JP3899746B2 - Control method for automated production line - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling an automated production line, and in particular, monitors the operating status of an automated production line (transfer line) in which a plurality of autonomously operating processing and assembly facilities are connected by a conveyor, etc. The present invention relates to a method for controlling an automated production line that starts operation of equipment and improves the overall operation rate of the production line.
[0002]
[Prior art]
In a transfer line where multiple processing and assembly facilities that operate autonomously are connected by a conveyor, etc., when one facility stops due to some abnormality, the equipment in the previous process of the facility that caused the abnormality has been processed and assembled in its own process. The work cannot be sent to the next process equipment where the product (work) has failed until the equipment is restored. As a result, the transfer line, for example, falls into a traffic jam state like cars lined up waiting for traffic lights. Once traffic jams occur, it takes time to clear the jams even if the abnormal equipment is restored, and the line operation rate is reduced.
[0003]
As an example of the prior art, Japanese Patent Application Laid-Open No. 3-17701 proposes a flexible production system that can perform high-efficiency small and medium-sized production by performing recovery control when an equipment abnormality occurs. In the past, when an equipment abnormality occurred, various processes such as data input and machine adjustment were required for restarting, and much effort and time were required for recovery. Even when an equipment abnormality occurs during operation and the operator intervenes and performs repair, the operator can automatically return to a normal operation state without performing special processing after the repair.
[0004]
That is, in this production system, a relay device that constantly monitors the state of each facility is provided for each facility, and a system in which a single central processing unit monitors a plurality of relay devices. Therefore, when an equipment abnormality occurs, the control device (central processing unit) executes a control sequence for the abnormality processing. After the abnormality is repaired, control is performed from an appropriate step in the normal control sequence according to the state of the equipment at that time. To resume. As a result, the operation control can be automatically restarted in a short time even after the equipment abnormality is repaired.
[0005]
However, in this production system, the central processing unit monitors the status of the relay device provided in each facility, and only performs efficient control of the production line after repairing the abnormality.
As another example of the prior art, Japanese Patent Application Laid-Open No. Sho 63-278750 discloses a stopper that stops a pallet in a production line in which a pallet on which a workpiece is placed is sequentially conveyed by a conveyor. A production line has been proposed in which a pallet is moved to a work table for each process and a stopper for the previous process can be controlled from the subsequent process.
[0006]
That is, in this production system, when the pre-process stopper control means provided in each process is operated from the post-process to release the pre-process stopper, the pallet stopped by the pre-process stopper is conveyed to the conveyor. It is sent to the post process. As described above, since the stopper is provided for each process, the stagnation of the production line can be prevented, and the optimum line balance and efficient production can be performed.
[0007]
However, this production system merely discloses a technique for releasing the stopper of the previous process regardless of the state on the conveyor when the abnormal equipment is restored.
[0008]
[Problems to be solved by the invention]
By the way, as one solution for eliminating the stagnation of the production line, a method of providing a space buffer between the facilities and absorbing the stagnation time of the production line using the buffer is widely known. However, in such a production line, since the buffer is arranged in each facility, the overall length of the line becomes longer, so that the so-called “area productivity” is deteriorated and the time for the buffer is also required. As a result, the production time increases, and as a result, the production cost increases.
[0009]
Such a conventional problem is that when the entire production line is brought into a stopped state due to an abnormal equipment, even if the abnormal equipment recovers, the rear of the equipment must be operated if the front equipment does not operate, as in the case of traffic jams. This occurs because the equipment becomes inoperable.
Therefore, the object of the present invention is to send an “operation restart signal” to the previous process equipment or send it to each equipment at once when the abnormal equipment is restored. Even if it exists, it aims at providing the control method of the automated production line which prevented the fall of the operation rate of a production line by performing stopper cancellation | release operation of each equipment. Furthermore, an object of the present invention is to improve the area productivity by suppressing the area of the buffer provided for each facility to about one work.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the production line control method in an automated production line in which a plurality of facilities each of which operates autonomously is connected by a conveyor, when the abnormality has occurred , the abnormality of the own facility is canceled. Sends an operation resumption signal indicating the resumption of operation to the equipment in the previous process, and the equipment that has received the operation resumption signal sequentially transmits the operation resumption signal to the equipment in the previous process, and the full load sensor is on. Even if there is an operation resumption signal, each equipment releases the stopper of its own equipment, so when the abnormality is recovered, the production line can be operated immediately. A decrease can be prevented. Furthermore, by resuming such a production line, the area of the buffer provided for each facility can be suppressed to about one work, and the area productivity can be improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram of a main part of a production system to which an automated production line control method of the present invention is applied. In the figure, 11 indicates the entire equipment (1) to (6), and the equipment (1) to (6) is, for example, a machine for processing and assembly. Reference numeral 12 denotes a controller provided for each facility. Reference numeral 13 denotes a workpiece (work) on the work pallet, which is sent to the next process when the processes such as processing and assembling of the own equipment are completed. A mechanical stopper 14 is provided on the output side of each facility and controls the outflow of the workpiece 13 to the next process facility. A full load sensor 15 is provided for each facility and detects the state of the workpiece on the conveyor. Reference numeral 16 denotes a signal line connecting the controllers, and, as will be described later, for example, a signal of one shot is quickly sent to an adjacent controller. The reason why the one-shot signal is appropriate is that a “handshake method” that requires troublesome communication such as so-called “request signal”, “response signal”, and “confirmation signal” between controllers is unnecessary.
[0012]
Further, 17 is a conveyor for connecting the facilities, and 18 is, for example, a space buffer means provided for each facility.
