Analysis of Throughput Bottleneck Indicators of Manufacturing Systems

Abstract

A method for identifying bottlenecks in a manufacturing system. The method includes: creating a flow chart showing how parts travel through the manufacturing system, wherein the manufacturing system includes stations and buffers; identifying workspaces in the flow chart to be analyzed; identifying predecessors and successors for each of the workspaces in the flow chart; receiving buffer usage and station blocking / starvation data for the manufacturing system; collecting buffer usage and station blocking / starvation data for predecessors and successors previously identified by a controller; calculating a block rate (BR) for the predecessors and successors previously identified by the controller; calculating a bottleneck index (BI) value for the workspace using the BRs of the predecessors and successors; and listing the BI values ​​from highest to lowest to identify the top bottleneck workspaces in the workspaces.

Description

Technical Field

[0001] introduction

[0002] The present disclosure relates generally to manufacturing and, more particularly, to manufacturing system throughput bottleneck indicator analysis. Background Art

[0003] While in a manufacturing environment, buffer utilization and station blocking / starvation status can be monitored as indicators of where bottlenecks exist, the bottleneck impact of workspaces needs to be analytically quantified to maximize the throughput of a manufacturing system. Summary of the invention

[0004] In the present disclosure, a method is used to analytically identify the top bottleneck work areas of a manufacturing system. By doing so, the manufacturing system can be controlled to address the top bottleneck work areas, thereby maximizing throughput. This analytical method allows bottleneck identification to be performed using both simulation output and plant floor data and produces results immediately. Therefore, the method does not necessarily require simulation analysis.

[0005] In aspects of the present disclosure, a method for identifying a bottleneck in a manufacturing system includes: creating, by a controller, a flow chart showing how parts travel through the manufacturing system, wherein the manufacturing system includes stations and buffers; identifying, by the controller, a workspace in the flow chart to be analyzed; identifying, by the controller, a predecessor and a successor for each of the workspaces in the flow chart, wherein each of the predecessor and the successor is at least one of a station or a buffer of the manufacturing system; receiving, by the controller, buffer usage and station blocking / starvation data for the manufacturing system; collecting, by the controller, buffer usage and station blocking / starvation data for predecessors and successors previously identified by the controller; calculating, by the controller, a block rate (BR) for the predecessor and successor previously identified by the controller; calculating, by the controller, a bottleneck index (BI) value for the workspace using the BR of the predecessor and successor; listing, by the controller, the BI values ​​from highest to lowest to identify a top bottleneck workspace in the workspace, wherein the top bottleneck workspace has the highest value in the BI values; and controlling the manufacturing system in view of the top bottleneck workspace to maximize the throughput of the manufacturing system.

[0006] In an aspect of the present disclosure, the working area includes an intermediate working area. The predecessor includes a single predecessor of the intermediate working area. The successor includes a single successor of the intermediate working area, such that the intermediate working area has a single predecessor immediately preceding the intermediate working area and a single successor immediately following the intermediate working area. Calculating, by the controller, the BI value of the working area using the BRs of the predecessor and the successor includes calculating the BI value of the intermediate working area using the following equation:

[0007]

[0008] in:

[0009] BI is the BI value of the middle working area;

[0010] BR pred is a single front-drive BR of the intermediate work area; and

[0011] BR succ It is a single successor BR of the intermediate work area.

[0012] In an aspect of the present disclosure, the work area includes an assembly work area. The predecessor includes a predecessor immediately in front of the assembly work area. The successor includes a single successor immediately behind the assembly work area, so that the assembly work area has a predecessor and a single successor.

[0013] In an aspect of the present disclosure, calculating, by the controller, the BI value of the work area using the predecessor and successor BRs includes calculating the BI value of the assembled work area using the following equation:

[0014]

[0015] in:

[0016] BI is the BI value of the assembly workspace;

[0017] Min(BR pred ) is the BR of the one with the lowest value among the predecessors; and

[0018] BR succ It is a single successor BR of the assembly workspace.

[0019] In an aspect of the present disclosure, the work area includes a disassembly work area. The predecessor includes a single predecessor immediately in front of the disassembly work area. The successor includes a successor immediately behind the disassembly work area, so that the disassembly work area has a single predecessor and multiple successors.

[0020] In an aspect of the present disclosure, calculating, by the controller, the BI value of the work area using the predecessor and successor BRs includes calculating the BI value of the disassembly work area using the following equation:

[0021] ;

[0022] in:

[0023] BI is the BI value of the disassembly work area;

[0024] BR pred is a single front-wheel drive BR; and

[0025] Max(BR succ ) is the BR of the one with the highest value among the predecessors.

[0026] In an aspect of the present disclosure, the working area includes a merged working area. Calculating, by the controller, the BI value of the merged working area using the predecessor and successor BRs includes calculating the BI value of the merged working area using the following equation:

[0027] ;

[0028] in:

[0029] BI is the BI value of the merged workspace;

[0030] PartCntWtdAvg(BR pred ) is the weighted average of the part counts of the predecessors immediately preceding the merged workspace; and

[0031] BR succ It is the single successor BR of the workspace.

[0032] In an aspect of the present disclosure, the work area includes a split work area. Calculating, by the controller, the BI value of the split work area using the predecessor and successor BRs includes calculating the BI value of the split work area using the following equation:

[0033] ;

[0034] in:

[0035] BI is the BI value of the split work area;

[0036] BR pred is a single front-drive BR of the intermediate work area; and

[0037] PartCntWtdAvg(BR succ ) is the weighted average of the subsequent part counts immediately following the split workspace.

