WO2007119315A1

WO2007119315A1 - Magnetic suspension device

Info

Publication number: WO2007119315A1
Application number: PCT/JP2007/054456
Authority: WO
Inventors: Mimpei Morishita
Original assignee: Toshiba Elevator Kabushiki Kaisha
Priority date: 2006-03-20
Filing date: 2007-03-07
Publication date: 2007-10-25
Also published as: CN101390283A; JP4509053B2; CN101390283B; JP2007259521A

Abstract

An excitation voltage value at a time when a target value of coil current is set to zero by a target value setting section (150) is obtained and stored in a voltage storing unit (154). In a voltage input compensation unit (156), the excitation voltage value stored in the voltage storing unit (154) is subtracted from an excitation voltage value supplied to a driver (116) as an offset voltage value to obtain a compensation value of the excitation voltage. The compensation value is input to a resistance calculation unit (158) to measure a coil resistance value, and according to the value, suspension control is performed.

Description

Specification

Magnetic levitation device

Technical field

TECHNICAL FIELD [0001] The present invention relates to a magnetic levitation apparatus that supports a levitated body in a non-contact manner by normal conducting magnetic levitation.

Background art

[0002] The normal conducting magnetic levitation device is a transport system in clean rooms in railways and semiconductor factories such as HSST (High Speed Surface Transport) and Trans-Rabbit where noise and dust are eliminated. Has been put to practical use. Attempts have also been made to apply this magnetic levitation device to elevator car guidance devices (see Patent Document 1) and to doors.

In this magnetic levitation apparatus, an electromagnet is made to face a ferromagnetic member, and the levitating body is levitated by using an attractive force generated between the electromagnet and the ferromagnetic member. For this reason, the magnetic levitation system is basically unstable, and it is necessary to take measures to stabilize it. In general, the gap height is detected by a gap sensor and feedback control is performed to the drive system to achieve stability. However, when detecting the flying gap length with a gap sensor, a sensor target suitable for the gap sensor to be used is required, and the sensor target must be laid along with the ferromagnetic member.

[0004] As described above, in order to stabilize the magnetic levitation system, parts such as a gap sensor and a sensor target are required, which is costly and secures the installation space. There was another problem when the equipment became larger!

[0005] In addition, in railways and transport systems, there are branch points on the tracks composed of ferromagnetic guides. Therefore, it is necessary to have a mechanism in which the sensor target and the guide cross each other so that the gap length cannot be detected. If the system is complicated! /, There is another problem.

[0006] In order to solve such problems, various methods have been proposed that do not require a gap sensor.

[0007] For example, the gap length is estimated by an exciting current force observer (state observer) of an electromagnet (See Non-Patent Document 1). In addition, there is a method in which gap information is included in the phase difference between the exciting voltage and exciting current of the electromagnet generated by magnetic levitation, and this is fed back to the exciting voltage (see Non-Patent Document 2). In addition, the excitation current value of the electromagnet is compared with the reference value with a hysteresis comparator, and when the excitation current is larger than the reference value, the excitation voltage is switched to negative, and when it is smaller, the excitation voltage is switched to positive to switch the switching frequency. There is a method (see Non-Patent Document 3) in which is proportional to the floating gap length.

[0008] However, when the above-described observer is used, the floating gap length when not in the floating state cannot be estimated. This is because the linear model force of the magnetic levitation system when the observer is in the levitated state is also derived. Therefore, there is a problem that control at the start of levitation becomes difficult, and that the levitation body cannot return to the levitation state again once it comes into contact with another structure.

[0009] When the excitation voltage of the electromagnet is controlled by a physical quantity including gap information, the levitation control system is a non-linear system. For this reason, it is difficult to determine stability, and there is a problem that the floating state cannot be maintained if the electric resistance of the electromagnetic coil changes due to mass change or temperature rise due to excitation.

[0010] The following methods are known as methods for dealing with these problems.

[0011] In the sensorless method of estimating the gap length with an observer using an exciting current force of an electromagnet, when the floating body is not in a floating state, the contact of the floating body is detected to initialize the integrator of the observer, Contact state force of levitated body Geometrically estimate the gap length at the time of contact. Based on the estimated gap length, an initial value is given to the integrator of the observer to return to the floating state (see Patent Document 2).

However, when this method is applied to zero power control (see Patent Document 3), the following problems occur.

[0013] That is, when the levitated body is in a steady levitating state, there is no particular problem because the exciting current of the electromagnet converges to zero. However, when a large external force is applied to the levitated body for a long time, a transient control current continues to flow through the coil of the electromagnet, and the coil temperature rises. As the temperature rises, the electrical resistance of the coil increases and the output error of the observer that estimates the floating gap length from the excitation current increases. As a result, It becomes difficult to maintain the upper state, and the floating body comes into contact.

[0014] When the floating body comes into contact with the floating body, control for returning to the floating state is attempted. However, even after returning to the levitation state, there is a large error in the estimated value of the levitation gap length at the time of levitation, so that the levitation body contacts again, and the contact state and the levitation state are repeated alternately. In such a state, since a large control current continues to flow through the electromagnet, the coil resistance of the electromagnet further increases, and finally the excitation current continues to flow with the floating body in contact. If the exciting current that continues to flow is large, the electromagnet may ignite.

[0015] On the other hand, regarding the fluctuation of the coil resistance value of the electromagnet in such sensorless magnetic levitation, the levitation control is performed while measuring the resistance value of the coil, and the observer parameters are determined based on the measured resistance value. Has been proposed (see Patent Document 4).

[0016] Further, when a transient exciting current continues to flow through the electromagnet, there is a problem that the offset voltage fluctuates with an increase in temperature in addition to an increase in the coil resistance value. This variation in the offset voltage increases the output error of the observer that estimates the levitation gap length, similarly to the variation in the coil resistance value. To solve this problem, the output error of the observer can be suppressed by adding the offset compensation amount to the excitation voltage for setting the observer speed estimate to zero.

[0017] However, even if the measures described above are used, the resistance value of the coil used in the observer is calculated from the DC component of the excitation voltage and the excitation current. There is a problem that the resistance value cannot be measured.

Patent Document 1: Japanese Patent Application No. 11 192224

Patent Document 2: Japanese Patent Application No. 2002-002646

Patent Document 3: Japanese Patent Laid-Open No. 61-102105

Patent Document 4: # 112003 344670 Publication

Non-Patent Document 1: Mizuno, et al .: “Research on practical application of displacement sensorless magnetic bearing”, Proc.

Non-Patent Document 2: Moriyama: “AC Magnetic Levitation Using a Differential Feedback Power Amplifier” 1997 IEEJ National Convention Proceedings, No. 1215

Non-Patent Document 3: Mizuno, et al .: “Self-sensing magnetic levitation using hysteresis amplifier” , Transactions of the Society of Instrument and Control Engineers, 32, No. 7, 1043 (1996)

Disclosure of the invention

[0018] As described above, the conventional magnetic levitation apparatus requires the gap sensor and the sensor target in order to realize a stable levitation state of the levitation body. For this reason, there is a problem that the apparatus becomes large and complicated, resulting in an increase in cost.

[0019] In order to avoid such a problem, even if the gap length information is feedback controlled without using the gap sensor, the stability of the levitation system depends on the offset voltage. For this reason, when the temperature fluctuates, stable control cannot be performed due to the fluctuation of the offset voltage.

