JP2793240B2 - Floating transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a levitation type transport device for transporting small articles, and in particular, can save energy and space and improve versatility. 1. Field of the Invention The present invention relates to a levitation type transport device that can be enlarged and reduced in cost.

(Prior Art) In recent years, as a part of office automation, moving slips, documents, cash, materials, and the like between a plurality of points in a building using a transport device has been widely performed.

It is required that the transport device for such a purpose be one that can quickly and quietly move the transported object. For this reason, in this type of transfer device, a transfer vehicle is supported on a guide rail in a non-contact manner. Above all, a method using a suction type levitation device that uses a carrier as a floating body and magnetically supports the floating body in a non-contact manner has an advantage of being excellent in followability to a guide rail, noise, and dust prevention effect. .

By the way, the conventional magnetic levitation type transport device supports a transport vehicle by an electromagnet, and stably supports the transport vehicle by controlling an exciting current to the electromagnet.
Therefore, the coil of the electromagnet must be constantly energized, and there is a disadvantage that power consumption is large. Therefore, in order to solve such a problem, most of the magnetomotive force required for the electromagnet is applied by a permanent magnet, as typified by Japanese Patent Application Laid-Open No. 61-102105. An apparatus that can reduce the power consumption of the electromagnet at the time of loading and at the time of loading the load is also considered.

That is, in this device, a magnetic support unit is constituted by the electromagnet and the permanent magnet, and the permanent magnet of each magnetic support unit generates an attractive force corresponding to the own weight of each magnetic support unit and the load sharing weight applied thereto. Control is performed such that such a gap is formed between the suction surface of the magnetic support unit and the suction surface of the guide rail. This control method is a desirable method for reducing the power consumption of the electromagnet. This device takes advantage of the fact that the power consumed by magnetic levitation is extremely small, and by mounting a battery as a power source, a completely non-contact levitation state can be realized for a long time.

However, the battery voltage decreases as the ascent time increases. Also, when a large disturbance is applied to the carrier and a large current is supplied to the electromagnet enough to overcome the disturbance,
The decline is even greater. Further, in this device, a power amplifier that excites an electromagnet with a voltage to be applied to the electromagnet based on an excitation signal is used as an exciting unit for exciting the electromagnet. For this reason, when a large disturbance is expected or when disturbance is frequently applied, it is necessary to increase the battery voltage in advance and increase the capacity in anticipation of the fluctuation of the battery voltage so as not to affect the operation of the power amplifier. was there. In general, the output voltage of the power amplifier is about 8 to 9% of the power supply voltage. In order to obtain a required output voltage, it is necessary to mount a power supply having a higher voltage on the carrier. . As a result, the size of the battery increases, and the weight increases accordingly. As a result, the size of the entire system such as a vehicle and a track is increased. Furthermore, since a power supply voltage equal to or higher than the output voltage is applied to the power amplifier, when a current required for exciting the electromagnet is supplied from the battery, the product of the difference between the output voltage of the power amplifier and the power supply voltage and the excitation current is obtained. The power amplifier is heated in proportion, and extra power is consumed. However, when the application of external force is small or the frequency of application is small, the size and weight of the battery are also suppressed, so that a device using a power amplifier is inexpensive and preferable.

On the other hand, when the applied external force is large or its frequency is high, it is desirable to excite the external force with a current to be passed through the electromagnet based on an excitation signal in order to suppress power consumption. However, the conventional control means used for calculating the excitation signal of the power amplifier is for controlling the excitation voltage of the electromagnet, and the current should be supplied to the electromagnet based on the excitation signal without changing the configuration. It is impossible to calculate the excitation signal of the excitation means that excites this with current. Therefore, if an exciting means for exciting the electromagnet with a current to be supplied to the electromagnet based on the exciting signal is used, a new control device is required, and mass production of the controlling means cannot be performed, resulting in an increase in cost.

(Problems to be Solved by the Invention) As described above, in the conventional levitation type transport device, when the applied external force is large or the applied frequency is high, the size of the battery and the weight of the vehicle are increased. In addition to this, when the excitation means is to be changed to solve such a problem, it is necessary to change the configuration of the control means accordingly.

In view of the above, the present invention is provided with an exciting unit capable of avoiding an increase in the size of the battery and an increase in the vehicle weight even in the case described above. It is an object of the present invention to provide a floating transfer device that does not need to be changed.