[0038] The BI of a workspace can be evaluated using any combination of predecessor and successor BR evaluations. That is, the BI can be evaluated in all of the following forms:

[0039]

[0040]

[0041] In the list above, this would be:

[0042] ● Single-in-single-out

[0043] ● Single entry - disassembled exit

[0044] ● Single-input-split-output

[0045] ● Assemble in-single out

[0046] ● Assemble in - disassemble out

[0047] ● Assemble in - Split out

[0048] ● Merge in-single out

[0049] ● Merge in - Disassemble out

[0050] ● Merge in - Split out

[0051] In aspects of the present disclosure, calculating, by the controller, the BRs of the predecessor and successor previously identified by the controller includes calculating the BR of the buffer using the following equation:

[0052] ;

[0053] in:

[0054] BR is the buffer block rate;

[0055] BufferFullRatio is the buffer fullness ratio; and

[0056] Exp Factor is the exponential factor;

[0057] Here, the buffer fill rate is calculated using the following equation:

[0058] ;

[0059] in:

[0060] AveragePartCount is the average number of parts observed in the buffer during the observation time;

[0061] Minimum Threshold is the minimum threshold of jobs that the buffer must have to prevent starvation of downstream systems; and

[0062] Maximum Threshold is the maximum number of jobs that can be stored in the buffer before upstream blocking occurs.

[0063] In aspects of the present disclosure, calculating the BR of a buffer zone includes calculating an exponential factor using the following formula:

[0064] ;

[0065] in:

[0066] Exp Factor is the exponential factor;

[0067] Min Threshold is the minimum threshold of jobs that the buffer has to prevent downstream starvation;

[0068] Max Threshold is the maximum number of jobs that the buffer can store before blocking upstream; and

[0069] Flatness equals 2.

[0070] In aspects of the present disclosure, calculating, by the controller, the BRs of the predecessor and successor previously identified by the controller includes calculating the BR of the station using the following equation:

[0071] ,

[0072] in:

[0073] Block% is the percentage of time the station is blocked during the observation time, and Starve% is the percentage of time the station is starved during the observation time. Where: BR is the block rate of the station.

[0074] In aspects of the present disclosure, calculating, by the controller, the BRs of the predecessor and successor previously identified by the controller includes calculating the BR of the predecessor at the beginning of the flowchart using the following equation:

[0075] ,

[0076] in:

[0077] BR pred is the BR that precedes the beginning of the flowchart; and

[0078] Block% is the percentage of time that the predecessor at the beginning of the flow graph is blocked during the predetermined observation time.

[0079] In aspects of the present disclosure, calculating, by the controller, the BRs of the predecessor and successor previously identified by the controller includes calculating the BR of the successor at the end of the flowchart using the following equation:

[0080] ;

[0081] in:

[0082] BR succ is the subsequent BR at the end of the flowchart; and

[0083] Starve% is the percentage of time that the successor at the end of the flowsheet is starved during a predetermined observation time.

[0084] In aspects of the present disclosure, the predecessor includes a topic predecessor and a plurality of topic successors immediately preceding the topic predecessor. Calculating, by the controller, the BR of the predecessor previously identified by the controller includes calculating the BR of the topic predecessor using the following equation:

[0085] ;

[0086] in:

[0087] BR pred is the block rate of the subject’s predecessor;

[0088] BR MinPredSucc is the minimum block rate of the predecessors and successors of the plurality of topics; and

[0089] BR MaxPredSucc is the maximum block rate of the predecessors and successors of the multiple topics.

[0090] In aspects of the present disclosure, wherein the successor comprises a topic successor and a plurality of topic predecessors immediately preceding the topic successor. Calculating, by the controller, the BR of the successor previously identified by the controller comprises calculating the BR of the topic successor using the following equation:

[0091] ;

[0092] in:

[0093] BR succ is the block rate of the subject successor;

[0094] BR MinSuccPred is the minimum block rate of the plurality of subject successors and predecessors; and

[0095] BR MaxSuccPred is the maximum block rate of the multiple topic successors and predecessors.

[0096] In aspects of the present disclosure, the predecessor may include a subject predecessor of the workspace without the predecessor itself because it is at the beginning of the flowchart, and calculating, by the controller, the BR of that predecessor previously identified by the controller includes calculating the BR of the subject predecessor using the following formula:

[0097] ;

[0098] in:

[0099] BR pred is a BR that is a predecessor of the subject; and

[0100] BR succ It is the successor BR.

[0101] In aspects of the present disclosure, a successor may include a subject successor of a workspace without the successor itself because it is at the end of the flow chart, and calculation by the controller of the BR of the successor previously identified by the controller is done using the following formula:

[0102]

[0103] in:

[0104] BR succ is the BR that is the successor to the subject; and

[0105] B pred It is a front-wheel drive BR (.