[0020] Therefore, an object of the present invention is to provide a magnetic levitation apparatus that can always perform stable levitation control in consideration of the influence of an offset voltage.

[0021] A magnetic levitation device according to an aspect of the present invention includes a guide made of a ferromagnetic member, and an electromagnet and a permanent magnet that face the guide through a gap and share a magnetic path in the gap. Magnet unit, a floating body that is supported in a non-contact manner by the attraction force of the magnet unit acting on the guide, a sensor unit that detects a current value flowing through the coil of the electromagnet, and a target value of the coil current of the electromagnet A target value setting unit that alternately sets zero to a non-zero value, a coil current converging unit that converges the coil current of the electromagnet to the target value set by the target value setting unit, and a coil current converging unit An excitation voltage calculation unit for calculating an excitation voltage value for stabilizing a magnetic circuit formed by the magnet unit based on a coil current value obtained by the sensor unit force along with the convergence operation; A voltage storage unit that stores the excitation voltage value obtained by the excitation voltage calculation unit when the target value is set to zero, and an excitation voltage value stored in the voltage storage unit from the excitation voltage value of the electromagnet An excitation voltage compensator that obtains an excitation voltage compensation value by subtracting as an offset voltage value, and a resistance calculator that computes the coil resistance value of the electromagnet based on the compensation value obtained by the excitation voltage compensation unit; A control unit that feeds back the coil resistance value obtained by the resistance calculation unit to the excitation voltage calculation unit and controls the floating body.

Brief Description of Drawings FIG. 1 is a diagram showing a basic configuration of a magnetic levitation apparatus for explaining the principle of the present invention.

FIG. 2 is a diagram showing the configuration of the magnetic levitation apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a detailed configuration of an attractive force control unit of the magnetic levitation apparatus in the same embodiment.

FIG. 4 is a diagram showing a configuration of a magnetic levitation apparatus according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a configuration of a frame portion of the magnetic levitation apparatus in the same embodiment.

FIG. 6 is a perspective view showing a configuration around a magnet unit of the magnetic levitation apparatus in the embodiment.

FIG. 7 is an elevation view showing the configuration of the magnet unit of the magnetic levitation apparatus in the same embodiment.

FIG. 8 is a block diagram showing a detailed configuration of the control device for the magnetic levitation apparatus in the embodiment.

FIG. 9 is a block diagram showing a configuration of a mode control voltage calculation circuit in the controller of the magnetic levitation apparatus in the same embodiment.

FIG. 10 is a block diagram showing a configuration of another mode control voltage calculation circuit in the control device of the magnetic levitation device in the same embodiment.

FIG. 11 is a diagram showing a configuration of a magnetic levitation apparatus according to a third embodiment of the present invention. FIG. 12 is a diagram showing a configuration of a magnetic levitation apparatus according to a fourth embodiment of the present invention. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

[0023] First, the basic principle of the present invention will be described.

FIG. 1 is a diagram showing a basic configuration of a magnetic levitation apparatus for explaining the principle of the present invention.

The overall configuration of a one-mass system magnetic levitation apparatus is indicated by reference numeral 1.

The magnetic levitation apparatus 1 includes a magnet unit 107 composed of a permanent magnet 103 and an electromagnet 105, a levitated body 111 composed of the magnet unit 107 and a load load 109, and a structural member (not shown). And a guide 113 fixed to the top. In addition, the magnetic levitation device 1 controls the attractive force of the magnet mute 107 to stably support the levitated body 111 in a non-contact manner, and the attractive force control unit 115 And a driver 116 for exciting the electromagnet 105 based on the output.

[0026] Reference numeral 131 denotes an auxiliary support portion. The auxiliary support part 131 has a U-shaped cross section, and the magnet unit 107 is fixed to the upper surface inside the lower part. The auxiliary support part 131 also serves as a table of a vibration isolation table in which the ground side force is guided by a guide part that does not act in the vertical direction, such as a linear guide (not shown).

Here, in order to support the levitated body 111 in a non-contact manner by the magnetic attractive force of the magnet unit 107, the guide 113 is made of a ferromagnetic member.

[0028] The electromagnet 105 is configured by mounting coils 119, 119 'on iron cores 117a, 117b. Iron cores 117a and 117b are disposed at both magnetic pole ends of the permanent magnet 103, respectively. The coils 1 19 and 119 ′ are connected in series so that the magnetic flux formed in the magnetic path formed by the guide 113 to the iron core 117 a to the permanent magnet 103 to the iron core 117 b to the guide 113 is strengthened (weakened) by excitation of the electromagnet 105.

In addition, the attractive force control unit 115 includes an excitation voltage calculation unit 125. The excitation voltage calculation unit 125 calculates a voltage for exciting the electromagnet 105 based on the flying gap length obtained by the gap sensor 121 and the coil current value obtained by the current sensor 123. The driver 116 supplies excitation current to the coils 119 and 119 ′ via the lead wire 128 based on the excitation voltage calculated by the excitation voltage calculation unit 125.

[0030] At this time, the magnetic levitation system of the magnetic levitation apparatus 1 can be linearly approximated near the levitation gap length z when the attractive force of the magnet unit 107 is equal to the weight of the levitation body 111.

0

It is described by a formula.

[Number 1]

[0031] F is the attractive force of the magnet unit 107. m is the mass of the levitated body 111. R is coil 1 z

The electrical resistance (hereinafter referred to as coil resistance) when 19, 119 'and the lead wire 128 are connected in series. z is the flying gap length. i is the exciting current of the electromagnet 105. φ is magnet

z

This is the main magnetic flux of the knit 107. e is the excitation voltage of the electromagnet 105.

[0032] Δ is the steady levitation state (z = z

= Δ ί))) Deviation from The symbol “·” is dZdt, and the partial differential 3 Z 3 h (h = z, i) is the partial differential value of the partial differential function in the steady levitation state (z = z. L is

It is expressed as follows.

[Equation 2]

LzO = ^L oo + N (2)

di In addition, the levitation system model of Equation 1 is the following equation of state.

[Equation 3]

X = Ax + be _z + du _s

(3)

γ = Cx

[0034] However, the state vector x, the system matrix A, the control matrix b, and the disturbance matrix d are expressed as follows. U

s is an external force.

[Equation 4]

(Four)

[0035] Here, each parameter in Equation 4 is as follows.

[Equation 5]

33

[0036] Each element x in Equation 3 is a floating system state quantity. C is an output matrix, and is determined by the state quantity detection method used for calculating the excitation voltage e.

[0037] In the magnetic levitation device 1, the gap sensor 121 and the current sensor 123 are used, and when the speed is obtained by differentiating the signal of the gap sensor 121, C becomes a unit matrix.

[0038] Here, when F is a proportional gain of X, K is an integral gain, and excitation voltage e is given by the following equation 6, magnetic levitation device 1 is levitated by zero power control as shown in Patent Document 3. To do. Here, it goes without saying that the excitation voltage calculation unit 125 calculates Equation 6.

a

[Equation 6] 2 οο 1 e _z = -Fx-J KiAi _z dt (6) Also, in the magnetic levitation device 1, without using the gap sensor 121, the levitation gap length deviation Δ ζ and its deviation from the excitation current Δ ί As an estimation means for estimating the velocity d (Δz) Zdt, for example, consider the case where a same-dimensional state observer (hereinafter referred to as an observer) is applied. At this time, according to the linear control theory, the observer is expressed by the following equation.