[Structure of the Invention] (Means for Solving the Problems) A floating transfer device according to the present invention is provided with a guide rail at least a lower surface portion of which is formed of a ferromagnetic material, and movably arranged along the guide rail. An electromagnet disposed so as to face the lower surface of the guide rail via a gap, and a magnetic circuit formed by the electromagnet, the guide rail and the gap to lift the carrier. One or more magnetic support units, each of which is constituted by a permanent magnet that supplies a magnetomotive force necessary for the vehicle and is mounted on the carrier, and a sensor unit attached to the carrier that detects a change in the magnetic circuit; Control means for controlling an excitation current of the electromagnet based on an output of a sensor unit and generating an excitation signal for stabilizing the magnetic circuit in a state where a current flowing through the electromagnet becomes zero. An exciter for exciting the electromagnet based on an excitation signal generated by the controller, wherein the integral compensator outputs the control signal by time-integrating the excitation signal with a predetermined gain. And a gain compensator that multiplies the output signal of the sensor unit by a predetermined gain and outputs the result. The output signal of the integration compensator and the output signal of the gain compensator are added or subtracted. And an arithmetic means for outputting as

(Operation) In the control for controlling the attraction force of the electromagnet to converge the excitation current of the electromagnet to zero while keeping the levitation system stable (so-called zero power control), the levitation control system is stable and the electromagnet is controlled. If the control for converging the excitation current of the excitation means to zero is performed, the excitation signal input to the excitation means also converges to zero. Conversely, if the excitation signal converges to zero, the excitation current of the electromagnet converges to zero.

On the other hand, an output signal of the stabilization control means for calculating an excitation signal for maintaining the stability of the levitation system is integrated by an integration compensator having a predetermined gain, and a deviation between the output signal of the integration compensator and the original excitation signal is obtained. Is a new excitation signal, the input to the integration compensator must converge to zero if the levitation control system is stable, so that the excitation signal can converge to zero over time.

Therefore, if such a control method is used, even if the excitation means excites the electromagnet with the current to be passed to the electromagnet based on the excitation signal, the excitation means excites the electromagnet with the voltage to be applied to the electromagnet based on the excitation signal. Even if there is, zero power control can be achieved by control means having the same configuration.

Therefore, there is no need to change the configuration of the control means in accordance with the excitation means, so that the versatility of the control means is expanded, mass production is possible, and costs can be reduced. Also,
Excitation means that excites the electromagnet with a current based on the excitation signal can be used, so that it is not necessary to increase the size of the battery even when the expected application of an external force is large or the frequency is high. Therefore, the weight of the carrier is not increased, and the entire system can be downsized and space can be saved as compared with a case where the electromagnet is excited by a voltage based on the excitation signal. Further, as the excitation means, for example, PWM
If a type inverter or the like is used, the electromagnet can be excited with a current based on the excitation signal without heating the excitation means, so that unnecessary power is not consumed. Therefore, energy saving can be achieved.

(Embodiment) Hereinafter, a floating type transport apparatus according to an embodiment of the present invention will be described with reference to the drawings.

2 to 4, reference numeral 11 denotes a track frame whose section is formed in an inverted U shape and which is laid, for example, in an office space so as to avoid obstacles. Two guide rails 12a and 12b are laid in parallel on the lower surface of the upper wall of the track frame 11. Emergency guides 13a and 13b, each having a U-shaped cross section, are laid on the inner surface of the side wall of the track frame 11 with their open sides facing each other.

Under the guide rails 12a, 12b, a transport vehicle 15 is arranged so as to be able to travel along the guide rails 12a, 12b. The stator 16 of the linear induction motor is disposed at a predetermined distance along the guide rail between the guide rails 12a and 12b on the lower surface of the upper wall of the track frame 11.

The guide rails 12a and 12b are formed by painting a flat member 21 made of a ferromagnetic material in white, and have a divided structure to facilitate installation work in an office. A predetermined joining process is applied to the joint portion A of each member 21.

