control coils 22A and 22C are close to each other, and the control coils 22B and 22D are close to each other. The control coils 22C and 22D are preferably wider in size along the x-axis than the control coils 22A and 22B. In the form shown in FIG. 7, the control coil 22A has the same dimensions as the control coil 22B, and the control coil 22C has the same dimensions as the control coil 22D.

  Of the magnetic field generated by the control coil 22, it is preferable that at least components parallel to the plane 18 substantially cancel each other at least in the vicinity of the equilibrium position 13. This canceling can be realized by making the dimensions of the control coil 22 appropriate and appropriately passing a current through the control coil 22A. In order to apply a stable magnetic force to the magnetic body 12, the current flows in a direction in which the inner control coils 22A and 22B are opposed to each other. For example, when the current flows through the control coil 22A in the clockwise direction, the current in the control coil 22B needs to flow in the counterclockwise direction. At the same time, the current flow in the control coil 22C is counterclockwise, and the current flow in the control coil 22D is clockwise. Thereby, a stable magnetic field can be generated, and an unstable force along the x-axis can be applied to the magnetic body 12. In addition, by reversing the direction of the current flowing through each of the control coils 22, the force acting on the magnetic body 12 along the unstable x-axis can be reversed.

  Note that the control coils 22 arranged as shown in FIG. 7 have the same number of windings and appropriate dimensions. A "quadrupole" is generated. At a point that becomes a “magnetic quadrupole”, the magnitude of the magnetic field is zero, and there is a linear and symmetric magnetic field gradient around the point. In this case, the control coil 22 generates a magnetic force for stabilization applied to the magnetic body 12. The magnitude of the magnetic force applied to the magnetic body 12 is proportional to the magnitude of the magnetic field gradient dBz / dx at the location of the magnetic body 12.

  FIG. 11 is a cross-sectional view of the xz plane passing through the control coil 22. For the control coil 22 for generating a “magnetic quadrupole” at the equilibrium position 13, the control coils 22A, 22B have equal width W1, the control coils 22C, 22D have equal width W2, and W1. Is preferably correlated to W2 and the spacing D3 by W1 = D3 and W2 ≧ D3. All of the control coils 22 preferably have the same length. The length of each control coil 22 in the direction acting laterally with respect to the unstable x-axis is larger than its width.

  The controller 24 preferably suppresses the operation of the magnetic levitation system 10 in preparation for being not detected by the position sensor 26 when the magnetic body 12 is in the vicinity of the equilibrium position 13. For example, when the magnetic body 12 stops functioning, it is preferable to prevent the controller 24 from trying to correct the positioning of the magnetic body 12 by passing a current through the control coil 22. This consumes energy, causes the control coil 22 to overheat, and, if extreme, can damage the control circuit that supplies power to the control coil 22. When the signal from the position sensor 26 indicates that the magnetic body 12 is not within the desired spacing of the equilibrium position 13, the controller 24 can be configured to switch to an inactive mode or inactive until reset. It can be configured to remain in a state. The magnetic levitation system 10 can include a reset switch that can be operated by a user to reset the controller 24.

  In some cases, it may be preferable to provide an additional magnet that increases the strength of the static magnetic field at the equilibrium position 13. The stability of the magnetic body 12 against the moment to turn over increases with the strength of the static magnetic field at the equilibrium position 13. This is because the magnetic poles of the magnetic body 12 are often naturally aligned with the surrounding magnetic field. When the magnetic poles of the magnetic body 12 deviate from the static magnetic field, the magnetic body 12 receives a torque for returning to the original state. The magnitude of the torque is proportional to the strength of the magnetic field at the position of the magnetic body 12.

  FIG. 8 shows an array of additional magnets 30 that increase the strength of the magnetic field at the equilibrium position 13 without adversely affecting the magnetic field gradient that generates the force used to maintain the magnetic body 12 at the equilibrium position 13. An example is shown. An additional magnet 30 is arranged on the ring 31. Each additional magnet 30 has a magnetic pole in the same direction as the magnet 14.

