KR100836815B1 - Control method for optimal carrying of agv system - Google Patents

Abstract

An optimal conveyance control method of an unmanned conveying system is disclosed. An object of the present invention is to implement a more efficient unmanned carrier system by greatly reducing the amount of traffic and the amount of communication of the unmanned carrier through an optimized carrier scheduling in an unmanned carrier system operating an unmanned carrier having two hands. The unmanned conveying system according to the present invention for this purpose includes an unmanned conveying vehicle having two hands, which performs at least two work orders having the same destination simultaneously using two hands at the corresponding destination. .

Description

Optimal conveyance control method of unmanned conveying system {CONTROL METHOD FOR OPTIMAL CARRYING OF AGV SYSTEM}

1 illustrates an unmanned carrier vehicle having two hands in accordance with an embodiment of the present invention.

Figure 2 is a block diagram showing the configuration of an unmanned conveying system according to an embodiment of the present invention.

3 is a flow chart showing an optimal conveyance control method of an unmanned conveying system according to an embodiment of the present invention.

FIG. 4 is a diagram for explaining setting of an unloading-loading pattern in the optimum conveyance control method of the unmanned conveying system shown in FIG.

FIG. 5 is a diagram for explaining setting of a loading-loading pattern in the optimal conveyance control method of the unmanned conveying system shown in FIG.

6 is a flowchart illustrating a pattern set operating method of an unmanned carrier system according to an exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

102, 206: Rail

114, 118: hand

124, 202a ~ 202j: process equipment                 

126, 208: stalker

128: Substrate

204: RGV

210: Stalker Table

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unmanned conveying system, and more particularly to a control method of an unmanned conveying system for conveying a wafer, an LCD substrate, or the like between a stocker and a process equipment according to a predetermined work schedule.

In general, an unmanned conveying system is used to automate the loading and transport of goods, and uses an unmanned conveying vehicle. An unmanned carrier vehicle, or AGV (Automatic Guided Vehicle), carries a load while moving along a guideline installed on the floor or moving to a desired position using a separate positioning system. The guideline is a magnetic tape continuously installed on the floor, and the AGV detects the magnetism from the guideline by using a magnetic sensor to identify the position of the guideline and travel along the guideline. In contrast, rail guided vehicles (RGVs) carry loads while moving along rails mounted on the floor.

In the semiconductor manufacturing process, an unmanned transport vehicle carrying wafers or LCD substrates is provided with a hand for holding a wafer or LCD substrate. A conventional unmanned transport vehicle, which has only one hand, travels between the process equipment and the stocker and moves the wafer. In loading and unloading, since only one hand is used, it is relatively free in loading and unloading, and the loading and unloading between the processing equipment and the stocker and the loading and unloading at the same time cannot be performed simultaneously. The moving distance is greatly increased. Above all, loading and unloading must be performed as separate tasks, thereby increasing the working time and increasing the number of times of communication and the amount of communication between the main control unit and the unmanned carrier.

An object of the present invention is to implement a more efficient unmanned carrier system by greatly reducing the amount of traffic and the amount of communication of the unmanned carrier through an optimized carrier scheduling in an unmanned carrier system operating an unmanned carrier having two hands.

The unmanned conveying system according to the present invention for this purpose includes an unmanned conveying vehicle having two hands, which performs at least two work orders having the same destination simultaneously using two hands at the corresponding destination. .

The unmanned conveying system according to the present invention includes an unmanned conveying vehicle having a buffer and two hands, and the unmanned conveying vehicle is configured to convey objects while moving between a plurality of first working positions and a plurality of second working positions. The control method of the unmanned conveying system according to the present invention is a combination of two loading commands having the same working position as the destination and a combination of a loading command and an unloading command having the same working position as the destination when there is free space in the buffer. The first pattern is set to be included in at least one command combination and stored in the memory. When there is free space in the buffer and the loading command of the first pattern is not performed, each of the single work instructions not included in the first pattern is set as the second pattern and stored in the memory. When there is no free space in the buffer, only the loading command for loading the object loaded in the buffer to the corresponding destination is searched and stored in the memory.

The unmanned conveying system according to the present invention includes a main control device for generating a work command and an unmanned transport vehicle for receiving a work command to perform a work. The control method of the unmanned conveying system according to the present invention firstly includes a main control device. Select patterns to be used from among a plurality of patterns consisting of a combination of work instructions generated from the user, determine the execution order and the total execution time of each selected pattern, register the selected patterns as one pattern set, and each registered pattern Determine the order of execution between the three sets.

