JP4014444B2 - Work transfer method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a workpiece transfer method, and more particularly, to a workpiece transfer method using a transfer device that distributes a transfer device so that the workpiece can be transferred efficiently in a method of loading or unloading a workpiece into a processing station or the like. .
[0002]
[Prior art]
If a processing machine can be arranged at an arbitrary position in a factory having a manufacturing facility, the utilization factor of the site can be increased as compared with the case where the processing machines are arranged in a line.
[0003]
In this case, a net-like transfer path is formed between the processing machines, and the transfer vehicle transfers the workpiece through the transfer path.
[0004]
In general, a plurality of transfer vehicles are prepared, and each transfer vehicle moves along a route stored by itself or receives a route command from another control device.
[0005]
[Problems to be solved by the invention]
By the way, in the above-described prior art, a countermeasure is taken into consideration between the processing machine and the transfer vehicle in consideration of the transfer efficiency with respect to which transfer vehicle shares the loading / unloading of the workpiece with respect to which processing machine. Not. In other words, when a transfer request or a load request is sent from a processing machine, an empty transfer vehicle in the vicinity of the processing machine shares the load / unload, or one transfer vehicle is assigned for each process. I try to assign it.
[0006]
In the method of sharing with a transfer vehicle that exists in the vicinity of the processing machine, if there is no transfer vehicle in the vicinity of the processing machine that is ready to carry out the workpiece, one of the transfer vehicles is processed. You have to wait for a relatively long time to arrive at the machine. Furthermore, even when there is an empty transfer vehicle in the vicinity, a so-called deadlock frequently occurs in a race condition in which another active transfer vehicle is in a state of simultaneously using the transfer path and the branching section. .
[0007]
Furthermore, even when a failure occurs in a part of a transfer vehicle or the like, the work transfer system as a whole is desired to have a flexible system configuration that can continue operation. In this case, it is desirable that the time required to shift to a temporary production system after a failure occurs is short. Further, in a temporary production system, it is preferable that a certain level of production efficiency can be maintained even if a decrease in production efficiency is unavoidable.
[0008]
The present invention has been made in consideration of such problems, and in a work transfer system that transfers work using a plurality of transfer devices between stations allocated to a process, when stopping the operation of the transfer device, It is an object of the present invention to provide a workpiece transfer method that enables a rapid transition to a system for continuing the operation of a workpiece transfer system.
[0009]
[Means for Solving the Problems]
A workpiece transfer method according to the present invention includes a transfer device that transfers a workpiece, and a plurality of stations that carry the workpiece into or out of the transfer device. A controller for controlling the transfer device and the station to transfer the workpiece; In a workpiece transfer method in a transfer system having The frequency calculator A first step for determining a frequency at which the work is carried in or out for each station; The basic area determining unit is obtained by the frequency calculating unit. The station is divided into a plurality of basic areas so that the sum of the frequencies is substantially the same, one transfer device is assigned to each basic area, and information on the basic area is obtained. In memory A second step of storing; The temporary area determination unit reads the basic area information from the storage unit, Assuming that one of the transfer devices is unusable, the basic area shared by the unusable transfer device and adjacent to the basic area other For the integrated area including the basic area, the stations in the integrated area are divided into temporary areas so that the sum of the frequencies is substantially the same, and one transfer device is assigned to each temporary area. information In memory A third step of storing; The controller reads the basic area information from the storage unit, While detecting the state of the transfer device, when the transfer device loads or unloads the workpiece to or from the station in the assigned basic area, and when one of the transfer devices is unusable, The controller reads information on the temporary area from the storage unit, Replacing the preset integrated area with the temporary area corresponding to the unusable transfer device , Causing the transfer device to carry the workpiece into or out of the station in the allocated temporary area. And a fifth step.
[0010]
In this way, assuming that one of the transfer devices is unusable, a temporary area that can complement the basic area shared by the unusable transfer device is set in advance, so that the transfer device actually operates. Can be quickly transferred to a system for continuing the operation of the workpiece transfer system.
[0011]
In this case, when an unusable transfer device is restored to use, The controller is Return the temporary area to the basic area.
[0012]
In the first step, the frequency corresponds to the actual operation when the actual frequency at which the work is carried in or out is calculated including the waiting time for the station waiting for processing. Can be set.
[0013]
Further, the plurality of stations may be classified into a plurality of ordered processes related to the processing of the workpiece, and in the first step, the frequency may be obtained from a processing sharing ratio in the process. .
[0014]
Based on the basic area and the temporary area, the operation of the transfer device and the station Simulation function Run the simulation with The temporary area determination unit Whether the basic area and the temporary area are properly classified may be determined. When it is determined that the temporary area is unsuitable, the temporary area can be set again to perform appropriate classification.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a work transfer method according to the present invention will be described with reference to FIGS.
[0016]
As shown in FIG. 1, a workpiece transfer system 10 used in the workpiece transfer method according to the present embodiment includes a plurality of transfer vehicles (transfer devices) 18 that transfer a workpiece 16, and the transfer vehicle 18 moves via wires 60. Or a plurality of transfer paths 20 that can be stopped in the middle, a plurality of attachment / detachment devices (stations) 24 that carry in and out the work 16 from the transfer vehicle 18, and a work 16 that is taken in and out of the attachment / detachment device 24. A branching device that is provided at a relay point or an end of the transfer path 20 and that can stop the transfer vehicle 18 that has entered from the transfer path 20 or advance to another transfer path 20. (Relay path) 22, a plurality of unit controllers 26 that directly control the operations of the transfer vehicle 18, the transfer path 20, the attachment / detachment device 24, and the branching device 22, and a plurality of units And a main controller (controller) 12 that controls the entire integrated controller 26.
