JP2000099151A - Carrier system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier system capable of making a carrier travel in the state of being adjusted to a proper gain corresponding to the load of articles at all the time. SOLUTION: Concerning the carrier system 1 provided with a linear carrier 3 for carrying cassettes 4 and a zone controller 7 for performing feedback control to the primary coil of the linear carrier 3 so that the linear carrier 3 travels in a predetermined speed pattern, in the case of starting the linear carrier 3, the zone controller 7 sets the gain of feedback control based on the load of cassettes 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transport system comprising a transport vehicle for transporting articles and a control means for feedback-controlling the propulsion means of the transport vehicle so that the transport vehicle travels in a predetermined speed pattern. It is about.

[0002]

2. Description of the Related Art Conventionally, there has been provided a linear transport vehicle that circulates on a traveling rail suspended from a ceiling, and a stocker provided with a station. 2. Description of the Related Art There has been known a transport system configured to transport to a stocker by a linear transport vehicle. In such a transport system, the linear transport vehicle is open-controlled, and does not always run at the target speed pattern, so when stopping, decelerate early with a margin, By setting the section traveling at an extremely low speed to be long, control is performed so that the vehicle can be reliably stopped at the stop position.

[0003]

As described above, in the conventional system, there is a problem that the cycle time becomes long because the section where the vehicle travels at an extremely low speed is set to be long. For this reason, the inventor has devised feedback control of the transport system. However, in the case of a linear transport vehicle in which a secondary conductor is provided in the main body and driven by a primary coil mounted on a traveling rail, the weight of the cassette occupies the entire weight of the linear transport vehicle because the linear transport vehicle body becomes lighter. Becomes very large, and the total weight of the linear transport vehicle greatly differs depending on whether a cassette is loaded or not, and further, when the cassette is loaded, how much work is stored in the cassette.

The feedback control is a control for obtaining a difference between a target speed and an actual speed, correcting the next command value based on the difference, and outputting the corrected command value. A coefficient used in the correction is a gain. For example, if the gain is set so that appropriate feedback control is performed when the weight of the entire linear carrier is heavy, if the weight of the entire linear carrier is light, acceleration and excessive deceleration are repeated, and before and after the stop position. In such a case, there occurs a problem that the overrun cannot be repeated and the stop cannot be performed, and if the difference between the target speed and the actual speed becomes too large, the control itself may become impossible. For this reason, it has been required to always perform feedback control of the linear carrier with an appropriate gain.

The present invention has been made by paying attention to such problems existing in the prior art. The challenge is
An object of the present invention is to provide a transport system that can always make a transport vehicle travel with an appropriate gain according to the load amount of articles.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a transport vehicle for transporting articles, and a transport vehicle for transporting the transport vehicle in a predetermined speed pattern. A control system for controlling the propulsion means of the vehicle in a feedback manner, wherein the control means sets a gain of the feedback control based on an amount of loaded articles when starting the transport vehicle. It is.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a station provided with a detecting means for detecting a load amount of the articles, and when the articles are transferred from the station to the carrier. And transmitting the loading amount of articles from the station to the control means.

[0008] According to a third aspect of the present invention, in the first or second aspect of the invention, the carrier has a secondary conductor mounted thereon and is linearly transported by a primary coil disposed on the ground side. The vehicle is a vehicle, wherein the control means controls energization of the primary coil.

Therefore, according to the first aspect of the present invention, when the carrier starts moving, the gain can be set based on the amount of articles loaded, so that the amount of articles loaded changes and the entire transport vehicle is changed. Even if the weight changes, the carrier can always be feedback-controlled with an appropriate gain.

According to the second aspect of the present invention, in addition to the operation of the first aspect, by providing the station with a load amount detecting means, the load amount can be detected before the articles are transferred to the transport vehicle. can do. Then, when transferring the goods to the carrier, by transmitting the load amount of the goods to the control means,
The movement of the article and the transmission of the information on the load amount can be matched.

According to the third aspect of the present invention, in addition to the operation of the first or second aspect of the present invention, since only the secondary conductor is provided on the carrier, the weight of the carrier can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A transport system 1 according to the present embodiment will be described with reference to the drawings. FIG. 1 is a plan view illustrating an outline of a transport system 1 according to the present embodiment. The transport system 1 according to the present embodiment is used, for example, in a semiconductor manufacturing process, and includes a linear transport vehicle 3 that goes around a loop-shaped traveling rail 2 suspended from a ceiling, and a cassette 4 (article).
Stocker 6 provided with a station for transferring
And control means for performing feedback control of the linear carrier 3 so as to match a predetermined speed pattern. Then, the transport system 1 of the present embodiment divides the traveling route into a plurality of zones (af) and controls the zone (af) for each zone (af). (Control means), a central controller 8 that integrally manages the zone controller 7, and a higher-level controller that sends a transport command to the central controller 8.

