JP3635342B2 - Magnetic levitation device - Google Patents

Description

ここで、リニアアクチュエータ(12)(60)によって第１永久磁石(13)を平衡点のまわりで浮上方向に振幅ε、角速度ωで振動させる。振動数を浮上系の固有振動数より十分高くすると、浮上体(11)の平衡点からの変位は非常に小さくなるので、無視できる。このとき、式(14)は次の式(15)のようになる。
【００６９】
ｍ・（ｄ² ｙ_a ／ｄｔ² ）−（ｋ^o _y −ｑ・ε・cos ωｔ）・ｙ_a ＝０ …(15)
式(15)は、支点の調和振動する倒立振子の運動方程式(11)と本質的に同じ式である。したがって、第１永久磁石(13)の振動の振幅と振動数を適切に選べば、横ずれ方向の運動が安定化できることがわかる。
【００７０】
また、第１永久磁石(13)と第２永久磁石(14)の外径を異なるものにする必要がある理由は、次のとおりである。
【００７１】
前記の式(11)に示すように、
ｍ_e ・（ｄ² θ／ｄｔ² ）−（ｋ_e −Δｋ_e ・cos ωｔ）・θ＝０
Δｋ_e ＝ｍ・Ｌ・ｅ・ω₂
が成立しているが、振子(61)が自立するときには、ｋ_e ＜Δｋ_e が必要となる。このことは、物理的には次のような意味を持つ。すなわち、倒立振子の支点が下降するとき、ばね定数（＝−（ｋ_e −Δｋ_e ・cos ωｔ））が正になって、復元力が働く期間が存在する。逆に、倒立振子の支点が上昇するときには、ばね定数は負のまま（復元力は働かない）の期間が存在する。したがって、ばね定数が変化する１周期の間に、（−（ｋ_e −Δｋ_e ・cos ωｔ））が正であって静的には安定である復元力が働く状態と、これが負であって静的には不安定である復元力が働かない状態とが交互に現れることにより、自立することが可能となる。ここで、注意すべきことは、Δｋ_e の中にω₂ の項があるため、支点の運動の周期を短くすると、すなわち支点が速く動くようにすると、必ず上記のように静的に安定な状態と不安定な状態とが交互に現れる状態になることである。一方、第７実施例のような反発形磁気浮上機構では、前記の式(15)からわかるように、ばね定数は、（−（ｋ^o _y −ｑ・ε・cos ωｔ））で、Δｋ_e に相当する部分にω₂ の項が含まれていないので、第１永久磁石(13)と第２永久磁石(14)の外径が等しい場合は、第１永久磁石(13)の振幅（ε）や振動数（ω）をどんなに大きくしても、（−（ｋ^o _y −ｑ・ε・cos ωｔ））の符号はいつも負であり、静的に安定な状態が現れない。このような理由から、第１永久磁石(13)と第２永久磁石(14)の外径が異なるという条件が必要となる。
【００７２】
第４実施例のような機構では、第１永久磁石(13)が上昇すると、横ずれ方向には、反発力によって復元力が働く。これが、倒立振子について前に説明した支点が下降するときの状態に対応する。一方、第１永久磁石(13)が下降すると、上下方向には反発力が働き安定になるので、逆に横ずれ方向には不安定になる。これが、倒立振子について前に説明した支点が上昇するときの状態に対応する。
【００７３】
倒立振子の場合には、支点の運動の振幅と振子の等値長の比が約０．５以下のときには、支点の振動数を増していくと、ある振動数から安定領域に入り、振動数が無限大に大きくなるまで安定のままとなる。ただし、振幅を小さくしすぎると安定領域は急速に狭くなるので、ある程度の大きさの振幅が必要である。このような振動を実現する機構の１例が、第４実施例に示すものである。
【００７４】
図１１は、第５実施例を示している。
【００７５】
第５実施例では、第１永久磁石(13)を反発方向と同方向に移動させる直線駆動手段として、第１実施例と同じ微小リニアアクチュエータ(12)、および大振幅リニアアクチュエータ(63)よりなるものが使用されている。２つのリニアアクチュエータ(63)(12)は、第１永久磁石(13)とベース(10)との間に上下に積み重ねた状態で固定されている。大振幅アクチュエータ(63)は、第１永久磁石(13)に上下方向の大振幅の振動を与えるものである。他は第１参考例の場合と同様であり、同じ部分には同一の符号を付している。
【００７６】
第５実施例の場合、微小リニアアクチュエータ(12)により、第１参考例の場合と同様に、第１永久磁石(13)に上下方向の微小振動が与えられ、大振幅リニアアクチュエータ(63)により、第１永久磁石(13)に上下方向の大振幅の振動が与えられる。第１永久磁石(13)に上下方向の微小振動を与えることにより、第１参考例の場合と同様に、浮上体(11)の振動の減衰および上下方向の位置の制御ができる。同時に、第１永久磁石(13)に上下方向の大振幅の振動を与えることにより、倒立振子の原理で浮上体(11)の水平方向の不安定さをなくして、浮上体(11)を安定に浮上支持することができる。また、大振幅リニアアクチュエータ(63)だけでも、安定浮上は可能である。
【００７７】
なお、上記各参考例および各実施例に使用される永久磁石としては、通常の磁性材で構成されたものの他に、超伝導体を永久磁石化したもので構成されたものを使用してもよい。
【００７９】
【発明の効果】
第１の発明の磁気浮上装置によれば、第１磁気部材を反発方向に所定の振幅で振動させることにより、浮上側部材の反発方向と直角をなす方向の不安定さをなくして安定に浮上支持することができ、したがって、反発方向と直角をなす方向に浮上側部材を支持するための支持部材を別に設ける必要がなくなる。直線駆動手段を微小リニアアクチュエータおよび共振体より構成すれば、共振体によって第１磁気部材に所定振幅の振動を与えることができ、しかも浮上側部材を倒立振子の原理で反発方向と直角をなす方向に安定浮上支持するのに必要な振動周波数で共振するように共振体を設計するだけで、制御を行わずに、浮上側部材を安定浮上支持することができる。また、直線駆動手段を微小リニアアクチュエータおよび大振幅リニアアクチュエータより構成すれば、浮上側部材の振動の減衰および反発方向の位置の制御ができると同時に、浮上側部材の反発方向と直角をなす方向の不安定さををなくして安定に浮上支持することができ、しかも大振幅アクチュエータにより第１磁気部材に大振幅の振動を確実に与えることができる。
【００８０】
第２の発明の磁気浮上装置によれば、リニアアクチュエータで第１磁気部材を反発方向である上下方向と直角をなす２つの水平方向に振動させることにより、上下方向および水平方向のあらゆる方向について、不安定さをなくして、浮上側部材を安定に浮上支持することができ、浮上部材を支持するための支持部材を別に設ける必要がなくなる。
【００８１】
第３の発明の磁気浮上装置によれば、浮上側部材の振動の減衰および反発方向の位置の制御が可能であり、同時に反発方向と直角をなす方向の不安定さをなくして、浮上側部材をあらゆる方向に安定に浮上支持することができ、したがって、浮上側部材を支持するための支持部材を別に設ける必要がなくなる。
【図面の簡単な説明】
【図１】 図１は、第１参考例を示す磁気浮上装置の概略斜視図である。
【図２】 図２は、磁気浮上装置の制御装置の要部の概略構成を示すブロック図である。
【図３】 図３は、磁気浮上装置の実験装置を示す垂直断面図である。
【図４】 図４は、実験装置のステップ応答を示すグラフである。
【図５】 図５は、第２参考例を示す磁気浮上装置の概略斜視図である。
【図６】 図６は、この発明の第１実施例を示す磁気浮上装置の概略斜視図である。
【図７】 図７は、この発明の第２実施例を示す磁気浮上装置の概略斜視図である。
【図８】 図８は、この発明の第３実施例を示す磁気浮上装置の概略斜視図である。
【図９】 図９は、この発明の第４実施例を示す磁気浮上装置の概略正面図である。
【図１０】 図１０は、倒立振子の原理を説明するための説明図である。
【図１１】 図１１は、この発明の第５実施例を示す磁気浮上装置の概略正面図である。
【符号の説明】
(10) ベース（静止側部材）
(11) 浮上体（浮上側部分）
(12) リニアアクチュエータ
(13) 第１永久磁石（第１磁気部材）
(14) 第２永久磁石（第２磁気部材）
(24) ベース（静止側部材）
(25) リニアアクチュエータ
(26) 第１永久磁石（第１磁気部材）
(27) 浮上体（浮上側部分）
(28) 第２永久磁石（第２磁気部材）
(30) 超伝導体（第２磁気部材）
(31) ベース（静止側部材）
(32) 浮上体（浮上側部分）
(34) リニアアクチュエータ
(35) 第１永久磁石（第１磁気部材）
(36) 第２永久磁石（第２磁気部材）
(45) ベース（静止側部材）
(46) 浮上体（浮上側部分）
(48) 第１リニアアクチュエータ