[0017]
In the following, “carrying in” is defined as representing the work of transferring the workpiece 16 from the transport vehicle 18 to the attachment / detachment device 24, and “carrying out” is defined as representing the reverse operation.
[0018]
As shown in FIG. 2, there are a plurality of attachment / detachment devices 24, and each attachment / detachment device 24 a to 24 m is provided with a processing machine 14 (see FIG. 1) corresponding to the processing process of the workpiece 16. The workpiece 16 is classified into two types of workpieces 16a and 16b (both not shown), and the processing machine 14 is a mixture of the workpieces 16a and 16b and those that perform dedicated machining on either one of them. Yes.
[0019]
The machining process of the workpiece 16 is sequentially classified into five processes A, B, C, D and a dispensing process. In the loading process, the workpiece 16 is transferred from the loading device 36 to the process A, and thereafter, the processes B, C, D Is completed, it is sent to the dispensing device 38 in the dispensing process. Note that the loading device 36 and the dispensing device 38 have functions of loading and unloading the workpiece 16, and exchange the transfer vehicle 18 and the workpiece 16 in the same manner as the loading / unloading device 24. It shall be handled in the same row.
[0020]
The process A includes attachment / detachment devices 24a to 24d, the process B includes attachment / detachment devices 24e to 24g, the process C includes attachment / detachment devices 24h to 24k, and the process D includes attachment / detachment devices 24L to 24m. The feeding device 36 and the dispensing device 38 are connected by a transfer path 20 arranged in a net shape. Further, the charging device 36, the dispensing device 38, and the attachment / detachment devices 24 a to 24 m are provided in the middle of each transfer path 20.
[0021]
The transfer path of the workpiece 16 is, for example, input from the input device 36 and processed in order by the attachment / detachment device 24b in the process A, the attachment / detachment device 24g in the process B, the attachment / detachment device 24k in the process C, and the attachment / detachment device 24L in the process D. The payout device 38 pays out.
[0022]
There are a plurality of branch devices 22, branch devices 22 a to 22 m are installed at relay points of the transfer path 20, and branch devices 22 n to 22 v are installed at the end of the transfer path 20. Further, the transfer path 20 extending from the relay point does not need to intersect 90 °, and can be set to an arbitrary angle like the branching devices 22i and 22m. Furthermore, the number of transfer paths 20 extending from the relay point is not limited to four intersecting, and can be set to an arbitrary number such as two or three as in the branching devices 22a and 22m.
[0023]
Further, the attaching / detaching devices 24a to 24m and the dispensing device 38 are divided into an appropriate number of basic areas, and the transfer vehicle 18 is assigned to each basic area. The method of dividing the basic area and the setting of a temporary area for interpolating the basic area when the transport vehicle 18 breaks down will be described later. Each transport vehicle 18 carries in the workpiece 16 only to the assigned attachment / detachment device 24 or the dispensing device 38, and enters the basic area on the previous process side when receiving the workpiece 16 unloading. When avoiding the transfer vehicle 18, it is assumed that the vehicle enters another adjacent basic area.
[0024]
FIG. 2 shows an example in which four transfer vehicles 18a to 18d are assigned to four basic areas α, β, γ, and δ, respectively. Speaking of the basic area β shared by the transport vehicle 18b, the work 16 is loaded into the attachment / detachment devices 24f, 24g, 24j, and 24k in the areas extending over the processes B and C, and the unloading work is performed in the previous process. An operation of receiving unloading from the attachment / detachment devices 24a, 24b, 24c, 24d, 24e, 24f, and 24g in a certain process A and process B is performed.
[0025]
As shown in FIG. 3, the attachment / detachment device 24 has a vertically long structure, and a chain / sprocket mechanism 59 is incorporated in rails 58 erected on both sides. The integrated upper and lower two-stage mounting bases 54 and 56 projecting horizontally from the rail 58 can be moved up and down along the rail 58 by a chain / sprocket mechanism 59, and the mounting bases 54 and 56 by a height sensor (not shown). The height can be detected. The chain / sprocket mechanism 59 is driven by a motor 52 connected to the unit controller 26 (see FIG. 1), and can adjust the height of the upper and lower mounting tables 54 and 56 while referring to the output value of the height sensor. It is.
[0026]
The detachable device 24 and the transfer vehicle 18 can load and unload the workpiece 16 with the upper mounting table 54, and can also load and unload with the lower mounting table 56 when the workpiece 16 is not on the mounting table 54. It is configured.
[0027]
Specifically, the transfer vehicle 18 evacuates once when the unprocessed workpiece 16x is lowered onto the mounting table 54. When the mounting table 56 is lowered to a height near the processing machine 14 and the processed workpiece 16y processed by the processing machine 14 is placed on the mounting table 56, the mounting tables 54 and 56 are further lowered. When the mounting table 54 reaches a height near the processing machine 14 and stops, and the unprocessed workpiece 16x is transferred to the processing machine 14, the mounting tables 54 and 56 are raised. When the mounting table 56 reaches a height near the transfer vehicle 18, the transfer vehicle 18 that has been saved moves to the loading position again, and the processed workpiece 16 y is loaded from the mounting table 56 onto the transfer vehicle 18.
[0028]
In this manner, the unprocessed workpiece 16x and the processed workpiece 16y can be carried in and out between the attachment / detachment device 24, the processing machine 14, and the transfer vehicle 18.
[0029]
As shown in FIG. 4, the branching device 22 includes a branching device main body 70, leg portions 80 projecting obliquely downward from the branching device main body 70 and connected to the transfer path 20, and immediately below the branching device main body 70. A revolving part 78 that is provided and revolves horizontally by a motor 82, a roller 74 that is provided in the revolving part 78 and that draws and feeds the transfer vehicle 18, and a motor 72 that rotates the roller 74. Further, the branching device 22 determines the position of the motor 68 that drives the wire 60 of the transfer path 20 via the pulleys 62 and 64, an angle sensor (not shown) that detects the turning angle of the turning portion 78, and the position of the transfer vehicle 18. A position sensor (not shown) for detection is included.