Referring to Figures 1 to 5 a preferred embodiment of the present invention made as described above are as follows. 1 is a diagram illustrating an unmanned carrier having two hands according to an embodiment of the present invention. As shown in FIG. 1, the RGV 100, which is an unmanned carrier vehicle according to an embodiment of the present invention, conveys a substrate 128 or a wafer (not shown) between the process equipment 124 and the stocker 126. The RGV 100 is installed to linearly move along the rail 102 and can rotate 360 degrees on the X-Y plane. The length of the rail 102 can extend as needed. The use of two hands 114 and 118 provided in the RGV 100 is more efficient by loading or unloading two substrates or wafers during one cycle of operation cycle. A buffer (not shown) which is a temporary storage space is mounted on the RGV 100, and a plurality of wafers or LCD substrates are loaded and transported in the buffer.

2 is a block diagram showing the configuration of an unmanned conveying system according to an embodiment of the present invention. As shown in FIG. 2, the RGV 204 is moved along the rail 206 pre-installed, and the process equipment 202a-202j, the stocker 208, the stocker table 210, and the like are provided around the rail 206. do. The RGV 204 conveys a wafer, a substrate, or the like between the process equipment 202a-202j and the stocker 208 while moving along the rail 206.

3 is a flowchart illustrating an optimal conveyance control method of an unmanned conveying system according to an exemplary embodiment of the present invention. As shown in FIG. 3, it is checked whether there is free space in the buffer of the RGV 204 (302), and if there is free space in the buffer of the RGV 204, at least an unloading operation (ie, process equipment 202a to 202j) or Process equipment for unloading and loading instructions (i.e., objects in the buffer of the RGV 204) is a condition that can carry out the lifting of the stocker 208 to be loaded into the buffer of the RGV 204. (202a to 202j) or an operation command to be placed on the stocker 208) to determine the unloading-loading patterns by associating with each other (304).

On the contrary, since the buffers of the RGV 204 are all filled with wafers and there is no free space, no further unloading operation can be performed. Therefore, the wafers currently in the buffers of the RGV 204 are processed by the process equipment 202a to 202j or the stocker 208. Search for and load loading instructions for loading (at step 324).                     

Unloading-loading pattern setting 304 is followed by setting a loading-loading pattern 306. Set the loading-loading patterns by searching for the EQ-loading commands (EL) having the same destination (process equipment) among the EQ-loading commands (EL) that are not set as the pattern when setting the aforementioned unloading-loading pattern. (306). EQ stands for Process.

Then it is checked once again whether there is free space in the buffer of the RGV 204 (308), and if the loading operation has already started (310). If the loading operation has not yet started while there is free space in the buffer of the RGV 204, the ST for unloading the wafer from the stocker table 210 to further fill the wafer in the free space of the buffer of the RGV 204. Search for whether an unloading instruction SU exists and store it in memory (312). ST stands for stocker table.

At this time, the number of ST-unloading instructions (SU) stored in the memory is limited to a preset maximum value. When the number of ST-unloading instructions (SU) in the memory reaches at least one of the following conditions, the ST- The retrieval and storage of the unloading instruction SU is stopped.

(1) nSU = nMaxSU: When the number of stored ST-unloading instructions (SU) reaches the preset maximum allowed number of stored (nMaxSU)

(2) nSU = nBufferLeft: When the number of stored ST-unloading instructions (SU) reaches the number of empty buffer space (nBufferLeft)

(3) nSU = nTCQty: When the number of stored ST-unloading instructions (SU) reaches the number of work instructions (nTCQty) transmitted from the main control unit.

If there is no free space in the buffer of the RGV 204 or if loading into the process equipment 202a-202j or stocker table 210 has already begun, it is impossible or inefficient to perform further unloading from the stocker table 210. Therefore, as described above, the storage device 210 searches for and stores whether there is a loading command for loading the wafer in the stocker table 210 or the process equipment 202a to 202j (324).

On the other hand, when there is room in the memory while searching for and storing whether the ST-unloading instruction SU exists, that is, the number of job instructions nMemoryJob stored in the memory is equal to or less than the preset maximum value nMaxWindow (314). When the number of work commands (nTCQty) transmitted from the main control unit is not reached (316), the EQ-unloading command (EU), the EQ-loading command (EL), and the ST-loading command (SL) are additionally searched. Store them (318, 320, 322).