  The ring 31 is located on the plane 18 or on a plane parallel to the plane 18. The equilibrium position 13 is located on a line extending perpendicularly to the plane of the ring 31 from the center of the ring 31. The radius of the ring 31 is selected such that the z component of the magnetic field generated by the additional magnet 30 is substantially free of gradient in the z direction at the equilibrium position 13 (ie, dB (30) at the equilibrium position 13). z / dz = 0). In the formula, B (30) z is the z component of the magnetic field generated by the magnet 30. In this situation, “substantially no gradient” means that the gradient of the static magnetic field generated by the magnets 14, 16 that levitates the magnetic body 12 in the air at the equilibrium position 13 is smaller, preferably the static magnetic field It means a gradient that is less than 25% of the gradient, more preferably less than 7%.

  The magnetic levitation system 10 can include a non-magnetic support member 40 that is movable relative to the magnets 14, 16 between a lowered position 42A and an elevated position 42B, as shown in FIG. When the support member 40 is in the raised position 42B, the magnetic body 12 is supported at the equilibrium position 13. In the magnetic levitation system 10, the support member 40 may be lowered to the lowered position 42 </ b> A after being operated so as to hold the magnetic body 12 at the equilibrium position 13.

  The support member 40 can include an arm, a table, a column, and the like. The support member 40 is movable between a first position supported by the magnetic body 12 and a second position away from the equilibrium position 13. Any mechanism can be provided to allow the support member 40 to move between the first position and the second position. The mechanism can comprise, for example, one or more hinges, pivots, slide members, flexible members, and the like.

  As shown in FIG. 3, the magnetic levitation system 10 may include one or more secondary electromagnets 22 '. The secondary electromagnet 22 ′ can further be used to stabilize the magnetic body 12. In one example, an electromagnet that is symmetric about the z-axis and is parallel to the plane 18 can generate a magnetic field gradient parallel to the z-axis that increases the static magnetic field from the magnets 14, 16. This magnetic field gradient generates a force acting on the magnetic body 12 in a direction parallel to the z-axis. The magnitude and direction of the force is controlled by the current flowing in the secondary electromagnet 22 '. A secondary sensor 26B that is directed to detect motion of the magnetic element along the z-axis provides feedback to the secondary controller 24B (which is the same hardware / used to provide feedback to the controller 24). It may be an independent control path supplied by software, or it may be a separate independent controller). The controller 24B controls the flow of current in the secondary electromagnet 22 ′. The secondary electromagnet system can be used to reduce the vibration of the magnetic body 12 along the z-axis, or to move the magnetic body 12 in the + z direction or the −z direction around the equilibrium position 13. By repeatedly reversing the flow of current in the secondary electromagnet 22 'at an appropriate speed, the controller 24B allows the magnetic body 12 to oscillate about the equilibrium position 13 along the z-axis.

  An electromagnet on the other side with a suitable feedback sensor can be supplied with a suitable controller and provides a force on the magnetic body 12 along the y-axis or a magnetic torque on the magnetic body 12. In this way, the levitated element can be steered about the equilibrium position 13 or oscillated in a certain direction to a limited extent.

  The magnetic levitation system 10 can include a mechanism for activating or illuminating the magnetic body 12. FIG. 10 shows an example of the new toy 50. The toy 50 includes a mechanism for activating the magnetic body 12 and a system for illuminating the magnetic element. In FIG. 10, detailed description of the mechanism for levitating the magnetic body 12 in the air is omitted. The air levitation mechanism is built in the base device 110.

  In the toy 50, the magnetic body 12 includes a lightweight shell 52 similar to the helicopter fuselage. The permanent magnet 54 is attached in the shell 52. The magnet 54 interacts with the air levitation system as described above to levitate the magnetic body 12 at the equilibrium position 13. The toy 50 includes an animation mechanism 60. The animation mechanism 60 includes a small motor 62 that drives the rotor 56. The motor 62 is powered by the power supplied by the high frequency coupling system. The coupling system can comprise an air core transformer. The transmission coil 66 attached to the base device 110 is excited by a high frequency (eg, radio frequency) electrical signal. The signal output by the transmission coil 66 is coupled to the receiving coil 67 in the magnetic body 12. This induces a current in the receiving coil 67. The current is rectified by a rectifier circuit 68 to generate electricity that drives the motor 62. The electricity from the rectifier circuit 68 can be used to power an electrical device other than or in addition to the motor 62. For example, the electricity can be used to operate a small lamp (eg, a light emitting diode (LED)).