[0030]
The branching device 22 can move the transfer vehicle 18 that is detachably fixed to the wire 60 by driving the wire 60 by the motor 68. The transfer vehicle 18 moves together with the wire 60 by a cam mechanism that bites and fixes the wire 60 during movement. The cam mechanism is automatically released when the branch device 22 is reached. After the cam mechanism is released, the cam 74 is drawn into the turning portion 78 by the roller 74.
[0031]
When the transfer vehicle 18 reaches the center position of the turning portion 78, the direction is changed by the motor 82, and the transfer vehicle 18 is sent again to the other transfer path 20 by the roller 74. Further, when the two transfer paths 20 are set in a straight line and the transfer vehicle 18 goes straight through the branching device 22, the turning operation of the turning portion 78 is unnecessary, and the transfer vehicle 18 passes through relatively quickly. be able to.
[0032]
The motors 68, 72, 82 and position sensors and angle sensors (not shown) of the branching device 22 are connected to the unit controller 26 (see FIG. 1), and the position of the transfer vehicle 18 and the angle of the turning unit 78 are controlled. .
[0033]
As shown in FIG. 5, the main controller 12 includes a main body 30, a monitor 32 that outputs a screen, a keyboard 34 of an input device, and the like.
[0034]
The main body 30 has a monitor function unit 30a for controlling the monitor 32, a parameter management function unit 30b for holding various configurations of the workpiece transfer system 10, and a numerical value input from the keyboard 34 to the parameter management function unit 30b. It includes a parameter setting function unit 30c and a communication function unit 30g that communicates with the unit controller 26 in a wired or wireless manner.
[0035]
Further, the main body 30 is connected to the communication function unit 30g and cooperates with an operation state management function unit 30d that manages the state of the work transfer system 10, a parameter management function unit 30b, an operation state management function unit 30d, and the like. It has a transfer route determination function unit 30e for determining a route along which the transfer vehicle 18 moves, and a simulation function unit 30f for simulating the operation of the transfer vehicle 18.
[0036]
The main body 30 includes a hard disk, a CPU, a memory, and the like (not shown), and the functional units 30a to 30f are normally stored in the hard disk as software. When each function is executed, the software is loaded on the memory and then executed by the CPU.
[0037]
The main controller 12 determines the transfer route of the transfer vehicle 18 according to the procedure shown in FIG. That is, the movement range shared by each transfer vehicle 18 is determined and input (step S1), and further, the movement range shared by the remaining transfer vehicles 18 assuming one failure of the transfer vehicle 18 is determined and input. (Step S2).
[0038]
Thereafter, the state of each transport vehicle 18 is determined in the main controller 12 (see FIG. 1) (step S3). The state of the transport vehicle 18 is determined based on the overload signal, the error signal, the operation speed of the transport vehicle 18 and the like detected by the branch device 22. If each transport vehicle 18 is normal, the process proceeds to step S4, and if abnormal, the process proceeds to step S5.
[0039]
In step S4, the movement range determined in step S1 is applied, and in step S5, the movement range determined in step S2 is applied.
[0040]
Next, the carry-out source and the carry-in destination of the transfer vehicle 18 are determined (step S6), the transfer route of the transfer vehicle 18 is searched (step S7), and the route candidates obtained by the search are listed (step S8). Further, the transfer route is corrected so as to be a rational transfer route (step S9), and the transfer time for each route candidate is calculated (step S10).
[0041]
Then, in consideration of actual operating conditions, a transfer route having the shortest transfer time is selected, and when the transfer vehicle 18 moves along the determined transfer route, the branching device 22 avoids competition with other transfer vehicles. Is reserved (step S11).
[0042]
When all the transfer paths that can be determined at that time are determined in this way, the process waits until the next calculation determination condition is satisfied (step S12). The next calculation judgment condition is, for example, a carry-in request signal from each attachment / detachment device 24, a carry-out request signal, and information that the transfer by the transfer vehicle 18 has been completed or passed through the branch device 22, and these conditions are calculated. What is necessary is just to return to step S3 again when it generate | occur | produces.
[0043]
Among these, the procedure for determining the movement range shared by each transport vehicle 18 in step S <b> 1 will be described in detail with reference to FIGS. 7 to 10.
[0044]
In the process of step S1, basically, the number of times of loading / unloading with respect to each attachment / detachment device 24 and the dispensing device 38 is calculated in consideration of the processing capacity and the standby time, and the number of times of loading / unloading is calculated for each transport vehicle. 18 is distributed evenly.
[0045]
First, in step S101 of FIG. 7, the processing capability for each attachment / detachment device 24 is obtained.
[0046]
As shown in the example of step A in FIG. 8, the processing times for processing the workpieces by the four attachment / detachment devices 24a, 24b, 24c, and 24d in step A are 200, 500, 500, and 500 [SEC / piece], respectively. If given, by multiplying each reciprocal by 3600 [SEC] (1 [HOUR]), the processing power values 18.0, 7.2, 7.2, 7.2 [piece / HOUR] are obtained. It is done. Further, the processing capability of the process A as a whole is obtained as a value 39.6 [piece / HOUR] obtained by adding these numerical values.
[0047]
The value of the individual processing capacity of each attachment / detachment device 24 and the value of the processing ability of each entire process are the number values that can process a workpiece when each attachment / detachment device 24 operates at a 100% operation rate with no standby time. However, when the waiting time occurs, the value decreases according to the operating rate. However, even when the standby time occurs, the ratio between the individual processing capability of each attaching / detaching device 24 and the processing capability of the entire process is constant as long as the operation rate of each attaching / detaching device 24 is the same.
