JPH0646511A - Stop positioning mechanism for noncontact levitation transfer system - Google Patents

Abstract

PURPOSE:To prevent adhesion by operating an analog switch to bring power-up input to zero when a value, obtained by differentially amplifying and detecting outputs from displacement sensors of a carrier in the moving direction and perpendicular direction thereto, exceeds a preset level representing adhesion phenomenon. CONSTITUTION:Differential output between displacement sensors 15, 16 in X and Y directions is amplified through a differential amplifier 26. It is then inputted to a detector 27 and compared with a preset signal level representing adhesion phenomenon. When the differential signal between the sensors 15, 16 exceeds the set level, an analog switch operation signal shaper 28 outputs an operation signal for grounding each analog switch 22. Consequently, each power-up 23 input signal goes zero thus interrupting current supply to brake coils X1, X2 and Y1, Y2. This constitution realizes a stabilized electromagentic brake system in which adhesion phenomenon is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stop positioning mechanism for a non-contact floating transportation apparatus.

[0002]

2. Description of the Related Art In a contact type transport device, an electromagnet consisting of a coil and a magnetic material yoke and a magnetic material target are used in a stop positioning mechanism, and the stop positioning force is caused by a magnetic centripetal force acting between the electromagnet yoke and the target. As an example of the mechanism to be performed, a stepping motor system as disclosed in JP-A-61-81104 is proposed. In the case of this mechanism, the suction force acts in the direction of increasing the contact friction of the bearing of the carrier, so that the carrier device as a whole works in a good direction and function. Also, JP-A-61-81
The proposal disclosed in Japanese Patent Laid-Open No. 105 is also disclosed in the above-mentioned Japanese Patent Laid-Open No. 61-811.
It has the same effect as the 04 publication. As described above, in the contact type, the attraction force of the device similar to the electromagnet brake device to be attracted acts in the direction of stabilizing the transfer device, and thus no problem occurs.

On the other hand, in the non-contact type conveying device, when the system proposed in Japanese Patent Application No. 2-329772 and Japanese Patent Application No. 2-401369 is carried out by open control, the contact type conveying device uses a bearing as a damping force. It is stationary because the frictional force with the rail is effective, but when it is applied to a transfer device that uses magnetic force as a non-contact transfer method, spring force is generated due to magnetic centripetal force, but the damping force decreases, so it is 10 times to 20 times.
Double (30 to 60 seconds) down time is required. Further, in this type, if too much current is applied, the load of another electromagnet (guide electromagnet) that originally stabilizes the attraction force (unstable rigidity) in the electromagnetic brake device will be too large and will be attracted. Therefore, it is not possible to increase the stopping rigidity (holding rigidity) by increasing the current value unnecessarily. Therefore, if the tip of the magnetic pole is narrowed down in order to reduce the attraction force and increase the stopping rigidity, a tentative effect was recognized, but this is not a fundamental measure.

Next, as a proposal for promptly stopping in a non-contact state, "Stable and repeatable accuracy is obtained with the mechanism shown in FIG. 13 of linear motor and control technology, mechanical design, Vol. 34, No. 17, 1990. In addition, a similar type of proposal has been made for the conveying device disclosed in Japanese Patent Laid-Open No. 1-103848.
In these proposals, the action of suction force is not a problem. However, it is reported that the device of the above publication has a very weak holding force and has no practical ability. It seems that the reason is that the tip of the magnetic pole is not squeezed into a thin state and that no appropriate countermeasure is taken against the generation of the attraction force.

On the other hand, Japanese Patent Application No. 2-
No. 329772 magnetic pole type and Japanese Patent Application No. 3-213292
The electromagnetic transfer device and the electromagnetic brake device disclosed in Japanese Patent Application No. 3-265952 can be stopped immediately.
However, when the control gain is increased, the adsorption phenomenon occurs. This problem can be solved by adjusting the degree of narrowing down the tip of the magnetic pole and adjusting the ability of another actuator that compensates for the phenomenon due to the attraction force to stabilize the entire conveying device.

[0006]

However, at the present time,
There is a demand for reducing the number of actuators in the direction of energy saving and cost reduction.