[Equation 7] it-Ax + By + Ee _z

One χ

x ^a 23- ^α 2

a33- ^α 3

Where ίϊ is the estimated state vector of the observer, α ₂ and α ₃ are parameters that determine the poles of the observer, y = Cx and C = [001]. [Equation 8] In this case, the estimation error of the state observer of Equation 7 is given by the following equation if the initial values at the start of computation of Equation 3 and Equation 7 are ₀ and x ₀ , respectively: . x (t) −x (t) = e ^At (x ₀ −xo) ( ⁸ ) At this time, in the excitation voltage calculation unit 125, for example, e _z = -Fx-J KiAi _z dt · ■ · (9) is calculated, and stabilization of the magnetic levitation system is achieved.

In general, the normal magnetic attraction type magnetic levitation system is unstable, so if there is an error in the estimated value of the state observer, it will be very difficult to stabilize, but as shown in Equation 8, the observer will operate in advance. _Χο, ie, the flying gap length deviation Δζ, its speed d (Az) I dt and the excitation current Ai are known by setting the observer's initial value ₀ as equal to x ₀ as possible From the beginning, the flying gear gap length deviation Δζ and its velocity d (Az) I dt can be estimated from the excitation current Ai _z with little error.

[0041] Here, if the error in the initial estimation is large, an abnormal excitation voltage is calculated by Equation 9, so that the floating state cannot be stabilized.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0043] (First embodiment)

FIG. 2 is a diagram showing the configuration of the magnetic levitation apparatus according to the first embodiment of the present invention. The overall configuration is indicated by 1.

In the magnetic levitation apparatus 1 ′, the gap sensor 121 is omitted. Instead, the floating body 111 and the contact detection unit 130 are provided in the vicinity of the floating body 111. The contact detection unit 130 detects that the levitation body 111 is in a non-contact state force, for example, using the piezoelectric rubber 129.

In addition to the contact detection unit 130, the suction force control unit 115 includes a posture estimation unit 133, a posture calculation unit 135, an estimation initialization unit 137, and an initial initial value setting unit 139.

[0046] Attitude estimation unit 133 determines excitation gap Ai force and levitation gap length deviation Δζ and its velocity d (z

A z) Estimates Zdt, and is composed of, for example, an observer. The posture calculation unit 135 calculates X to be the initial value of the observer when shifting from the posture maintained by the auxiliary support unit 131 to the floating state. The estimation initialization unit 137 detects the observer by touching.

0

Return the output value to the initial state. The initial value setting unit 139 sets X calculated by the posture calculation unit 135 as an initial value in the initialized observer. [0047] Excitation current Ai, levitation gap length deviation Δζ estimated by posture estimation unit 133 and

ζ

The speed d (Δz) Zdt is input to the excitation voltage calculation unit 125, and the electromagnet 105 is excited via the driver 116 by the output of the excitation voltage calculation unit 125.

[0048] As described above, when the observer is initialized and given a predetermined initial value, the levitated body 111 is levitated from the stopped state, or the levitated state is changed from the levitated state to the contact state due to an external force or other reasons. But exciting current Ai force levitation gap length deviation Δ ζ and its speed

ζ

d (A z) Zdt can be estimated with an initial error and error being suppressed. As a result, the levitated body 111 can be reliably transferred to the levitation state and maintained in the levitation state.

[0049] When a transient external force is continuously applied to the levitated body 111 that is in the levitating state while the force is applied, suction force control is performed to keep the levitating state against the external force. At this time, the exciting current continuously flows in the coils 1 19 and 119 ′, the temperature of the coils 119 and 119 ′ increases, and the coil resistance R increases accordingly. As a result, the parameter a in Equation 4 increases.

33

On the other hand, for the observer described in Equation 7, the parameter a remains as set. this

33

Therefore, there is a difference between the actual magnetic levitation system and the observer, and the actual value and estimated value of the excitation current Ai z, the levitation gap length deviation Δ z, and its velocity d (Δ z) Zdt diverge. Become. In the normally unstable normally attracted magnetic levitation system, the deviation between the actual value and the estimated value makes it very difficult to stabilize the levitation state by feedback control.

Here, as in Patent Document 4, for example, the magnetic levitation device 1 ′ is provided with a resistance measurement unit 140 for measuring the resistance R of the coils 119, 119 ′. For example, the resistance measurement unit 140 measures the coil resistance R from the voltage equation of the excitation voltage e according to the following equation.

z

[Equation 10] dai _z

ez _ ^L z0 ~ ―

R = ■ (10)

Δι _ζ

In the present invention, since the levitated body 111 is levitated by zero power control, the excitation current Ai caused by a transient and continuous external force crosses the zero point. Excitation current Ai is zero

z z

Then, in order to make division of Expression 10 impossible, Expression 10 is changed as follows.

[0052] However, ε is ε less 1, and is set to an appropriate value based on the noise magnitude of the value obtained by Equation 11 and the required measurement accuracy. Then, if an appropriate noise removal process such as a low pass filter average value calculation is performed on the output of Equation 11, the value of the coil resistance R can be measured.

[0053] If the coil resistance value obtained in this way is output from the resistance measurement unit 140 and introduced into the posture estimation unit 133 and the parameter a in Equation 7 is changed, Equation 4 increased due to temperature rise.

33

The value of parameter a inside matches the value of parameter a in Equation 7. Therefore, the actual magnetic

33 33

The actual and estimated values of the excitation current A i, the levitation gap z yap length deviation Δ z, and its velocity d (Δ z) Zdt can be deviated from each other without structural differences between the levitation system and the observer. Absent.

[0054] Furthermore, in the present invention, even if an excitation current increases due to the application of a transient external force or the like, and an offset voltage is generated in the driver 116 due to the increase, the generation of the offset voltage is caused by the estimated floating gear length or An estimation error correction unit 142 is provided so as not to cause an error in the speed estimation value.

[0055] This estimation error correction unit 142 applies a predetermined gain to the estimated speed value of the posture estimation unit 133.

OS

Multiplier gain compensator 144, integrator 146 that integrates the output of gain compensator 144, and adder 148 that adds the output of integrator 146 and the excitation voltage value of excitation voltage calculator 125

. The estimation error correction unit 142 outputs the output of the adder 148 as an excitation voltage value introduced into the posture estimation unit 133.

With such a configuration, even if an offset voltage is generated due to temperature fluctuation, the influence on the estimated value can be minimized.

In addition, in the present invention, as shown in FIG. 3, when measuring the coil resistance value, the excitation voltage calculation unit 125 includes the target value setting unit 150 and the excitation voltage calculation unit 125 so that the offset voltage does not affect the measurement value. A coil current converging unit 152 is provided.

[0058] The target value setting unit 150 sets the target value of the coil current to zero or non-zero at predetermined time intervals. Set the value alternately. The coil current converging unit 152 converges the coil current value that is the sensor output to the target value set by the target value setting unit 150.

In addition, the resistance value measurement unit 140 includes a voltage storage unit 154, a voltage input compensation unit 156, and a resistance calculation unit 158.

The voltage storage unit 154 stores the excitation voltage value when the target value setting unit 150 sets the target value to zero. The voltage input compensation unit 156 subtracts the offset voltage value output from the voltage storage unit 154 from the excitation voltage value of the electromagnet 105 obtained based on the coil current value that is the sensor output as the excitation voltage compensation value. Output. The resistance calculation unit 158 measures the coil resistance R according to the equation 11 using the excitation voltage compensation value and the coil current value.