  Toy 50 further includes a lighting system 70. The illumination system 70 includes a high-intensity light source 72 in the base device 110. The light source 72 generates a light beam 73. The beam 73 illuminates the photoreceptor 74 of the magnetic body 12. In this embodiment, the photoreceptor 74 includes a lens 75 that focuses light from the beam 73 onto a bundle of optical fibers 76. The optical fiber 76 extends into the location of the shell 52 corresponding to a navigation light or the like. The beam 73 may be tightly closed so that it is not easily visible to the person monitoring the toy 50. A mirror, diffuser, or other optical member directs light from the photoreceptor 74 to illuminate the surface features of the magnetic body 12 in place of or in addition to the optical fiber 76. Can be used for

  A component (eg, magnet, assembly, device, circuit, etc.) is referred to above, but unless otherwise specified, a reference to that component performs the function of the described component as an equivalent of that component. It should be construed to include any component (ie, it is functionally equivalent) and includes components that are not structurally equivalent to the disclosed structures that perform the functions in the illustrated exemplary form of the invention.

As will be apparent to those skilled in the art from the foregoing disclosure, many changes and modifications may be made in the practice of the invention without departing from the spirit or scope of the embodiments. For example,
-In the illustrated form, the magnetic poles of the magnets 14 and 16 are parallel to each other. In this embodiment, one or both of the magnets 14, 16 are oriented so that their magnetic poles are at an acute angle with respect to the plane 18.
In the illustrated embodiment, the uppermost poles of the magnets 14 and 16 are on the same plane and are all located close to the plane 18. The magnets 14 and 16 are not necessarily on the same plane.
In the illustrated form, the north poles of the magnets 14, 16 face the equilibrium position 13. The polarity of the magnets 14, 16 can be reversed so that the south pole of the magnets 14, 16 faces the equilibrium position 13.
The control coil 22 is not necessarily formed from a plurality of discrete coils. Even a single winding can be arranged to provide approximately the same magnetic field as that provided by multiple discrete coils.
An additional ring magnet concentric with the ring 31 can be provided. The ring or rings preferably generate a magnetic field with dB (30) z / dz = 0 at equilibrium position 13 where there are rings of different diameters. Each ring is preferably located at a different distance from the equilibrium position 13 in order to maintain dB (30) z / dz = 0.
The ring 31 can include one or more ring-shaped magnets instead of a plurality of magnets.
One or both of the magnets 14, 16 can be replaced with a symmetrically arranged arrangement of smaller magnets that generate a similar magnetic field. Nevertheless, it is generally preferred to use a small number of magnets rather than a large number to minimize the space occupied by the magnets.
The control coil 22 is illustrated as a rectangular one, whereas other coil shapes can be used to further generate a magnetic force for stabilization of the magnetic body 12. is there. For example, the coils may be triangular like the coils 22E and 22F in FIG. 12, or semicircular like 22G and 22H in FIG.
Any suitable non-contact sensor can be used as the position sensor 26. The position sensor 26 may comprise, for example, a suitable optical sensor, capacitive sensor, or other sensor. The position sensor 26 can detect the position of the magnetic body 12 along the unstable axis in any suitable manner. In a preferred form, the position sensor 26 detects the movement of the magnetic body 12 along an unstable axis from a position that is moved from the equilibrium position 13 by a distance equal to the distance between the plane 18 and the equilibrium position 13. It is of a possible type.

  FIG. 1 shows an embodiment of the magnetic levitation apparatus 1 in which the levitation of the magnetic body 12 is unstable only in the x-axis direction, and the control coils 22 (22A, 22B) are arranged along the x-axis. Of course, the control coils 23 (23A, 23B) can also be arranged in the direction along the y-axis (see FIG. 14). In this case, the position sensor 26 detects not only the position in the x-axis direction but also the position in the y-axis direction with respect to the equilibrium position 13 of the magnetic body 12, and the controller 24 supplies a current to be supplied to the control coil 22 depending on the position in the x-axis direction. Similar to the control, the current flowing through the control coil 23 is controlled by the position in the y-axis direction.