On the contrary, when there is no room in the memory, that is, when the number of job commands (nMemoryJob) stored in the memory exceeds the preset maximum value (nMaxWindow) and reaches the number of job commands (nTCQty) transmitted from the main control unit. Only the EQ-loading command (EL) and the ST-loading command (SL) are additionally retrieved and stored, excluding the EQ-unloading command (EU) (i.e. blocks 320 and 322 for NO in blocks 314 and 316). Proceed to).

Subsequent to the loading command retrieval and storage operation 324 described above, it is searched whether there is an ST-unloading command SU which is not set as a pattern among the work commands transmitted from the main control device (326). If there is no ST-unloading instruction (SU) not set in the pattern, the scheduling is terminated immediately. On the contrary, if there is an ST-unloading instruction SU not set in the pattern, the search 312 of the ST-unloading instruction SU is performed to perform job scheduling once again. Since rescheduling is performed only once, it is determined whether the current rescheduling is the first rescheduling. In the case of the first rescheduling, the ST-unloading instruction (SU) search operation 312 is performed. If so, the scheduling ends without further rescheduling (328).

4 is a view for explaining the setting of the unloading-loading pattern in the optimal conveyance control method of the unmanned conveying system shown in FIG. 3, and analyzing and correlating work commands transmitted from the main control device for more efficient conveying operation. It is a view showing a method for binding to each other to set at least one pattern, and to perform the operation according to the patterns provided in this way.

As shown in Fig. 4, the EQ- for fetching the wafer from the process equipment 202a to 202j during all wafer transfer commands sent from the main control device to the RGV 204 when there is free space in the buffer of the RGV 204. First, it is searched if there are unloading commands EU_a to EU_j (for example, in FIG. 4, it is assumed that an EQ-unloading command EU_b for unloading the wafer W1 located in the process equipment 202b has been searched). lets do it).

This time, it is searched whether there is an EQ-loading instruction EL_b for conveying and loading the wafer to the process equipment 202b. That is, the EQ-loading instruction EL_b for the wafer (for example, wafer W2 or W3 in FIG. 4) to be unloaded from the process equipment 202b and then newly loaded into the empty process equipment 202b is generated. Search for existence The unloading-loading pattern is set by combining the retrieved EQ-unloading command EU and the EQ-loading command EL.

In order to load the wafer W2 or W3 into the process equipment 202b, the wafer W2 or W3 must first be unloaded from the stocker table 210 or the process equipment 202j. Therefore, an unloading command for unloading the wafer W2 or W3 is retrieved and stored in the memory as a pair with the previously unloading-loading pattern. The command to unload the wafer W2 is to unload the wafer W3 from the ST-unloading instruction SU or the process equipment 202j to unload the wafer W2 from the stocker table 210. This is the EQ-unloading command EU_j for loading.

In order to set the pattern of the work instruction, the work instruction is searched in the order of EU_b-EL_b-SU (EU_j), but the actual work is performed in the order of SU (EU_j)-EL_b-EU_b. That is, the RGV 204 approaches the stocker table 210 to unload the wafer W2 or approaches the process equipment 202j to unload the wafer W3 and thus unloads the wafer W2 or W3. To the process equipment 202b. Since the RGV 204 approaching the process equipment 202b has two hands, the wafer in the process equipment 202b may be formed using an empty hand other than the hand holding the wafer W2 or W3. After unloading W1), the conveyed wafer W2 or W3 is loaded into the process equipment 202b (EL_b). At this time, since loading and unloading are performed through two hands of the RGV 204, the work time and moving distance can be greatly reduced, and the unloading and loading are combined in one pattern so that the result of work on the main control device The amount of communication for sending a message is also greatly reduced.

FIG. 5 is a diagram for explaining setting of a loading-loading pattern in the optimal conveyance control method of the unmanned conveying system shown in FIG. FIG. 7 is a diagram illustrating a scheduling method for setting and performing a task according to the patterns provided as described above.

As shown in Fig. 5, when two EQ-loading instructions EL_e1 and EL_e2 are retrieved for loading two wafers W4 and W5 into the process equipment 202e, the two loading instructions are bundled and one loading- Set to the loading pattern.