(49) 第２リニアアクチュエータ
(50) 第１永久磁石（第１磁気部材）
(51) 第２永久磁石（第２磁気部材）
(60) 共振体
(63) 大振幅リニアアクチュエータ[0001]
[Industrial application fields]
The present invention relates to a magnetic levitation device.
[0002]
[Prior art]
As a magnetic levitation device, a device using a magnetic repulsion force between a permanent magnet and a permanent magnet or a magnetic repulsion force between a permanent magnet and a superconductor is conventionally known.
[0003]
[Problems to be solved by the invention]
A magnetic levitation device using a magnetic repulsive force has an advantage that it is stable without control, but generally has a problem that a damping characteristic is poor. In addition, since the levitation force (repulsive force) cannot be adjusted, it is impossible to realize a minute movement function alone. Furthermore, it is unstable in the direction perpendicular to the repulsion direction (the direction in which the repulsive force acts, that is, the flying direction), and thus another support mechanism is required in the same direction.
[0004]
An object of the present invention is to provide a magnetic levitation apparatus that solves the above-described problems, can precisely control the position and vibration in the repulsion direction, and can stabilize the direction perpendicular to the repulsion direction.
[0005]
[Means for Solving the Problems]
  In the magnetic levitation apparatus according to the first aspect of the present invention, a first magnetic member made of a permanent magnet is provided on one of a stationary member and a floating member that can move relative to each other, and a second magnetic magnet or a superconductor is provided on the other. In the magnetic levitation apparatus in which the magnetic member is provided and the floating member is levitated with respect to the stationary member by the magnetic repulsive force between the first magnetic member and the second magnetic member, the first magnetic member and the magnetic member are provided. Linear drive means for applying vibration in the same direction as the repulsion direction to the first magnetic member is provided between the stationary member and the floating member.The first and second magnetic members are cylindrical or ring-shaped, and the outer diameters of the first and second magnetic members are different.It is characterized by this.
[0008]
For example, the linear drive means applies vibration in the same direction as the repulsion direction to the first magnetic member. In this case, for example, the linear drive means includes a micro linear actuator that generates micro vibrations and a resonator that resonates with the micro vibrations of the micro linear actuator and applies large amplitude vibrations. Alternatively, for example, the linear drive means includes a micro linear actuator that applies micro vibration and a large amplitude linear actuator that applies large amplitude vibration.
[0009]
  First2The magnetic levitation device according to the invention ofDownWith stationary side memberThe upper part is movable relative to the stationary member in the vertical direction.A first magnetic member made of a permanent magnet is provided on one of the floating members, and a second magnetic member made of a permanent magnet or a superconductor is provided on the other, and the magnetic force between the first magnetic member and the second magnetic member is provided. In the magnetic levitation device in which the floating member is levitated with respect to the stationary member by a repulsive force,
  The first magnetic member is disposed between the first magnetic member and the stationary member or the floating member provided with the first magnetic member.In two horizontal directions orthogonal to each otherA linear actuator that vibrates is provided.