In the stocker 6, a pair of shelves 61 for temporarily storing the cassettes 4 are arranged at predetermined intervals, and a station 5 is arranged above the shelves 61. A crane 62 for delivering the cassette 4 is provided.

In the station 5, as shown in FIG.
A cassette mounting table 51 on which the cassette 4 is mounted and a transfer device 52 for transferring articles between the cassette mounting table 51 and the linear transport vehicle 3 are provided. The transfer device 52 is a scalar arm type transfer device, and is configured such that a plurality of members are connected to each other so as to be freely bent and extend and contract. Transfer device 5
2 is a first arm 53 oscillated by a motor (not shown).
A second arm 54 supported on the swinging shaft of the first arm 53 and swinging in the opposite direction, and a hand member 55 for supporting the cassette 4 supported on the second arm 54 by the swinging shaft. It has. Assuming that the rotation angle of the first arm 53 is 1, the second arm 54 is -2, and the hand member 55 is 1. Therefore, the hand member 55 advances from the station 5 in the same direction, and can transfer the cassette 4 to the linear transport vehicle 3 with a minimum interference range. The expansion and contraction of the transfer device 52 is performed by rotating the swing shaft by transmitting the rotation of the motor by a drive transmission member (not shown) built in each arm.

The cassette mounting table 51 has a cassette supporting portion 51a for supporting the bottom surface of the cassette 4, and has a working space for the transfer device 52. In addition, a load cell 56 (a means for detecting a load amount) is provided on the cassette support portion 51a.
Are provided so as to contact the bottom surface of the cassette 4,
The cassette 4 is placed on the cassette mounting table 51 by the crane 62.
Is placed, the weight of the cassette 4 can be detected.

The cassette 4 detected by each load cell 56
Is sent to the weight determining means 57 provided in the station 5, and the weight determining means 57 calculates the average of the two weights and divides the calculated average weight into weights obtained by dividing the weights into predetermined ranges. The corresponding weight information is selected by referring to the weight table 58 in which a plurality of pieces of information are set. Then, the weight information is transmitted from the communication means provided in the station 5 to the communication means of the zone controller 7. As described above, the detected weight is not transmitted as it is, but is converted into the weight division and transmitted. The information transmitted to the zone controller 7 is reduced as much as possible, thereby shortening the communication time and preventing the communication trouble. At the same time, the load on the zone controller 7 is reduced.

The weight information is transmitted from the weight determining means 57 to the zone controller 7 while the cassette 4 is being transferred between the station 5 and the linear transport vehicle 3 by the transfer device 52. For this reason, the gain can be changed based on the weight information before the linear carrier 3 starts moving, and the cassette 4 and the weight information move simultaneously, so that the movement of the cassette 4 and the movement of the weight information are separately performed. As compared with the case where the cassette 4 is managed, for example, the cassette 4 in which the weight information is not transmitted although the cassette 4 is transferred.
And weight information are less likely to be inconsistent.

As shown in FIG. 3, the zone controller 7 performs control based on control information sent from the central controller 8.
A controller for controlling the linear motor and the transfer device 52 in the zone;
And a control means 72 of the linear carrier 3 and a gain determination means 73 for determining a gain from the weight information. The central controller 8 receives a transport command (from information and to information) sent from a higher-level controller connected to a host computer that performs production management, and receives a zone controller 7 with a stocker 6 corresponding to the from information.
To information is transmitted.

Upon receiving the to information, the zone controller 7 moves the linear carrier 3 to a position corresponding to the stocker 6 when the linear carrier 3 on which the cassette 4 is not loaded enters the zone. Stop. The control unit 71 of the transfer device 52 transfers the cassette 4 from the stocker 6 to the linear transport vehicle 3 while controlling the transfer device 52. At this time, the weight information is transmitted to the zone controller 7, and the gain of the servo circuit is set to the gain determined by the gain determining means 73 described later.