In addition, the ST-unloading instruction SU for unloading the wafer W4 from the stocker table 210 and the EQ-unloading command EU_h for unloading the wafer W5 from the process equipment 202h are provided. It is retrieved and stored in memory as a pair with the loading-loading pattern set previously.

In this case, the RGV 204 unloads the wafer W4 of the stocker table 210 and the wafer W5 of the process equipment 202h according to the job priority, loads it into its buffer, and the process equipment 202e as a destination. ), Two wafers W4 and W5 mounted in its buffer are loaded into the process equipment 202e.

Since the RGV 204 according to the embodiment of the present invention has two hands, it is possible to simultaneously load two wafers W4 and W5 into the processing equipment 202e. Therefore, the loading time is significantly shorter than the RGV using one hand, and the overall conveying time is also greatly shortened.

FIG. 6 is a flowchart illustrating a method for operating a pattern set of an unmanned carrier system according to an embodiment of the present invention, in which a pattern to be used is determined and registered as one pattern set, thereby improving conveying efficiency by operating such pattern sets in order. It shows the way. The pattern setting according to the embodiment of the present invention classifies each work command by priority and sets the work commands related to each other among the work orders having the same priority as one pattern. In addition, the work of the nearest place is first performed, and then the main control device performs the designation forcibly, and the order of each pattern and the order of each pattern set are determined to satisfy this.

As shown in FIG. 6, first, patterns to be used among the patterns UL, LL, U, and L of a work command are selected (602). If the patterns to be used are checked, it is determined in what order to operate the patterns in each pattern set, and the execution time of the pattern set is also determined (604). Here, the execution time of the pattern set is the total time of executing one pattern set, and is determined as the time when the system operator is expected to be the most efficient. For example, if one pattern set is determined and the execution time is set to 20 minutes, the return of logistics is performed for 20 minutes according to the pattern set. When the pattern order and execution time in the pattern set are determined as described above, the corresponding pattern set is registered in the system (606). When the registration of the pattern set is completed, the order between each pattern set is determined and applied to the system (608). This allows each set of patterns to be performed in a given order during a set unique execution time. At this time, it is checked whether the inherent execution time of the currently executed pattern set has elapsed at a predetermined time interval (for example, one second interval) (610). 612.

In the control method of the unmanned conveying system according to the present invention, loading and unloading is performed more efficiently by performing a conveying operation using an unmanned conveying vehicle having two hands, thereby moving and moving the unmanned conveying vehicle. The time, the number of times of communication with the main control device, and the amount of communication are greatly reduced, enabling a more efficient unmanned carrier system.

Claims (11)

delete delete delete In the control method of the unmanned conveying system which has an unmanned conveying vehicle which has a buffer and two hands, and conveys an object moving between a some 1st working position and a some 2nd working position, A first combination such that a combination of a loading command and an unloading command having a same work position as a destination and a combination of two loading instructions having the same work position as a destination is included when there is free space in the buffer; Set a pattern and store it in memory; When there is free space in the buffer and the loading command of the first pattern is not performed, each of the single work instructions not included in the first pattern is set as a second pattern and stored in the memory; And a loading command for loading an object mounted in the buffer to a corresponding destination when there is no free space in the buffer, and storing the loaded command in the memory. The method of claim 4, wherein when there is free space in the buffer and the loading command of the first pattern is not performed, Retrieve and store an unloading command having the plurality of first working locations as a destination; Unmanned conveying system for retrieving and storing an unloading command and a loading command having the plurality of second working positions as a destination and a loading command having the plurality of first working positions as a destination in order when the memory of the work command is free. Control method. The method of claim 4, wherein The unmanned conveying system further includes a main control device for transmitting a work command to the unmanned conveying vehicle; And determining that there is room in the memory when the number of work commands stored in the memory is less than or equal to a preset maximum value and less than the total number of work commands transmitted from the main control device. The method of claim 4, wherein And a loading command having the plurality of second working positions as a destination and a loading command having the plurality of first working positions as a destination in order when the memory is not free. The method of claim 4, wherein When there is no free space in the buffer, only a loading instruction for loading an object mounted in the buffer to a corresponding destination is searched and stored in the memory, and then set as a pattern among the work instructions having a plurality of first working positions as a destination. And re-scheduling one or more unscheduled work commands to retrieve and store unloading commands having the plurality of first work positions as destinations. delete delete delete

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