On the other hand, the present applicant has filed Japanese Patent Application No. 3-3217.
In No. 28, we proposed a technology to minimize the number of actuators. In the arrangement according to the technique, the electromagnetic braking device is below the carrier. Therefore, the attraction force in question is a load on the control electromagnet, but is compensated. However, there is no method of compensating for the adsorption phenomenon when the electromagnetic broom device is arranged between the control electromagnets above the carrier table, that is, where the linear motor is present.
At present, there is a levitation control sensor below, and it is considered preferable to use an aluminum material as the sensor target in terms of sensor sensitivity and weight reduction of the carrier. Considering that the degree of freedom of the transfer device can be increased (planar transfer), the lower surface of the transfer table can be made of a good non-magnetic conductor without using a magnetic material, and the sensor and linear motor can be placed below. Considered desirable. However, it is necessary to have a degree of freedom with respect to the mounting position of the electromagnetic brake device.

FIG. 12 shows a structure in which the attraction phenomenon caused by the electromagnetic brake device embodying the present invention is particularly problematic. For example, when the attractive force of magnetic force is used, the electromagnets 41, 41 are located above the carrier 40. Further, when utilizing the electromagnetic induction phenomenon, the actuator is located below the carrier table 40. Further, when the static pressure of gas or liquid is used, the air pocket is the carrier table 40.
Will be located below. All of these are for supporting the own weight of the carrier 40. When the electromagnetic brake device is applied to these devices, the attraction force (Fz and Fx in FIG. 13 are magnetic centripetal forces) becomes a problem when installed above the carrier 40. In the figure, reference numeral 42 is a magnetic pole, and 42 is
Reference symbol a is its tip, 43 is a coil, 44 is a target magnetic pole, 45 is a position detection sensor, and 46 is a sensor target.

It is an object of the present invention to provide a stop positioning mechanism in a non-contact levitation transfer device which is equipped with a self-compensation mechanism for a suction phenomenon caused by an electromagnetic brake device for stop positioning.

[0010]

According to the present invention, the carrier of a non-contact levitation carrier which supports a carrier on which a carrier is mounted in a non-contact state is provided with an electromagnet composed of a coil and a magnetic material yoke, and a magnet. In a stop positioning mechanism of a non-contact levitation transporting device, which uses a material target and a positioning force is a magnetic centripetal force acting between the electromagnet and the target, the stop positioning mechanism is provided with a suction preventing control circuit.

Further, according to the present invention, the adsorption prevention control circuit presets the operation amplifier for detecting the signals from the carrier moving direction sensor and the carrier moving orthogonal direction sensor, and the signal from the amplifier. A detector that compares the signal value recognized as a certain adsorption phenomenon, and an analog switch that operates the analog switch in the preceding stage of the power amplifier for the coil to set the power amplifier input signal to zero when the signal exceeds the signal value. And an operation signal shaper.

Further, according to the present invention, the adsorption prevention control circuit includes a signal processor for detecting the amount of lift of the carrier based on signals from at least three levitation control sensors, and the signal processor detects the detection signal. Connected to the vessel.

Further, according to the present invention, the suction preventing control circuit presets an operation amplifier for detecting signals from the carrier moving direction sensor and the carrier moving orthogonal direction sensor, and a signal from the amplifier. From a detector that compares a signal value recognized as a certain adsorption phenomenon, and a control signal of a coil control circuit and a DC voltage supply device through a gain adjuster by adjusting the phase of an analog signal when the signal exceeds the signal value. And a signal processing device for interrupting the power amplifier input signal to zero with respect to the ground.

Further, according to the present invention, the adsorption prevention control circuit includes a signal processor for detecting the amount of ascent of the carrier table based on signals from at least three levitation control sensors, and the signal processor detects the detection signal. Connected to the vessel.

Further, according to the present invention, the carrier has an adsorption prevention circuit having a switch for making the current supplied to the coil zero based on the information indicating that the adsorption phenomenon has occurred.

[0016]

In the stop / positioning mechanism of the non-contact levitation transport device configured as described above, the adsorption prevention control device operates the analog switch when the differential amplification value of both sensors exceeds the set signal value. Power amplifier input voltage to zero and coil current to zero to prevent adsorption.

When the differential amplification value of both sensors exceeds the set signal value, the values are phase-processed and the gain is adjusted so that the input voltage of the power amplifier becomes zero, and the coil current becomes zero. To prevent adsorption.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the x-axis represents the transport direction, that is, the moving direction of the transport platform (hereinafter referred to as a cart) 1, the y-axis represents the guide direction, and the z-axis represents the levitation direction. On the upper and lower surfaces of the cart 1, a plate-shaped upper surface nonmagnetic good conductor 2 and lower surface nonmagnetic good conductor 4 are provided, respectively. The good conductor 2 is formed with a taper surface x-direction displacement sensor target surface 3, and the good conductor 4 is formed with a taper surface y.
A directional displacement sensor target 5 is formed. Also,
On both upper surfaces of the cart 1 in the x-axis direction, levitation control electromagnet targets 6, 6 are provided separately from the center. Then, on both upper surfaces of the cart 1 in the y-axis direction, the electromagnetic brake device target portions 7a, 7a are separated from the center.
a is provided.