When the linear carrier 3 is started, the zone controller 7 communicates with the next zone controller 7 in the traveling direction to obtain information such as whether there is a preceding linear carrier 3 in the next zone. At the same time, if there is no linear transport vehicle 3, the linear transport vehicle 3 is started, and control information such as to information and weight information is sent to the next zone controller 7. The next zone controller 7 executes to
If it is not the zone corresponding to the information, the control unit controls the linear motor with the gain based on the weight information, passes the linear carrier 3, and sends the control information to the next zone. If there is a linear transport vehicle 3 in the next zone, it is kept on standby until the preceding linear transport vehicle 3 starts from the next zone. In the zone corresponding to the to information, the linear transport vehicle 3 is stopped by controlling the linear motor with a gain based on the weight information, and the cassette 4 is transferred.

The gain determining means 73 includes a gain table 74 in which gains corresponding to the weight information are respectively set. The gain corresponding to the weight information sent from the weight determining means 57 is selected and determined from the gain table 74 and determined. The gain thus set is transmitted to the servo circuit 75. The reason why the gain table 74 is provided to select the gain is to reduce the load on the gain determining means 73 and to shorten the time from obtaining the weight information to determining the gain.

Here, the linear transport vehicle 3 will be described. In the present embodiment, as shown in FIGS.
The main body 31 having wheels runs on the inside of the traveling rail 2 which is hollow so that the inside can travel. A main body 31 is provided with a permanent magnet 32 as a secondary conductor, and a primary coil 2 of a linear motor having a laminated coil and an iron core arranged at a predetermined position on the traveling rail 2.
1 (propulsion means). The primary coils 21 are densely arranged in a portion where a stop is required in each zone, and are arranged with a slightly wider interval in a section where the primary coil 21 is not stopped. Further, in the primary coil 21, the Hall elements 22 are arranged in a line at predetermined intervals along the longitudinal direction of the traveling rail 2, and when the linear carrier 3 passes, the Hall elements 22 are fixed by permanent magnets 32 provided on the linear carrier 3. The Hall element 22 is excited. For this reason,
The actual speed of the linear carrier 3 can be detected by detecting from which Hall element 22 to which Hall element 22 is excited by the passage of the linear carrier 3 within a predetermined minute time.

Referring to the feedback control and the gain performed by the servo circuit 75, the feedback control performed in the present embodiment, as shown in FIG. 5, is performed such that the primary control is performed so as to match a predetermined target speed pattern P0. In this control, the speed of the linear transport vehicle is made to coincide with a target speed pattern by controlling the coil energization time while correcting the current. More specifically, from the difference between the target speed V1 at t1 seconds and the actual speed v1 obtained by the above method, the energization at which the speed at the next t2 seconds will match the target speed V2. The output of the primary coil is controlled by obtaining the length of time (operating amount). Even at t2 seconds, the length of the next energization time is determined from the difference between the target speed V2 and the actual speed v2. By repeating this, control is performed so that the target speed pattern P0 and the speed of the linear transport vehicle 3 match.

At this time, if the weight of the entire linear transport vehicle 3 is largely different, a difference occurs in the actual speed of the linear transport vehicle even if a current flows through the primary coil for the same time. The solid line in FIG. 5 is the target speed pattern P0, the one-dot chain line P1 is the case where the gain is too large, and the two-dot chain line P2 is the case where the gain is too small. If the gain is too high,
If the weight of the entire linear carrier 3 is light, too much acceleration occurs,
Over-deceleration is repeated, and in severe cases, the vehicle does not approach the target speed pattern P0. Furthermore, when the acceleration and deceleration are repeated and the target speed pattern P0 is greatly deviated, control becomes impossible. Conversely, if the gain is too small, the target speed will not easily reach the target speed if the overall weight of the linear transport vehicle 3 is heavy. there is a possibility.

In the linear carrier having the secondary side provided in the main body as in this embodiment, for example, the main body is about 30 kg, the empty cassette is about 20 kg, and one work piece is 1 kg.
It is about 0 km. Assuming that ten work pieces can be stored in the cassette 4, the weight of the entire linear transport vehicle 3 is 30 kg when the cassette 4 is not mounted, and the weight of the fully loaded cassette 4 is 30 kg.
Is large, the difference is large at 150 kg, and the difference in weight is large depending on the number of workpieces.
If the weight of the entire linear carrier 3 is light, the gain is reduced, and the output of the primary coil 21 is adjusted so as to shorten the energization time. If the weight of the entire linear carrier is heavy, the gain is increased. By adjusting the output of the primary coil 21 so as to make the energizing time longer, even if the weight of the entire linear carrier 3 greatly changes, the target can be quickly set while appropriately controlling the acceleration / deceleration of the linear carrier 3. Speed pattern.