In such a configuration, every time the target value setting unit 150 outputs zero, the voltage storage unit 154 detects the DC component of the excitation voltage value during that time, and the target value setting unit 150 is not zero. Each time the output is changed to zero, the value of the DC component is output to the voltage input compensation unit 156. Therefore, the output of the resistance calculation unit 158 is updated each time the target value setting unit 150 changes the output from zero to a non-zero value.

[0062] In general, in a normal conducting magnetic levitation apparatus, the excitation current i

The current sensor 123 is used to detect z. Now, let us consider output offsets depending on the respective temperatures of the current sensor 123 and the driver 116. The former offset is the current offset i, and the latter zoff offset is the voltage offset e.

zoff

[0063] When the levitated body 111 is in the levitated state and zero is output from the target value setting unit 150, the value of the excitation voltage to the driver 116 is e, and the value of the coil resistance R connected to the driver 116 is If R is R, the following voltage equation holds.

z

[Equation 12] ez z = ^-R zizof f- ^e zof f "'is 2)

[0064] During this time, voltage storage unit 154 receives a signal reporting that zero is output from target value setting unit 150, and extracts the DC component value of e and outputs the previous extraction result. . Subsequently, when the non-zero value I is output from the target value setting unit 150, the coil current convergence unit 1 nz

With the action of 52, the excitation current i converges to a value that satisfies the following formula.

z

[Equation 13] iz + izoff = ^J nz… (丄^J )

Here, the following voltage equation is established for the voltage signal e input to the driver 116 z

To do.

[ _Equation 14] e _z + e _zoff = R _z i _z (14)

[0067] Equation 14 can be modified as follows by Equation 13 above.

[Equation 15] + e _zo ff = ^ ζ ^ ηζ-of f)… (15)

In this way, when the target value setting unit 150 outputs the non-zero value I, the voltage storage unit 15 nz

4, the voltage value e extracted when the target value setting unit 150 outputs zero is stored in the voltage holding unit 154, and the value is output to the voltage input compensation unit 156 as an offset voltage.

[0069] The excitation voltage compensator 156 includes the output value e of the input voltage storage unit 154 and the driver 11 zz

Using the voltage signal e to 6, calculate the compensation excitation voltage e according to the following equation.

z zm

[Equation 16] ezm = ^e z- ^e zz = ^e z + Rz! Zoff + ^e zof f… (16)

[0070] The resistance calculation unit 158 calculates the coil resistance using the algorithm related to Equation 11 above based on the compensation excitation voltage e output from the excitation voltage compensation unit 156 and the target value I of the excitation zm current i z nz

To do. The measurement result calculated at this time is R

If m, then the following equation holds.

[Equation 17] ezm = ^x m ^I nz… Le '') Substituting Equation 16 into Equation 17 and rearranging it can be transformed as follows. [Equation 18] ez = ^R m ^I nz ― ^R zizof f ― ^e zoff '"(18)

At this time, Equation 15 which is a voltage equation related to the driver 116 can also be transformed into the following equation.

[Equation 19] e _z = ^R z¾z- ^R zizoff- ^e zoff… (19)

[0073] From the equations 18 and 19, the following equations are established.

[Equation 20]

R _m = R _z "" (20) [0074] That is, in the resistance calculation unit 158, the output value e of the voltage input compensation unit 156 is used.

zm

When the value of the coil resistance connected to driver 116 is measured, current offset i and current

zof

Even if the pressure offset e fluctuates, the measurement result can always match the true value.

zoff

In other words, even if an offset voltage occurs in the current detection unit (current sensor 123) or excitation unit (driver 116) due to temperature fluctuations, etc., it is always corrected using the compensation value of the excitation voltage according to the offset voltage, The resistance value can be measured.

Furthermore, posture estimation section 133 can always output a correct gap length estimation value and speed estimation value based on the resistance value. This makes it possible to maintain a stable floating state with respect to temperature fluctuations.

In the present invention, the coil resistance R measured by the resistance measurement unit 140 is introduced into the excitation voltage calculation unit 125. In the excitation voltage calculator 125, for example, the feedback constant F in Equation 9 is determined so that a predetermined transient response is obtained with respect to the disturbance. When F is given as a function of the coil resistance R when designing the control system, if the value of F is changed based on the coil resistance R, the transient response of the levitated body to the disturbance becomes constant with respect to temperature fluctuations.

As described above, in the present invention, the value of the feedback constant F is changed in the coil current converging unit 152 based on the coil resistance R measured by the resistance measuring unit 140. As a result, the response of the levitated body 111 becomes constant with respect to temperature fluctuation, and the stability of the levitated state can be ensured. As a result, the reliability can be improved and the gap sensor is not required, simplifying the device. And miniaturization and cost reduction.

[0078] (Second Embodiment)

Next, a second embodiment of the present invention will be described.

[0079] The second embodiment is characterized in that an excitation voltage and an excitation current are calculated for each mode of the moving coordinate system of the levitated body. Here, the case where the magnetic levitation apparatus of the present invention is applied to an elevator will be described as an example.

FIG. 4 is a diagram showing a configuration of a magnetic levitation apparatus according to the second embodiment of the present invention. The configuration when this magnetic levitation device is applied to an elevator is indicated by reference numeral 10 as a whole. FIG. 5 is a perspective view showing the configuration of the frame portion of the magnetic levitation apparatus. FIG. 6 is a perspective view showing a configuration around the magnet unit of the magnetic levitation apparatus. FIG. 7 is an elevation view showing the configuration of the magnet unit of the magnetic levitation apparatus.

As shown in FIG. 4, guide rails 14, 14, a moving body 16, and four guide units 18 a to 18 d are formed on the inner surface of the elevator shaft 12. The guide rails 14 and 14 are made of a ferromagnetic member and are laid in the elevator shaft 12 by a predetermined mounting method.

[0082] The moving body 16 corresponds to the floating body of the magnetic levitation apparatus described above. The moving body 16 moves up and down along the guide rails 14 and 14 'via a drive mechanism (not shown) such as a rope 15 lifting machine. The guide units 18a to 18d are attached to the moving body 16, and guide the moving body 16 to the guide rails 14, 14 'without contact.

[0083] A car 20 and guide units 18a to 18d are attached to the moving body 16. The moving body 16 includes a frame portion 22 having a strength capable of maintaining a predetermined positional relationship between the guide units 18a to 18d. As shown in FIG. 5, guide units 18a to 18d facing the guide rails 14 and 14 'are attached to the four corners of the frame portion 22 by a predetermined method.

[0084] As shown in FIG. 6, the guide unit 18 includes an X-direction proximity sensor 26 (26b, 26b '), a y-direction proximity sensor, and a non-magnetic material (for example, aluminum or stainless steel) or a plastic base 24. 28 (28b, 28b ') and the magnet unit 30 are mounted by a predetermined method. The proximity sensors 26 and 28 function as a contact detection unit that detects contact between the guide unit 18 and the guide rails 14 and 14. [0085] The magnet unit 30 includes a central iron core 32, permanent magnets 34 and 34 ', and electromagnets 36 and 36'. As shown in FIG. 7, the same polarity of the permanent magnets 34 and 34 'is provided. They face each other through the central iron core 32! / As a whole, they are assembled into an E shape.