[0106] The present disclosure also describes a control system. In an aspect of the present disclosure, the control system includes a controller configured to communicate with a manufacturing system. The controller is programmed to: create a flowchart showing how a part travels through a manufacturing system, wherein the manufacturing system includes stations and buffers; identify workspaces to be analyzed in the flowchart; identify predecessors and successors for each of the workspaces in the flowchart, wherein each of the predecessors and successors is a station or buffer of the manufacturing system; receive buffer usage and station blocking / starvation data for the manufacturing system; collect buffer usage and station blocking / starvation data for the predecessors and successors previously identified by the controller; calculate the block rate (BR) of the predecessors and successors previously identified by the controller; use the BRs of the predecessors and successors to calculate a bottleneck index (BI) value for the workspace; list the BI values ​​from highest to lowest to identify the top bottleneck workspace in the workspace, wherein the top bottleneck workspace has the highest value in the BI value; and control the manufacturing system taking into account the top bottleneck workspace to maximize the throughput of the manufacturing system.

[0107] The present invention provides the following technical solutions:

[0108] 1. A method for identifying a bottleneck in a manufacturing system, the method comprising:

[0109] creating, by a controller, a flow chart showing how parts travel through the manufacturing system, wherein the manufacturing system includes stations and buffers;

[0110] identifying, by the controller, a work area in the flowchart to be analyzed;

[0111] identifying, by the controller, a predecessor and a successor for each of the workspaces in the flow chart, wherein each of the predecessor and the successor is at least one of the station or the buffer of the manufacturing system;

[0112] receiving, by the controller, buffer usage and station blocking / starvation data of the manufacturing system;

[0113] collecting, by the controller, the buffer usage and station blocking / starvation data for the predecessor and the successor previously identified by the controller;

[0114] calculating, by the controller, a block rate (BR) of the predecessor and the successor previously identified by the controller;

[0115] calculating, by the controller, a bottleneck index (BI) value of the work area using the predecessor and successor BRs;

[0116] listing, by the controller, the BI values ​​from highest to lowest to identify a top bottleneck operating region among the operating regions, wherein the top bottleneck operating region has a highest value among the BI values; and

[0117] The manufacturing system is controlled taking into account the top bottleneck work area to maximize the throughput of the manufacturing system.

[0118] The method according to technical solution 1, wherein the working area includes an intermediate working area, the predecessor includes a single predecessor of the intermediate working area, and the successor includes a single successor of the intermediate working area, so that the intermediate working area has a single predecessor immediately in front of the intermediate working area and a single successor immediately behind the intermediate working area, wherein the controller uses the BR of the predecessor and the successor to calculate the BI value of the working area, including using the following equation to calculate the BI value of the intermediate working area:

[0119]

[0120] in:

[0121] BI is the BI value of the intermediate working area;

[0122] BR pred is a single predecessor BR of the intermediate working area; and

[0123] BR succ It is the single successor BR of the intermediate working area.

[0124] A method according to Technical Solution 1, wherein the work area includes an assembly work area, the predecessor includes a predecessor immediately in front of the assembly work area, and the successor includes a single successor immediately behind the assembly work area, so that the assembly work area has the predecessor and the single successor.

[0125] According to the method of technical solution 3, wherein the controller uses the predecessor and the successor BR to calculate the BI value of the working area, including using the following equation to calculate the BI value of the assembly working area:

[0126] ;

[0127] in:

[0128] BI is the BI value of the assembly workspace;

[0129] Min(BR pred) is the BR of the one of the plurality of predecessors having the lowest value; and

[0130] BR succ It is the single successor BR of the assembly workspace.

[0131] A method according to Technical Solution 1, wherein the work area includes a disassembly work area, the predecessor includes a single predecessor immediately in front of the disassembly work area, and the successor includes multiple successors immediately behind the disassembly work area, so that the disassembly work area has the single predecessor and multiple successors.

[0132] According to the method of technical solution 5, the controller uses the BR of the predecessor and the successor to calculate the BI value of the working area, which includes using the following equation to calculate the BI value of the disassembly working area:

[0133] ;

[0134] in:

[0135] BI is the BI value of the disassembly work area;

[0136] BR pred is a single front-wheel drive BR; and

[0137] Max(BR succ ) is the BR of the one with the highest value among the multiple predecessors.

[0138] The method according to technical solution 1, wherein the working area includes a merged working area, and calculating the BI value of the merged working area by the controller using the predecessor and the successor BR includes calculating the BI value of the merged working area using the following equation:

[0139] ;

[0140] in:

[0141] BI is the BI value of the merged workspace;

[0142] PartCntWtdAvg(BR pred ) is the weighted average of the part counts of the predecessors immediately preceding the merged workspace; and

[0143] BR succ is the single successor BR of the workspace.

[0144] The method according to technical solution 7, wherein the working area includes a split working area, and calculating the BI value of the split working area by the controller using the predecessor and the successor BR includes calculating the BI value of the split working area using the following equation:

[0145] ;

[0146] in:

[0147] BI is the BI value of the split working area;

[0148] BR pred is a single predecessor BR of the workspace; and

[0149] PartCntWtdAvg(BR succ ) is the weighted average of the subsequent part counts immediately following the segmented workspace.

[0150] The method according to technical solution 1, wherein calculating, by the controller, the BRs of the predecessor and the successor previously identified by the controller comprises calculating the BR of the buffer using the following equation:

[0151] ;

[0152] in:

[0153] BR is the block rate of the buffer;

[0154] BufferFullRatio is the buffer fullness ratio; and

[0155] Exp Factor is the exponential factor;

[0156] Here, the buffer fill rate is calculated using the following equation:

[0157] ;

[0158] in:

[0159] AveragePartCount is the average number of parts observed in the buffer during the observation time;

[0160] Minimum Threshold is the minimum threshold of jobs that the buffer must have to prevent starvation of downstream systems; and

[0161] Maximum Threshold is the maximum number of jobs that can be stored in the buffer before upstream blocking occurs.