  Subsequently, as one embodiment of the present invention, not only the magnetic body 12 is levitated at the above-described equilibrium position 13 (see FIG. 15), but also an unbalanced position shifted from the equilibrium position 13 (FIGS. 16 and 17). The structure of the magnetic levitation apparatus 1 that levitates the magnetic body 12 will be described below with reference to block diagrams and the like (see FIGS. 14 to 18). The magnetic levitation apparatus 1 of the present embodiment includes a stable position control unit 101, a target position determination unit 102, a PID control unit 103, a current control circuit 104, and the like in addition to the elements in the above-described form.

  The stable position control unit 101 outputs a stable position stored in advance as a stable position command. When the equilibrium position (stable position) 13 differs depending on the levitating magnet (hereinafter also referred to as the levitating magnet) 12, a sensor or the like that can determine the selection of the levitating magnet 12 to be levitated is prepared, whereby the levitating magnet 12 is prepared. It is possible to output a stable position (equilibrium position 13) corresponding to. The stable position control unit 101 of this embodiment also has a role of controlling the stable position so as to minimize the current generated by the current control circuit 104.

  The target position determination unit 102 receives acceleration information from the acceleration detection unit 113, and adds a value (Ka) proportional to the acceleration (a) to the stable position signal in the stable position command output by the stable position control unit 101 ( (See FIG. 18). The value Ka can be a negative value depending on the position of the levitating magnet 12, the contents of the stable position signal, and the like.

  The PID control unit 103 performs PID control using feedback from a position sensor (hereinafter also referred to as a levitation magnet position detection unit) 26 so that the levitation magnet 12 reaches the target position determined by the target position determination unit 102. And generate a magnetic force command to the current control circuit 104.

  The current control circuit 104 receives a magnetic force intensity command from the PID control unit 103 and causes a current having a magnitude proportional to the magnetic force intensity to flow through the control coil 22. In addition, the magnitude | size of an electric current may become negative (a flow direction becomes reverse), and when it becomes negative, the polarity of the control coil 22 is reversed.

  In this embodiment, the levitating magnet position detection unit 26 detects how much the levitating magnet 12 is displaced from the central position of the base device 110. Such a levitated magnet position detector 26 can be configured by, for example, a magnetic sensor, an infrared sensor, or the like.

  The acceleration detection unit 113 is a device that detects acceleration when the base device 110 of the magnetic levitation device 1 moves. In the present embodiment, the acceleration detection unit 113 moves the magnetic levitation device 1 itself along the unstable axis (described above). If it is the form which carried out, the movement to the x-axis direction of the said magnetic levitation apparatus 1) will be detected (refer FIG. 18 etc.). Such an acceleration detection unit 113 includes, for example, an acceleration sensor or a speed sensor, and is fixed to the base device 110 or the like of the magnetic levitation device 1. When moving along, for example, acceleration generated in the base device 110 of the magnetic levitation device 1 is detected, and acceleration information is generated and transmitted.

  In such a magnetic levitation apparatus 1, the magnetic body 12 can be levitated even at an unbalanced position 13 ′ shifted from the equilibrium position 13 (see FIGS. 16 and 17). That is, when the magnetic levitation device 1 (or its base device 110) is moved, the positions of the magnets and the control coil 22 also change, and the relative position of the levitated levitation magnet 12 shifts due to inertia. In this case, in the magnetic levitation device 1 of the present embodiment, the deviation of the relative position of the levitation magnet 12 caused by the acceleration acting on the magnetic levitation device 1 itself (or its base device 110) is canceled, and the levitation magnet 12 does not fall. It is possible to control. According to this, even when the levitating magnet 12 deviates from the equilibrium position 13 due to the action of inertia, the magnetic force is adjusted based on each information so that the levitating magnet 12 remains in the unbalanced position 13 ′. Can do. Therefore, in the magnetic levitation device 1 including the levitation magnet 12, the magnetic levitation device 1 itself (or the base device 110 that is a part of the magnetic levitation device 1) is moved or shaken, which is an effect that cannot be performed by the conventional device. It can also be realized.

  Subsequently, as a further embodiment of the present invention, a mode in which the levitating magnet 12 is controlled to always move is shown (see FIG. 19). Here, the target position of the equilibrium position 13 (or the unbalanced position 13 ′ deviated from the equilibrium position 13) is changed, and the stable position itself is continuously shifted, so that the levitation magnet 12 is shaken, which is not balanced. It can be kept in position. In order to realize such control, the magnetic levitation apparatus 1 of the present embodiment further includes a target position control unit 201, an inertia compensation control unit 203, and a magnetic strength command determination unit 204 (see FIG. 19).