[0010]
  First3In the magnetic levitation device according to the present invention, a first magnetic member made of a permanent magnet is provided on one of a stationary member and a floating member that can move relative to each other, and a second magnetic member made of a permanent magnet or a superconductor is provided on the other. In the magnetic levitation apparatus in which the floating member is levitated with respect to the stationary member by the magnetic repulsive force between the first magnetic member and the second magnetic member, the first magnetic member and the magnetic levitation device are provided. A linear actuator that vibrates the first magnetic member in the same direction as the repulsion direction and a linear actuator that vibrates in a direction perpendicular to the repulsion direction are provided between the stationary member or the floating member. To do.
[0012]
[Action]
  First1According to this invention, the first magnetic member and the second magnetic member have different outer diameters, and the first magnetic member is vibrated with a predetermined amplitude in the repulsion direction, so that the floating member can be The instability in the direction perpendicular to the repulsion direction can be eliminated, and the floating side member can be stably levitated and supported. When the linear drive means is composed of a micro linear actuator and a resonator that resonates with the micro vibration of the micro linear actuator and applies a large amplitude vibration, the resonator can apply a predetermined amplitude vibration to the first magnetic member, In addition, it is possible to design the resonator so as to resonate at the vibration frequency necessary to stably levitate and support the floating member in the direction perpendicular to the repulsion direction by the principle of the inverted pendulum, and to control the floating member without performing control. Can be supported in a stable manner. Further, when the linear drive means is composed of a micro linear actuator and a large amplitude linear actuator, the vibration of the floating member can be attenuated by causing the first magnetic member to vibrate slightly in the repulsion direction. By adjusting the position of the repulsive direction of the floating member, it is possible to control the position of the repelling member in the repulsive direction, and by giving a large amplitude vibration to the first magnetic member, The instability in the direction that forms a right angle can be eliminated, and the floating member can be stably levitated and the vibration with a predetermined amplitude can be reliably applied to the first magnetic member by the large amplitude actuator.
[0013]
  First2According to the invention, the first magnetic member is repelled by the linear actuator.Up and down directionAt right angles toTwo horizontalIn the directionvibrationBy lettingFor all directions in the vertical and horizontal directions,Instability can be eliminated and the floating member can be stably levitated and supported.
[0014]
  ThirdofAccording to the invention, it is possible to control the vibration damping and the position of the rebound direction of the floating side member, and eliminate the instability in the direction perpendicular to the repulsive direction.In all directionsIt is possible to support the surface stably.
[0015]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0016]
  FIG.First reference example of a magnetic levitation apparatus to which the present invention is appliedIs shown.
[0017]
In FIG. 1, the magnetic levitation device includes a base (10) that is a stationary member and a levitation body (11) that is a floating member. The lower end surface of the vertical columnar micro linear actuator (12) is fixed to the upper surface of the base (10), and the first permanent magnet (13) constituting the first magnetic member is fixed to the upper end surface of the linear actuator (12). Yes. A second permanent magnet (14) constituting the second magnetic member is fixed to the lower surface of the levitating body (11). The first and second permanent magnets (13) and (14) form a ring shape whose axis is vertical. The first permanent magnet (13) has an N pole at the upper end and an S pole at the lower end, and the second permanent magnet (14) has an S pole at the upper end and an N pole at the lower end. The N pole and the N pole at the lower end of the second permanent magnet (14) are vertically opposed. The floating body (11) is levitated with respect to the base (10) by the magnetic repulsive force in the vertical direction of these two permanent magnets (13) and (14). If necessary, the magnetic levitation device is provided with a position detector (15) for detecting the position of the levitating body in the vertical direction (repulsion direction). Although not shown, an appropriate support member for supporting the floating body (11) so as not to move in the horizontal direction is provided. The linear actuator (12) is minutely deformed or slightly displaced corresponding to a voltage value or a current value applied thereto, thereby giving minute vibrations in the vertical direction to the first permanent magnet (13). The linear actuator (12) constitutes a linear drive means for moving the first permanent magnet (13) in the same direction as the repulsion direction. By vibrating the first permanent magnet (13) in the vertical direction, which is the repulsion direction, by the linear actuator (12), the vibration of the floating body (11) can be attenuated. Further, the vertical position of the levitated body (11) can be controlled by adjusting the vertical position of the first permanent magnet (13) with the linear actuator (12).
[0018]
As the linear actuator (12), a piezoelectric element, a magnetostrictive element, a voice coil motor, or the like can be used selectively or in combination depending on the required movable range, response speed, and the like.
[0019]
The main part of the control device of the linear actuator (12) is shown in FIG.
[0020]
In FIG. 2, the output of the position detector 15 is input to an appropriate control circuit 16 such as a PD control circuit or a PID control circuit. The control circuit (16) calculates the displacement of the levitating body (11) with respect to the target position from the output of the position detector (15), and adds a control signal obtained by adding the displacement signal to the target position signal via the amplifier (17). Output to the linear actuator (12). As a result, the linear actuator (12) is driven, and as a result, the vertical position of the first permanent magnet (13) is controlled. That is, when the levitation body (11) is displaced upward from the target position, the first permanent magnet (13) is moved downward, whereby the levitation body (11) is moved downward to reach the target position. Return. When the levitating body (11) is displaced downward from the target position, the first permanent magnet (13) is moved upward, whereby the levitating body (11) moves upward and returns to the target position. As described above, the linear actuator (12) is driven in accordance with the displacement of the floating body (11) to cause the first permanent magnet (13) to vibrate minutely, whereby the vibration of the floating body (11) is attenuated. Further, by changing the target position signal that is constantly applied to the linear actuator (12), the vertical position of the levitated body (11) can be changed.
[0021]
  In addition, instead of the position detector (15), a speed detection sensor such as an acceleration sensor or a speed detection coil is attached to the levitating body (11) or the base (10) to detect the moving speed of the levitating body (11). This can also be fed back to the control circuit (16) to drive the linear actuator (12) and cause the first permanent magnet (13) to vibrate slightly, thereby attenuating the vibration of the floating body (11). In this case, the position control isreferenceSimilar to the example, it can be performed by changing the target position signal that is constantly applied.