[0162] According to the method of technical solution 9, calculating the BR of the buffer zone includes calculating the exponential factor using the following formula:

[0163] ;

[0164] in:

[0165] Exp Factor is the exponential factor;

[0166] Min Threshold is the minimum threshold of jobs that the buffer has to prevent downstream starvation;

[0167] Max Threshold is the maximum number of jobs that the buffer can store before blocking upstream; and

[0168] Flatness is equal to 2.

[0169] According to the method of technical solution 10, wherein calculating, by the controller, the BR of the predecessor and the successor previously identified by the controller comprises calculating the BR of the station using the following equation:

[0170] ,

[0171] in:

[0172] Block% is the percentage of time that the station 304 is blocked during the observation time, and Starve% is the percentage of time that the station 304 is starved during the observation time, where:

[0173] BR is the block rate of the station.

[0174] The method according to technical solution 1, wherein calculating, by the controller, the BR of the predecessor and the successor previously identified by the controller comprises calculating the BR of the predecessor at the beginning of the flowchart using the following equation:

[0175] ,

[0176] in:

[0177] BR pred is the BR preceding the beginning of the flowchart; and

[0178] Block% is the percentage of time that the predecessor at the beginning of the stream is blocked within a predetermined observation time.

[0179] The method according to technical solution 1, wherein calculating, by the controller, the BRs of the predecessor and the successor previously identified by the controller comprises using the following equation to calculate the BR of the successor at the end of the flowchart:

[0180] ;

[0181] in:

[0182] BR succ is the subsequent BR at the end of the stream; and

[0183] Starve% is the percentage of time that the successor at the end of the stream is starved over a predetermined observation time.

[0184] The method according to technical solution 1, wherein the subject predecessor includes the plurality of successors immediately following the predecessor, and calculating by the controller the BR of the predecessor previously identified by the controller includes calculating the BR of the subject predecessor using the following equation:

[0185] ;

[0186] in:

[0187] BR pred is the block rate of the predecessor of the subject;

[0188] BR MinPredSucc is the minimum block rate of the predecessors and successors of the plurality of topics; and

[0189] BR MaxPredSucc is the maximum block rate of the predecessors and successors of the multiple topics.

[0190] The method according to technical solution 1, wherein the subject successor includes the plurality of predecessors immediately preceding the successor, and calculating by the controller the BR of the successor previously identified by the controller includes calculating the BR of the subject successor using the following equation:

[0191] ;

[0192] in:

[0193] BR succ is the block rate of the subject successor;

[0194] BR MinSuccPred is the minimum block rate of the plurality of subject successors and predecessors; and

[0195] BR MaxSuccPred is the maximum block rate of the multiple topic successors and predecessors.

[0196] The method according to technical solution 1, wherein the predecessor includes a subject predecessor of the workspace without the predecessor itself because it is at the beginning of the flowchart, and the controller calculates the BR of the predecessor previously identified by the controller, including using the following formula to calculate the BR of the subject predecessor:

[0197] ;

[0198] in:

[0199] BR pred is a BR that is a predecessor of the subject; and

[0200] BR succ is the successor BR.

[0201] The method according to technical solution 1, wherein the successor includes a topic successor without a successor itself, and calculating by the controller the BR of the successor previously identified by the controller includes using the following formula to calculate the BR of the topic successor:

[0202] ;

[0203] in:

[0204] BR succ is the block rate of the successor to the subject; and

[0205] B pred is the BR of the front drive.

[0206] A control system comprising:

[0207] A controller configured to communicate with a manufacturing system, wherein the controller is programmed to:

[0208] creating a flow chart showing how parts travel through the manufacturing system, wherein the manufacturing system includes stations and buffers;

[0209] Identifying a work area in the flowchart to be analyzed;

[0210] identifying a predecessor and a successor for each of the workspaces in the flow chart, wherein each of the predecessor and the successor is at least one of the station or the buffer of the manufacturing system;

[0211] receiving buffer usage and station blocking / starvation data of the manufacturing system;

[0212] collecting the buffer usage and station blocking / starvation data for the predecessor and the successor previously identified by the controller;

[0213] calculating a block rate (BR) of the predecessor and the successor previously identified by the controller;

[0214] Calculating a bottleneck index (BI) value of the work area using the predecessor and successor BRs;

[0215] listing the BI values ​​from highest to lowest to identify a top bottleneck operating area among the operating areas, wherein the top bottleneck operating area has the highest value among the BI values; and

[0216] The manufacturing system is controlled taking into account the top bottleneck work area to maximize the throughput of the manufacturing system.

[0217] According to the control system of technical solution 18, the working area includes an intermediate working area, the predecessor includes a single predecessor of the intermediate working area, and the successor includes a single successor of the intermediate working area, so that the intermediate working area has a single predecessor immediately before the intermediate working area and a single successor immediately after the intermediate working area, wherein the controller is programmed to calculate the BI value of the working area using the following equation:

[0218]

[0219] in:

[0220] BI is the BI value of the intermediate working area;

[0221] BR pred is a single predecessor BR of the intermediate working area; and

[0222] BR succ It is the single successor BR of the intermediate working area.