Next, the configuration of the transport vehicle 15 will be described. That is, the flat base 25 is arranged so as to face the lower surfaces of the guide rails 12a and 12b. The base 25 has a connecting mechanism 27 that rotatably connects the two divided plates 26a and 26b arranged in the traveling direction and the quantity divided plates 26a and 26b in a plane orthogonal to the traveling direction.
It is composed of At the four corners of the upper surface of this base 25,
Each of the magnetic support units 31 is mounted. These magnetic support units 31 are mounted on the upper surface of the base 25 using bolts 32 and pedestals 33 as shown in FIG.
An optical gap sensor 34 for detecting a gap length between the magnetic support unit 31 and the lower surfaces of the guide rails 12a and 12b is attached to the magnetic support unit 31. In addition, each split plate 26
As shown in FIG. 4, connecting members 35a, 35b
Containers 37, 38 for accommodating articles to be conveyed are mounted via b, 36a, 36b, respectively. And these containers 37,38
A control device 41 for controlling each of the four magnetic support units 31 described above and a constant voltage generation device 42
And a small-capacity power supply 43 for supplying electric power to them, two each, a total of four. Four corners on the lower surface of the base 25 are provided for supporting the carrier 15 in the vertical direction by contacting the inner surfaces of the upper and lower walls of the emergency guides 13a and 13b when the magnetic force of the magnetic support unit 31 is lost. Vertical vehicle 45a
And four lateral wheels 45b for contacting the inner surfaces of the side walls of the emergency guides 13a and 13b to support the transport vehicle 15 in the left-right direction, respectively. Further, seven phototransistors 46 for transmitting a command from the track side to a control system mounted on the carrier 15 are mounted at predetermined positions on the upper surface of the base 25. These phototransistors 46 are arranged so as to face seven LEDs (light emitting diodes) 47 attached to the track frame at predetermined positions (stations). The base 25 also serves as a conductor plate which is an operating element of the above-described linear induction motor, and is arranged at a height facing the stator 16 with a slight gap when the apparatus is operating. I have.

As shown in FIG. 5, the magnetic support unit 31 includes two electromagnets 51 and 52 arranged in a direction perpendicular to the traveling direction of the carrier 15 so that the upper end faces the lower end of the guide rails 12a and 12b. And a permanent magnet 53 interposed between the lower side surfaces of the electromagnets 51 and 52, and has a U-shape as a whole. Each of the electromagnets 51 and 52 includes a yoke 55 formed of a ferromagnetic material and a coil 56 wound around the yoke 55, and each coil 56 is formed by the electromagnets 51 and 52. They are connected in series such that the magnetic fluxes are added to each other.

Next, in describing the configuration of the control device 41, the basic concept of this control system will be described.

First, the magnetic support unit 31 and the guide rails around it
Consider a magnetic circuit composed of 12a, 12b, gap P, yoke 55, and permanent magnet 53. For the sake of simplicity, the leakage flux in this magnetic circuit will be ignored. The magnetic resistance R _m of this magnetic circuit is Can be represented by Where μ ₀ is the magnetic permeability of vacuum,
S is the cross-sectional area of the magnetic circuit, z is the gap length, _μs is the non-magnetic permeability other than the gap portion, and l is the magnetic circuit length other than the gap portion.

Further, when the exciting current is not flowing through the coil 56, the strength of the magnetic field generated in the air gap P is H _m , the length of the permanent magnet 53 is 1 _m , the total number of turns of the coil 56 is N, and the exciting current to the coil 56 is When I, the total magnetic flux phi occurring to the magnetic circuit, phi = the _{(NI + H m l m)} / R m ... (2). Therefore, the guide rails 12a and 12b and each yoke 55
The total suction force F acting between Can be represented by Here, when the direction indicated by z is set as the direction of gravity, and the equation of motion of the transport vehicle is derived, Becomes Here, m is the load applied to the magnetic support and the total mass of the magnetic support, g is the gravitational acceleration, u _m
Is the external force applied to the carrier.

On the other hand, the number of magnetic fluxes φ linked by the coil 56 connected in series is φ
_N, since a _{φ N = (NI + H m} l m) N / R m ... (5), the voltage equation of the coil 56, the total resistance of the coil 56 R, the applied voltage E, Becomes

Here, R _m is a function of the gap length z as is apparent from the equation (1). Therefore, when I = 0, the gap length when the suction force F and the gravity mg are balanced is z ₀ , and the total magnetic resistance is R
_{Assuming m0} , the above formulas (4) and (6) are used to calculate the gap length z = z ₀ , Linearization is performed near the current I = 0. in this case, Is a small amount of each As Can be represented by

Therefore, the suction force F in the above equation (4) is Linearizing near Becomes After all, Becomes Therefore, the above equation (4) can be summarized as follows.