[0022]
  FirstreferenceFIG. 3 shows an outline of an experimental apparatus that was prototyped to grasp the basic characteristics of the magnetic levitation apparatus of the example. 3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals.
[0023]
In the case of this experimental apparatus, a magnetostrictive element including a columnar magnetostrictive material (12a) and a driving electromagnet coil (12b) is used as the linear actuator (12). The base (10) has a U-shape when viewed from the side, and the magnetostrictive material (12) of the linear actuator (12) is placed on the plate-like lower support member (18) fixed to the upper surface of the lower horizontal portion (10a). 12a) is fixed. A short columnar upper support member (19) is fixed to the upper end surface of the magnetostrictive material (12a), and a first permanent magnet (13) is fixed to the upper surface of the flange-shaped portion at the upper end of the support member (19). ing. The coil (12b) of the linear actuator (12) is disposed around the magnetostrictive material (12a) and is fixed to the base (10) by an appropriate support member (not shown). Bias permanent magnets (20) and (21) for applying a bias magnetic flux to the magnetostrictive material (12a) are provided around the support member (19) immediately above and the support member (18) immediately below the magnetostrictive material (12a). It is fixed. One end of a pair of upper and lower leaf springs (22) and (23) which are substantially horizontal is fixed to the upper part of the vertical portion (10b) of the base (10), and the free ends of these leaf springs (22) and (23) The levitating body (11) is fixed to the surface. The lower leaf spring (23) is fixed to the lower surface of the floating body (11), and the second permanent magnet (14) is fixed to the lower surface of the leaf spring (23). A position detector (15) is fixed to the lower surface of the upper horizontal portion (10c) of the base (10) so as to face the upper surface of the floating body (11). A capacitance type displacement meter is used as the position detector (15).
[0024]
The displacement of the first permanent magnet (13) in the vertical direction (z-axis direction) driven by the linear actuator (12) is z._b, The vertical displacement of the levitated body (11) is z_aIf the repulsive force acting between the permanent magnets (13) and (14) is approximated by an undamped spring, the motion of the levitated body (11) is expressed by the following equation (1).
[0025]
m · (d²z_a/ Dt²) = K_z・ (Z_b-Z_a) + P_z(t)… (1)
m: Mass of levitated body (11) (0.61 kg)
k_z: Spring constant in the floating direction (2.5 × 10⁸N / m)
p_z: Disturbance force (z component) acting on levitated body (11)
It is assumed that the linear actuator (12) is driven so that the input signal to the drive circuit and the displacement are substantially proportional. In the prototype experimental device, a bias magnetic flux is applied in advance to the magnetostrictive material (12a) of the linear actuator (12). Is almost proportional. Therefore, the input to the excitation amplifier (current control type) of the drive circuit is u_zThen, the following relationship (2) is established.
[0026]
z_b(t) = k_a・ U_z(t)… (2)
k_a: Transfer function of drive mechanism [1.0 × 10^-8m / A (constant)]
In this experiment, PD control was adopted as a control law in order to confirm that the flying characteristics and attenuation characteristics can be adjusted. In this case, the control input u_zIs defined by the following equation (3).
[0027]
u_z(t) = p_d・ Z_a(t) + p_v・ (Dz_a(t) / dt) (3)
From the equations (1) to (3), the following equation (4) is derived.
[0028]
m · (d²z_a/ Dt²) + K_z・ K_a・ P_v・ (Dz_a/ Dt) + k_z・ (K_a・ P_d+1) ・ z_a= P_z(t)… (4)
From equation (4), it can be seen that stiffness and damping characteristics can be adjusted by feedback of displacement and speed.
[0029]
FIG. 4 shows a comparison of the step response (step width: about 0.7 μm) in the case of no control ((a) in the figure) and in the case of speed feedback ((b) in the figure). From FIG. 4, it can be confirmed that the transient response characteristic can be improved by increasing the damping coefficient of the vibration component by speed feedback.
[0030]
  FirstreferenceIn the example, the levitating body (11) is levitated using a pair of the first permanent magnet (13) and the second permanent magnet (14). However, when the mass of the levitating body is large, The levitated body can be levitated using a plurality of two magnetic members.
[0031]
  FIG. 5 shows the second applied in such a case.referenceAn example is shown.
[0032]
  In FIG. 5, four micro linear actuators (25) are fixed to the upper surface of the base (24), and the first permanent magnet (26) is fixed to the upper surface of each linear actuator (25). Four second permanent magnets (28) respectively corresponding to the first permanent magnets (26) are fixed to the lower surface of the floating body (27) disposed above the base (24). Further, four position detectors (29) are arranged above the levitating body (27) corresponding to the second permanent magnets (28). Regarding the arrangement of the linear actuator (25), the first permanent magnet (26), the second permanent magnet (28), and the position detector (29),referenceAs in the case of the example, the linear actuator (25) constitutes linear drive means for moving the first permanent magnet (26) in the same direction as the repulsion direction.
[0033]
  SecondreferenceIn the example, the corresponding linear actuator (25) can be individually controlled based on the output of each position detector (29). Further, the position and inclination of the levitating body (27) are detected by the position detector (29) or the position detector appropriately arranged above the levitating body (27) shown in FIG. The four linear actuators (25) can be comprehensively controlled.
[0034]
  FIG.1An example is shown.
[0035]
  First1In the embodiment, as the second magnetic member, the firstreferenceInstead of the second permanent magnet (14) in the example, a superconductor (30) is used. Although not shown in the drawings, the levitation body (11) is provided with a suitable cooling device for cooling the superconductor (30) to a superconducting state. When the superconductor (30) is cooled and becomes in a superconducting state, the first permanent magnet (13) and the superconductor (30) repel each other due to the diamagnetism and float on the base (10). (11) is surfaced. Others are firstreferenceIt is the same as that of the example, and the same code | symbol is attached | subjected to the same part.