[0086] The electromagnets 36 and 36 are inserted into the coil 40 (40,) after the L-shaped iron core 38 (38,) is inserted into the iron core 38.

A flat core 42 is attached to the tip of (38 '). A solid lubricating member 43 is attached to the tip of the central iron core 32 and the electromagnets 36 and 36 ′. This solid lubricating member 43 prevents the magnet unit 30 from being attracted and fixed to the guide rail 14 (14 ') by the attractive force of the permanent magnets 34, 34' when the electromagnets 36, 36 'are not excited. In addition, the solid lubricating member 43 is provided so as not to hinder the moving up and down operation of the moving body 16 even if the magnet unit 30 is attracted. As this solid lubricating member 43, for example, there is a material containing Teflon (registered trademark), graphite, molybdenum disulfide or the like.

[0087] Hereinafter, for the sake of simplicity, the alphabets (a to d) of the guide units 18a to 18d are attached to the numbers indicating the main parts.

[0088] In the magnet unit 30b, the coils 40b and 40b can be separately excited and controlled independently of the attractive force direction acting on the guide rail 14 and the X direction. Details of this control method are disclosed in Patent Document 1, and detailed description thereof is omitted here.

[0089] Each suction force of the guide units 18a to 18d is controlled by the control device 44 used as the suction force control unit described above, and the car 20 and the frame part 22 are not in contact with the guide rails 14, 14, and so on. Be guided to.

[0090] It should be noted that the control device 44 may be configured as a single force as a whole as shown in FIG. 8, for example, as shown in FIG.

FIG. 8 is a block diagram showing a configuration within the control device in the same embodiment. FIG. 9 is a block diagram showing the configuration of the mode control voltage arithmetic circuit in the control device. In the block diagram, the arrow line indicates the signal path, and the bar line indicates the power path around the coil 40.

The control device 44 includes a sensor unit 61, an arithmetic circuit 62, and power amplifiers 63a, 63a ′ to 63d, 63d ′, and these are the attraction forces of the four magnet units 30a to 30d. X axis, The y axis is controlled independently.

The sensor unit 61 is attached to the car 20 and detects magnetomotive force or magnetic resistance in the magnetic circuit formed by the magnet units 30a to 30d, or changes in the motion of the moving body 16.

The arithmetic circuit 62 calculates an applied voltage for exciting the coils 40a, 40a, ˜40d, and 40d ′ that guide the moving body 16 in a non-contact manner based on the signal from the sensor unit 61. Used as a suction force control unit. The power amplifiers 63a, 63a ′ to 63d, 63d ′ are used as excitation units for supplying power to the coils 40 based on the output of the arithmetic circuit 62.

In addition, the power supply 46 supplies power to the power amplifiers 63a, 63a ′ to 63d, 63d ′ and also supplies power to the constant voltage generator 48 at the same time. The power source 46 has a function of converting the alternating current supplied from the elevator shaft 12 external force by a power line (not shown) for lighting and door opening / closing to a direct current suitable for supplying power to the amplifier. .

[0096] The constant voltage generator 48 always maintains the operation circuit 62 and the proximity sensors 26a, 26a 'to 26d, 26d at a constant voltage even if the voltage of the power source 46 fluctuates due to the supply of a large current to the power amplifier 63. ', 28a, 28a' to 28d, 28d '[Supply power. From this point, the arithmetic circuit 62 and the proximity sensors 26a, 26a 'to 26d, 26d', 28a, 28a 'to 28d, 28d' are normally operated.

The sensor unit 61 includes the proximity sensors 26a, 26a ′ to 26d, 26d ′, 28a, 28a ′ to 28d, 28d, and the current detectors 66a, 66a,. 66d, 66d '.

The arithmetic circuit 62 performs guidance control of the moving body 16 for each mode of the motion coordinate system shown in FIG. Here, the above-mentioned modes are y mode (back and forth motion mode) representing the back and forth movement along the y coordinate of the center of gravity of the moving body 16, X mode (left and right motion mode) representing the left and right motion along the X coordinate, and movement. Θ mode (roll mode) representing rolling around the center of gravity of the body 16, mode representing pitching around the center of the moving body 16 (pitch mode), and Φ mode (yo mode) representing gyration around the center of gravity of the moving body 16 is there.

[0099] In addition to these five modes, the arithmetic circuit 62 also performs guidance control in the ζ mode (full suction mode), δ mode (twist mode), and γ mode (distortion mode). Ie `` Total attractive force '' exerted on the guide rails 14, 14 'by the magnet units 30a to 30d, `` Torsion torque''around the z-axis exerted on the frame part 22 by the magnet units 30a to 30d, and the magnet units 30a, 3 Od force S There are three modes related to the “distortion force” that exerts a force on the frame 磁石 22 and the magnet unit 30b, 30c force on the S frame 咅 22.

[0100] For the above eight modes, by converging the coil currents of the magnet units 30a to 30d to zero, the moving body can be stably supported only by the attractive force of the permanent magnet 34 regardless of the weight of the load. To do. This is guidance control by so-called “zero power control”.

[0101] The calculation circuit 62 has a first calculation function and a second calculation function. The first calculation function is a function for calculating an excitation current for each mode expressed by a linear combination of excitation currents that generate an attractive force that contributes to the freedom of movement of the moving body 16 that is a floating body. The second function to calculate is the mode-specific excitation voltage that is expressed by a linear combination of excitation voltages. Specifically, it is configured as follows.

That is, as shown in FIG. 8, the calculation circuit 62 includes a target value setting unit 74, a resistance measurement unit 64, a current deviation coordinate conversion circuit 83, a control voltage calculation circuit 84, and a control voltage coordinate reverse conversion circuit. It consists of 85.

[0103] The target value setting unit 74 alternately outputs zero or non-zero values at predetermined intervals as the excitation current target value of the ζ mode (all suction mode) among the eight modes. Further, the target value setting unit 74 outputs a predetermined value when the apparatus is stopped, which will be described later, in the y mode and the X mode.

[0104] The resistance measuring unit 64 is configured to detect the excitation current detection values of the coils 40a, 40a 'to 40d, 40d' and the excitation voltage signals to the respective amplifiers 63a, 63a, to 63d, 63d of the arithmetic circuit 62. Based on ea, ea, ˜ed, ed ′ and the output value of the target value setting unit 74, the electrical resistance value of each coil is output.

[0105] The current deviation coordinate conversion circuit 83 has a current deviation signal A ia,

Δ ia, ~ Δ id, Δ id ′, current deviation related to y direction motion of the center of gravity of moving body 16 Δ iy, electrical deviation related to motion in X direction A ix, current deviation related to rolling around the center of gravity Δ ί θ, current deviation A i ξ related to pitching of moving body 16, bowing around the same center of gravity Is calculated, and current deviations Δίζ, Δίδ, and Δίγ are calculated for stress ζ, δ, and γ that apply stress to the frame portion 22.

The control voltage calculation circuit 84 serves as a mode excitation voltage calculation unit, and outputs Aiy, Δίχ, Δίθ, Μξ, Μφ,, output of the resistance measurement unit 64, the target value setting unit 74, and the current deviation coordinate conversion circuit 83, respectively. From Δίζ, Δίδ, Δίγ, y-, χ-, θ-, ξ-, φ-, ζ-, δ-, γ-mode electromagnet control voltages ey, ex, eΘ, e6 , βφ, e ζ, e δ, ey <S.

