JPH0646510A - Magnetic levitation transfer system - Google Patents

Abstract

PURPOSE:To realize stabilized traveling by a constitution wherein signals from thrust signal transmitters, disposed at a predetermined interval on a track for magnetic levitation carrier, are received by the carrier where magnetic attracting force generated at the time of acceleration/deceleration of a linear motor and corresponding gap are calculated and delivered to a target function generator. CONSTITUTION:Thrust signal transmitters 12, 13 are disposed at a predetermined interval along a magnetic rail 10. Before the stator 11 of a linear motor acts on the secondary conductor 17 of a carrier 14, a receiver 18 in the carrier 14 receives a thrust signal from the transmitter 12 and delivers the thrust signal to a parameter setter 21. The setter 21 calculates attracting force acting normal to the secondary conductor 17 and a gap corresponding to the attracting force causing no disturbance in the levitation control of the carrier 14, and the calculation results are delivered to a target function generator 22. Before the stator 11 acts on the secondary conductor 17, the function generator 22 switches a normal gap set in a levitation control circuit 20 to an attracting force corresponding gap through slow down. This constitution protect an object to be transferred against impact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic levitation transport device. More specifically, the present invention relates to a magnetic levitation transfer device that enables a transfer trolley to maintain stable levitation even when a linear motor for propelling the transfer trolley is operated.

In recent years, as a dust-free mechanism in a semiconductor manufacturing process, a magnetic levitation transfer device which levitates along a rail track during wafer transfer has been provided. The generated magnetic attraction force is a cause of disturbing the levitation control. Therefore, it is necessary to develop a control method that does not disturb the levitation and realize stable levitation.

[0003]

2. Description of the Related Art FIG. 7 shows a conventional magnetic levitation transport device.
This is composed of a rail 1 made of a magnetic material suspended from the ceiling and a carriage 2 that floats on the rail 1 by a magnetic attraction force. The carriage 2 has a levitation magnet 3 and a levitation magnet. Gap sensor 4 for detecting the gap between rail 3 and rail 1
And are provided to keep the gap (flying height) constant. In order to drive the carriage 2 for propulsion, a rail 5 is provided with a stator 5 of a linear motor.
Is provided with a secondary conductor 6 of a linear motor.

[0004]

In the conventional magnetic levitation transport apparatus described above, the levitation gap of the carriage 2 maintains a set gap (constant value) regardless of whether or not the linear motor acts. Therefore, the carriage 2 is vertically attracted to the stator 5 side of the linear motor due to the magnetic attraction force generated when the linear motor operates. As a result, the levitation gap deviates from the set gap, leaving a problem that the levitation control is disturbed. Therefore, the magnetic attraction force during the operation of the linear motor acts as a disturbance of the levitation control, and as a result, the set gap shifts, the power consumption of the levitation electromagnet increases, and levitation tends to oscillate. There was a problem such as giving a shock to the transported object).

The present invention is intended to realize a magnetic levitation transfer device which can maintain a stable levitation of a bogie even when a linear motor for propelling the bogie is operated.

[0006]

In the magnetic levitation transport apparatus of the present invention, a levitation electromagnet 15 that generates an attractive force to the magnetic rail 10, and a gap sensor 16 that detects a gap between the rail surface and the levitation electromagnet 15. A magnetic levitation transportation vehicle 14 having a levitation control circuit 20 that calculates a control amount for the transportation vehicle 14 to maintain a constant set gap based on the output from the gap sensor 16 and supplies an appropriate current to the levitation electromagnet 15.
And a magnetic levitation transport apparatus including a magnetic rail 10 provided with a stator 11 of a one-sided linear motor, a thrust signal transmitter 12, 13 is provided on the rail side, and a thrust signal transmitter 12, 13 is provided on the transport carriage 14. The thrust signal receivers 18 and 19 capable of receiving the thrust signal transmitted from the motor, and the magnetic attraction force generated during acceleration / deceleration of the linear motor and the stable levitation can be maintained by connecting to the thrust signal receivers. The parameter setting device 21 having the function of calculating the suction force corresponding gap, the function of supplying the calculated suction force corresponding gap to the target function generator 22, and the setting gap set in the levitation control circuit 20 are A target function setting unit 22 having a function of changing the suction force corresponding gap supplied from the parameter setting unit 21 in slowdown is provided. It is characterized in. By adopting this configuration, it is possible to obtain a magnetic levitation transfer device capable of maintaining a stable levitation of the bogie even when the linear motor for propelling the bogie is operated.

