JP3627507B2 - Dolly operation system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cart operation system for driving a cart traveling on an endless track laid in a clean room under operation control by communication with a transfer control device.
[0002]
[Prior art]
A semiconductor wafer process performed in a clean room is a batch process of several hundred processes. For this batch process, a person has conventionally transported a wafer cassette to each processing apparatus. However, since the worker is the largest source of contamination, it is a common practice to automate the conveyance in the clean room for the purpose of improving the production yield. In this inter-process transfer in the clean room, a transfer system that uses a linear motor to transfer a carriage loaded with a wafer cassette at high speed is proposed, and the wafer cassette is automatically transferred via a stocker. became.
[0003]
However, among the automatic transfer system using a carriage that is driven by this linear motor, the one that supplies power by bringing the current collector provided on the carriage side into contact with the power line is the most important wear dust and dust in the clean room. Therefore, it is desired to employ a non-contact current collecting mechanism.
[0004]
On the other hand, the conveyance control along the track of the carriage is performed based on a command from the conveyance control device that is remote from the carriage, and therefore the conveyance control device wirelessly communicates with the carriage for the conveyance control. Is going. In order to make this communication possible regardless of the movement position of the carriage, the radios of the transport control device are installed at a plurality of locations such as stations where the carriage works, and for communication with the carriage. Cable was laid between the radio and the transport control device.
[0005]
[Problems to be solved by the invention]
However, in such a communication method for automatic conveyance control, in order to be able to perform reliable communication, it takes labor and time to select a position where the radio of the conveyance control device is installed. When a machine is installed in a station, there are restrictions such as that the carriage needs to stop and receive instructions from the station, and radio waves (microwaves) are shielded by fire walls and nearby obstacles. However, there is a problem that the command may not be reliably transmitted to the cart. Even when the command is given by light, it is more frequently affected by the obstacle.
[0006]
On the other hand, in order to avoid communication failure by shielding radio waves and light, a communication line for supplying a command signal from the transfer control device is laid along the guide rail in parallel with the power line of the transfer control device. A method has also been proposed in which the carriage communicates with the transfer control device via the line, but in this case, since the communication line is laid in addition to the power line, the installation work and maintenance work are troublesome, There was a problem of high costs.
[0007]
The present invention solves the above-described problems, and it is possible to reliably communicate with the transport control device through the power pickup coil with any of the carts at any position on the track. The purpose is to obtain a cart operation system that can be realized at low cost.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a cart operating system according to the invention of claim 1 includes a loop-shaped power line wired along an endless track laid in a clean room, and a pickup coil for power without contact from the power line. A transport control device that performs communication between the carriage traveling on the track and the carriage while performing automatic transfer of the conveyed object using the electric power induced by the carriage, and controls the carriage of the carriage And superimposing a communication signal having a frequency that is different from the frequency of the power on the power supplied to the power line through the power pickup coil, so that the cart and the transport control device a carriage operation system for transmitting and receiving information relating to the transport between, provided such adjacent multiple loop power line along one endless raceway In these power supply switches sites to the carriage from the power line, in which the power line with each other is to be arranged to overlap each other in the track direction.
[0009]
Further, in the cart operation system according to the invention of claim 2, the portion where the power supply from each of the power lines to the cart is switched is arranged so that the power lines are obliquely overlapped in the track direction .
Further, in the bogie operating system according to the invention of claim 3, the power supply from each power line to the bogie is switched between the power lines, one power line end with respect to the other power line end. They are arranged so as to overlap each other in the front-rear direction or the vertical direction.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block connection diagram conceptually showing the cart operation system of the present invention. In the figure, reference numeral 1 denotes an AC power source of 50 amperes (A), 10 kilohertz (KHz), for example, and a 300 meter power line (feed line) 2 is connected in a loop. The power line 2 is wired along a track (not shown) on which one or a plurality of carriages 3 travel.
[0011]
Reference numeral 3 denotes a transport control device which is connected to the power line 2 in a contactless manner, and a pickup coil 4 for transmission and a pickup coil 5 for reception that superimpose a carrier wave of a communication signal on the power on the power line 2. And a modulator 7 that digitally modulates a communication signal from the host computer 6 and outputs it to the pickup coil 4 for transmission, and a host computer 6 that demodulates the communication signal induced from the power line 2 to the pickup coil 5 for reception. And a demodulator 8 that inputs the signal.