In the present embodiment, when the weight information is only for the cassette (A), the cassette contains 1-2 pieces (B), 3-4 pieces (C), 5-6 pieces (D), 7 pieces of work. ８8 sheets (E) and 9〜１０10 sheets (F) are stored, and the weight table 5
8 is stored. The gain table 74 has a gain corresponding to the weight information and a gain when the linear carrier is empty. For example, if five workpieces are stored in a cassette and are transferred from the stocker to the cassette mounting table 51, for example, the load cell may be 2
If one is provided, referring to FIG.
The detection result of g, 69.5 kg is sent to the weight determining means 57, and the weight determining means 57 calculates an average value of 70 kg, and selects D as the weight information by referring to the weight table 58. The weight information D is sent to the gain determining means 73 of the zone controller 7, and the gain determining means 73 selects and determines the gain corresponding to the weight information D from the gain table 74, and sends the gain to the servo circuit 75.

In the present embodiment, the load cell 56
After making the weight from the weight information by the weight determination means 57,
Although it is transmitting to the zone controller 7, the load cell 5
6 may be sent directly to the zone controller 7, and the zone controller 7 may obtain the average of the weights, and the gain corresponding to the average weight may be obtained from the gain table. Further, the detection result or the calculation result may be used as it is, instead of dividing the weight or the gain into a specific range by using a gain table, a weight table, or the like. In the present embodiment, the weight data is transmitted from the station 5 in the form of weight information to the zone controller 7.
However, the gain may be obtained at the station 5 and the gain may be sent to the zone controller 7.

Further, in the present embodiment, the load amount is detected by the load cell 56. However, the load amount may be detected by detecting the number of works by a photoelectric sensor or a CCD camera.

[0029]

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

According to the first aspect of the present invention, since the gain can be set based on the load of articles, the gain can always be set to an appropriate value even if the weight of the entire transport vehicle changes. In addition, feedback control can be performed with the target speed pattern immediately after the vehicle starts moving.

According to the invention described in claim 2, according to claim 1
In addition to the effects of the invention described in the above, it is possible to detect the load amount before transferring the articles to the carrier, and to prepare for transmission of the load before transferring the articles to the carrier. it can. By matching the movement of the article with the movement of the information on the load, it is possible to prevent a problem that the article does not match the information on the load.

According to the invention described in claim 3, according to claim 1
Alternatively, in addition to the effect of the invention described in claim 2, since only the secondary conductor is provided on the carrier, the carrier can be reduced in weight and a large propulsive force can be obtained with a small force.
Further, even if the transport vehicle is made lightweight, the energization of the primary coil can be controlled by the gain according to the load amount of the articles, and the articles can be transported smoothly.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating an outline of a transport system according to an embodiment.

FIG. 2 is a front view showing a station and a traveling rail according to the embodiment.

FIG. 3 is an explanatory diagram showing a schematic configuration of the present embodiment.

FIG. 4 is a side view showing an outline of a linear carrier and a traveling rail according to the present embodiment.

FIG. 5 is a graph showing a relationship between a speed pattern and a gain.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transport system 3 Linear transport vehicle 4 Cassette (article) 7 Zone controller (control means) 21 Primary coil (propulsion means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B65G 54/02 B60L 13/02 MF term (Reference) 3F021 AA01 BA02 CA06 DA03 DA04 3F022 AA08 EE05 FF01 JJ02 KK18 NN22 NN26 PP03 QQ04 QQ07 5H113 BB01 BB09 CC01 CC08 DD01 FF08 GG24 HH06 HH12 HH26 5H301 AA02 BB05 CC03 CC06 EE02 EE12 EE26 FF02 JJ02 JJ05 KK02 KK04 KK06 KK08 KK12 KK13

Claims (3)

[Claims] 1. A transport system comprising: a transport vehicle that transports an article; and a control unit that feedback-controls a propulsion unit of the transport vehicle so that the transport vehicle travels in a predetermined speed pattern. A transport system, wherein a gain of feedback control is set based on a loaded amount of articles when a transport vehicle is started. 2. A method according to claim 1, further comprising a station provided with detecting means for detecting a load of the articles, wherein the load of the articles is transmitted from the station to the control means when the articles are transferred from the station to the carrier. 2. The transport system according to claim 1, wherein: 3. The carrier is a linear carrier equipped with a secondary conductor and propelled by a primary coil disposed on the ground side, and the control means controls energization of the primary coil. The transport system according to claim 1 or 2, wherein