[0223] A control system according to Technical Solution 18, wherein the working area includes an assembly working area, the predecessor includes a predecessor immediately in front of the assembly working area, and the successor includes a single successor immediately behind the assembly working area, so that the assembly working area has the predecessor and the single successor.

[0224] The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of modes for carrying out the present teachings when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0225] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0226] Figure 1 is a schematic front view of the manufacturing system.

[0227] Figure 2 is a flow chart of a method for identifying bottlenecks in a manufacturing system.

[0228] Figure 3 yes Figure 1 Flowchart of the manufacturing system. DETAILED DESCRIPTION

[0229] When reading in conjunction with the accompanying drawings, the above summary of the invention and the following detailed description of certain embodiments will be better understood.As used herein, the element or step that is narrated in the singular and is preceded by the word "one" or "one" should be understood to not necessarily exclude multiple elements or steps.Further, reference to "one embodiment" is not intended to be interpreted as excluding the existence of the additional embodiment that also combines the narrated feature.In addition, unless clearly stated to the contrary, an embodiment "including" or "having" an element or multiple elements with a specific property may include additional elements that do not have this property.

[0230] The following detailed description is merely exemplary in nature and is not intended to limit application and use. In addition, it is not intended to be bound by the explicit or implicit theory presented in the previous technical field, background technology, invention content or the following detailed description. As used herein, the term "module" refers to hardware, software, firmware, electronic control components, processing logic, and / or processor devices, individually or in combination thereof, including but not limited to: application-specific integrated circuits (ASICs), electronic circuits, processors (shared, dedicated or groups) and memories that execute one or more software or firmware programs, combinational logic circuits, and / or other suitable components that provide the described functions.

[0231] Embodiments of the present disclosure may be described herein in terms of functional and / or logical block components and various processing steps. It should be appreciated that such block components may be implemented by many hardware, software, and / or firmware components configured to perform a specified function. For example, embodiments of the present disclosure may employ various integrated circuit components, such as memory elements, digital signal processing elements, logic elements, lookup tables, etc., which may implement various functions under the control of one or more microprocessors or other control devices. In addition, those skilled in the art will appreciate that embodiments of the present disclosure may be practiced in conjunction with many systems, and the systems described herein are merely exemplary embodiments of the present disclosure.

[0232] For the sake of brevity, technologies related to signal processing, data fusion, signaling, control, and other functional aspects of the system (and the various operating components of the system) may not be described in detail herein. In addition, the connecting lines shown in the various figures included herein are intended to represent example functional relationships and / or physical connections between various elements. It should be noted that alternative or additional functional relationships or physical connections may exist in embodiments of the present disclosure.

[0233] refer to Figure 1 , a manufacturing system 100 is configured to assemble parts P together. An operator O may operate or at least monitor the manufacturing system 100. In the depicted embodiment, the manufacturing system 100 includes one or more conveyor belts 102 for moving parts, and one or more workstations 104 for performing work on those parts P. When using the manufacturing system 100, some workstations 104 may cause bottlenecks (see workstation 104b), thereby causing other workstations 104 to be blocked (see workstation 104a) or starved (see workstation 104c). Therefore, it is necessary to identify throughput bottlenecks in the manufacturing system 100. In the present disclosure, buffer utilization and station blocking / starvation data are used to identify throughput bottlenecks in the manufacturing system 100.

[0234] The manufacturing system 100 may include or be connected to a controller 106 to help identify throughput bottlenecks. The controller 106 is part of the control system 105 and includes at least one processor 108 and a non-transitory computer-readable storage device or medium 110. The processor 108 may be a custom processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the controller 106, a semiconductor-based microprocessor (in the form of a microchip or chipset), a macroprocessor, a combination thereof, or a device generally used to execute instructions. For example, the computer-readable storage device or medium 110 may include volatile and non-volatile storage devices in the form of read-only memory (ROM), random access memory (RAM), and keep-alive (KAM). KAM is a persistent or non-volatile memory that can be used to store various operating variables when the processor 108 loses power. The computer readable storage device or medium 110 may be implemented using any number of memory devices, such as a PROM (programmable read-only memory), an EPROM (electrical PROM), an EEPROM (electrically erasable PROM), flash memory, or another electrical, magnetic, optical, or combination memory device capable of storing data, some of which represents executable instructions used by the controller 106 to control the manufacturing system 100.

[0235] The manufacturing system 100 may include one or more sensors 112, such as laser sensors, to detect buffer usage data and / or station blocking / starvation data. The sensors 112 may communicate with an external system 114 and / or the controller 106. The external system 112 may include a processor and may communicate with the controller 106.

[0236] Figure 2 is for using buffer utilization data and station blocking / starvation data to identify manufacturing system 100 ( Figure 1 ) in a bottleneck. The method 200 begins at block 202. At block 202, the controller 106 creates a flowchart showing a part P ( Figure 1 ) Flowchart 300 of how to proceed through the manufacturing system 100 ( Figure 3 ).