In the automated production line in which such facilities (1) to (6) are connected by the conveyor 17, when all the facilities are normal, the workpiece 13 is processed using a predetermined processing unit (not shown). After the processing is completed, if the full load sensor 15 arranged on the conveyor 17 is off, that is, if the conveyor is not full of work, the work 13 flows out to the next process equipment by releasing the stopper 14. Let In this case, the buffer means 18 for at least one work is arranged between the facilities so as to absorb the asynchronous time difference between the facilities.
[0013]
The controller 12 of each facility controls the operation of the stopper 14 and the like, and is composed of a general control device such as a sequencer, for example. Each controller is connected between each I / O unit (not shown) by a signal line 16. Thereby, the own process equipment can easily detect the state of the next process equipment.
Next, for example, when the last equipment (6) is abnormal and stops for a certain period of time, in the conventional method, the work 13 is in a traffic jam state, and even if the abnormality is released, the movement of each work 13 is a series. Therefore, it takes a considerable time for the work of the first facility (1) to reach the last facility (6), and as a result, the operating rate of the line is lowered.
[0014]
Therefore, in the present invention, if the abnormality of the facility that caused the abnormality is canceled and the operation is resumed, the facility indicates that the abnormality is canceled and the operation is resumed for each facility waiting for the work outflow. A one-shot “operation restart signal” is sent all at once, or sent to the previous process equipment and sequentially transmitted to the previous process equipment. Each equipment that has received this operation resume signal releases the stopper 14 at once and works The stagnation of the production line is eliminated instantly by letting out.
[0015]
FIG. 2 is a process flowchart in the case where the facility in which the abnormality has occurred is restored and the operation restart signal is output to release the stopper. First, it is checked whether or not the own equipment has an abnormality (step S21). If there is no abnormality (NO), the stopper 14 of the own equipment is released (mechanically removes the stopper) (S24). On the other hand, if there is an abnormality in the own equipment (YES), the controller checks whether the abnormality has been canceled (S22). If the abnormality is not repaired (NO), the check is repeated and the process waits until the abnormality is repaired.
[0016]
And when abnormality is cancelled | released in step S22 (YES), for example, the "operation restart signal" of 1 shot is output to a pre-process installation (or all installations) (S23). And the stopper release operation | movement of an own equipment is performed (S24), and a workpiece | work flows out to the next process equipment. Receiving the operation resumption signal, each facility simultaneously performs the operation of releasing the stopper of its own facility.
[0017]
FIG. 3 is a processing flowchart when the normal equipment receives an operation resumption signal from the abnormal equipment. First, the own equipment (normal equipment) starts a process such as processing and assembly of the own process, and further checks whether or not the work of the own process equipment is in a state of waiting for outflow (S31). If it is not waiting for the workpiece to flow out (NO), it is determined whether or not a predetermined machining / assembly process has been completed.
[0018]
When waiting for the workpiece to flow out in step S31 (YES), it is checked whether or not the full load sensor 15 is on (S32). If the full load sensor 15 is off (NO), the processing / assembly state of the own equipment is determined. Regardless of the operation, the stopper release operation is performed (S35). For example, if the work stays in the buffer means, the work is discharged.
On the other hand, when the full load sensor 15 is ON (YES), it is checked whether or not there is an operation restart signal output from the next process facility or the facility whose abnormality has been recovered (S33). NO), it returns to the check of the full load sensor 15 in step S32. In step S33, if there is an operation restart signal from the next process facility or the facility whose abnormality has been recovered (YES), for example, a one-shot operation restart signal is output to the previous process facility before the own process facility (S34). . Thereafter, the stopper is released from the own process equipment to cause the work to flow out (S35).
[0019]
If the stopper is released, it is determined whether or not a new workpiece has arrived next (S36). If not (NO), this determination is repeated. On the other hand, if a new workpiece has arrived (YES), a predetermined processing / assembly operation is performed at the own process equipment (S37). Further, the self-process equipment determines whether or not the predetermined processing / assembly in the self-process is completed (S38), and if not completed, the processing / assembly operation is continued (S37), and the predetermined processing / assembly process is performed. If completed (YES), the process returns to the first step S31.
[0020]
【The invention's effect】
As described above, according to the present invention, the operation restart signal indicating that the abnormal equipment has resumed operation is transmitted to the previous process equipment or each equipment at the same time. Since it flows out, the stagnation of the production line can be eliminated instantly. For this reason, since the buffer means between facilities can also be a minimum area, the area productivity can be improved, and the line operation rate can be prevented from being lowered due to an abnormality or facility stoppage due to setup.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a main part of a production system to which an automated production line control method of the present invention is applied.
FIG. 2 is a processing flowchart in a case where an equipment in which an abnormality has occurred is restored and an operation restart signal is output to release the stopper.
FIG. 3 is a processing flowchart in a case where a normal facility receives an operation restart signal from an abnormal facility.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Equipment 12 ... Controller 13 ... Work piece 14 ... Stopper 15 ... Full load sensor 16 ... Signal line 17 ... Conveyor 18 ... Buffer means

Claims (1)

A plurality of facilities that each operate autonomously are connected by a conveyor, and a stopper for controlling the outflow of the workpiece is provided on the outflow side of the workpiece from each facility, and the state of the workpiece on the conveyor is detected between the facilities. In a production line control method in an automated production line that includes a full load sensor, and the stopper operates when the full load sensor is in an ON state indicating a full load on a conveyor ,
The equipment that caused the abnormality
Determine whether your equipment is abnormal,
In the case of an abnormality, determine whether the abnormality has been canceled further,
When an abnormality has been released, it sends the operation restart signal indicating resumption of the previous step setting Bei operation,
The equipment that has received the operation restart signal sequentially transmits the operation restart signal to the equipment in the previous process,
Each facility that receives the operation restart signal releases the stopper of its own facility even if the full sensor is in an on state indicating a full load on the conveyor .
A method for controlling an automated production line.

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