[0036]
  First1In the embodiment, the base (10) as the stationary member is provided with the superconductor (30) as the second magnetic member, and the linear actuator (12) and the first magnetic member as the floating member (11) as the floating member. A first permanent magnet (13) can be provided. Thus, if a superconductor is provided in a stationary side member, cooling of a superconductor will become easy.
[0037]
  FirstreferenceExample (Fig. 1) and No.1In the case of the embodiment (FIG. 6), the floating body (11) can be positioned by open loop control. Even when closed-loop control is performed, the position detector (15) only needs to have high accuracy because it is an originally stable system, and high-speed response is not required.
[0038]
  FIG.2An example is shown.
[0039]
In FIG. 7, the magnetic levitation apparatus includes a rectangular frame-shaped base (31) that is a stationary member, and a floating body (32) that is a floating member disposed above the base (31). A rectangular parallelepiped intermediate member (33) is disposed inside the base (31), and includes four side surfaces (33a) of the intermediate member (33) and four side walls (31a) inner surfaces of the base (31) corresponding thereto. A micro linear actuator (34) is attached between them. Each linear actuator (34) is arranged so that its length direction, that is, the driving direction is perpendicular to the side surface (33a) of the intermediate member (33), and the four linear actuators (34) are appropriately driven. As a result, the intermediate member (33) is moved in the horizontal plane. The first permanent magnet (35) constituting the first magnetic member is fixed to the upper surface of the intermediate member (33), and the second permanent magnet (36) constituting the second magnetic member is fixed to the lower surface of the floating body (32). Has been. The shapes and polarities of the first and second permanent magnets (35) and (36) are the same as in the first embodiment. The levitating body (32) has a rectangular parallelepiped shape, and is arranged directly above the intermediate member (33) so that each side surface (32a) thereof is substantially parallel to the corresponding side surface (33a) of the intermediate member (33). . Four position detectors (37) for detecting the horizontal position of the levitated body (32) are arranged so as to face each side surface (32a) of the levitated body (32).
[0040]
  First2In the embodiment, the linear actuator (34) is driven in a direction (two horizontal directions orthogonal to each other) perpendicular to the repulsion direction (vertical direction). Then, the linear actuator (34) is driven based on the horizontal displacement of the levitated body (32) obtained from the output of the position detector (37) to control the horizontal position of the first permanent magnet (35). By doing so, the instability in the horizontal direction perpendicular to the repulsion direction of the levitating body (32) can be eliminated, and the levitating body (32) can be stably levitated and supported. That is, when the floating body (32) is displaced in the right direction, the first permanent magnet (35) is moved in the right direction. As a result, the second permanent magnet (36) of the levitated body (32) receives a repulsive force in the left direction from the first permanent magnet (35), moves in the left direction, and returns to the target position. The same applies when the levitated body (32) is displaced leftward. The same applies to the front-rear direction. For this reason, it is not necessary to separately provide a support member for supporting the floating body (32) in the horizontal direction.
[0041]
  In the levitation mechanism using the repulsive force between permanent magnets, the system becomes unstable in the direction perpendicular to the repulsion direction (lateral displacement direction).2The movement in this direction can be stabilized by moving the first permanent magnet (35) in the lateral displacement direction by the linear actuator (34) as in the embodiment. The principle of operation of this mechanism is to prevent the floating body (32) that would deviate from the equilibrium point if nothing is done by moving the first permanent magnet (35) based on its movement. Therefore, it can be regarded as a kind of inverted pendulum.
[0042]
Next, the above operation principle will be described in more detail.
[0043]
  The first2In the embodiment, the movement in the lateral shift direction is two-dimensional, but here, the movement in one direction (y-axis direction) will be described. Movements in other directions can be handled in the same way. Furthermore, for simplicity, it is assumed that the lateral displacement is small, the lateral displacement force is proportional to the displacement from the equilibrium point, and the flying height is constant. Further, unless a special mechanism such as an eddy current damper is provided, the damping acting on the levitated body (32) is small and will be ignored here. At this time, if the displacement of the floating body (32) from the equilibrium point in the y-axis direction is ya and the displacement of the first permanent magnet (35) in the same direction is yb, the lateral displacement direction (y-axis direction) of the floating body (32) ) Is expressed as the following equation (5).
[0044]
m · (d²y_a/ Dt²) =-K_y・ (Y_b-Y_a) …(Five)
k_y: Slip coefficient
Further, the linear actuator (34) has an input signal u to the drive circuit as expressed by the following equation (6)._yAnd displacement y_bAre driven so as to be approximately proportional to each other.
[0045]
y_b(t) = k_a'U_y(t)… (6)
When PD control is adopted as the control law, control input u_yIs expressed by the following equation (7).
[0046]
u_y(t) = p_d・ Y_a(t) + p_v・ (Dy_a(t) / dt)} (7)
From the equations (5) to (7), the following equation (8) is derived.
[0047]
m · (d²y_a/ Dt²) + K_y・ K_a'・ P_v・ (Dy_a/ Dt) + k_y・ (K_a'・ P_d-1) · y_a= 0 (8)
From equation (8), it can be confirmed that the lateral displacement motion can be stabilized by appropriately selecting the displacement and velocity feedback gains.
[0053]
  Figure8The second3An example is shown.
[0054]
  Figure8The magnetic levitation apparatus includes a rectangular frame-shaped base (45) that is a stationary member and a levitation body (46) that is a levitation member disposed above the base (45). A rectangular parallelepiped intermediate member (47) is disposed inside the base (45), and the four side surfaces (47a) of the intermediate member (47) and the corresponding inner surfaces of the four side walls (45a) of the base (45). A first micro linear actuator (48) is attached between them. The lower end surface of the vertical columnar second minute linear actuator (49) is fixed to the upper surface of the intermediate member (47), and the first permanent magnet (50) constituting the first magnetic member on the upper end surface of the second linear actuator (49). ) And the second permanent magnet (51) constituting the second magnetic member is fixed to the lower surface of the levitated body (46). The shape and polarity of the first and second permanent magnets (50) and (51)referenceThe same as in the example. The levitating body (46) has a rectangular parallelepiped shape, and is arranged directly above the intermediate member (47) so that each side surface (46a) thereof is substantially parallel to the corresponding side surface (47a) of the intermediate member (47). . Four first position detectors (52) for detecting the horizontal position of the levitated body (46) are arranged so as to face the side surfaces (46a) of the levitated body (46), respectively. A second position detector (53) for detecting the vertical position of (46) is arranged to face the upper surface (46b) of the levitated body (46).