[0237] Figure 3 is in method 200 ( Figure 2 ) is created at block 202 of the schematic flow chart 300. The controller 106 ( Figure 1 ) to create the flowchart 300. In the depicted embodiment, the parts P flow through a particular arrangement of buffers 302 and stations 304 of the manufacturing system 100. However, it is contemplated that the manufacturing system 100 may have a different arrangement. In the present disclosure, the term "part" means an object flowing through the manufacturing system 100, which includes the buffers 302 and stations 304. Therefore, the flowchart 300 is a system diagram of the flow of parts through the buffers 302 and stations 304, and thus shows how the parts P travel through the buffers 302 and stations 304 of the manufacturing system 100. In the present disclosure, the term "buffer" means a location (in the manufacturing system 100) where parts between stations 304 are stored and no work is performed. When a part P travels through the buffer 302, travel time may elapse. In the present disclosure, the term "station" means a location (in the manufacturing system 100) where work is performed on one part P or multiple parts P at the same time. This work takes time, and the time may vary. The term "working area" means a single station or a subset of a stream (which includes stations and buffers).

[0238] In the flowchart 300, the first station 304a performs work on the part P on the carrier C (i.e., the part PC on the carrier). Specifically, the first station 304a can assemble one or more parts P. Therefore, the work performed at the first station 304a can be considered as assembly. In the present disclosure, the term "assembly" means the situation when multiple parts P or one part and a carrier C are taken from multiple predecessors and made into one. Therefore, the term "assembly work area" means the work area where multiple parts P or one part and a carrier C are taken from multiple predecessors and made into one. Alternatively, the term "assembly" means the situation when one part P or one part P is taken from multiple predecessors and made into one. Therefore, the term "assembly work area" means the work area where multiple parts P or one part and a carrier C are taken from multiple predecessors and made into one. The first station 304a can be called an assembly work area and is preceded by one or more buffers 302. The buffer 302 at the beginning of the flowchart 300 can be called a first buffer or a first precursor FP. Therefore, one of the buffers 302 is a precursor of the first station 304a. In the present disclosure, the term "predecessor" means the station(s) 304 and / or buffer(s) 302 that are located in front of the work area 305 in the flowchart 300. The first station 304a is considered to be the work area 305. In the present disclosure, the term "work area" means a single station or a subset of a stream (which may include stations and buffers). Further, the first station 304a may be after another buffer 302. Therefore, the buffer 302 may be a successor to the first station 304a. In the present disclosure, the term "successor" means the station(s) 304 and buffer(s) 302 that are located after the work area 305 in the flowchart 300. In the depicted embodiment, there is a split 306 after the buffer 302. In the present disclosure, the term "split" means the situation when a part is sent to one of a plurality of successors. After the split 306, the part P proceeds to the second stations 304ba and 304bb. The second stations 304ba and 304bb may form a parallel work area 305ms together. After work is performed on the part P at the second stations 304ba and 304bb, the part P is merged at the merge 308. In the present disclosure, the term "merge" means the situation when a part is taken from one of multiple predecessors. After the merge, the part P travels to another buffer 302. The part PC on the carrier can travel through the buffer 302. The buffer 302 and station 304 described above can be a blocked station and buffer 310. In the present disclosure, the term "blocking" and its past tense "blocked" describe the situation when the station 304 and buffer 302 have completed their work or travel, but cannot move forward in the flow to the successor because the successor is full of part(s) P.

[0239] After the part P or parts travel through the buffer 302 following the merge 308, the part P or parts P travel through the third station 304c. The third station 304c can be considered a bottleneck. In the present disclosure, the term "bottleneck" means a location where there is a transition from a higher block rate to a lower block rate. This highest transition is a number 1 bottleneck. After the third station 304c, the part(s) P then proceed to another buffer 302. After this buffer 302, the part(s) P proceed to the fourth station 304d. The third station 304c, the fourth station 304d, and the buffer 302 between the third station 304c and the fourth station 304d can be considered an intermediate work area 305m. In the flowchart 300, there is another buffer 302 after the fourth station 304d. This buffer 302 is a successor to the fourth station 304d and a predecessor to the fifth station 304e. The intermediate work area 305m may have only one successor and only one predecessor. Alternatively, the intermediate working area 305m may have multiple successors and multiple predecessors.

[0240] The fifth station 304e may constitute a work area 305 and may perform work that may be considered as disassembly. For this reason, the fifth station 304e may be referred to as a disassembly work area. In the present disclosure, the term "disassembly" means the situation when one part P or part PC on a carrier is sent to multiple successors as multiple parts P or parts PC on a carrier. Therefore, the term "disassembly work area" means a work area in which one part P or part PC on a carrier is sent to multiple successors as multiple parts P or parts PC on a carrier. Alternatively, the term "disassembly" means the situation in which a part P is disassembled into multiple parts P and sent to multiple predecessors. Another buffer 302 may be behind the fifth station 304e, and therefore may be considered as a successor to the fifth station 304e. The buffer 302 immediately following the fifth station 304e may be referred to as the last buffer 302e at the end of the flowchart 300. The buffer 302 in front of the fourth station 304d, the buffer 302 behind the fourth station 304d, the fifth station 304e, and the buffer 302 behind the fifth station 304d can be considered as starved stations and buffers 312. In the present disclosure, the term "starved" or its past tense "starved" means a situation when a station 304 or buffer 302 is available to accept a part P, but cannot do so due to a lack of part(s) P by a predecessor. An additional buffer 302 exists between the fifth station 304e and the first station 304a. Carrier C can travel from the fifth station 304e back to the first station 304a.