The control voltage coordinate inverse transformation circuit 85 is configured to output the electromagnet excitation voltages ea of the magnet units 30a to 30d from the outputs ey, ex, e Θ, e 6, Θ, θζ, e6, ey of the control voltage calculation circuit 84, respectively. , ea 'to ed, ed'. The calculation result of the control voltage coordinate inverse transformation circuit 85, that is, ea, ea 'to ed, ed', and the other amplifiers 63a, 63a 'to 63d, 63d' are given.

Note that the target value setting unit 74 may be configured by at least one target value setting unit 140 in the first embodiment. Further, when the target value setting unit 74 is configured by a plurality of target value setting units 140, there is no phase shift in the period in which each output value becomes zero! Needless to say,! /.

[0109] Also, in the cycle of outputting a non-zero value, the target power of supplying a minute current for resistance measurement to all the coils is acceptable if the target value of at least one mode is a non-zero value. There is no problem even if there is a mode in which the target value setting unit 74 always outputs zero as the excitation current target value.

Here, in the present embodiment, the target value setting unit 74 is configured so that the ζ mode (full suction mode) becomes a non-zero value. In this case, the same value of excitation current can be supplied to all coils. Since the suction force generated at that time acts as a stress on the frame part 22, the rider can feel comfortable against the change in the output value of the target value setting part 74 in which the posture of the moving body 16 does not change. There is no evil.

Note that the current deviation coordinate conversion circuit 83, the control voltage calculation circuit 84, and the control voltage coordinate reverse conversion circuit 85 in FIG.

[0112] Further, the control voltage calculation circuit 84 includes a longitudinal movement mode control voltage calculation circuit 86a, a left / right movement mode control voltage calculation circuit 86b, a roll mode control voltage calculation circuit 86c, and a pitch mode control circuit. A control voltage calculation circuit 86d, a normal mode control voltage calculation circuit 86e, an all suction mode control voltage calculation circuit 88a, a torsion mode control voltage calculation circuit 88b, and a distortion mode control voltage calculation circuit 88c.

[0113] The longitudinal motion mode control voltage calculation circuit 86a calculates the y-mode electromagnet control voltage ey from A iy. The left / right mode control voltage calculation circuit 86b calculates the X mode electromagnet control voltage ex from Aix. The roll mode control voltage calculation circuit 86c calculates the 0 mode electromagnet control voltage e Θ from A i 0. The pitch mode control voltage calculation circuit 86d calculates the ξ mode electromagnet control voltage e ξ from A i. The mode control voltage calculation circuit 86e calculates the φ-mode electromagnet control voltage e φ from A i φ.

[0114] The full suction mode control voltage calculation circuit 88a calculates the ζ-mode electromagnet control voltage e ζ from A i ζ. The torsion mode control voltage calculation circuit 88b calculates a δ mode electromagnet control voltage e δ from A i δ. The distortion mode control voltage calculation circuit 88c calculates the γ-mode electromagnet control voltage e γ from Δ ί γ.

[0115] The control voltage calculation circuit in these modes has the same configuration as the attractive force control unit 115 shown in Figs.

That is, as shown in FIG. 9, the longitudinal movement mode control voltage calculation circuit 86a includes a resistance value averaging unit 90, a gain compensator 91, a resistance value imbalance correction unit 92, a subtractor 93, and an integral compensator 94. , Adder 95, subtractor 96, estimation error correction unit 142, figure mode posture estimation unit 97, estimation initialization unit 98, posture calculation unit 99, initial value setting unit 100, and adder 101

The resistance value averaging unit 90 calculates the average value of the resistance values of the coils 40a, 40a ′ to 40d, 40d measured by the resistance measurement unit 64. The gain compensator 91 multiplies the estimated values of A y, A y, and A iy (indicated by “′” in the figure) by an appropriate feedback gain.

[0118] The resistance value imbalance correction unit 92 determines each coil resistance value based on the output of the resistance measurement unit 64 based on the excitation current (Δ ix to Δ i γ) for each of the seven modes other than the forward / backward movement mode. Multiply the resistance correction gain for each mode obtained by linear combination of and output the sum of these seven multiplication results.

The subtractor 93 subtracts A iy from the output of the target value setting unit 74. The integral compensator 94 subtracts Integrate the output value of unit 93 and multiply by the appropriate feedback gain. The adder 95 calculates the sum of the output values of the gain compensator 91. The subtractor 96 subtracts the output value of the adder 95 from the output value of the integral compensator 94 and outputs the first mode excitation voltage eyl in the y mode (forward / reverse operation mode).

[0120] The estimation error correction unit 142, as a mode estimation error correction unit, corrects the offset voltage component of the power amplifier 63 in the first mode-specific excitation voltage for each mode. As with the posture estimation unit 133, the mode posture estimation unit 97 calculates the estimated values of Ay, Δγ, and Δiy from the output value of the estimation error correction unit 142 and the current deviation Aiy for each mode.

[0121] The estimation initialization unit 98 initializes the integral operation in the mode posture estimation unit 97 based on ONZOFF of the 16 proximity sensor signals. The attitude calculation unit 99 calculates the attitude when the moving body 16 is in contact based on ONZOFF of the 16 proximity sensor signals, and outputs the position deviation of each magnet unit 30 by mode.

[0122] The initial value setting unit 100 sets the calculation result of the posture calculation unit 99 as the initial value of the integration operation when the mode posture estimation unit 97 is initialized. The adder 101 adds the first mode-specific excitation voltage eyl and the output of the resistance value imbalance correction unit 92, and outputs the addition result as the second mode-specific excitation voltage ey.

It should be noted that mode posture estimation unit 97, estimation initialization unit 98, posture calculation unit 99, and initial value setting unit 100 are described in detail in Patent Document 4, and detailed description thereof is omitted.

[0124] Also, the left / right mode control voltage calculation circuit 86b, the roll mode control voltage calculation circuit 86c, the pitch mode control calculation circuit 86d, and the short mode control calculation circuit 86e are the same as the vertical mode control voltage calculation circuit 86a. The corresponding input / output signal is indicated by the signal name, and the description thereof is omitted.

On the other hand, all the three mode control voltage calculation circuits 88a to 88c of ζ, δ and γ have the same configuration. Further, since it has the same constituent elements as the vertical movement mode control voltage calculation circuit 86a, the same reference numerals are given to the same parts, and the structure is shown in FIG.

In this embodiment, the subtractors 93 and 93 ′, the gain compensators 91 and 91 ′, the integral compensators 94 and 94 ′, the subtractors 96 and 96 ′, and the adder 95 shown in FIG. 10 are mode-excited. Forming a current converging section ing.

[0127] Next, the operation of the magnetic levitation apparatus configured as described above will be described.

[0128] When the apparatus is in a stopped state, the tips of the central iron cores 32 of the magnet units 30a and 30d are opposed to the guide rail 14 via the solid lubricating member 43, and the tips of the electromagnets 36a 'and 36d' are It is adsorbed to the opposing surface of the guide rail 14 via the solid lubricating member 43. At this time, the moving of the moving body 16 is not hindered by the action of the solid lubricating member 43.

[0129] When the present apparatus is started in this state, the control apparatus 44 causes the electromagnets 36a, 36 to generate a magnetic flux in the same direction as or opposite to the magnetic flux generated by the permanent magnet 34 by the action of the levitation control calculation unit 65. a 'to 36d, 36d'. Further, the current flowing in each coil 40 that maintains a predetermined gap length between the magnet units 30a to 30d and the guide rails 14, 14 'is controlled.