[0012]
Furthermore, 9 is a plurality of carts that travel along the track, and only two are shown here. These carts 9 are connected to the power line 2 in a contactless manner, a pickup coil 10 for transmission and a pickup coil 11 for reception that superimpose a carrier wave of a communication signal on the power on the power line 2, and a cart-side computer 12. A modulator 13 that digitally modulates the communication signal from the signal and outputs the modulated signal to the transmission pickup coil 10; and a demodulator 14 that demodulates the communication signal induced in the reception pickup coil 11 and inputs the demodulated signal to the cart-side computer 12. It is composed of
[0013]
The frequency of the communication signal output from the modulator 7 to the pickup coil 4 for transmission by the host computer 6 is, for example, 300 KHz. On the other hand, the cart side computer 12 performs digital modulation of the communication signal by the modulator 13. The frequency of the communication signal to be superimposed on the power on the power line 2 through the transmission pickup coil 10 is set to 350 KHz, for example. Each of these frequencies is set to a high frequency different from the frequency of the AC power supply 1. Accordingly, the demodulator 8 on the host computer 6 side demodulates the communication signal of 350 KHz, and the demodulator 14 on the side of the carriage computer 12 demodulates the communication signal of 300 KHz. For this reason, each demodulator 8, 14 is provided with a band-pass filter that separates and passes a specific frequency.
[0014]
In FIG. 1, only the case where the conveyance control device 3 and the cart 9 are provided with their own transmission pickup coils 4, 5, 10, and 11 for transmission and reception of communication signals is shown. Is connected to the power line 2 for each of the conveyance control device 3 and the carriage 9, and the transmission pickup coils 4, 5, 10, and 11 are connected to these power pickup coils. It is also used in. That is, the conveyance control device 3 and the carriage 9 are supplied with power through the power pickup coil and transmit / receive the communication signal. As a result, the number of parts used in the system can be reduced, the configuration can be simplified, and the cost can be significantly reduced.
[0015]
Further, the frequency of the communication signal supplied from the modulators 7 and 13 to the power line 2 is reflected or reduced because the wavelength becomes too short from the radio wave law and from the total length (for example, 400 meters) of the power line 2. In order not to prevent communication due to the phase difference, it is set as low as possible and is not affected by the power line frequency of the power line, for example, 300 KHz.
[0016]
That is, in such a closed circuit power line 2, the communication signal is determined from the relationship with the filter from the minimum wavelength that is four times or more the length of the power line in order to avoid interference with the return signal. Select and use signals up to the maximum wavelength of 1/2 or less of the power wave.
[0017]
2 and 3 show a transmission side circuit and a reception side circuit of the carriage 9, respectively. Among these, the transmission side circuit shown in FIG. 2 inputs the position and loading information of the cart 9 determined by the cart computer to a frequency displacement keying device (modulation device) 21 using a phase locked loop (PLL). Then, the digital signal is converted into an analog signal and modulated so that it can be communicated through an analog transmission line. Further, two sets of switch elements connected in series to a DC power source 23 of 24 VDC, for example, are connected in parallel through the gate driver 22. The inverter 24 thus formed is driven.
[0018]
That is, the gate driver 22 synchronously turns on / off the switch elements 24a, 24c and the switch elements 24b, 24d constituting the inverter 24, and a signal corresponding to the on / off operation is used for resonance via the resistor 25. Are input to the capacitor 26 and the coil 27 and a communication signal of a predetermined frequency is taken out and output to the power line 2 through the pickup coil 10 for transmission. A switch element 28 that is normally closed is connected in parallel to the pickup coil 10.
[0019]
By the way, since each cart 9 has such a resonance circuit composed of the capacitor 26 and the coil 27, it is conceivable that a transmission signal from one cart wraps around the transmission circuit of the other cart via the power line 2. For example, when a communication signal of 1.7 V is applied from one carriage, an induced voltage of 85 V is generated in the resonance circuit of the other carriage, and therefore the output voltage of the inverter 24 is also increased from 24 V to 200 V, for example. Resulting in.
[0020]
Therefore, the switch element 28, which is normally off, is turned on only at the moment when the cart 9 designated by the host computer 6 of the transport control device 3 transmits a communication signal, and the transport from the cart to the transport control device 3 is performed. Enables transmission of communication signals related to management. Further, when the communication signal is not transmitted, the pickup coil 10 is short-circuited to prevent the communication signal from being circulated from the other carriage.
[0021]
In the receiving circuit shown in FIG. 3, a received signal is obtained from a receiving pickup coil 11 that is electrically connected to the power line 2 in a contactless manner, and this is received via a booster 29, a limiter 30, and a parallel resistor 31. Then, the transmission signal in a predetermined frequency region is taken out through the band pass filter 32, and further the 350 KHz transmission signal demodulated by the demodulator 33 using the PLL is taken out and inputted to the computer 12 for the carriage.
[0022]
Here, the pickup coils 10 and 11 are provided separately for transmission and reception, and are not shared. As a result, the reception side circuit can always wait for reception, and the switch 28 can prevent the transmission signal from being sent from another carriage 9 or the like to the transmission circuit. Further, the secondary coils of the current transformer CT can be used for the pickup coils 10 and 11.
[0023]
That is, in the carrier communication using the power line 2 as described above, the digital information is superimposed on the power on the power line 2 and the digital information is extracted from the power line 2 without using the capacitor coupling or the pulse transformer. A transformer CT can be used as each of the pickup coils. Since the current transformer CT has a coil wound around the core, a sufficient power detection function can be obtained, and therefore the non-contact distance between the carriage 9 and the power line 2 can be sufficiently increased. As a result, there is an advantage that the design and installation conditions of the transport system are greatly relaxed.
[0024]
On the other hand, when the transport distance in the clean room, that is, the orbital length is increased, the power line 2 is also increased accordingly, and reflection and loss of digital communication signals may be increased. For this reason, when the track becomes long, as shown in FIG. 4, a plurality of sets of loop-shaped power lines 2 are arranged along one endless track, and each power line 2 is located near the power source 1. Each power line is multidrop-connected to the transport control device 3 via the connected digital / analog converter 35 corresponding to the modulator 7 and the demodulator 8.
[0025]
In this way, the digital communication signal from the transport control device 3 is transmitted to the vicinity of the power source 1 of each power line 2 using parallel lines, and further modulated / demodulated through the digital / analog converter (modem / demodulator) 35 and amplified. It can be supplied to each power line 2 later. Therefore, regardless of which power line 2 the carriage 9 is on, the communication signal can be transmitted and received with the transport control device 3 under the same conditions.
[0026]
Further, in such a cart operation system in which a plurality of power lines 2 having the power source 1 are laid along one track, when the cart 9 is transferred from one of the adjacent power lines 2 to the other, the transfer control device 3 May be interrupted. For example, as shown in FIG. 5, when two power lines 2A and 2B having power sources 1A and 1B are wired along a track C, a gap G is generated between the power lines 2A and 2B. 9, the communication signal from the transfer control device 3 is interrupted.
[0027]
Therefore, in the present invention, as shown in FIG. 6, the power lines 2A and 2B are arranged obliquely at the gap G so as to overlap in the orbit C direction. For this reason, since the gap G has a certain length in the direction of the track C, power and communication signals are always received from both the power lines 2A and 2B when the carriage passes through any position of the long gap. These are never interrupted on the side of the carriage 9, and the loss of transmission information can be reliably prevented.
[0028]
Moreover, as shown in FIG. 7, even if the power line 2A end overlaps the power line 2B end in the front-rear direction or the vertical direction, the same effect as in FIG. 6 can be obtained. In this case, the gap G in the track direction does not occur.
[0029]
Further, the carriage 9 traveling on the track C is configured as shown in FIG. 8, for example. FIG. 8 conceptually shows the configuration. Reference numeral 41 denotes a track frame having a substantially U-shaped cross section constituting the track C. A plurality of strip-shaped magnets 44 are embedded in the center of the bottom of the track frame in the running direction of the carriage 9. Has been. Further, on the inner surfaces of the opposing side plates of the track frame 41, guide rails 42 having guide pieces 42a bent at L-shape at the tip are symmetrically installed at the middle level.
[0030]
Furthermore, two upper and lower electric wire support members 43 made of an insulating material protrude from the inner surface of the side plate above the guide rails 42. Of these, the upper left and right electric wire support members 43 support, for example, two parallel power lines 2A having a power source 1A as shown in FIG. Are supported by two parallel lines of another power line 2B having a power source 1B adjacent to the power line 2A.
[0031]
On the other hand, in the track frame 41, a cart 9 having a caster 45 that rolls in contact with the bottom of the track frame 41 is provided along the track C direction. The carriage 9 has a plurality of armature coils 46 arranged in parallel in the track C direction so as to face the magnets 44 on the lower surface of the central portion. The armature coils 46 and the magnets 44 are induction type. It constitutes a linear motor.
[0032]
Further, support arms 47 are provided on the left and right sides of the carriage 9 so that the guide arms 42a of the guide rails 42 projecting on both side plates of the track frame 41 can be attached to and detached from the upper ends of the support arms 47. In addition, a guide roller 48 is provided that can freely roll. Therefore, when the carriage 9 travels in the track frame 41, the traveling direction is determined by the two guide pieces 42a.
[0033]
Further, a support bar 49 projects vertically from the center of the carriage 9, and a loading platform on which the wafer cassette 50 is placed at the upper end of the support bar 49 protruding from the upper opening of the track frame 41. 51 is attached. A pickup means 52 is attached to a position of the support bar 49 that faces the track frame 41.
[0034]
The pickup means 52 includes a pickup coil (not shown) provided in the vicinity of the power lines 2A and 2B and a core 53 that winds the pickup coil to form a current transformer CT. The core 53 is provided with a notch 54 for guiding the power lines 2A and 2B close to the pickup coil as shown in the figure. That is, each power line 2A, 2B is inserted into each notch 54 in a state of being close to the pickup coil. Therefore, power and communication signals can be guided to the pickup coil from the power lines 2A and 2B with high sensitivity.
[0035]
By the way, depending on the state of the track C, the power lines 2A and 2B may be provided on both sides of the carriage 9 as shown in FIG. Therefore, in power carrier communication, in order to induce a communication signal from the power line, the pickup coils as described above are required on the left and right sides of the carriage 9.
[0036]
As described above, when the power line 2A or 2B is provided only on the left side or the right side of the carriage 9, the pickup coils are switched by a command from the transport control device 3 and guided to this. Therefore, it is necessary to take out a communication signal to be transmitted, and thus it is necessary to install a switching means. However, in such a case, the left and right pickup coils are connected in parallel to each other, so that the communication signal induced to any pickup coil can be surely taken into the cart-side computer 12 of the cart 9, The pick-up coil switching means becomes unnecessary.
[0037]
Even if the left and right pickup coils are each provided with a filter and an amplifier, and the communication signals obtained by the left and right pickup coils are added in the amplification stage, as in the case of the parallel connection, from the left or right power line. The induced communication signal can be reliably extracted.
[0038]
Further, among the communication signals obtained from the left and right pickup coils, one pickup coil having a high signal level is discriminated by a signal strength discriminator, and a communication signal on the pickup coil having a high signal strength is automatically selected and taken out. It may be.
[0039]
【The invention's effect】
As described above, according to the present invention, a loop-shaped power line wired along an endless track laid in a clean room and power induced by a power pickup coil in a non-contact manner from the power line are used. A carriage that travels on the track while performing automatic transfer of the article to be conveyed, and a conveyance control device that communicates with the carriage and controls the conveyance of the carriage. Transmission and reception of information related to the conveyance between the carriage and the conveyance control device by superimposing a communication signal having a frequency that is different from the frequency of the electric power to the supplied electric power through a pickup coil for electric power. Therefore, any of the carts at any position on the track can be controlled by using the power line and the power pickup coil. Communication can be reliably performed, and this can be realized at a low cost with an extremely simple configuration, and the power line can also be used for transmission of communication signals. Therefore, there is no need to arrange them in parallel, and the system configuration and maintenance work can be further simplified and the cost can be reduced.
[0040]
Further, according to the present invention, a plurality of loop-shaped power lines are provided adjacent to each other along one endless track, and the power lines are connected at a portion where power supply from these power lines to the carriage is switched. Since they are arranged so as to overlap each other, it is possible to reliably prevent interruption of communication signals and power supply transmitted / received between the conveyance control device and the carriage even when the carriage is transferred to another adjacent power line. .
[Brief description of the drawings]
FIG. 1 is a block connection diagram showing a cart operation system according to an embodiment of the present invention.
2 is a circuit diagram showing a transmission side circuit of the carriage in FIG. 1. FIG.
FIG. 3 is a circuit diagram showing a receiving side circuit of the carriage in FIG. 1;
FIG. 4 is a block connection diagram showing a cart operation system having a plurality of power lines according to the present invention.
FIG. 5 is an explanatory diagram showing an arrangement example of a plurality of power lines according to the present invention.
FIG. 6 is an explanatory diagram showing an arrangement example of a plurality of power lines according to the present invention.
FIG. 7 is an explanatory diagram showing an arrangement example of a plurality of power lines according to the present invention.
FIG. 8 is a conceptual diagram showing a configuration of a carriage and a track according to the present invention.
[Explanation of symbols]
1, 1A, 1B Power source 2, 2A, 2B Power line 3 Conveyance control device 4, 5, 10, 11 Pickup coil 9 Car 28 Switch element 35 Digital / analog converter C Track

Claims (3)

Using a loop-shaped power line wired along an endless track laid in a clean room and the power induced by the power pickup coil in a non-contact manner from the power line, A carriage that travels on the track, and a conveyance control device that communicates with the carriage to control the carriage, and the frequency of the electric power is supplied to the electric power line. A carriage operation system for transmitting and receiving information related to the conveyance between the carriage and the conveyance control device by superimposing a communication signal having a frequency different from that of the digital modulation through the pickup coil for power ,
A plurality of loop-shaped power lines are provided adjacent to each other along one endless track, and the power lines overlap each other in the track direction at a portion where power supply from each power line to the carriage is switched. A cart operation system characterized by being arranged as follows . 2. The cart operation system according to claim 1, wherein a portion where the power supply from each power line to the cart is switched is arranged so that the power lines are obliquely overlapped in the track direction. The part where the power supply from each power line to the carriage is switched is arranged such that the power lines overlap one power line end with the other power line end in the front-rear direction or the vertical direction. The cart operation system according to claim 1 characterized by things.

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