[0048]
Next, in step S102, the frequency ratio of loading / unloading by each attaching / detaching device 24 is determined for each process from the value of the individual processing capacity and the value of the processing capacity of the entire process. In other words, since the number of times the loading / unloading request signal is transmitted from each attachment / detachment device 24 is proportional to the processing capacity, the frequency ratio of loading / unloading from each attachment / detachment device 24 is the loading / unloading request for the entire process. It can be determined as a ratio to the number of times the signal is transmitted.
[0049]
In the example of the attaching / detaching device 24a of FIG. 8, since it is obtained as a dimensionless number of 18.0 / 39.6 = 0.45, this value is recorded in the column of “loading / unloading frequency ratio”. The attachment / detachment devices 24b, 24c, and 24d are similarly obtained and recorded in the respective columns. The sum of these values is “1.0” for each process.
[0050]
In the example shown in FIG. 9, the processing time of the four attachment / detachment devices 24a to 24d in the process A is 500 [SEC / piece]. For the other processes B, C, and D, the processing time of the attachment / detachment device 24 in the process is the same value for each process, which is 330, 400, and 300 [SEC / piece], respectively. In this case, the calculation for obtaining the carry-in / carry-out frequency ratio can be represented by the reciprocal 1 / M of M, where M is the number of attachment / detachment devices 24 in each process. Therefore, for example, the process A may be calculated as 1/4 = 0.25. Hereinafter, description will be made along the example of FIG.
[0051]
Next, in step S103, the process with the lowest processing capability among the processes A, B, C, and D is specified. That is, when the processing capability values of the respective processes A, B, C, and D are obtained, as shown in the “total” column of “processing capability” in FIG. 9, 28.8, 32.7, 36. 0 and 24.0 [pieces / HOUR], and if the payout device 38 is also regarded as one process, the processing capacity value is represented as 180.0 [pieces / HOUR]. Since 24 [pieces / HOUR] of the process D is the lowest value among these processing capacity values, it is understood that the processing capacity of other processes is limited by this value.
[0052]
Next, in step S104, the number N of transfer vehicles 18 to be used is determined. The number N of the transport vehicles 18 is temporarily determined and may be an appropriate number empirically.
[0053]
Next, in step S105, a process sharing reference value for carrying in / out the N transfer vehicles 18 is obtained.
[0054]
The number of times of carrying in / out of each process is regarded as 24 [times / HOUR], which is the same numerical value as 24 [pieces / HOUR] of the process D (so-called bottleneck process) having the lowest processing capacity. If this is set to “1” as the unit work amount, the work amount of all the steps (steps A to D and the payout step) is “5”.
[0055]
Since it is desirable that the N transfer vehicles 18 be equally assigned to carry-in / unload processing, the load / unload process sharing reference value is obtained as 5 / N with respect to the work amount “5” of all processes. .
[0056]
If the number N of transfer vehicles 18 is N = 3 [units], the processing sharing reference value for carrying in / out is 5 / 3≈1.67. This can also be determined to indicate that the transport vehicle 18 per vehicle should share 1.67 processes out of all 5 processes.
[0057]
Next, in step S106, each attachment / detachment device 24 is divided into several N basic areas. In each basic area, the attachment / detachment device 24 is divided so that the total value of the loading / unloading frequency ratio obtained in step S102 matches the loading / unloading processing sharing reference value obtained in step S105 as much as possible.
[0058]
For example, if N = 3 [units] and the process sharing reference value for loading / unloading is 1.67, as shown in FIG. 10, the three basic areas α, β, γ are respectively transferred to the transport vehicles 18a, 18b. , 18c may be set as a basic area for sharing. The basic area α shared by the transport vehicle 18a is the attachment / detachment devices 24a to 24f, the basic area β shared by the transport vehicle 18b is the attachment / detachment devices 24g to 24L, and the basic area γ shared by the transfer vehicle 18c is the attachment / detachment device 24m and the dispensing device 38. Yes. In this case, the total carry-in / out frequency ratio is 1.66 for the basic area α, and 1.83 and 1.50 for the basic area β and the basic area γ, respectively. Since these numerical values are not significantly different from the loading / unloading processing sharing reference value of 1.67, it can be seen that the processing sharing of the transport vehicles 18a to 18c is almost equally allocated.
[0059]
In order to determine the suitability of such division into basic areas, for example, a variance value of the total value of the carry-in / carry-out frequency ratio for each basic area may be obtained and determined based on the magnitude.
[0060]
As a method of dividing into basic areas, the operator may perform it by his / her own judgment, but it may be automatically performed according to an appropriate procedure.
[0061]
Note that, as described above, since the loading destination into which the workpiece 16 is loaded is defined as the basic area, the loading device 36 does not need to be incorporated in the basic area.
[0062]
Next, in step S107 in FIG. 7, the workpiece transfer system 10 is provisionally executed according to the conditions determined up to step S106. In the temporary execution, when it is difficult to frequently operate / stop the workpiece transfer system 10, the simulation may be performed by the simulation function unit 30f included in the main controller 12. Further, the simulation may be performed on a computer independent from the workpiece transfer system 10.
[0063]
While this temporary execution is being performed, the number of workpieces 16 processed as a whole process and the operation rate of process D, which is the process with the lowest processing capacity, are examined, and the execution ends when an appropriate time has elapsed.
[0064]
Next, in step S108, it is determined based on two conditions whether or not the transfer capability required for the entire process is satisfied.
[0065]
The first condition is to satisfy the number of workpieces 16 per unit time that must be processed as a whole process, and the second condition is that the operation rate of the slowest process D is 100%. Is mentioned.
[0066]
That is, as a whole process, the number of workpieces 16 to be processed is usually given as a required specification, and the processing capacity of the slowest process D limits the processing capacity of other processes A, B, and C. Therefore, it is desirable to operate at the maximum operating rate.
