JPS6285305A - Operation controlling system for unmanned carrying truck - Google Patents

Abstract

PURPOSE:To raise the operation rate of the whole work station group by estimating a float until no-work is generated, with respect to each work station. CONSTITUTION:A carrying candidate extracting/carrying-in float calculating part 208 extracts a carrying candidate which can be carried, based on line state tables 205, 206 and 207, and a process path/carrying time table 209, and calculates a pallet carrying-in float to a carrying destination with respect to it. Subsequently, by grasping a fact that the smaller float the carrying candidate has, the higher its priority degree is, an empty carrying truck which can be brought to access most quickly is allocated in order of its priority degree. This result is transmitted to a carrying truck running control device 202. In this way, the operation rate of the whole work station group can be raised.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is directed to FA (Factory Automation)
on) system.

In particular, in systems where the processing time for winter items cannot be determined in advance due to work stations that require human intervention, or work stations that are automated or that are subject to many disturbances (equipment abnormalities, etc.), the operating rate of one work station group as a whole can be improved. This invention relates to an operation control method for automatic guided vehicles to improve the performance of automated guided vehicles.

[Background of the invention]

In order to facilitate understanding of the present invention, first, 1 shown in FIG.
Explain the flow of goods based on a typical process layout.

A product is completed through multiple steps. Transportation between processes is often carried out by the automatic guided vehicle 101 so as to be able to flexibly respond to changes in layout and the like. Items processed at the upstream process work station 102 (mounted on pallets 103) are delivered to the upstream process line 104. The pallet 103 is transported to a downstream process line 106 by a transport 101 in order to receive the next processing at a downstream process work station 105. Which downstream process line 1
06 is determined by the upstream process line and the type of object on the pallet, but the difference between the two is irrelevant to the present invention, and for the sake of simplifying the explanation, The description of the present invention assumes the former target.

Now, the purpose of transport is to transport objects in a timely manner so as to improve the operating efficiency of one work station group as a whole. In order to achieve this, a key point is to evaluate the degree of risk that work stations will become idle due to running out of supplies. Once the degree of risk is determined, tasks can be assigned to transport vehicles so that objects are transported preferentially to work stations with a high degree of risk.

As a method for evaluating the above-mentioned degree of risk, a patent application was filed in 1986-112.
In No. 723, regarding pallets on the downstream process line 106, the time at which one work station becomes idle is calculated by summing up the processing times at the work stations. In addition, for each pallet. Processing time data at each work station is given in advance as a constant.

This method is effective for objects for which the processing time does not vary and is always constant. However, as seen in electronic component assembly, there are some work stations that require human intervention, and some that are automated.

In a system including work stations with many disturbances (facility abnormalities, etc.), the processing time varies even when processing the same type of material, and the above-described method is not effective.

It should be noted that one possible way to solve the above-mentioned problem is to have a large number of intermediate layers between processes.

This method is not appropriate in the current situation where there is a strong demand for a drastic reduction in intermediate inventory.

[Purpose of the invention]

An object of the present invention is to transport objects to each work station in a timely manner so as to improve the operating rate of the work station group as a whole. The purpose of the present invention is to provide a transportation control system for transport vehicles.

[Summary of the invention]

In order to achieve the above object, the present invention provides means for measuring the actual value of the production pitch (corresponding to the processing time of each pallet) at the work station, and based on the actual value, the next expected production The pitch is estimated, and based on that, the risk of each work station being idle is evaluated. In addition,
Next, to estimate the expected production pitch, we will use some new data from past actual production pitch values.
As for the specific usage method, whether to use the average value of those data, whether to use new data, increase the degree of use, or give special weight between data is determined depending on the characteristics of the controlled object. .

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2 to 8.

FIG. 2 shows a block configuration of a conveyance control system according to the present invention. This system is roughly divided into three blocks. The first block is a line control device 201,
The second block that controls the upstream process line 104 and the downstream process line 106 is a transport vehicle travel control bag M2O2. Performs steering control and travel control to carry out. The third block is a conveyance vehicle operation control device 203, which is based on the present invention, and is a conveyance command (transfer source, conveyance destination) that improves the operating rate of the entire work station based on the line state and the conveyance vehicle state.

The transport vehicle Nu) to be used is determined and transmitted to the transport vehicle travel control device 1202.

Next, the contents of the guided vehicle operation control device 203 will be explained. The line status management unit 204 roughly grasps three line statuses based on signals from the line control bag 5!201. One is the contents of the upstream process line status table 205, the details of which are shown in FIG. 3. This is for checking which upstream process line has a pallet that can be carried out. This is a case where the status is normal, the number of loaded pallets≠0, and the transportation allocation has not been completed. The second is the contents of the downstream process line status table 206, details of which are shown in FIG.

This is to check the downstream process line where pallets can be carried in, and whether it is possible to carry in, normal, has a carry-in area, or
Delivery allocation has not yet been completed. The third is the content of the production pitch related information table 207, details of which are shown in FIG. the latest data) are stored, and based on these, the next production pitch T'
is estimated.

The transportation candidate extraction/delivery allowance time calculation unit 208 is.