Accordingly, as shown in FIG. 7, from the path of the permanent magnet 34 to the iron core 38, 42 to the gap G to the guide rail 14 (14 ') to the gap G "to the central iron core 32 to the permanent magnet 34. The magnetic circuit Mc and the permanent magnet 34 'to the iron core 38, 42 to the gap G' to the guide rail 14 (14 ') to the gap G "to the central iron core 32 to the magnetic circuit Mc that forms the path force of the permanent magnet 34 are formed. Is done.

[0131] At this time, the gap length in the gaps G, G ', G "is the y-axis direction in which the magnetic attractive force of each of the magnet units 30a to 30d due to the magnetomotive force of the permanent magnet 34 acts on the center of gravity of the moving body 16 The length is exactly the same as the longitudinal force, lateral force in the X direction, torque around the X axis passing through the center of gravity of the moving body 16, torque around the y axis, and torque around the z axis.

[0132] When an external force is applied to the moving body 16 to maintain this balance, the control device 44 performs excitation current control of the electromagnets 36a, 36a, to 36d, 36d. As a result, so-called zero power control is performed.

[0133] Now, when the moving body 16 that is being non-contact guided by zero power control starts to move up and down along the guide rails 14 and 14 by a lifting machine (not shown), the guide rails 14 and 14 Suppose that the moving body 16 sways due to the distortion of. Even in this case, the magnet units 30a to 3Od have permanent magnets that share a magnetic path with the electromagnet in the air gap. Can be suppressed.

[0134] Also, due to uneven movement of personnel and cargo, or rope swings caused by earthquakes, etc. Then, it is assumed that an excessive external force is applied to the moving body 16. In such a case, the temperature of the electromagnets of the magnet units 30a to 3Od rises, and the electric resistance of the electromagnet coil and the offset voltage of the power amplifier and current detector fluctuate. In particular, when zero power control that can extremely reduce power consumption is used, when a large excitation current flows due to excessive external force, each electromagnet coil and power amplifier generate heat suddenly, and other control such as constant gap length control is performed. The resistance value fluctuates more than in this control method. If this happens, the error between the gap length estimation value and the speed estimation value increases in each motion mode, and the ride quality is extremely deteriorated.

However, according to the present invention, the resistance of the coil 40 is determined based on the equation 18 after considering the offset voltage of the power amplifier and the current detector by the action of the target value setting unit 74 and the resistance measurement unit 64. The value is measured accurately.

Accordingly, the parameters of the mode attitude estimation unit 97 and the resistance value imbalance correction units 92 and 92 ′ adjusted by the output value of the resistance measurement unit 64 are accurately adjusted, and the gain compensator 9 1, 91 ′. Integral compensators 94 and 94 ′ can set the gain using the resistance value as a parameter. Therefore, if the stability of the non-contact guidance is maintained with respect to the fluctuation of the offset voltage and the coil resistance value, it is possible to maintain a good and constant ride comfort without the force.

[0137] In addition, an estimation error occurs in the deviation for each mode and the deviation speed for each mode with respect to the fluctuation of the offset voltage of the power amplifier. . However, the speed at which the estimated value of the mode attitude estimation unit 97 converges to the true value depends on the accuracy of the coil resistance measurement value. Therefore, when the resistance measurement unit 67 performs accurate resistance measurement in consideration of the offset voltage, the estimated value of the mode posture estimation unit 97 quickly converges to a true value.

[0138] When the apparatus stops operation and stops, the target value setting unit 74 gradually sets the target values in the y mode and the X mode to negative values from zero force. As a result, the moving body 16 gradually moves in the y-axis and X-axis directions, and finally the electromagnet is formed on the opposite surface of the guide rail 14 via the tip 1S solid lubricating member 43 of the central core 32 of the magnet units 30a and 30d. The tips of 36a 'and 36d' are adsorbed to the opposing surface of the guide rail 14 through the solid lubricating member 43, respectively. When the apparatus is stopped in this state, the output of the target value setting unit 74 is reset to zero and the moving body 16 is attracted to the guide rail. [0139] (Third embodiment)

Next, a third embodiment of the present invention will be described.

[0140] In the first and second embodiments, the magnet unit is mounted on the floating body side. 1S This does not limit the mounting position of the magnet unit at all. As shown in FIG. It may be arranged on the side. For simplification of description, the same reference numerals are used for the parts common to the first and second embodiments.

FIG. 11 is a diagram showing the configuration of a magnetic levitation apparatus according to the third embodiment of the present invention. The overall configuration is denoted by reference numeral 300.

[0142] The magnetic levitation device 300 includes an auxiliary support 302, a magnet unit 107, a guide 304, a vibration isolation table 306, a linear guide 308, an attractive force controller 115, a power amplifier 313, and a current sensor 1.

Has 23.

[0143] The auxiliary support 302 has a U-shaped cross section and is formed of a nonmagnetic material such as an aluminum member. The auxiliary support portion 302 is installed on the ground. The magnet unit 107 is attached downward on the upper lower surface of the auxiliary support portion 302.

The guide 304 has a U-shaped cross section facing the magnet unit 107, and is formed of a ferromagnetic member such as iron. The anti-vibration table 306 includes the guide 304 on the upper surface of the bottom, and is formed in a U shape as a whole. The linear guide 308 is attached to the side surface of the vibration isolation table 306 and gives the vibration isolation table 306 freedom of movement only in the direction perpendicular to the ground.

The attraction force control unit 115 controls the attraction force of the magnet unit 107 so as to support the anti-vibration table 306 in a non-contact manner. The power amplifier 313 is connected to a power source (not shown) for exciting the magnet unit 107 based on the output of the attractive force control unit 115. The current sensor 123 detects the excitation current of the magnet unit 107.

Here, the attractive force control unit 115 has the following configuration.

That is, the attractive force control unit 115 includes the resistance measurement unit 140, the contact detection unit 130, the posture calculation unit 135, the posture estimation unit 133, the initial value setting unit 139, the estimation initialization unit 137, and the excitation voltage calculation unit 1 25. It has.

[0148] Resistance measurement unit 140 uses lead current 1 from the excitation current and excitation voltage to magnet unit 107. Measure the series resistance of 28 and coils 119 and 119 '. The contact detection unit 130 includes a micro switch 310 attached to the bottom upper surface of the auxiliary support unit 302 and a piezoelectric rubber 312 attached to the magnetic pole surface of the magnet unit 107.

The posture calculation unit 135 calculates the floating gap length when the contact detection signal force of the contact detection unit 130 is in contact with the auxiliary support 302 or the magnet unit 107 of the vibration isolation table 306. The posture estimation unit 133 estimates the flying posture of the vibration isolation table 306 based on the output of the resistance measurement unit 130, the excitation current to the magnet unit 107, and the excitation voltage force.

The initial value setting unit 139 sets an estimated initial value in the posture estimation unit 133 based on the output of the posture calculation unit 135. The estimation initialization unit 137 initializes the posture estimation unit 133 based on the output of the contact detection unit 130. The excitation voltage calculation unit 125 calculates the excitation voltage to the magnet unit 107 for magnetically levitating the vibration isolation table 306 based on the output of the posture estimation unit 133.