[0007]

According to the present invention, as shown in FIG. 1, before the stator 11 of the linear motor acts on the secondary conductor 17 of the carrier vehicle 14, the thrust signal receiver 18 installed at the front end of the carrier vehicle 14 is linearly moved. A thrust signal is received from a thrust signal transmitter 12 installed in front of the stator 11 of the motor, and the signal (thrust signal) is transmitted to the parameter setter 21. Parameter setter 21 that received the thrust signal
Calculates the suction force that acts vertically on the secondary conductor 17 based on the thrust signal, and at the same time calculates the suction force corresponding gap that does not disturb the levitation control of the carrier vehicle 14 when the linear motor is operating, and calculates the target function generator. 22.

The target function generator 22 supplied with the suction force-corresponding gap slowly slows down the normal gap set in the levitation control circuit 20 before the secondary conductor 17 is acted on by the stator 11 of the linear motor. Switch to the suction force compatible gap. At this time, as shown in FIG. 2, the time t is set so as not to give an impact to the transported object (wafer, etc.).
Slow down from ₁ to t ₂ (slow descent)
The operation is performed.

Further, as shown in FIG. 3, the operation when the action of the linear motor is finished and the suction force corresponding gap returns to the normal gap is, as shown in FIG. 3, a thrust signal provided at the rear end of the carrier vehicle 14 with respect to the traveling direction. The receiver 19 receives a release signal from the thrust signal transmitter 13 installed behind the stator 11 of the linear motor, and the release signal is transmitted to the parameter setter 21, and the levitation control is performed via the same transmission path as above. The suction force corresponding gap used in the circuit 20 is switched to the normal gap. The change in the gap at this time is also performed by the slow-up operation from time t ₃ to time t ₄ as shown in FIG.

[0010]

FIG. 4 is a diagram showing an embodiment of the present invention. In this embodiment, as shown in the figure, a magnetic rail 10 suspended from the ceiling side, a stator 11 of a linear motor provided on the rail, and a thrust signal transmitter provided near the side of the rail. 12 and 13, and a carriage 14 that magnetically attracts and floats on the rail 10. A gap sensor 16 for detecting a gap between the levitation electromagnet 15 and the rail 10 is provided on the carrier vehicle 14.
And the secondary conductor 17 of the linear motor that propels the carrier vehicle.
And thrust signal receivers 18 and 19 for receiving signals from the thrust signal devices 12 and 13, a levitation control circuit 20 for controlling the levitation electromagnet 15, a parameter setter 21, and a target function generator 22. ing. Reference numeral 23 is an object to be conveyed.

The circuit for controlling the flying height is shown in the block diagram of FIG. That is, the parameter setter 21 has a counting circuit 24, a memory circuit 25, and a gap indicating circuit 26, and the gap indicating circuit is connected to the target function generator 22. The target function generator 22 controls the levitation control circuit 20. It is connected to the constant setting circuit unit 27. The levitation control circuit 20 has a control constant setting circuit section 27 and a control current calculation circuit section 28, and the control current calculation circuit section 28 is connected to the gap sensor 16 and the levitation electromagnet 15.

The operation of this embodiment thus constructed will be described with reference to FIGS. 4, 5 and 6. First, in FIG.
The thrust signal transmitter 12 provided in front of the stator 11 of the linear motor receives an optical signal (the magnitude of the thrust signal depending on the intensity of the emitted beam light when the thrust signal receiver 18 in the front part of the carrier vehicle 14 passes right beside the thrust signal receiver 18). To send thrust signal receiver 1
8 to the thrust signal. The thrust signal receiver 18, which has received the thrust signal, transmits the thrust signal to the counting circuit 24 of the parameter setter 21, as shown in FIG.