[0067]
If it is confirmed that these conditions are satisfied, the obtained basic areas α, β, γ are stored in the area information table 90 (see FIG. 11) (step S110). If the condition is not satisfied, the process proceeds to step S109.
[0068]
Information on the basic areas α, β, γ is recorded in the “normal time” column of the area information table 90 as shown in FIG. That is, the number of the transport vehicle 18 that shares the loading process and the number of the basic areas α to δ are recorded for each of the attachment / detachment devices 24a to 24m and the payout device 38. FIG. 11 shows an example in which four transfer vehicles 18a to 18d are applied.
[0069]
In step S109, the transfer conditions are changed to perform provisional execution again. The transfer conditions to be changed include, for example, the addition of the transfer vehicle 18, the addition of the transfer path 20, and the improvement of the moving speed of the transfer vehicle 18.
[0070]
For example, if there are three transfer vehicles 18 and the condition of step S108 cannot be satisfied, it is considered to add four transfer vehicles 18 in step S109. If it is determined that the number of transfer vehicles 18 is four, the process returns to step S105, and the process sharing reference value for carrying in / out is determined as 5/4 = 1.25. In the next step S106, for example, the basic area shared by the additional transport vehicle 18d is set as the basic area δ, and basic areas α, β, γ, and δ as shown in FIG. 2 may be set. In this case, the total values of the carry-in / carry-out frequency ratios in the basic areas α, β, γ, and δ are 1.33, 1.16, 1.5, and 1.0, respectively. It is relatively consistent with 1.25.
[0071]
Further, if it can be determined from the simulation result that the condition of step S108 can be satisfied without making a major change, the condition is not changed in step S109, but in step S106, as shown in FIG. Alternatively, only the basic areas α, β, and γ may be changed.
[0072]
Furthermore, even when the condition of step S108 is satisfied, for example, when the operation rate of the transfer vehicle 18 is low, that is, when the standby time is long, the number of the transfer vehicles 18 is reduced and the provisional execution is performed again. You may do it.
[0073]
Next, in step S2 in the main flow chart shown in FIG. 6, that is, when one of the transfer vehicles 18 breaks down (including the case where it cannot be used due to functional deterioration, maintenance, etc.), the remaining transfer vehicles 18 are assigned to each. The procedure for determining the movement range to be performed will be described in detail with reference to FIGS.
[0074]
In the flowchart shown in FIG. 12, assuming that each transport vehicle 18 has failed, the basic area shared by the failed transport vehicle 18 is reassigned so that the other transport vehicles 18 share the basic area. Divide and set a temporary area.
[0075]
First, in step S201 of FIG. 12, it is confirmed whether or not processing (S202 to S210) assuming a failure is performed for each of the transport vehicles 18. In the example shown in FIG. 2, when the setting of the temporary area is completed for the basic areas α to δ shared by all the transport vehicles 18a to 18d, the processing of FIG. 12 is finished and the processing shown in FIG. Return to. When there is an unprocessed transport vehicle 18, the process proceeds to step S202.
[0076]
In step S202, one of the unprocessed transport vehicles 18 is assumed to be a failed transport vehicle. In subsequent steps S203 to S210, a temporary area is set for the basic area shared by the transport vehicle 18 assumed in step S202.
[0077]
Next, in step S203, one or two of the other basic areas adjacent to the basic area shared by the transport vehicle 18 assumed to have failed in step S2 are selected.
[0078]
As adjacent basic areas, those having overlapping or adjacent processes between the basic areas may be selected. Specifically, in the example illustrated in FIG. 2, the basic area α and the basic area β are adjacent basic areas because the process B is overlapped. Since the basic area α and the basic area γ include any one of the adjacent processes B and C, they are adjacent basic areas. Further, since the basic area β and the basic area δ are separated by the process D, they are not adjacent basic areas.
[0079]
Further, when there is one adjacent basic area, that basic area is selected. When there are two or more adjacent basic areas, one or two of them are selected.
[0080]
As a guideline for this selection, it is preferable that the number of processes included in the integrated area obtained as a result of selection is as small as possible. This is because if the number of processes included in the integrated area is small, the number of processes included in the temporary area for re-dividing the integrated area also decreases, and the transfer distance of the transport vehicle 18 that shares the temporary area becomes short. Therefore, the loss at the time of transferring the workpiece 16 can be reduced. In the example shown in FIG. 2, the number of processes included in the integrated area is preferably 4 or less, and the number of processes included in the temporary area obtained by dividing the integrated area is preferably 3 or less.
[0081]
A method for setting an integrated area when a failure is assumed for each of the transport vehicles 18a to 18d will be described.
[0082]
When a failure of the transport vehicle 18a is assumed, as is understood from FIG. 2, the basic areas adjacent to the basic area α shared by the transport vehicle 18a are the basic area β and the basic area γ. Therefore, these basic areas β and γ are selected and combined with the basic area α to be an integrated area ε.
[0083]
Further, the basic area α and the basic area β may be integrated. In this case, one transfer vehicle 18b will share the integrated area obtained.
[0084]
Furthermore, there may be an option of integrating the basic area α and the basic area γ, but in this case, one transport vehicle 18c shares the range including the four processes A to D, and the transport loss is greatly inappropriate. It is.
[0085]
Next, a failure of the transport vehicle 18b is assumed. The transport vehicle 18b shares a basic area β across the processes B and C. On the other hand, the process B is also included in the basic area α, and the process C is also included in the basic area γ. That is, even if the transfer vehicle 18b breaks down, the workpiece 16 can be transferred in the order of processes, and the workpiece transfer system 10 does not stop. However, if the attaching / detaching devices 24f, 24g, 24i, and 24k included in the basic area β are not operated, the production efficiency is remarkably lowered. Therefore, the basic area β is integrated with another adjacent basic area to set an integrated area.