On the other hand, on the lower surface of the track, that is, the stop position S of the stator 10, the levitation control electromagnets 11, 11 are provided at positions facing the levitation control electromagnet targets 6, 6, and below the stop position S, Ascent control sensors 12, 1
2 is provided close to the lower surface of the cart 1.

Referring also to FIGS. 3 and 4, on the lower surface of the stop position S of the stator 10, a pair of electromagnetic brake device x-axis electromagnetic portion 13 and electromagnetic brake device y-axis electromagnetic portion 14 are respectively distributed from the stop position S. And are suspended. The magnetic poles of the electromagnet portions 13 and 14 are formed in a downward C shape, and the brake coils X1 and X2 and the brake coils Y1 and Y2 are wound around them. Both of the magnetic pole lower end portions 13a and 13b of the x-axis electromagnetic portion 13 are tapered in the y-axis direction (for example, the tip end portion has a thickness of 0.3 to 1 mm). These lower end portions 13a and 13b are formed in the median direction in the y-axis direction with respect to the electromagnetic brake device targets 7a and 7b, and are formed in the x-axis direction at a distance slightly narrower than the distance between the targets 7a and 7b. At the stop position S of the stator 10, the brake x-direction displacement sensor 15 is hung so as to be close to the upper surface of the cart 1, and at the stop position S, the brake y-direction displacement sensor 16 is provided.
Is provided close to the lower surface of the.

With such a configuration, the cart 1 detects the state by the levitation control sensor 5, the signal is processed by a control device (not shown), the control current is supplied to the levitation control electromagnet 11, and the levitation control electromagnet target 6 is supplied. Stable levitation is controlled by the magnetic attraction force that acts between and. Then, the suction prevention control circuit C, which will be described later, of the electromagnetic brake device, each brake coil X1, X according to the outputs of the brake x-direction displacement sensor 15 and the brake y-direction displacement sensor 16.
A control current is output to 2, Y1 and Y2.

FIG. 5 shows the adsorption prevention control circuit C. A sensor amplifier 17, an offset adjuster 18, a compensating circuit 19 and a gain adjuster 20 are provided in series in the circuit L1 connected to the brake x-direction displacement sensor 15. This circuit L1 includes two circuits L2 and L3.
And the circuit L2 is connected to the brake coil X1 via the rectifier 21, the analog switch 22, and the power amplifier 23.
It is connected to the. On the other hand, the circuit L3 is connected to the brake coil X2 via the inverter 24, the rectifier 21, the analog switch 22, and the power amplifier 23. Further, a DC voltage supply device 25 is connected between the rectifier 21 and the analog switch 22.

On the other hand, circuits L4, L5 and L connecting the brake y-direction sensor 16 to the brake coils Y1 and Y2.
6 has the same configuration as the circuits L1, L2 and L3. The differential amplifier 26 is connected between the offset adjuster 18 of the circuits L1 and L4 and the compensation circuit 19 by the circuits L7 and L8. The differential amplifier 26 is connected to all the analog switches 22 by a circuit L9 and a circuit L10 including an inverter, that is, a waveform converter 29 via a detector 27 and an analog switch operation signal shaper 28. As is well known, the waveform converter 29 inverts the pulse signal and removes noise and the like. One of the analog switches 22 is a control line of an ordinary electromagnetic brake device, and the other is a power amplifier input signal to the ground. It is grounded to zero (V).

Next, the control mode will be described.

In FIG. 5, the adsorption prevention control circuit C is
The signals from the x-direction displacement sensor 15 and the y-direction displacement sensor 16 are detected by the differential amplifier 26, and compared with a signal value which is set in advance by the wave detector 27 and is recognized as an adsorption phenomenon. When the sensor signal exceeds the signal value, that is, when the adsorption phenomenon is detected, the analog switch operation signal shaper 2
The operation signal is output from 8 and each analog switch 22 is activated to ground and the power amplifier input signal is zero (V).
Then, the supply current to each of the brake coils X1, X2, Y1, and Y2 is cut to suppress the adsorption phenomenon.

FIG. 6 shows another embodiment of the present invention. The control circuit C1 for preventing adsorption is the control circuit C
Signal processor 3 in which the differential amplifier 26 of FIG.
In this example, the signal processor 30 is replaced with 0, and at least three or more levitation control sensors 12 (FIG. 2) are connected. In this embodiment, three or more levitation control sensors 12 detect the adsorption phenomenon from the amount of ascent of the cart 1, and the same control as the control circuit C is performed.