  The target position control unit 201 sets the target position as appropriate in consideration of how far from the stable position the target is based on the stable position stored in advance. At this time, if the target position is continuously changed, it is possible to make the floating magnet 12 appear to move continuously or to appear as if it is swaying. Such a target position control unit 201 transmits a target position command to the PID control unit 103 and transmits target position command history information to the inertia compensation control unit 203. The target position control unit 201 and the PID control unit 103 constitute a movement control unit 202 that generates magnetic strength information for causing the levitated magnet 12 to reach the target position from the target position information and the location information.

  The inertia compensation control unit 203 calculates, from the target position and deviation information, in which direction and at what speed the levitating magnet 12 is moving, and issues a magnetic strength command necessary for correcting or canceling the movement. Generate. In this case, the magnetic strength is proportional to the speed of the target levitating magnet 12. The inertia compensation control unit 203 according to the present embodiment receives deviation history information from the PID control unit 103 as information on the deviation, and calculates and estimates in which direction the levitating magnet 12 is about to move from this information. .

  The magnetic strength command determination unit 204 adds the magnetic force command for inertia compensation generated by the inertia compensation control unit 203 to the magnetic strength command generated by the PID control unit 103 (see FIG. 19). The added information is transmitted to the current control circuit 104 as a magnetic force intensity command.

  In such a magnetic levitation apparatus 1, magnetic strength information for causing the levitation magnet 12 to reach the target position is generated based on the target position information and the location information indicating the location of the levitation magnet 12. Based on the above, the controller 24 controls the energization to the control coil 22. According to the magnetic levitation apparatus 1 of this embodiment capable of such control, the levitation magnet 12 can be moved to a target position away from the equilibrium position 13 or can be retained. In addition, by continuously changing the target position, it is possible to realize an effect that could not be performed by the conventional device, such as continuously moving the levitation magnet 12 or making it move in a shaking manner.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, as a preferable example of the acceleration detection unit 113, a sensor that is provided integrally with the base device 110 and detects the acceleration applied to the acceleration detection unit 113 itself has been described. For example, a detection device that receives location information of the levitating magnet 12 and detects acceleration based on the change in the received location information can be used as the acceleration detection unit 113.

  In the embodiment described so far, the acceleration when the base device 110 moves is detected by the acceleration detection unit 113. Instead of detecting the acceleration using the sensor in this way, the base device 110 is moved to a predetermined position. It is also possible to obtain movement information relating to the movement amount from a control device of an actuator (not shown) for causing the acceleration to be detected or extracted based on this movement information. In this case, it is possible to estimate the acceleration using movement information such as the expected movement of the actuator and obtain acceleration data from the estimation result.

  Moreover, although the example demonstrated so far showed the example which uses PID control as a typical control method in the PID control part 103, it can also control using another feedback control method.

  In the embodiment described so far, a three-axis orthogonal coordinate system (Cartesian coordinate system) in which the two axes of the x-axis and the y-axis are orthogonal to each other on the horizontal plane 18 and the z-axis is orthogonal to these axes is exemplified. Of course, this is only a preferred example. That is, the magnetic levitation apparatus 1 (the magnetic levitation system 10) shown in FIG. 1 is the smallest of two pairs of magnets (magnets 14 and 16) that generate a magnetic field and one axis (x-axis) that is unstable. In this case, only the “unstable axis” direction (x-axis direction) is resistant to the movement of the base device 110, but two or more “unstable axes” are provided. In this way, it is resistant in all directions when the levitated magnet (magnetic body) 12 moves in a direction parallel to a plane formed by the base device (base portion) 110 (or a plane parallel to the moving direction of the base device 110). It becomes possible to have. In other words, it can be said that a coordinate system in which three or more axes intersect on a plane is set. Incidentally, if, for example, three axes are set on the plane 18, these three axes are preferably set at equal intervals (every 120 degrees). In this case, three pairs of electromagnets (one of these may be a pair of magnets) are arranged along each axis.

  The present invention is suitable for application to a magnetic levitation device for levitating a magnetic material in the air.