[0055]
  First3In the embodiment, the first linear actuator (48) is driven in a direction perpendicular to the repulsion direction (vertical direction), thereby controlling the horizontal position of the intermediate member (47) and the first permanent magnet (50). Is done. The second linear actuator (49) is driven in the repulsion direction, thereby controlling the vertical position of the first permanent magnet (50). Then, the first linear actuator 48 is driven based on the horizontal displacement of the floating body 46 determined from the output of the first position detector 52, and the horizontal direction of the first permanent magnet 50 is driven. By controlling the position of the floating body, the horizontal position perpendicular to the repulsion direction of the floating body (46) is controlled, and the vertical direction of the floating body (46) obtained from the output of the second position detector (53) By driving the second linear actuator (49) based on the displacement of the first permanent magnet (50) and controlling the vertical position of the first permanent magnet (50), the vibration of the levitating body (46) is attenuated and the vertical direction is also reduced. The position is controlled.
[0056]
  First3In the embodiment, the first permanent magnet (50) is minutely vibrated in the vertical direction by the second linear actuator (49), and the first permanent magnet (50) is minutely vibrated in the horizontal direction by the first linear actuator (48). As a result, the vibration of the levitating body (46) can be attenuated and the position in the vertical direction can be controlled, and the levitating body (11) can be stably levitated and supported with no horizontal instability. Yes. However, this can also be done using only the linear drive means that moves the first permanent magnet in the same direction as the rebound direction.
[0057]
  Figure9Applied in such cases4An example is shown.
[0058]
  First4In the embodiment, as the linear drive means for vibrating the first permanent magnet (13) in the same direction as the repulsion direction, a linear actuator (12) and a resonator (60) are used. The resonator (60) and the linear actuator (12) are fixed in a state where they are stacked vertically between the first permanent magnet (13) and the base (10). The outer diameters of the first permanent magnet (13) and the second permanent magnet (14) are different from each other. In this case, the outer diameter of the first permanent magnet (13) is slightly smaller than the inner diameter of the second permanent magnet (14). It has become. The resonator (60) resonates with the vibration of the linear actuator (12), and gives the first permanent magnet (13) vibration with a predetermined amplitude. That is, vibration with a high frequency is given by the linear actuator (12), and vibration with a large amplitude is given by the resonator (60). Others are firstreferenceThis is the same as in the case of the example, and the same parts are denoted by the same reference numerals.
[0059]
  First4In the case of the embodiment, the horizontal vibration of the levitated body (11) is determined by the principle of an inverted pendulum due to the high frequency minute vibration given from the linear actuator (12) and the large amplitude vibration given from the resonator (60). The floating body (11) can be stably levitated and supported without the stability. The second4In the case of the embodiment, it is only necessary to design the resonator (60) to resonate at the vibration frequency necessary to stably support the levitating body (11) in the direction perpendicular to the repulsion direction by the principle of an inverted pendulum. The floating body (11) can be stably levitated and supported without performing control.
[0060]
  Next4For the operating principle of the example,10Further details will be described with reference to FIG.
[0061]
  In an inverted pendulum, a phenomenon has been reported that a dynamic stable state can be obtained by vibrating a fulcrum in the vertical direction. First2The stabilization of the lateral movement of the permanent magnet repulsion type magnetic levitation mechanism as in the embodiment is based on the same principle as the stabilization of the inverted pendulum.4Even in the permanent magnet repulsive magnetic levitation mechanism as in the embodiment, there is a possibility that the first permanent magnet (13) can be stabilized only by vibrating in the vertical direction. The principle will be described below.
[0062]
  Figure10If the swing angle θ of the pendulum (61) is very small in the inverted pendulum as shown in (1), the equation of motion when the fulcrum (62) moves in the vertical direction is obtained as the following equation (9).
[0063]
(I + m · L²) ・ (D²θ / dt²) −m · L · {g + (d²s / dt²)} ・ Θ = 0 (9)
I: Moment of inertia around the center of gravity (G) of the pendulum (61)
m: Mass of pendulum (61)
L: Distance from fulcrum (62) of pendulum (61) to center of gravity (G)
s: Vertical displacement of fulcrum (62)
From equation (9), it can be seen that the effect of the movement of the fulcrum (62) is equivalent to a change in the negative spring constant (more precisely, the gravitational constant) of the pendulum (61). Here, if the movement of the fulcrum (62) is as shown in the following equation (10), the following equation (11) is obtained.
[0064]
s = e · sin ωt (10)
m_e・ (D²θ / dt²)-(K_e-Δk_e・ Cos ωt) ・ θ = 0 (11)
m_e: Equivalent mass (= I + m · L²)
k_e: Equivalent spring constant (= m · L · g)
Δk_e: Amplitude of pulsation with spring constant (= m · L · e · ω₂)
Equation (11) is known as Mathieu's equation, and its exact solution is not required, but the stability of the solution is well examined. It should be noted that even in a system with a negative spring constant such as an inverted pendulum, if there is periodic pulsation in the spring constant, the solution will be stable if the pulsation amplitude and frequency satisfy certain conditions. That is, the inverted pendulum is independent. This has been confirmed experimentally.
[0065]
  First4In the permanent magnet repulsive magnetic levitation mechanism as in the embodiment, the lateral deviation coefficient is greatly influenced by the distance d between the permanent magnets (13) and (14). Therefore, the equation describing the movement in the lateral slip direction is expressed as the following equation (12).