FIG. 7 shows another embodiment of the present invention. A sensor amplifier 17, a compensation circuit 18, and a gain adjuster 20 are interposed in a circuit L11 connected to the brake x-direction displacement sensor 15 of the adsorption prevention control circuit C2. Brake coil X branched from the circuit L11
1, a rectifier 21 and a power amplifier 23 are installed in the circuit L12 connected to X2, and an inverter 24, a rectifier 21, and a power amplifier 23 are installed in the circuit L13 connected to the brake coil X2. There is. Further, a DC voltage supply device 25 is connected between the rectifier 21 and the power amplifier 23. Further, circuits L14 and L1 for connecting the y-direction displacement sensor 16 for brake and the brake coils Y1 and Y2.
5 and L16 are configured similarly to the circuits L11, L12 and L13. The circuit L is provided between the offset adjuster 18 and the compensating circuit 19 of the circuits L11 and L14.
18 and L19 are connected to the differential amplifier 31.
The differential amplifier 31 uses a circuit L20 to detect a detector 32,
Via the signal processing device 33 and the gain adjuster 34, the circuit L1
2, L13, L15, and L16 are respectively connected to connection points a with the DC voltage supply device 25.

At the time of control, the adsorption prevention control circuit C2 detects the signals from the sensors 15 and 16 with the differential amplifier 31,
The detector 32 compares the signal value with the signal value recognized as the adsorption phenomenon which is set in advance. Then, when the sensor signal exceeds the set value, that is, when the adsorption phenomenon is detected, the phase of the detected analog signal is adjusted by the signal processing device 33. Next, at the connection point a via the gain adjuster 34, the control signal of the control line and the DC signal from the DC voltage supply device 25 are interrupted, and the input signal of the power amplifier 23 is set to zero (V). In addition, the signal processing system similar to the magnetic bearing performs phase lead compensation on the signal corresponding to the amount of displacement of the cart 1 ascending, thereby stabilizing the attraction force.

FIG. 8 shows another embodiment of the present invention. The adsorption prevention control circuit C3 is the control circuit C.
The differential amplifier 31 of No. 2 is replaced with a signal processor 35, and at least three or more levitation control sensors 1 are provided in the signal processor 35.
It is an example of connecting to 2. In this embodiment, the adsorption phenomenon is detected from the amount of ascent of the cart 1 by three or more levitation control sensors 12, and the same control as the control circuit C2 is performed thereafter.

To prevent adsorption, the coils X1, X2, Y
An adsorption prevention circuit suitable for temporarily shutting off the control current supplied to 1 and Y2 is shown in FIGS.
The coil in these figures is typically indicated by the reference symbol Cl. In these figures, I is an input terminal,
P indicates a power supply source. In the example of FIG. 9, the switch SW1 is provided in the circuit between the power amplifier 23 and the coil Cl. Therefore, when the switch SW1 is turned off, the coil Cl is demagnetized to prevent the adsorption phenomenon. In the example of FIG. 10, the power amplifier 29 is provided with a circuit in parallel with the coil Cl in which the switch SW2 and the resistor R are connected in series, and closing the switch SW2 prevents the current from flowing through the coil Cl. In the example of FIG. 11, the switch S is connected to the power supply circuit from the power supply source P to the power amplifier 23.
This is an example in which W3 is provided.

In each of the embodiments shown in FIGS. 9 to 11, the switches SW1, SW2 and SW3 set the control current supplied to the coil Cl to zero on the basis of the information indicating that the carrier 1 has caused the adsorption phenomenon. It is to prevent adsorption.

Any appropriate means can be used to determine the information indicating that the adsorption phenomenon has occurred. For example, an arbitrary setting signal is given before use, and there is no input exceeding the signal value. As long as the output is zero, it may be judged as adsorption when the output occurs, or the adsorption direction, that is, the gap length may decrease from the speed component (change amount) of the input signal and the direction of the variation. The adsorption prevention circuit may be activated upon judgment.

[0034]

Since the present invention is constructed as described above, it has the following effects.

It is possible to prevent the adsorption phenomenon and provide a stable electromagnetic brake device.

Further, the degree of freedom of arrangement of the electromagnetic brake device can be increased.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is an orthogonal view of FIG.

FIG. 3 is a top view illustrating the arrangement of brake coils.

FIG. 4 is an enlarged view of a circle portion in FIG.

FIG. 5 is a suction prevention control circuit diagram.