Similarly, the above equation (6) Linearizing near Becomes The above equations (7) and (8) can be summarized into the following state equations.

Where a ₂₁ , a ₂₃ , a ₃₂ , a ₃₃ , b ₃₁ , d ₂₁ are respectively It is. Here simply for the equation _{(9), = Ax + BE + Du m} ... it represents a (10). The linear system represented by the equation (9) is generally an unstable system, but the state vector of the equation (9) Thus, the applied voltage E is obtained by various methods, and the system is subjected to feedback control to stabilize the system, and so-called zero power control is performed to always converge the current deviation Δi to zero even when a step-like external force is applied. be able to.

Now, consider a control system that determines the applied voltage E by the following equation in the control object represented by the equation (10).

Where F ₁ , F ₂ , and F ₃ are , K _E is the integral gain of E, _er is the output value of the target value generator of E, and 0 when zero power control is performed.
It is.

Differentiating equation (11) gives At this time, If you go to equation (12), Is transformed.

By summing up the equations (10) and (14), the state equations of the entire system to which the feedback is applied can be obtained.

(15) is subjected to Laplace transform to obtain [x (s) v (s)] ^T (T represents a position). Becomes Here, II represents a 3 × 3 unit matrix, and x ₀ and v ₀ represent initial values of x and v, respectively.

The state transition matrix Φ (s) in equation (16), that is, Using u _m (s) and e _r (s) Represents Δz can be detected by a gap sensor, Is obtained by differentiating the signal of the gap sensor, and Δi can be measured by the current detector. Can be considered

Therefore, from equation (16), Where Δ ₄ (s) = s ⁴ + (− a ₃₃ + b ₃₁ F ₃ + _KE ) s ³ + (− a ₂₃ a ₃₂ + a ₂₃ b ₃₁ F ₂ −a ₂₁ −a ₃₃ K _E ) s ² + ( a ₂₃ b ₃₁ F ₁ + a ₂₁ a ₃₃ −a ₂₁ b ₃₁ F ₃ −a ₂₃ a ₃₂ K _E −a ₂₁ K _E ) s + a ₂₁ a ₃₃ K _E Y = s ³ + (− a ₃₃ + b ₃₁ F ₃ ) s ² + - a _{(a 23 a 32 + a 32} b 31 F 2 -a 21) s + a 23 b 31 F 1 + a 21 a 33 -a 21 b 31 F 3.

here, Is obtained by Δ ₄ (s) = 0. Accordingly, by appropriately determining the values of the _{F 1, F 2, F 3} , K E, Are arranged on the left half surface of the complex plane to stabilize the magnetic levitation system.

FIG. 6 is a block diagram of a magnetic levitation control system when such control is performed on the magnetic support unit. In the figure, The, C ₁ is the control target, C ₂ is the gain compensator, C ₃ is the integral compensator, C ₄ respectively represent a target value generator.

The system of FIG. 6 is stabilized, and if e _r = 0, from equation (17), the response of Δi to the external force u _m is: Is required. If f ₀ is the magnitude of the step-like external force, From equation (19), Becomes This equation (20) is Since it is intended to ensure, after all, the steady-state deviation of the current or without the external force u _m converges to zero. Therefore, (11)
If the applied voltage E is determined by the equation, zero power control can be achieved.

The system of the expression (9) is established when the excitation current I of the coil 56 is controlled by the applied voltage E as in the case of exciting the coil 56 using a power operational amplifier or the like.

Next, using a current control device (for example, a PWM type inverter) capable of exciting the coil 56 with a current that instantaneously follows the current command value, even when magnetic levitation is performed, the excitation signal is obtained in the same manner as in equation (11). Is described, zero power control is achieved.

When performing the magnetic levitation control with the exciting current Ie that matches the current command value, the voltage equation of the equation (6) is omitted. Therefore, the control target of the equation (9) can be expressed as follows.

Here, for the sake of simplicity, Equation (21) It expresses.

Now, the exciting current Ie in the control object represented by the equation (22) is determined by the following equation.

Here, ir is the output value of the target value generator for Ie, and is 0 during zero power control. F ₁ ′ and F ₂ ′ are , K _E ′ is the integral gain of Ie.

Differentiating equation (23), similar to equation (11), Then, equation (23) becomes Becomes However, It is.