DESCRIPTION OF SYMBOLS 1 ... Magnetic levitation apparatus 10, 10A ... Magnetic levitation system, 12 ... Levitation magnet (magnetic body), 13 ... Equilibrium position, 13 '... Unbalanced position shifted from equilibrium position, 14 (14A, 14B) ... Magnet 16 (16A, 16B) ... magnet, 18 ... plane, 20 ... stable plane, 22 (22A, 22B) ... control coil, 22 '... secondary electromagnet, 23 (23A, 23B) ... control coil, 24 ... controller, 26 ... Position sensor (position detection unit), 26B ... Secondary sensor, 30 ... Additional magnet, 31 ... Ring, 40 ... Support member, 42A ... Lowering position, 42B ... Ascending position, 50 ... Toy, 52 ... Shell, 54 ... Permanent magnet, 56 ... Rotor, 60 ... Animation mechanism, 62 ... Motor, 66 ... Transmission coil, 67 ... Receptor coil, 70 ... Illumination system, 72 ... Light source, 73 ... Beam, DESCRIPTION OF SYMBOLS 4 ... Photoreceptor, 75 ... Lens, 76 ... Optical fiber, 101 ... Stable position control part, 102 ... Target position determination part, 103 ... PID control part, 104 ... Current control circuit, 110 ... Base apparatus (base part), DESCRIPTION OF SYMBOLS 113 ... Acceleration detection part, 201 ... Target position control part, 202 ... Movement control part, 203 ... Inertia compensation control part, 204 ... Magnetic strength command determination part

Claims (6)

A magnetic levitation device for levitating a magnetic material in the air,
The magnetic body is arranged to generate a static magnetic field that provides a position-dependent energy that depends on the resultant force of gravity and magnetic force, and the position-dependent energy is converted into the magnetic field at an equilibrium position that the static magnetic field provides. At least a pair that decreases when moving away from the equilibrium position along an unstable axis and increases when moving away from the equilibrium position along the direction perpendicular to the unstable axis. With magnets,
A position detection unit that generates location information indicating the location of the magnetic body on the unstable axis;
An electromagnet that generates, by energization, a magnetic field having a gradient along the unstable axis at the equilibrium position;
A controller that receives the location information and controls energization of the electromagnet;
With
An acceleration detection unit that detects movement of the magnetic levitation device along the unstable axis and generates acceleration information indicating acceleration of the movement;
The controller controls the energization of the electromagnet based on the location information and the acceleration information.   The magnetic levitation apparatus according to claim 1, further comprising: a base portion to which the magnet and the electromagnet are fixed, wherein the magnetic body is levitated on the base portion.   The magnetic levitation apparatus according to claim 2, wherein the acceleration detection unit is an acceleration sensor that is provided integrally with the base unit and detects an acceleration applied to the detection unit itself.   The magnetic levitation apparatus according to claim 1, wherein the acceleration detection unit is configured to receive the location information and detect an acceleration based on a change in the received location information.   The apparatus according to claim 2, further comprising a driving device that drives the base unit based on movement information for moving the base unit to a predetermined position, and the acceleration detection unit detects an acceleration based on the movement information. Magnetic levitation device. A magnetic levitation device for levitating a magnetic material in the air,
The magnetic body is arranged to generate a static magnetic field that provides a position-dependent energy that depends on the resultant force of gravity and magnetic force, and the position-dependent energy is converted into the magnetic field at an equilibrium position that the static magnetic field provides. At least a pair that decreases when moving away from the equilibrium position along an unstable axis and increases when moving away from the equilibrium position along the direction perpendicular to the unstable axis. With magnets,
A position detection unit that generates location information indicating the location of the magnetic body on the unstable axis;
An electromagnet that generates, by energization, a magnetic field having a gradient along the unstable axis at the equilibrium position;
A controller that receives the location information and controls energization of the electromagnet;
With
A target position control unit for generating target position information indicating a target position away from the equilibrium position;
The controller calculates a moving direction and a moving speed of the magnetic body from deviation information indicating a deviation from the target position information, and generates an inertia compensation control unit for canceling the calculated direction, and the target position information; A magnetic force intensity information generated by each of the movement control unit for generating magnetic force intensity information for causing the magnetic body to reach the target position from the information and the location information, and the inertia compensation control unit and the movement control unit. A magnetic levitation device comprising: a magnetic strength information determination unit to add.

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