[0066]
m · (d²y_a/ Dt²) =-K_y(d) ・ (y_b-Y_a… (12)
However, d is as the following formula (13).
[0067]
d = do + (z_a-Z_b) …(13)
do: distance between the permanent magnets at the equilibrium point
Lateral slip coefficient k_yWhen (d) is linearly approximated at the equilibrium point, equation (12) becomes the following equation (14).
[0068]
m · (d²y_a/ Dt²)-{K^o _y+ Q · (z_a-Z_b)} ・ Y_a= 0 (14)
k^o _y= K_y(Do)
[Expression 1]

Here, the first permanent magnet 13 is vibrated around the equilibrium point with the amplitude ε and the angular velocity ω by the linear actuators 12, 60. If the frequency is sufficiently higher than the natural frequency of the levitated system, the displacement of the levitated body (11) from the equilibrium point becomes very small and can be ignored. At this time, the equation (14) becomes the following equation (15).
[0069]
m · (d²y_a/ Dt²)-(K^o _y−q · ε · cos ωt) · y_a= 0 (15)
Equation (15) is essentially the same equation as the equation of motion (11) of an inverted pendulum that vibrates harmoniously at the fulcrum. Therefore, it can be understood that the movement in the lateral displacement direction can be stabilized by appropriately selecting the amplitude and frequency of the vibration of the first permanent magnet (13).
[0070]
The reason why the outer diameters of the first permanent magnet (13) and the second permanent magnet (14) are required to be different is as follows.
[0071]
As shown in equation (11) above,
m_e・ (D²θ / dt²)-(K_e-Δk_e・ Cos ωt) ・ θ = 0
Δk_e= M ・ L ・ e ・ ω₂
When the pendulum (61) is self-supporting,_e<Δk_eIs required. This has the following physical meaning. That is, when the fulcrum of the inverted pendulum descends, the spring constant (= − (k_e-Δk_eThere is a period in which cos ωt)) becomes positive and the restoring force works. Conversely, when the fulcrum of the inverted pendulum rises, there is a period in which the spring constant remains negative (restoring force does not work). Therefore, during one period when the spring constant changes, (-(k_e-Δk_eThe state where cos ωt)) is positive and a statically stable restoring force works and the state where this is negative and the statically unstable restoring force does not work alternately appear It becomes possible to become independent. Here, it should be noted that Δk_eΩ in₂Therefore, if the fulcrum movement cycle is shortened, that is, if the fulcrum moves faster, the statically stable state and the unstable state always appear as described above. is there. On the other hand, in the repulsive magnetic levitation mechanism as in the seventh embodiment, the spring constant is (− (k^o _y−q · ε · cos ωt)), Δk_eIn the part corresponding to₂If the outer diameters of the first permanent magnet (13) and the second permanent magnet (14) are equal, the amplitude (ε) and the frequency (ω) of the first permanent magnet (13) are not included. No matter how large (-(k^o _yThe sign of −q · ε · cos ωt)) is always negative, and a statically stable state does not appear. For this reason, the condition that the outer diameters of the first permanent magnet (13) and the second permanent magnet (14) are different is necessary.
[0072]
  First4In the mechanism as in the embodiment, when the first permanent magnet 13 is raised, a restoring force is exerted by a repulsive force in the lateral displacement direction. This corresponds to the state when the fulcrum described previously for the inverted pendulum descends. On the other hand, when the first permanent magnet (13) is lowered, a repulsive force acts in the vertical direction and becomes stable, so that it becomes unstable in the lateral displacement direction. This corresponds to the state when the fulcrum described previously for the inverted pendulum rises.
[0073]
  In the case of an inverted pendulum, when the ratio of the amplitude of the fulcrum motion to the equivalent length of the pendulum is about 0.5 or less, if the frequency of the fulcrum is increased, the frequency enters the stable region from a certain frequency, and the frequency It remains stable until becomes infinitely large. However, if the amplitude is made too small, the stable region will be narrowed rapidly, so a certain amount of amplitude is required. One example of a mechanism that realizes such vibration is the first4Examples are shown in the examples.
[0074]
  Figure11The second5An example is shown.
[0075]
  First5In the embodiment, as the linear drive means for moving the first permanent magnet (13) in the same direction as the repulsion direction, the same linear actuator as that of the first embodiment (12) and the large amplitude linear actuator (63) are used. in use. The two linear actuators (63) and (12) are fixed in a state of being vertically stacked between the first permanent magnet (13) and the base (10). The large amplitude actuator (63) applies a large amplitude vibration in the vertical direction to the first permanent magnet (13). Others are firstreferenceIt is the same as that of the example, and the same code | symbol is attached | subjected to the same part.
[0076]
  First5In the case of the embodiment, the first linear actuator (12)referenceAs in the case of the example, vertical vibration is given to the first permanent magnet (13), and large amplitude vibration is given to the first permanent magnet (13) by the large amplitude linear actuator (63). It is done. By giving the first permanent magnet (13) a minute vibration in the vertical direction,referenceAs in the case of the example, the vibration of the levitating body (11) can be attenuated and the position in the vertical direction can be controlled. At the same time, the first permanent magnet (13) is vibrated with large amplitude in the vertical direction, thereby eliminating the horizontal instability of the levitating body (11) by the inverted pendulum principle and stabilizing the levitating body (11). Can be levitated and supported. In addition, stable levitation is possible with only the large-amplitude linear actuator (63).
[0077]
  The aboveReference examples andAs a permanent magnet used in each embodiment, in addition to a permanent magnet, a permanent magnet made of a superconductor may be used.