Summarizing equations (22) and (25), the state equation of the whole system to which feedback is applied can be expressed as follows.

(26) Laplace transform of the equation, And ask for Becomes Where II ′ is a 2 × 2 unit matrix, Is the initial value of.

(27) State transition matrix That is, For u _m (s) and i _r (s) Denoting the transfer function G '(s), P' (s) Therefore, these are However ^{_{Δ 3 (s) = s 3}} + (K E '+ a 23 F 2') s 2 + (- a 21 + a 23 F 1 ') s -a 21 K E' H = s 2 + a 23 F 2 's −a ₂₁ + a ₂₃ F ₁ ′.

here, Is obtained by Δ ₃ (s) = 0. Therefore, by appropriately determining the values of F ₁ ′, F ₂ ′, and K _E ′,
Stabilization of the magnetic levitation system can be achieved. FIG. 7 shows a block diagram of the magnetic levitation control system in this case. In addition,
In the figure, y 'represents c'x'.

Stabilization of the system of Figure 7 is achieved, if i _r = 0, the transfer function of v 'with respect to an external force u _m from (28) In the frequency domain, s is replaced by jω, It is expressed as If the step response of the external force u _m in size f ₀ gain of t → v in ∞ '/ u _m is by substituting omega = 0 in (30), And v ′ is It converges to.

Similarly, when the convergence value of Δz, Δz at → ∞ is obtained, Becomes

Then, substituting equations (31) to (33) into equation (24),
When Ie at t → ∞ is obtained, And Ie = 0. Therefore, the coil in equation (23)
By controlling the exciting current flowing through 56, the exciting current converges to zero from t → ∞, and zero power control is achieved.

Further, t → ∞ of x (s) and x ′ (s) for e _r and i _r
When the convergence value at is calculated in the same manner, from equations (18) and (29), Becomes

However, a _{L = a 23 b 31 F 1} + a 21 a 33 -a 21 b 31 F 3.

Therefore, from Eqs. (13) and (24), E and Ie are given by E =
e _r, Ie = i _r, and the match each target value.

Therefore, when the transport vehicle has emerged with zero power control _{(e r, i r = 0} ), e r, if ask gradually changing the i _r, excitation signal coincides with the target value is given, levitation gap The length can be changed.

Based on the above points, FIG. 1 shows an electrical configuration of the present device centering on the control device 41. The controller 41 is attached to the carrier 15 and detects a magnetomotive force, a magnetic resistance or a change in the movement of the carrier 15 in a magnetic circuit formed by the magnetic support unit 31. And a power amplifier 63 as excitation means for applying a voltage to the coil 56 based on an excitation signal from the arithmetic circuit 62. It is composed of

Power from the power supply 43 is supplied to the power amplifier 63 via the main switch 64 and the switch 65. The arithmetic circuit 62 and the sensor unit 61 are supplied with power from the power supply 43 via the main switch 64, the constant voltage generator 42, and the switch 66. The constant voltage generator 42 includes a reference voltage generator 42a and a current amplifier 42b, and outputs a constant voltage. The constant voltage from the constant voltage generator 42 is also supplied to the starting device 67. The output of the starting device 67 is given to the switches 65 and 66 and the arithmetic circuit 62 as a command signal.

The sensor unit 61 includes a modulation circuit 68 that modulates a signal of the optical gap sensor 34 to suppress the influence of external noise, and a coil.
A current for detecting a current value of 56 and a detector 69 are provided.

The arithmetic circuit 62 implements the feedback system shown in FIG. 6 when floating at zero power. First, the target value generator 70
And the gap length detected by the optical gap sensor 34 are subtracted by the subtractor 71. Subtractor
The output of 71 is input to the feedback gain compensators 73 and 74 directly and via the differentiator 72. Further, the current detection signal from the current detector 69 is input to the feedback gain compensator 75. Compensation outputs from these feedback gain compensators 73 to 75 are added by an adder 76 and provided as one input of a subtractor 77. The output signal of the subtractor 77, that is, the excitation signal of the coil 56, is compared with the excitation voltage target value (“0” in the zero power control state) from the target value generator 79 in the subtractor 78, and the result is switched. The signal is input to the integration compensator 81 via 80, is subjected to integration compensation, and is provided as the other input of the subtractor 77.
Then, the output of the subtracter 77 is used for adjusting the output voltage of the power amplifier 63 again. As a result, a zero power feedback loop L composed of the subtractor 77 → the subtractor 78 → the integral compensator 81 is formed.