FIG. 6 is a control circuit diagram for preventing adsorption according to another embodiment of the present invention.

FIG. 7 is a control circuit diagram for adsorption prevention according to another embodiment of the present invention.

FIG. 8 is a control circuit diagram for adsorption prevention according to another embodiment of the present invention.

FIG. 9 is a diagram showing an example of a suction prevention circuit.

FIG. 10 is a diagram showing another adsorption prevention circuit.

FIG. 11 is a diagram showing another adsorption prevention circuit.

FIG. 12 is a side view showing a conventional mechanism.

FIG. 13 is an enlarged view of a circle portion in FIG.

[Explanation of symbols]

 a ... Connection points C, C1 to C3 ... Adsorption prevention control circuit Cl ... Coil F ... Suction force Fx ... Magnetic centripetal force Fz ... Suction force S ... Stop position X1, X2, Y1, Y2 ... Brake coil I ... Input terminal P ... Power supply source SW1, SW2, SW3 ... Switch R ... Resistance 1 ... Cart 2 ... Upper surface non-magnetic Good conductor 3 ... x-direction sensor target 4 ... Lower surface non-magnetic good conductor 5 ... y-direction sensor target 6 ... Levitation control electromagnet target 7a, 7b ... Electromagnetic brake device target 10 ... stator 11 ... levitation control electromagnet 12 ... levitation control sensor 13a, 13b ... electromagnetic brake device x-axis electromagnet part 14a, 14b ... electromagnetic brake device y-axis electromagnet part 15 ... For brake Directional displacement sensor 16 ... y-direction displacement sensor for brake 17 ... Sensor amplifier 18 ... Offset adjuster 19 ... Compensation circuit 20, 34 ... Gain adjuster 21 ... Rectifier 22 ... Analog switch 23 ... Power amplifier 24 ... Inverter 25 ... DC voltage supply device 26, 31 ... Differential amplifier 27, 32 ... Detector 28 ... Analog switch operation signal shaper 29 ... Waveform converter 30, 35 ... Signal processor 33 ... Signal processing device 40 ... Carrier 41 ... Electromagnet 42 ... Magnetic pole 43 ... Coil 44 ... Target magnetic pole 45 ... Position detection sensor 46 ... Sensor target

Claims (6)

[Claims] 1. A non-contact levitation transport apparatus for supporting a carrier for carrying a transported object in a non-contact state, wherein the carrier is composed of an electromagnet consisting of a coil and a magnetic material yoke, a magnetic material target, and a positioning force. Is a stop positioning mechanism for a non-contact levitation transfer device that is performed by a magnetic centripetal force acting between the electromagnet and the target, and the stop positioning mechanism is provided with a suction prevention control circuit. mechanism. 2. The suction preventing control circuit recognizes an operation amplifier for detecting signals from a carrier moving direction sensor and a carrier moving orthogonal direction sensor, and a signal from the amplifier as a preset suction phenomenon. A detector that compares the signal value with an analog switch operation signal shaper that operates the analog switch in the preceding stage of the power amplifier for the coil to make the power amplifier input signal zero with respect to the ground when the signal exceeds the signal value. The stop positioning mechanism in the non-contact floating transportation apparatus according to claim 1, further comprising: 3. The adsorption prevention control circuit comprises a signal processor for detecting the amount of lift of the carrier based on signals from at least three levitation control sensors, the signal processor being connected to the detector. The stop positioning mechanism in the non-contact floating transportation apparatus according to claim 2, wherein: 4. The suction preventing control circuit recognizes an operation amplifier for detecting signals from a carrier moving direction sensor and a carrier moving orthogonal direction sensor, and a signal from the amplifier as a preset suction phenomenon. The detector for comparing the signal value and the control signal of the coil control circuit and the DC signal from the DC voltage supplier via the gain adjuster by adjusting the phase of the analog signal when the signal exceeds the signal value. 2. A stop positioning mechanism in a non-contact floating transportation apparatus according to claim 1, further comprising: a signal processing device that interrupts the power amplifier input signal with respect to the ground when it is added. 5. The adsorption prevention control circuit includes a signal processor that detects the amount of lift of the carrier based on signals from at least three levitation control sensors, and the signal processor is connected to the detector. The stop positioning mechanism in the non-contact floating transportation apparatus according to claim 4, wherein 6. The non-contact type according to claim 1, wherein the carrier has an adsorption prevention circuit having a switch for making the current supplied to the coil zero based on information indicating that the adsorption phenomenon has occurred. Stop positioning mechanism in the levitating transfer device.