[0241] Return to Figure 2 , in creating the flowchart 300 ( Figure 3 ), the method 200 proceeds to block 204. At block 204, the controller 106 identifies the flowchart 300 ( Figure 3) to be analyzed in the workspace 305. It is contemplated that all of the workspaces 305 in the flowchart 300 may be identified as the workspaces 305 to be analyzed by the method 300. Alternatively, some of the workspaces 305 may be identified as the workspaces 305 to be analyzed. After block 204, the method 200 proceeds to block 206.

[0242] At block 206, the controller 106 identifies the stations 304 and buffers 302 that are predecessors (multiple) and successors (multiple) of each work area 305 in the flowchart 300 identified at block 204. It is contemplated that the controller 106 may identify successors and predecessors of all work areas 305 in the flowchart 300. The method 300 then proceeds to block 208.

[0243] At block 208, the external system 114 generates buffer usage and station blocking / starvation data for each based on input from the sensor 112. Alternatively, the controller 106 may be indirectly connected to the sensor 112. Thus, the controller 106 generates buffer usage and station blocking / starvation data based on input from the sensor 112. Therefore, the sensor 112 may be connected to each workspace 305 of the manufacturing system 100. Then, the method 300 continues to block 210. The buffer usage and station blocking / starvation data may include, for example, the number of parts P in each buffer 302, the part capacity of each buffer 302, the average number of parts P in each buffer 302 over a predetermined time period, etc. At block 210, the controller 106 collects buffer usage and station blocking / starvation data for the predecessor and successor identified at block 208. To this end, the external system 114 communicates buffer usage and station blocking / starvation data for the predecessor and successor identified at block 208. Then, the method 300 continues to block 212.

[0244] At block 212, the controller 106 calculates the block rate (BR) for all predecessors and successors identified at block 206. The BR of the buffer 302 may be the average number of parts P in the buffer 302 divided by the part capacity of the buffer 302. However, there are many considerations to make the formula more robust. Instead of using the maximum capacity of the buffer 302, a maximum threshold is used to calculate the BR of the buffer 302. Further, instead of using zero (0) as the minimum value, a minimum threshold is used to calculate the BR of the buffer 302. The buffers 302 may vary in size, and for this reason, the scaling method flattens the middle portion of the BR instead of using a linear formula. The flattening is less significant in smaller buffers 302 and more significant in larger buffers 302. Therefore, for the buffer 302, the BR is equal to . BufferFull Ratio is the buffer full ratio and is defined by the following formula: . AveragePartCount is the average number of parts observed in the buffer during the observation time. Minimum Threshold is the minimum threshold of jobs that the buffer must have to prevent starvation of the downstream system. Maximum Threshold is the maximum number of jobs that can be stored in the buffer before upstream blocking occurs. Exp Factor is the exponential factor and is equal to . Flatness equals 2.

[0245] For station 304, the BR of station 304 is equal to , where Block% is the percentage of time that a station 304 is blocked during the observation time, and Starve% is the percentage of time that a station 304 is starved during the observation time. Since the capacity of a station 304 is only 1, no flattening is required. However, this formula is not used in flowchart 300 because all workspaces 304 are surrounded by buffers 302.

[0246] The BR of a front-wheel drive without a front-wheel drive is equal to , where Block% is the percentage of time the predecessor is blocked during the observation time. The BR of a successor without a successor is equal to This formula is used in flowchart 300 for buffer 302 in front of working area 305 with first station 304a. Starve% is the percentage of time that the successor is starved during the observation time. This formula is used in flowchart 300 for buffer 302 in front of working area 305 with last station 304e.

[0247] Use the following formula to calculate the BR of a predecessor with multiple successors: , where BR pred is the BR of the forerunner, Starve% is the percentage of the forerunner that is hungry during the observation time, and Starve% MinPredSucc is the minimum Starve% of all predecessors' successors, and Starve% MaxPredSucc is the maximum Starve% of the successor of all predecessors. Use the following formula to calculate the BR of a successor with multiple predecessors: , where BR pred is the block rate of the predecessor, Block% is the percentage of time the successor is blocked during the observation time, Block% MaxSuccPred is the maximum Block% of all subsequent predecessors, and Block% MinSuccPredis the minimum Block% of all successors of the predecessor. In the flowchart 300, this equation is not used because the second stations 304ba and 304bb are located in the work area 305. After calculating the BR as explained above, the method 200 proceeds to block 214. In the case of multiple successors for a predecessor or multiple predecessors for a successor, the highest contributor of Starve% or Block% is identified accordingly, and the BR of the object of interest must be adjusted appropriately. Alternatively, in this formula, the BR value can be used instead of the Block Starve% value. Starve% and Block% are part of the station blocking / starvation data and can be determined using the sensor 112.