[0151] According to such a configuration, since the magnet unit 107 is arranged on the ground side, there is no longer any wiring from the vibration isolation table 306, which is a movable part, and there is an advantage that the reliability of the apparatus is improved. .

[0152] (Fourth embodiment)

Next, a fourth embodiment will be described.

In the first to third embodiments, the case where the present invention is applied to a sensorless magnetic levitation apparatus that does not require a gap sensor has been described. However, the present invention is not limited to application to a sensorless magnetic levitation apparatus, but may be applied to an attraction type magnetic levitation apparatus using a gap sensor as shown in FIG. For simplicity of explanation, the same reference numerals are used for the parts common to the first to third embodiments.

FIG. 12 is a diagram showing the configuration of the magnetic levitation apparatus according to the fourth embodiment. The overall configuration is indicated by reference numeral 400.

[0155] In the magnetic levitation apparatus 400 in the present embodiment, the gap sensor 121 that obtains information on the levitation gap length and the velocity used for stabilization of the magnetic levitation system in the attitude estimation unit 133 in the first embodiment. And using the pseudo-differentiator 402. [0156] The output of the gap sensor 121 is directly input to the excitation voltage calculator 125 as information on the flying gap length, and is also converted to a speed signal via the pseudo-differentiator 402 and input to the excitation voltage calculator 125. The In addition, the excitation current of the coils 119 and 119 ′ is input to the excitation voltage calculation unit 125 by the current sensor 123.

Here, the offset voltage of the power amplifier 313 and the current sensor 123 is taken into account in the same manner as in the first embodiment by the functions of the target value setting unit 150 and the resistance measurement unit 40 in the excitation voltage calculation unit 125. The coil resistance value is measured. Based on the coil resistance value, the excitation voltage for levitating the levitated body 111 with a stable and constant transient response is calculated.

[0158] With such a configuration, it is possible to always maintain a stable floating state with respect to temperature fluctuations with a simple control device.

[0159] In the above embodiments, the control device (attraction force control unit 115) that performs magnetic levitation is described as an analog configuration. The present invention is not limited to an analog control method. It is also possible to configure with digital control.

[0160] Further, the power using the power amplifier as the configuration of the excitation unit. This is not limited to the driver system, and may be of the PWM (Pulse Width Modulation) type, for example.

In addition, various modifications can be made without departing from the scope of the present invention. In short, the present invention is not limited to the above-described embodiments as they are, but can be specifically modified by modifying constituent elements without departing from the scope of the invention. Moreover, various forms can be formed by appropriately combining a plurality of constituent elements disclosed in the respective embodiments. For example, some constituent elements such as all the constituent elements shown in the embodiment may be omitted. Furthermore, constituent elements over different embodiments may be appropriately combined.

Industrial applicability

[0162] According to the magnetic levitation apparatus of the present invention, even when the offset voltage changes due to the influence of temperature fluctuation or the like, these can be accurately measured, and the stability of the levitation state is maintained based on the measured value. The levitation control parameters can be adapted as possible. This makes it possible to maintain the stability of the magnetic levitation system and the transient response to external disturbances at the time of design. This improves the reliability of the device.

Claims

The scope of the claims

[1] a guide composed of a ferromagnetic member;

A magnet unit composed of an electromagnet and a permanent magnet facing the guide through a gap and sharing a magnetic path in the gap;

A levitated body that is supported in a non-contact manner by the attractive force of the magnet unit acting on the guide;

A target value setting unit for alternately setting the target value of the coil current of the electromagnet to zero or a non-zero value;

A coil current converging unit for converging the coil current of the electromagnet to the target value set by the target value setting unit;

An excitation voltage calculation unit for calculating an excitation voltage value for stabilizing the magnetic circuit formed by the magnet unit based on the coil current value obtained from the sensor unit in accordance with the convergence operation by the coil current convergence unit; ,

A voltage storage unit for storing the excitation voltage value obtained by the excitation voltage calculation unit when the target value is set to zero;

An excitation voltage compensator for obtaining a compensation value of the excitation voltage by subtracting the excitation voltage value stored in the voltage storage unit as an offset voltage value from the excitation voltage value of the electromagnet, and obtained by the excitation voltage compensation unit. A resistance calculation unit for calculating a coil resistance value of the electromagnet based on the compensation value,

A control unit that performs feedback control of the floating body by feeding back the coil resistance value obtained by the resistance calculation unit to the excitation voltage calculation unit;

A magnetic levitation apparatus comprising:

2. The magnetic levitation device according to claim 1, wherein the excitation voltage calculation unit calculates an excitation voltage of the electromagnet based on an output of the resistance calculation unit.

[3] A posture estimation unit that estimates the posture of the floating body and the posture change speed with respect to the ferromagnetic member based on the coil current value obtained by the sensor unit force and the coil resistance value obtained by the resistance calculation unit. The magnetic levitation device according to claim 1, further comprising:

[4] A mode excitation voltage calculation unit that calculates an excitation voltage for generating a suction force that contributes to the degree of freedom of movement of the levitated body for each predetermined mode;

A mode excitation current calculation unit that calculates an excitation current for generating a suction force that contributes to the degree of freedom of movement of the levitating body for each predetermined mode;

The attitude estimation unit is configured to determine the attitude of the levitating body with respect to the ferromagnetic member and the temporal change of the attitude based on the outputs of the mode exciting current calculating unit and the mode exciting voltage calculating unit. 4. The magnetic levitation apparatus according to claim 3, wherein the estimation is performed for each degree of freedom of movement.

5. The magnetic levitation apparatus according to claim 4, wherein the target value setting means sets a target value for the excitation current for each mode obtained by the mode excitation current calculation unit.

6. The magnetic levitation apparatus according to claim 4, wherein in the coil current convergence, the excitation current for each mode obtained by the mode excitation current calculation unit is converged to a target value of the mode.

[7] An auxiliary support portion that maintains the positional relationship between the floating body and the guide in a predetermined state when the floating body is not in the floating state;

A contact detection unit that detects contact between the floating body and the guide;

A posture calculation unit that outputs the posture of the floating body with respect to the guide at the time of contact based on the output of the contact detection unit;

An estimation initialization unit that initializes the posture estimation unit at the time of contact based on the output of the contact detection unit;

An initial value setting unit that sets an output value of the posture calculation unit as an initial value of the posture estimation unit when the posture estimation unit is initialized;

The magnetic levitation apparatus according to claim 3, further comprising:

[8] The posture change speed estimated value obtained by the posture estimating unit is multiplied by a predetermined gain and integrated, and the integration result is added to the excitation voltage value, and the addition result is used as a new excitation voltage value. The magnetic levitation apparatus according to claim 3, further comprising an estimation error correction unit that feeds back to the posture estimation unit.

[9] The posture change speed estimated value obtained by the posture estimator is multiplied by a predetermined gain, and the integration result is added to the excitation voltage value for each mode, and the addition result is added for each new mode. 5. The magnetic levitation apparatus according to claim 4, further comprising a mode estimation error correction unit that feeds back to the posture estimation unit as an excitation voltage value.

10. The magnetic levitation apparatus according to claim 1, wherein the levitation body includes the magnet unit.

11. The magnetic levitation apparatus according to claim 1, wherein the levitation body includes the ferromagnetic member.

12. The magnetic levitation apparatus according to claim 1, wherein the sensor unit includes a gap sensor that measures the gap.