The above-mentioned line status table 205. which is the core of the present invention.
206 and 207, and the process route/transport time table 209 (see Figure 6) that stores the transport destination (downstream process line Ha) for pallets on the upstream process line and the transport time (see Fig. 6). Candidates are extracted, and the allowance time TV for carrying the pallet to the W& destination is calculated. This processing flow will be explained later. Note that the calculation results are stored in the transportation candidate/delivery allowance time storage table 210.
(See Figure 7).

Once the transport candidates and the spare time for pallet delivery to their transport destination have been determined, the transport candidates with the shortest spare time are considered to have the highest priority, and the empty transport vehicles that can be accessed the earliest are selected in order of priority. It is only necessary to make the assignment and send the result to the transport vehicle traveling control device [202]. Since this part is easy to process and there are known examples, it is not the point of the present invention, so it will be briefly explained below.

The guided vehicle state management unit 211 is connected to the guided vehicle running control device 202.
Based on the signals from the
Also, know where you are. The state is stored in the transport vehicle state table 212. Based on this content and the content of the transport candidate/delivery allowance time storage table 210 described above, the work assignment/control command unit 213 to the transport vehicle
As described above, work is assigned to the guided vehicles, and the results are transmitted to the guided vehicle travel control device [202].

Next, the processing in the transportation candidate extraction/carrying allowance time calculation section 208 will be explained with reference to FIG.

First, the transport candidate/delivery allowance time storage table 210 is initialized (zero cleared) (box 801). next,
Transport candidates are extracted as shown below (box 8
02). Based on the upstream process line status table 205 (details are shown in FIG. 3), an upstream process line that can be carried out is determined.

Let this line be X. The destination of the pallet on this line X is checked from the process route/transport time table 209 (details are shown in FIG. 6), and the downstream process line Nα is set as y. Next, based on the downstream process line status table 207 (details are shown in FIG. 4), it is checked whether the corresponding downstream process line y can be loaded. If it is possible to carry it in, the transport from the upstream process line Wax, which is the transport source, to the downstream process line Nay, which is the transport destination, is a transport candidate.

Next, if there is a transportation candidate (box 803), one transportation candidate for which the carry-in allowance has not been calculated is taken out.

The transport candidate is defined as (transport source X", transport destination y") (box 804).

Next, the next production pitch T' for the downstream process line NQy'' is estimated using the following formula (box 805
).

T' = Σ wiXTt However, the above TI is based on the production pitch related information table (Figure 5)
Since the work efficiency stored in 0 normally 1 does not change rapidly, the new production pitch actual value is used for estimating T'.
It's worth using ( v t > WJ for i <
j) e Next, the downstream process line island y4'-
Calculate the pallet loading time Ty (box 8).
06).

Ty=(t+T')-(to+Tu) However.

(Process route/transport time table...FIG. 6) The first bracket in the above formula indicates the time when the work station connected to the downstream process line y41 is estimated to be idle. The inside of the second bracket indicates the time at which the pallet on the upstream process line NQx" can be delivered to the downstream process line Nay" at the earliest. Therefore, the difference between the two means the extra time for delivering the pallet to the downstream process line island. .

If the following processing has not been completed for all transport candidates (box 807), the process returns to box 804. If completed, exit.

As described above, if this embodiment is used, even if the processing time for the same work varies at work stations, the transportation candidate extraction/delivery allowance time calculation unit 208 shown in FIG. for each work station based on the processing flow shown in .

In order to estimate the slack time until no work occurs (assuming no new pallets are brought in), priority is given to transport to stations with less slack time, thereby improving the operating rate of the entire work station group. . Also,
In the present invention, the transportation candidate extraction/carrying allowance time calculation unit 208
Since the processing time for each pallet is automatically determined as the production pitch, there is no need for humans to set the time in advance as in the past.

〔Effect of the invention〕

According to the present invention, even if there are work stations where work efficiency varies, the risk of non-work occurring at that station can be accurately grasped, so priority transfer to the work station with a high risk can improve the overall efficiency of the station group. This will result in an improvement in the operating rate. Also.

Since the present invention has a means for automatically determining the processing time for each pallet, there is no need for humans to set the time in advance as in the past, and the work time at the work station is frequently changed when the characteristics of the object are changed. Good conveyance control can be performed even in cases where the

[Brief explanation of drawings]

Fig. 1 is a typical process layout diagram of an FA system, Fig. 2 is a block diagram of a conveyance control system according to the present invention, Fig. 3 is an upstream process line status table, Fig. 4 is a downstream process line status table, Figure 5 is the production pitch related information table, Figure 6 is the process route/transport time table, and Figure 7 is the production pitch related information table.
The figure is a transport candidate/carry-in allowance time table, and FIG. 8 is a flowchart showing the processing procedure of the transport candidate extraction/carry-in allowance time calculation section.

Claims (1)

[Claims] In a system consisting of multiple work stations and a group of transport vehicles that transport objects between the stations, a means is provided to measure the actual value of the production pitch at the work station, and based on the measured actual value, the following Based on the estimated pitch and the start time of the item currently being processed, calculate the time when the work station is expected to be idle unless items are brought in. An automatic guided vehicle operation control system characterized by preferentially transporting objects for which there is a smaller difference between the time at which the object was placed and the earliest time at which the object can be transported.