[0086]
The basic areas adjacent to the basic area β shared by the transport vehicle 18b are the basic area α and the basic area γ. Therefore, these basic areas α and γ are selected and combined with the basic area β to be the same integrated area as the integrated area ε.
[0087]
When a failure of the transport vehicle 18c is assumed, one or two basic areas are selected from the basic areas α, β, and δ adjacent to the basic area γ shared by the transport vehicle 18c.
[0088]
When a failure of the transport vehicle 18d is assumed, since only the basic area γ is adjacent to the basic area δ shared by the transport vehicle 18d, this is selected.
[0089]
Next, in step S204, a frequency ratio of carrying in / out with each attaching / detaching device 24 in the integrated area is obtained. As the frequency ratio, the value obtained in step S102 may be used as it is. That is, the value of the carry-in / carry-out frequency ratio in FIG. 9 may be used.
[0090]
Next, in step S205, the number P of transport vehicles 18 in the integrated area is obtained. This number P is P = 1 when the integrated area is an integration of two basic areas, and P = 2 when the integrated area is an integration of three basic areas. .
[0091]
Next, in step S206, a process sharing reference value for carrying in / out the P transfer vehicles 18 is obtained.
[0092]
The process sharing reference value for loading / unloading may be obtained by dividing the total value of the frequency ratio of loading / unloading of each attachment / detachment device 24 in the integrated area by the number P.
[0093]
For example, for the integrated area ε (see FIG. 2) when a failure of the transport vehicle 18a is assumed, the total of the frequency ratios (see FIG. 9) for carrying in / out the respective attachment / detachment devices 24 is “4”. Since P is “2”, the process sharing reference value for carrying in / out is obtained as 4/2 = 2.
[0094]
Next, in step S207, each attachment / detachment device 24 in the integrated area is divided into the number P of the transport vehicles 18 to make a temporary area. In each temporary area, the attachment / detachment device 24 is selected so that the total value of the carry-in / carry-out frequency ratio (see FIG. 9) obtained in step S204 matches the carry-in / carry-out process sharing reference value obtained in step S206 as much as possible. .
[0095]
For example, for the integrated area ε, it is preferable to set two temporary areas ζ and η. Since the temporary area ζ includes the attachment / detachment devices 24a, 24b, 24c, 24d, 24f, 24g, and 24k, the total value of the loading / unloading frequency ratio (see FIG. 9) in the temporary area ζ is 0.25 × 4 + 0. 33 × 2 + 0.25 = 1.91. Since the temporary area η includes the attachment / detachment devices 24e, 24h, 24i, 24j, 24L, and 24m, the total value of the carry-in / out frequency ratio in the temporary area η is 0.33 + 0.25 × 3 + 0.5 × 2 = 2. .08. Since these values 1.91 and 2.08 are not significantly different from the loading / unloading processing sharing reference value 2.0, the processing sharing of the transport vehicles 18b and 18c is almost equally allocated. I understand that.
[0096]
Further, the temporary areas ζ and η each have 3 processes. Therefore, it is a relatively small value compared with 5 which is the total number of processes, and it is preferable because there is little conveyance loss.
[0097]
In this step S207, when P = 1 [units], the area division processing is unnecessary, and the integrated area becomes a temporary area as it is.
[0098]
Next, in step S208, the workpiece transfer system 10 is provisionally executed. The provisional execution method is the same as in step S107, and a computer simulation function can be used.
[0099]
Next, in step S209, it is determined based on two conditions whether or not the conveyance capability required for the entire process is satisfied. This determination is the same as in step S108. However, since this temporary execution assumes that any one of the transport vehicles 18a to 18d has failed, the conditions in step S108 may be relaxed somewhat. For example, the operating rate of the bottleneck process D may be set to a value less than 100%.
[0100]
When it is confirmed that these conditions are satisfied, the obtained temporary areas ζ, η and the like are stored in the area information table 90 (see FIG. 11) of the main controller 12 (step S210). If the condition is not satisfied, the process returns to step S206.
[0101]
Information on the temporary areas ζ and η is recorded in the “when the transport vehicle 18a fails” column of the area information table 90, as shown in FIG. That is, the number of the transport vehicle 18 that shares the carrying-in process and the numbers of the temporary areas ζ and η are recorded for each of the attachment / detachment devices 24a to 24m and the payout device 38. In addition, the basic area δ where the area is not changed is also recorded. Similarly, information regarding the temporary area to be set is recorded in the area information table 90 when a failure of the transport vehicles 18b, 18c, 18d other than the transport vehicle 18a is assumed.
[0102]
With this area information table 90, when any one of the transport vehicles 18a to 18d breaks down, a temporary area can be set immediately with reference to the corresponding column.
[0103]
Next, a modified example of the workpiece transfer method according to the present embodiment will be described with reference to FIGS. 9 and 13.
[0104]
As shown in FIG. 13, the present modification is executed in substantially the same procedure as in the above-described embodiment, and steps S301 to S310 in FIG. 13 correspond to steps S101 to S110 in FIG. 7, respectively. . Among these, step S302, step S304, step S305, and step S306, which are different in procedure from the above-described embodiment, will be described.
[0105]
In step S302, as in step S102, after determining the frequency ratio at which the loading / unloading request signal is transmitted for each process, the loading / unloading frequency is further calculated. In other words, since it is difficult to know how many times loading / unloading is performed only from the numerical value of the loading / unloading frequency ratio at which the loading / unloading request signal is transmitted, loading / unloading per unit time is performed. Is converted into a numerical value representing the number of times, that is, the loading / unloading frequency. If the unit time is 1 hour, the carry-in / carry-out frequency ratio may be obtained by multiplying the carry-in / carry-out frequency ratio by the processing capability 24 [piece / HOUR] of the process D having the lowest processing capability. Then, the loading / unloading frequency [times / HOUR] in each attachment / detachment device 24 is obtained as shown in the “loading / unloading frequency” column of FIG. 9. Further, when these numerical values are summed up for each process, it is naturally 24 [times / HOUR].
[0106]
Then, in step S303, similarly to step S103, after specifying the process D having the lowest processing capacity, in the next step S304, it is assumed that the transfer processing capacity of the transport vehicle 18 is represented by H [times / HOUR]. Since the number of transfer vehicles 18 to be input can be calculated as a guide value as 24 × 5 / H [units], the number N of transfer vehicles 18 is selected as a natural number larger than this value. Here, “24” is the loading / unloading processing capacity of the process D having the lowest processing capacity, and “5” is the number of processes.
[0107]
Next, in step S305, a loading / unloading process sharing reference value is obtained. The loading / unloading process sharing reference value here applies the transfer processing capacity H [times / HOUR] of the transport vehicle 18 as it is.
[0108]
Next, in step S306, each attaching / detaching device 24 is divided into the number N of transport vehicles 18 as in step S106. However, here, the “loading / unloading frequency” obtained in step S302 is used instead of the “loading / unloading frequency ratio” as a numerical value that is used as the basis for area division. Then, the attachment / detachment device 24 is selected so that the total value of the loading / unloading frequency of each basic area matches the transfer processing capacity H [times / HOUR] of the transfer vehicle 18 as much as possible.
[0109]
And the process of subsequent step S307-S310 should just be performed similarly to said step S107-S110.
[0110]
As described above, in the first modification, instead of the “carry-in / carry-out frequency ratio”, the transfer condition is determined using the value of “carry-in / carry-out frequency” which is a constant multiple thereof. Although it is the same processing as the above-mentioned embodiment, it can be examined based on an easily understandable unit of [times / HOUR]. Further, since the transfer processing capacity of the transfer vehicle 18 can be expressed in the same unit, it is easy to compare with the processing of the attachment / detachment device 24.
[0111]
As described above, in the work transfer method according to the present embodiment, the number of transfer vehicles 18 and other devices is increased or decreased, and temporary execution is repeated while changing the basic area shared by the transfer vehicle 18. Suitable transfer conditions can be obtained.
[0112]
In addition, the frequency at which the workpiece 16 is carried in or out is obtained for each attachment / detachment device 24, and the attachment / detachment device 24 is divided into basic areas corresponding to the number of the transport vehicles 18 so that the total of the frequencies substantially matches. The processing share of the transport vehicle 18 assigned to each area can be made substantially equal.
[0113]
In addition, since the sharing of each transport vehicle 18 is set in each basic area, each transport vehicle 18 is less likely to enter another basic area, and as a result, the number of times the transport vehicles 18 compete with each other on the route is reduced. be able to. This is the same when the temporary area is applied, and each transfer vehicle 18a to 18d can reduce the number of times of competition between the transfer vehicles 18 because the shared area is fixed to the basic area or the temporary area.
[0114]
The frequency of loading or unloading is such that the actual frequency at which the workpiece 16 is loaded or unloaded, including the time during which the mounting / demounting device 24 is in a standby state, is obtained. Compared to the case of calculating from the above, a more accurate plan can be made.
[0115]
Furthermore, the attachment / detachment device 24 is divided into steps A to D for processing the workpiece 16 and a dispensing step, and the loading / unloading frequency can be obtained from the processing share ratio of the attachment / detachment device 24 in each step.
[0116]
Furthermore, among the processes, the process with the slowest average processing time for processing the workpiece, that is, the process with the smallest number of processes per unit time is identified, and provisional execution is performed under the transfer conditions. And since it is confirmed by the temporary execution that the operation rate of the specified process is 100%, it is possible to maintain the minimum processing capability as the entire process. Here, if temporary execution is performed by simulation using a computer, execution time and electric power can be saved, and more frequent execution and stop are possible. If the sum of the loading / unloading frequencies is set so as to substantially match the transfer frequency capability of the transfer vehicle 18, the required number of transfer vehicles 18 can be calculated.
[0117]
Moreover, according to this Embodiment, when each of the transfer vehicles 18a-18d breaks down, it can transfer to the structure which continues operation | movement of the workpiece transfer system 10 rapidly. That is, assuming that a failure has occurred in each of the transport vehicles 18a to 18d, temporary areas shared by the remaining transport vehicles 18 are set and stored. Therefore, when a failure actually occurs, it is possible to cope with almost no time lag by applying these temporary areas.
[0118]
In addition, since the operation of each transport vehicle 18 in the case where the temporary area is applied is confirmed by simulation, the workpiece 16 can be transferred relatively efficiently even at the time of failure.
[0119]
Further, the temporary area is included in the integrated area because the integrated area is set to include the adjacent area based on the basic area shared by the broken carriage 18 and is divided into the temporary areas. There is no effect on the basic areas that are not. Accordingly, the temporary area only needs to be set in the integrated area, and the setting is easy. In addition, when one of the transport vehicles 18 breaks down, at least two of the other transport vehicles 18 whose basic area to be shared is changed to a temporary area will affect other transport vehicles 18. There is no.
[0120]
Furthermore, when the broken carriage 18 returns to operation, the stored original basic areas α, β, γ and δ are reapplied (step S4 in FIG. 6), so that the original state is immediately restored. Can return to.
[0121]
In the workpiece transfer method according to the present embodiment, the attachment / detachment device 24 may perform only one of carry-in or carry-out. For example, when the molding machine storing the material is an apparatus that carries out the product after molding the product from the material, no loading operation is required.