The switch 80 is for selectively stopping the function of the integration compensator 81 based on a command from the activation device 67. Specifically, as shown in FIG. 8, the switch 80 short-circuits the capacitor C connected between the input and output of the operational amplifier 82 constituting the integration compensator 81 by the output from the starting device 67. Is configured. With this configuration, the gain K _E = −1 / RC of the integral compensator 81 becomes 0 according to the output of the starting device 67, so that the output of the operational amplifier 82 also becomes 0.

The target value generators 70 and 79 also sequentially change their target values based on the output of the activation device 67. These target value generators 70 and 79 correspond to FIGS. 9 (a) and 9 (b), respectively.
It is configured as shown in FIG. That is, the operational amplifier 8
3, 84, resistors Ra and Rb, capacitors Ca and Cb, between the input and output of the filter constituting the first-order lag system is provided with switches 85 and 86 that open and close according to the output from the starter 67, and a predetermined input By setting the values V ₁₀ , V _ΔZ0 , and V _ZD and then _turning the switches 85 and 86 from the closed state to the open state, a target value that gradually changes from a predetermined value to another value can be generated.

On the other hand, the activation device 67, for example, as shown in FIG.
It comprises an external command converter 91 and a switch operation device 92. The external command converter 91 includes a lighting device 93 that drives the seven LEDs 47 mounted on the start frame 11 based on an external command, the LED 47 mounted on the start frame 11, and the LED 47 facing the station unit. And a voltage generator 94 for outputting a binary voltage based on the outputs of the central five phototransistors 46 among the outputs of the phototransistors 46. It is composed of Further, the switch operation unit 92 controls each pit of the 5-bit output from the external command converter 91 to correspond to each open / close state of the switches 65, 66, 80, 85 and 86, and controls the open / close state of these switches. The remaining two phototransistors arranged on both sides
The output of 46 detects whether or not the LED 47 and the phototransistor 46 are correctly opposed to each other. Only when the two phototransistors 46 simultaneously receive light from the LED 47, the output from the track side to the carrier side is changed. An external command is transmitted. For this reason, it is possible to prevent erroneous transmission of an external command caused by the carrier not stopping at the correct position.

Next, the operation of the thus configured floating type transport apparatus according to the present embodiment will be described.

In the present embodiment, when the apparatus is in a stopped state, the vertical wheels 45a of the transport vehicle 15 are driven by the emergency guide 1 by the attractive force of the permanent magnet 53.
Switches 65 and 6 are in contact with the upper surface of the inner wall of 3a (13b).
6 is open and the switches 80, 85, 86 are closed.

In this state, when the main switch 64 is turned on, the starting device 67 is started via the constant voltage generating device 42, and a command is sent to close the switch 66. Then, the control device 41 starts to start.

Then close the switch 65, and outputs a command to the switch 86 opens, so that gradually the control to increase until Z ₀ the target value Z _D in a state of stopping the operation of the zero power feedback loop L is performed. As a result, the control device 41
Is an electromagnet that generates a magnetic flux in the opposite direction to the magnetic flux generated by the permanent magnet 53.
Generated by 51, 52, magnetic support unit 31 and guide rail 1
The current flowing through the exciting coil 56 is controlled so as to generate a predetermined gap length between the exciting coil 2a and 12b. Thereby, as shown in FIG. 5, the permanent magnet 53, the yoke 55, the gap P, and the guide rail
A magnetic circuit consisting of the path of 12a, (12b), the gap P, the yoke 55, and the permanent magnet 53 is formed, and the carrier starts to float slowly.

At this time, when an external command such as opening the switch 80 is output, the zero power feedback loop L starts to operate, and the magnetic circuit is operated by the electromagnets 51 and 52 in a steady state where no external force is applied to the carrier 15. A predetermined gap length z ₀ is set so as to have a magnetic attractive force that does not require any magnetic flux.
Keep.