The counting circuit 24 calculates a magnetic attraction force generated according to the thrust force and a gap corresponding to the attraction force, and supplies it to the target function generator 22 through the gap instruction circuit 26. The target function generator 22 changes the normal gap set in the control constant setting circuit section 27 in the levitation control circuit 20 to the gap corresponding to the attraction force by slowing down as described in FIG. Two
A control current serving as a gap corresponding to the attraction force is supplied to the levitation electromagnet 15 via 8.

Further, when the operation of the linear motor is finished, the thrust signal transmitter 13 provided at the rear of the stator 11 of the linear motor shown in FIG. 4 to the thrust signal receiver 19 provided at the rear end of the carriage 14. A release signal is transmitted as an optical signal toward the optical signal. Thrust signal receiver 1 that received the signal
9 transmits a release signal to the memory circuit 25 of the parameter setter 21, as shown in FIG.

In the memory circuit 25, the previously stored normal gap is supplied to the target function generator 22 through the gap indicating circuit 26. The target function generator 22 slows down the suction-corresponding gap incorporated in the control constant setting circuit unit 27 in the levitation control circuit 20 to the normal gap as described with reference to FIG. A control current that normally provides a gap is supplied to the levitation electromagnet 15. In this way, the carrier vehicle 14 can be stably run.

[0016]

According to the present invention, even when the linear motor accelerates or decelerates, the carrier truck does not tend to oscillate, and a stable floating state can be maintained. Since the above performance can be sufficiently brought out, it greatly contributes to the performance improvement of the magnetic levitation transport device.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a change in a gap of a carrier truck in the apparatus of FIG.

FIG. 3 is a diagram illustrating the principle of the present invention.

FIG. 4 is a perspective view showing an embodiment of the present invention.

FIG. 5 is a block diagram showing a control system in the embodiment of the present invention.

FIG. 6 is a block diagram showing a control system in the embodiment of the present invention.

FIG. 7 is a diagram showing a conventional magnetic levitation transfer device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Magnetic rail 11 ... Stator of linear motor 12, 13 ... Thrust signal transmitter 14 ... Conveyance vehicle 15 ... Levitation electromagnet 16 ... Gap sensor 17 ... Secondary conductor 18, 19 ... Thrust signal receiver 20 ... Levitation control circuit 21 ... Parameter setter 22 ... Target function generator 23 ... Conveyed object 24 ... Count circuit 25 ... Memory circuit 26 ... Gap instruction circuit 27 ... Control constant setting circuit unit 28 ... Control current calculation circuit unit

Claims (1)

[Claims] 1. A levitation electromagnet (15) for generating an attraction force to a magnetic rail (10), a gap sensor (16) for detecting a gap between the rail surface and the gap sensor (1).
Based on the output from 6), the control amount for the carrier vehicle (14) to maintain a constant set gap is calculated, and the levitation electromagnet (1
5) A magnetic levitation carrier vehicle (14) having a levitation control circuit (20) for supplying an appropriate electric current, and a magnetic rail (1) provided with a stator (11) of a one-sided linear motor.
0) and the magnetic levitation transport device, the thrust signal transmitters (12, 13) are provided on the rail side, and the thrust signal transmitted from the thrust signal transmitters (12, 13) is transmitted to the transport carriage (14). Thrust signal receiver (18,1)
9), a function of connecting to the thrust signal receiver, capable of calculating a magnetic attraction force generated during acceleration / deceleration of the linear motor, and a attraction force corresponding gap capable of maintaining stable levitation at that time, and the calculated attraction force. The corresponding gap is calculated by the objective function generator (2
Parameter setter (2
1) and a target function setting device having a function of changing the setting gap set in the levitation control circuit (20) to the suction force corresponding gap supplied from the parameter setting device (21) in a slowdown manner. (22) A magnetic levitation transport device comprising: