JP3627506B2 - 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 due to shielding of radio waves and light, a communication line for supplying a command signal from the transport control device is laid along the guide rail in parallel with the power line of the transport 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-mentioned problems, and it is possible to reliably communicate with the transport control device without any trouble with any of a plurality of carts at any position on the track, and to make this a very simple configuration. 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 operation system according to the invention of claim 1 is configured to provide a loop-shaped power line wired along an endless track laid in a clean room, and electric power induced in a non-contact manner from the power line. Using a carriage that travels on the track while performing automatic transfer of a conveyed product, and a conveyance control device that performs communication between the carriage and controls the conveyance of the carriage, to the power supplied to the power line, by superimposing a communication signal of a frequency of performing the different digital modulation from the frequency of the power, line physician transmission and reception of information relating to the transport of the carriage between the carriage and the transfer control device The loop-shaped power line is configured to flow a communication signal having a wavelength that is at least four times the length of the power line and 1/2 or less of the power wave .
[0009]
In addition, the cart operation system according to the invention of claim 2 is configured to convey a loop-shaped power line wired along an endless track laid in a clean room, and electric power induced in a non-contact manner from the power line. A cart that travels on the track while performing automatic transfer of an object, and a conveyance control device that communicates with the cart and controls the conveyance of the cart, and is supplied to the power line By superimposing a communication signal having a frequency that is digitally modulated different from the frequency of the power, on the power, information related to the transport of the cart is transmitted and received between the cart and the transport control device. A plurality of carriages are provided so as to be able to travel, and a switch for short-circuiting a pickup coil for transmission is provided in the transmission circuit of each carriage that communicates with the conveyance control device except during transmission.
[0011]
Moreover, the cart operation system according to the invention of claim 3 is such that the pickup coil is a secondary coil of a current transformer having the power line as a primary side.
[0012]
Moreover, the cart operation system according to the invention of claim 4 is provided with a plurality of loop-shaped power lines along one endless track, and the transport control device is placed near the power source of these power lines for each of the power lines. A multi-drop connection is made through a connected digital / analog converter.
[0013]
In addition, in the cart operation system according to the invention of claim 5, the power line is laid in the vicinity of the pickup coils provided on the left and right of the cart, and the left and right pickup coils are connected in parallel.
[0014]
Further, in the cart operation system according to the invention of claim 6, the power line is laid in the vicinity of the pickup coils provided on the left and right of the cart, and the signal strength discriminator is obtained from these left and right pickup coils. The signal having the higher signal strength among the signals is discriminated and output.
[0015]
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 9 travel.
[0016]
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.
[0017]
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
[0018]
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.
[0019]
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.
[0020]
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.
[0021]
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.
[0022]
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.
[0023]
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.
[0024]
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.
[0025]
Therefore, in the present invention, only when the cart 9 designated by the host computer 6 of the transport control device 3 transmits a communication signal, the switch element 28, which is normally off, is turned on, and the transport control device starts from this cart. 3 can transmit a communication signal related to transport 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.
[0026]
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.
[0027]
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.
[0028]
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.
[0029]
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.
[0030]
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.
[0031]
Moreover, the cart 9 traveling on the track is configured as shown in FIG. 5, for example. FIG. 5 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.
[0032]
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. The member 43 supports two parallel lines of another power line 2B having a power source 1B adjacent to the power line 2A. Here, G is a gap between the power lines 2A and 2B.
[0033]
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.
[0034]
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.
[0035]
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.
[0036]
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.
[0037]
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.
[0038]
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.
[0039]
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.
[0040]
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.
[0041]
【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 the power induced in a non-contact manner from this power line are used to automatically A carriage that travels on the track while performing transfer, and a conveyance control device that performs communication between the carriage and controls the conveyance of the carriage, with respect to the electric power supplied to the power line Since the transmission signal is transmitted and received between the carriage and the conveyance control device by superimposing a communication signal having a frequency that is digitally modulated different from the frequency of the power, Any of the plurality of carriages at the position can surely perform communication with the transfer control device without any obstacles, and can achieve this with an extremely simple configuration at low cost.
[0042]
Further, according to the present invention, a plurality of carriages are provided on the track so as to be able to travel freely, and a switch for short-circuiting the pickup coil for transmission is provided in the transmission circuit of each carriage that communicates with the transport control device except during transmission. Therefore, it is possible to transmit the communication signal from the carriage to the conveyance control device without any trouble, and to obtain the effects that the communication signal from the carriage other than the carriage designated by the conveyance control device can be prevented. In addition, since the communication signal having a wavelength not less than four times the length of the power line and not more than ½ of the power wave is caused to flow through the loop-shaped power line, the reflection and interference of the communication signal on the power line are obviated. In addition, since the pickup coil is a secondary coil of a current transformer having a power line as a primary side, the transmission / reception sensitivity of each pickup coil can be increased by increasing the non-contact distance between the carriage and the power line. Thus, the design and installation conditions of the bogie operation system can be relaxed.
[0043]
Further, according to the present invention, a plurality of loop-shaped power lines are provided along one endless track, and the conveyance control device is connected to each power line in the vicinity of the power source of these power lines. Since the multi-drop connection is made through the section, the communication quality between the carriage and the transport control device can be maintained evenly through any of the plurality of power lines when the endless track distance is long. In addition, since the power line is laid in the vicinity of the pickup coils provided on the left and right of the carriage, and the left and right pickup coils are connected in parallel, the communication signal on the power line is at least one of the left and right pickup coils. It can be reliably taken out to the cart side. Further, the power line is laid in the vicinity of the pickup coils provided on the left and right sides of the carriage, and the signal strength discriminator selects the signal having the larger signal strength among the signals obtained from the left and right pickup coils. Therefore, it is always possible to reliably extract only a high-level communication signal transmitted through the power line to the carriage side.
[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 a conceptual diagram showing a configuration of a carriage and a track 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.
[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 (6)

A loop-shaped power line wired along an endless track laid in a clean room;
A cart that travels on the track while automatically transferring a transported object using electric power induced in a non-contact manner from the power line,
A transfer control device that performs communication with the carriage and performs control related to the carriage of the carriage;
By superimposing the power supplied to the power line with a communication signal having a frequency that is digitally modulated different from the frequency of the power, information related to the carriage of the carriage is transmitted and received between the carriage and the conveyance control device. The bogie operating system is characterized in that a communication signal having a wavelength not less than four times the length of the power line and not more than 1/2 of the power wave is passed through the loop-shaped power line . A loop-shaped power line wired along an endless track laid in a clean room;
A cart that travels on the track while automatically transferring a transported object using electric power induced in a non-contact manner from the power line,
A transfer control device that performs communication with the carriage and performs control related to the carriage of the carriage;
By superimposing a communication signal having a frequency that is digitally modulated different from the frequency of the power on the power supplied to the power line, information related to the carriage of the carriage is transmitted and received between the carriage and the conveyance control device. A plurality of carriages are provided on the track so that they can run freely, and a transmission circuit for each carriage that communicates with the transport control device is provided with a switch that shorts the pickup coil for transmission except during transmission. truck operating system which is characterized. The pickup coil, carriage operation system according to claim 1 or 2, characterized in that the secondary coil of the current transformer to the power line and the primary side. A plurality of loop-shaped power lines are provided along one endless track, and the transport control device performs multi-drop for each of the power lines via a digital / analog converter connected in the vicinity of the power source of these power lines. It is connected, The cart operation system in any one of Claim 1 or 2 characterized by the above-mentioned. The power line is laid in the vicinity of the pickup coil provided on the left and right of the carriage, trolley travel according to any one of claims 1 or 2 of these right and left pickup coil, characterized in that connected in parallel system. A signal strength discriminator that lays out in the vicinity of the pickup coils provided on the left and right of the carriage and discriminates and outputs a signal having a larger signal strength among signals obtained from the left and right pickup coils. the truck operation system according to claim 1 or 2, characterized in that provided.

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