Here, when the external force u _m is applied, and sends a detection signal to the arithmetic circuit 62 via the modulation circuit 68 the gap sensor 34 detects this. The arithmetic circuit 62 calculates a gap length deviation signal Δz by subtracting the gap length target value z ₀ from the signal by the subtractor 71. The gap length deviation signal Δz is input to the feedback gain compensator 73 and, after being converted into the velocity deviation signal Δz by the differentiator 72, is input to the feedback gain compensator 74. On the other hand, the current deviation signal Δi is
Obtained by the measurement signal of the current detector 69 and input to the feedback gain compensator 75. Also, the excitation voltage signal E
Is compared with a zero level which is the output of the target value generator 79 by a subtractor 78, and the difference signal is input to an integration compensator 81. The output signals of the three feedback gain compensators 73 to 75 added by the adder 76 and the integration compensator
The 81 signal is given a predetermined gain and fed back to the power amplifier 63. Thus, in the system,
The control shown in FIG. 6 is performed, and the current deviation Δi is stabilized in a state where it becomes zero.

Now, assuming that the carrier 15 is directly below the stator 16 of the linear induction motor, when the stator 16 is energized, the base 25 receives electromagnetic force from the stator 16, so that the carrier 15 is in a magnetic levitation state. The vehicle starts traveling along the guide rails 12a and 12b.
If the stator 16 is disposed again until the transport vehicle 15 completely stops due to the influence of air resistance or the like, the transport vehicle 15 is re-energized and continues to move along the guide rails 12a and 12b.
This movement continues to the destination. Thus,
The carrier 15 can be moved to the destination in a non-contact state.

When an external command to open the switch 85 is given to the transport vehicle 15 that has reached the destination point (testion) in this way, the output of the target value generator 79 gradually changes from zero level to a predetermined value, and the gap length Z decreases. Eventually, the vertical wheel 45a of the transport vehicle 15 comes into contact with the upper surface of the inner wall of the emergency guide 13a (13b). At this time, when a command to open the switch 65 and close the switches 80, 85, and 86 is issued, power transmission to the electromagnets 51 and 52 is stopped, and the carrier
15 is fixed to the emergency guide 13a (13b) by suction, and the operation of the zero power feedback loop L and the internal states of the target value generators 70 and 79 are reset in preparation for the next floating. Thereafter, if it is necessary to start the transport vehicle 15 toward another destination, a command to close the switch 65 and open the switch 86 may be issued, and the above procedure may be repeated.

On the other hand, when the transport vehicle 15 is to be suction-fixed at the mounting point for a long time, the switch 66 may be opened by an external command to save the power consumed by the control device 41. If the main switch 64 is subsequently opened, the operation of the apparatus can be completely stopped.

In addition, instead of the power amplifier 63, as shown in FIG.
When the inverter 96 is used as a means for exciting a current to flow through the coil 56 based on the excitation signal from the arithmetic circuit 62, the gain compensator 7
3, 74, 75, and each gain of the integral compensator 81 is F ₁ = F ₁ ′, F ₂ =
By simply resetting F ₂ ′, F ₃ = 0, and K _E = K _E ′, the same levitation control as when the power amplifier 63 is used can be performed without any change in the configuration.

In the example shown in FIG. 11, a DC-DC converter 97 for boosting the output voltage of the power supply 43 is connected, and its output terminal is connected to the inverter device 96. Power amplifier 63
Requires a power supply voltage that is about 10 to 20% higher than the maximum output voltage, whereas the inverter device 96 requires a power supply voltage required to supply the maximum exciting current to the coil 56. With such a configuration, there is an advantage that the voltage of the power supply 43 can be set low. In addition, in this example, DC-DC
Converter 97 raises the voltage of power supply 43 and supplies it to constant voltage generator 42 and inverter 96, so that the power supply voltage may be even lower. As a result, the capacity of the power supply can be reduced, and space can be saved. Further, in the power amplifier, the power amplifier is heated in proportion to the product of the difference between the output voltage and the power supply voltage and the exciting current. In this example, however, the power amplifier is not heated and energy can be saved.

The present invention is not limited to the embodiments described above. For example, in the above-described embodiment, the gain is reset when the power amplifier 63 and the inverter device 96 are exchanged, but this is achieved by selectively switching the switches 101 to 104 as shown in FIG. It can be set and there is no problem. In the above embodiment, an analog control device is used, but this may be a digital control device. In short, an integral compensator that performs time integration of the excitation signal with a predetermined gain and outputs the same, a gain compensator that multiplies the output signal of the sensor unit by a predetermined gain and outputs the output signal, an output signal of the integration compensator and gain compensation Any control device including an arithmetic unit that subtracts or adds the output signal of the unit and outputs the operation result as an excitation signal may be any of an analog system and a digital system. In addition, various changes can be made without departing from the scope of the present invention.