[0079]
【The invention's effect】
  First1According to the magnetic levitation device of the present invention, the first magnetic member is vibrated with a predetermined amplitude in the repulsion direction, so that the instability in the direction perpendicular to the repulsion direction of the floating member is eliminated and stably levitated and supported. Therefore, it is not necessary to separately provide a support member for supporting the floating member in a direction perpendicular to the repulsion direction. If the linear drive means is composed of a micro linear actuator and a resonator, the resonator can give a vibration of a predetermined amplitude to the first magnetic member, and the floating member is perpendicular to the repulsion direction by the principle of an inverted pendulum. By simply designing the resonator so as to resonate at the vibration frequency necessary for stable levitation support, the floating member can be stably levitation supported without performing control. In addition, if the linear drive means is composed of a micro linear actuator and a large amplitude linear actuator, it is possible to control the damping of the floating member and the position in the repulsion direction, and at the same time, the direction perpendicular to the repulsion direction of the floating member. Instability can be eliminated and stable levitation support can be achieved, and large amplitude vibration can be reliably applied to the first magnetic member by the large amplitude actuator.
[0080]
  First2According to the magnetic levitation device of the invention ofBy vibrating the first magnetic member in two horizontal directions perpendicular to the vertical direction that is the repulsion direction with a linear actuator, there is no instability in all the vertical and horizontal directions, and the floating member is stabilized. Can be supportedThere is no need to provide a separate support member for supporting the floating member.
[0081]
  First3According to the magnetic levitation device of the present invention, it is possible to attenuate the vibration of the floating member and control the position in the repulsion direction, and at the same time, eliminate the instability in the direction perpendicular to the repulsion direction., The floating member in all directionsCan be stably supported to floatFloatingThere is no need to provide a separate support member for supporting the upper member.
[Brief description of the drawings]
[Figure 1]Figure 1 shows the first reference exampleIt is a schematic perspective view of the magnetic levitation apparatus which shows.
[Figure 2]FIG.It is a block diagram which shows schematic structure of the principal part of the control apparatus of a magnetic levitation apparatus.
[Fig. 3]FIG.It is a vertical sectional view showing an experimental device of a magnetic levitation device.
[Fig. 4]FIG.It is a graph which shows the step response of an experimental apparatus.
[Figure 5]Figure 5 shows the second reference exampleIt is a schematic perspective view of the magnetic levitation apparatus which shows.
[Fig. 6]FIG.First of this invention1It is a schematic perspective view of the magnetic levitation apparatus which shows an Example.
[Fig. 7]FIG.First of this invention2It is a schematic perspective view of the magnetic levitation apparatus which shows an Example.
[Fig. 8]FIG.First of this invention3Example of magnetic levitation apparatusOverview ofIt is a schematic perspective view.
FIG. 9 is a schematic of a magnetic levitation apparatus showing a fourth embodiment of the present invention.frontFIG.
FIG. 10FIG. 10 is an explanatory diagram for explaining the principle of the inverted pendulumIt is.
FIG. 11FIG. 11 is a schematic front view of a magnetic levitation apparatus showing a fifth embodiment of the present invention.It is.
[Explanation of symbols]
(10) Base (stationary member)
(11) Levitation body (floating part)
(12) Linear actuator
(13) First permanent magnet (first magnetic member)
(14) Second permanent magnet (second magnetic member)
(24) Base (stationary side member)
(25) Linear actuator
(26) First permanent magnet (first magnetic member)
(27) Levitation body (floating part)
(28) Second permanent magnet (second magnetic member)
(30) Superconductor (second magnetic member)
(31) Base (stationary side member)
(32) Levitation body (floating part)
(34) Linear actuator
(35) First permanent magnet (first magnetic member)
(36) Second permanent magnet (second magnetic member)
(45) Base (stationary side member)
(46) Levitation body (floating part)
(48) First linear actuator
(49) Second linear actuator
(50) First permanent magnet (first magnetic member)
(51) Second permanent magnet (second magnetic member)
(60) Resonator
(63) Large amplitude linear actuator

Claims (6)

A first magnetic member made of a permanent magnet is provided on one of a stationary member and a floating member that can move relative to each other, and a second magnetic member made of a permanent magnet or a superconductor is provided on the other, and the first magnetic member In the magnetic levitation device in which the floating member is levitated with respect to the stationary member by the magnetic repulsive force between the member and the second magnetic member,
Between the first magnetic member and the stationary side member or the floating side member on which the first magnetic member is provided, linear driving means for applying vibration in the same direction as the repulsion direction to the first magnetic member is provided ,
The magnetic levitation apparatus according to claim 1, wherein the first and second magnetic members have a columnar shape or a ring shape, and the first magnetic member and the second magnetic member have different outer diameters . It said linear drive means, magnetic levitation apparatus according to claim 1, characterized in that to provide a vibration of the rebound in the same direction as the direction to the first magnetic member. 3. The magnetic levitation apparatus according to claim 2 , wherein the linear driving means includes a micro linear actuator that generates micro vibrations and a resonator that resonates with the micro vibrations of the micro linear actuator and applies large amplitude vibrations. 4. The magnetic levitation apparatus according to claim 3 , wherein the linear drive means includes a micro linear actuator that applies micro vibrations and a large amplitude linear actuator that applies large amplitude vibrations. A first magnetic member made of a permanent magnet is provided on one of the lower stationary member and the upper floating member that can move relative to the stationary member in the vertical direction, and the other is made of a permanent magnet or a superconductor. In the magnetic levitation apparatus, the second magnetic member is provided, and the floating member is levitated with respect to the stationary member by a magnetic repulsive force between the first magnetic member and the second magnetic member.
A linear actuator that vibrates the first magnetic member in two horizontal directions orthogonal to each other is provided between the first magnetic member and a stationary member or a floating member provided with the first magnetic member. Magnetic levitation device. A first magnetic member made of a permanent magnet is provided on one of a stationary member and a floating member that can move relative to each other, and a second magnetic member made of a permanent magnet or a superconductor is provided on the other, and the first magnetic member In the magnetic levitation device in which the floating member is levitated with respect to the stationary member by the magnetic repulsive force between the member and the second magnetic member,
Between the first magnetic member and the stationary member or floating member which is provided, in the direction forming a linear actuator Contact and rebound direction perpendicular to vibrate the first magnetic member in the repulsion in the same direction A magnetic levitation device comprising a linear actuator that vibrates.

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