[0122]
The division into basic areas performed in steps S106 and S207 may be automatically performed according to an appropriately determined procedure. For example, if the number N of the transport vehicles 18 is three, the first to third basic areas are virtually set, and the attaching / detaching device 24 and the dispensing device 38 are distributed and recorded. At this time, if an apparatus having a large carry-in / carry-out frequency ratio is selected and distributed in order, it is possible to automatically perform distribution so that the processing share of the transport vehicle 18 becomes substantially equal. In this procedure, one basic area may be divided into a plurality of discontinuous parts, but if the moving speed of the transport vehicle 18 is sufficiently high compared to the processing time of the attaching / detaching device 24 and the dispensing device 38. Applicable without problems.
[0123]
Further, in steps S106 and S207, the example in which the area division processing is performed so that the processing share is equally applied to each transfer vehicle 18 has been described. However, there are a plurality of types of transfer vehicles 18 and the transfer processing capabilities thereof are different. In this case, distribution according to the capability value may be performed.
[0124]
Further, for example, the net-like transfer path is not limited to a two-dimensional one but can be applied to a three-dimensional warehouse or the like. The transfer vehicle 18 is not limited to the other traveling type that receives power from the wire 60, and may be a self-propelled type that moves on the floor surface, an autonomous type, or the like.
[0125]
Furthermore, the workpiece transfer method according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.
[0126]
【The invention's effect】
As described above, according to the workpiece transfer method according to the present invention, in the workpiece transfer system that transfers workpieces using a plurality of transfer devices between the stations allocated to the process, some of the transfer devices fail and function. When the operation is stopped due to lowering and maintenance, the effect that the operation of the workpiece transfer system can be continued is achieved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a workpiece transfer system.
FIG. 2 is an explanatory diagram showing a reticulated transfer path in the present embodiment.
FIG. 3 is a perspective view showing an attachment / detachment device and a transfer vehicle.
FIG. 4 is an explanatory diagram showing a branching device.
FIG. 5 is a functional block diagram of a workpiece transfer system.
FIG. 6 is a flowchart showing a procedure for determining a transfer route of a transfer vehicle.
FIG. 7 is a flowchart showing a procedure for setting a basic area.
FIG. 8 is an explanatory diagram showing a first example of a calculation table for obtaining a carry-in / carry-out frequency ratio.
FIG. 9 is an explanatory diagram showing a second example of a calculation table for obtaining a carry-in / carry-out frequency ratio.
FIG. 10 is an explanatory diagram showing an example in which a reticulated transfer path is divided into three basic areas in the present embodiment.
FIG. 11 is an explanatory diagram showing an area division information table in which a basic area and a temporary area set for each attachment / detachment device are recorded.
FIG. 12 is a flowchart showing a procedure for setting a temporary area on the assumption that each transport vehicle stops operating.
FIG. 13 is a flowchart showing a procedure of a workpiece transfer method according to a modification of the embodiment.
[Explanation of symbols]
10 ... Work transfer system 12 ... Main controller
14 ... Processing machine
16, 16a, 16b, 16x, 16y ... Workpiece
18, 18a to 18d ... transfer vehicle 20 ... transfer path
22, 22a-22v ... Branching device 24, 24a-24m ... Detachment device
26 ... Unit controller 30 ... Main unit
30a: Monitor function unit 30b: Parameter management function unit
30c: Numerical parameter setting function unit 30d: Operating state management function unit
30e: Transfer route determination function unit 30f: Simulation function unit
30 g ... Communication function part 32 ... Monitor
34 ... Keyboard 36 ... Loading device
38 ... Dispensing device 60 ... Wire
α, β, γ, δ: Basic area ε: Integrated area
ζ, η… Temporary area

Claims (5)

A transfer device for transferring workpieces;
In a workpiece transfer method in a transfer system comprising a plurality of stations where the workpiece is carried in or out of the transfer device, and a controller for controlling the transfer device and the station to transfer the workpiece,
A first step in which a frequency calculation unit obtains a frequency at which the work is carried in or out for each station;
The basic area determining unit divides the station into a plurality of basic areas so that the sum of the frequencies obtained by the frequency calculating unit substantially matches, and assigns one transfer device to each basic area, A second step of storing basic area information in the storage unit ;
A temporary area determination unit reads information on the basic area from the storage unit, and assumes a case where one of the transfer devices is unusable, and a basic area shared by the unusable transfer device and a basic adjacent to the basic area For the integrated area including the area, the stations in the integrated area are divided into temporary areas so that the sum of the frequencies substantially matches, and one transfer device is assigned to each temporary area, and information on the temporary area is obtained. A third step of storing in the storage unit ;
The controller reads out information on the basic area from the storage unit and detects the state of the transfer device, and causes the transfer device to carry the workpiece into or out of the station in the assigned basic area. Steps,
When one of the transfer devices is unusable, the controller reads information on the temporary area from the storage unit , replaces a preset integrated area corresponding to the unusable transfer device with the temporary area, and transfers the transfer the apparatus comprising: a fifth step of Ru is carried or unloading the workpiece into the station in said temporary area assigned,
A workpiece transfer method characterized by comprising: The workpiece transfer method according to claim 1,
The work transfer method, wherein the controller returns the temporary area to the basic area when an unusable transfer device returns to the usable state. In the workpiece transfer method according to claim 1 or 2,
In the first step, the frequency may be an actual frequency at which the work is carried in or out, including a waiting time for the station to wait for processing. In the workpiece transfer method according to any one of claims 1 to 3,
The plurality of stations are related to the processing of the workpiece, and are classified into a plurality of ordered steps,
In the first step, the frequency is obtained from a processing share ratio in the process. In the workpiece transfer method according to any one of claims 1 to 4,
Based on the basic area and the temporary area, the operation of the transfer device and the station is simulated by a simulation function unit , and the temporary area determination unit determines whether the basic area and the temporary area are properly classified. Characteristic workpiece transfer method.

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