[Effects of the Invention] As described above, according to the present invention, a control device having the same configuration can be used regardless of the coil excitation method, so that the versatility of the device can be expanded. Further, since mass production becomes possible with the expansion of versatility, the cost of the apparatus can be reduced. In addition, since an inverter can be used as the excitation means, the power supply voltage can be reduced, a smaller battery can be used, and space can be saved. in addition,
Power consumption due to resistance loss of the excitation means can be suppressed, and energy saving can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control device incorporated in a levitation type transport device according to an embodiment of the present invention and an electric configuration around it, and FIG. 2 shows a configuration of the levitation type transport device according to the example. FIG. 3 is a perspective view, FIG. 3 is a longitudinal sectional view of the device, FIG. 4 is a side view in which the device is partially cut away, FIG. 5 is a cross-sectional view for explaining a magnetic circuit of the device, FIGS. FIG. 7 is a block diagram showing a levitation control system of the above embodiment, FIG. 8 is a circuit diagram showing an integral compensator and its periphery in the control device, and FIG. 9 is a diagram showing a target value generator and its periphery in the control device. FIG. 10 is a block diagram showing an electrical configuration of a starting device in the transfer device, and FIGS. 11 and 12 are block diagrams showing modified examples of the control device. 11… track frame, 12a, 12b… guide rail, 13a, 13b…
Emergency guide, 15… Carrier, 16… Stator of linear induction motor, 25… Base, 27… Connecting mechanism, 31… Magnetic support unit, 34… Gap sensor, 41… Control device ,
42 ... constant voltage generator, 43 ... power supply, 46 ... phototransistor, 47 ... LED, 51, 52 ... electromagnet, 53 ... permanent magnet, 55 ... yoke, 56 ... coil, 63 ... …Power Amplifier,
69 …… Activator, 70,79 …… Target value generator, 73-75 ……
Gain compensator 96 Inverter 97 DC-DC converter

Claims (7)

(57) [Claims] 1. A guide rail having at least a lower surface portion formed of a ferromagnetic material, a transport vehicle arranged to run along the guide rail, and facing a lower surface of the guide rail via a gap. An electromagnet arranged, and a permanent magnet interposed in a magnetic circuit formed by the electromagnet, the guide rail and the gap, and supplying a magnetomotive force necessary to levitate the carrier, and mounted on the carrier. One or more magnetic support units, a sensor unit attached to the carrier and detecting a change in the magnetic circuit, and controlling the exciting current of the electromagnet based on the output of the sensor unit to the electromagnet. Control means for generating an excitation signal for stabilizing the magnetic circuit in a state where the flowing current is zero, and an excitation hand for exciting the electromagnet based on the excitation signal generated by the control means Wherein the control means multiplies the output signal of the sensor section by a predetermined gain and outputs the integrated signal, and an integration compensator for time-integrating and outputting the excitation signal with a predetermined gain. A floating compensator comprising: a gain compensator; and a subtraction unit that adds or subtracts an output signal of the integration compensator and an output signal of the gain compensator, and outputs the result as the excitation signal. apparatus. 2. The control means according to claim 1, wherein said control means outputs a deviation between said excitation signal and a predetermined target value, and an integral compensator outputs a signal obtained by integrating the output signal of said deviation calculation means with a predetermined gain. The levitation transfer device according to claim 1, further comprising: 3. The levitation type transport apparatus according to claim 1, wherein said exciting means is a device for exciting said electromagnet with a current to be passed through said electromagnet based on said excitation signal. 4. The levitation type transport apparatus according to claim 1, wherein said excitation means excites said electromagnet with a voltage to be applied to said electromagnet based on said excitation signal. 5. The levitation transfer apparatus according to claim 1, wherein said excitation means is an inverter supplied with a power required for exciting said electromagnet from a DC power supply. 6. The floating carrier according to claim 1, wherein said exciting means is supplied with electric power required for exciting said electromagnet from a DC power supply via a voltage converter. 7. The levitation type transport apparatus according to claim 1, wherein the control means includes a switch for switching a gain value of the gain compensator or a gain value of the integral compensator to another value. .