[0248] At block 214, the controller 106 uses the predecessor's BR and the successor's BR to calculate the bottleneck index (BI) value for all workspaces 305. The BI value is the predecessor's BR minus the successor's BR. Therefore, for a single predecessor and a single successor, the BI value is equal to , among which, BR pred is the block rate of the predecessor, and BR succ is the BR of the successor. For the merging of the predecessor and the splitting of the successor, the BI value is equal to , where PartCntWtdAvg(BR pred ) is the weighted average of the parts count of each predecessor, and PartCntWtdAvg(BR succ ) is the weighted average of the parts count of each successor. For the assembly of the predecessor and the disassembly of the successor, the BI value is equal to , where Min(BR pred ) is the BR of the predecessor with the lowest value, and Max(BR succ ) is the BR with the highest value of the successor. The above combinations can be mixed. When the work area 305 is located at the starting point or the end point of the flowchart 300, there is no predecessor or successor. Therefore, in this case, the BR is missing from the BI formula described above. pred or BR succ The BR of the work area 305 at the beginning of the flowchart 300 is calculated using the following formula: pred : To calculate the BR of the work area 305 at the end of the system succ , the following formula can be used: The method 300 then proceeds to block 216 .

[0249] At block 216, the controller 106 lists the BI values ​​from highest to lowest. The highest BI value is the top bottleneck. Then, the method 200 proceeds to block 218. At block 218, one or more actions are taken to resolve the top bottleneck working time / variance, thereby improving the throughput of the manufacturing system 100. In other words, the controller 106 controls the manufacturing system 100 taking into account the top bottleneck working area to maximize the throughput of the manufacturing system. For example, the controller 106 may command one or more conveyor belts 102 to increase or decrease their speed. All of the formulas and actions of the method 200 mentioned help the control system 105 to efficiently and effectively determine the top bottleneck working area, thereby improving the operation of the manufacturing system 100.

[0250] As used herein, a system, device, structure, article, element, component, or hardware that is "configured to" perform a specified function is indeed capable of performing the specified function without modification, rather than merely having the potential to perform the specified function after further modification. In other words, a system, device, structure, article, element, component, or hardware that is "configured to" perform a specified function is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function. As used herein, "configured to" represents existing characteristics of a system, device, structure, article, element, component, or hardware that enable the system, device, structure, article, element, component, or hardware to perform the specified function without further modification. For purposes of this disclosure, a system, device, structure, article, element, component, or hardware that is described as "configured to" perform a specific function may be additionally or alternatively described as "adapted to" and / or described as "operating to" perform the function.

[0251] The terms "comprising", "including" and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements or components. The order of steps, processes and operations may be changed when possible, and additional or alternative steps may be adopted. As used in this specification, the term "or" includes any one and all combinations of the associated listed items. The term "any of..." is understood to include any possible combination of the referenced items, including "any of" the referenced items. The term "any of..." is understood to include any possible combination of the referenced items of the appended claims, including "any of" the referenced items.

[0252] The illustrations of the embodiments described herein are intended to provide a general understanding of the structures of the various embodiments. The illustrations are not intended to serve as a complete description of all elements and features of the devices and systems utilizing the structures or methods described herein. Upon reviewing this disclosure, many other embodiments may be apparent to those skilled in the art. Other embodiments may be utilized and derived from this disclosure so that structural and logical replacements and changes may be made without departing from the scope of this disclosure. Unless otherwise specifically limited, any feature of any embodiment may be used in combination with any other feature or element in any other embodiment or may be used in place of any other feature or element. Therefore, this disclosure and the accompanying drawings will be considered illustrative rather than restrictive.

Claims

1. A method for identifying a bottleneck in a manufacturing system, the method comprising: creating, by a controller, a flow chart showing how parts travel through the manufacturing system, wherein the manufacturing system includes stations and buffers; identifying, by the controller, a work area in the flowchart to be analyzed; identifying, by the controller, a predecessor and a successor for each of the workspaces in the flow chart, wherein each of the predecessor and the successor is at least one of the station or the buffer of the manufacturing system; receiving, by the controller, buffer usage and station blocking / starvation data of the manufacturing system; collecting, by the controller, the buffer usage and station blocking / starvation data for the predecessor and the successor previously identified by the controller; calculating, by the controller, a block rate (BR) of the predecessor and the successor previously identified by the controller; calculating, by the controller, a bottleneck index (BI) value of the work area using the predecessor and successor BRs; listing, by the controller, the BI values ​​from highest to lowest to identify a top bottleneck operating region among the operating regions, wherein the top bottleneck operating region has a highest value among the BI values; and controlling the manufacturing system taking into account the top bottleneck work area to maximize the throughput of the manufacturing system, Wherein, calculating, by the controller, the BRs of the predecessor and the successor previously identified by the controller comprises calculating the BR of the buffer using the following equation: ； in: BR is the block rate of the buffer; BufferFullRatio is the buffer fullness ratio; and Exp Factor is the exponential factor; Here, the buffer fill rate is calculated using the following equation: ； in: AveragePartCount is the average number of parts observed in the buffer during the observation time; Minimum Threshold is the minimum threshold of jobs that the buffer must have to prevent starvation of downstream systems; and Maximum Threshold is the maximum number of jobs that can be stored in the buffer before upstream blocking occurs. Calculating the BR of the buffer zone includes calculating the exponential factor using the following formula: ； in: Exp Factor is the exponential factor; Min Threshold is the minimum threshold of jobs that the buffer has to prevent downstream starvation; Max Threshold is the maximum number of jobs that the buffer can store before blocking upstream; and Flatness is equal to 2.

2. The method according to claim 1, wherein: The working area includes an intermediate working area, the predecessor includes a single predecessor of the intermediate working area, and the successor includes a single successor of the intermediate working area, so that the intermediate working area has a single predecessor immediately before the intermediate working area and a single successor immediately after the intermediate working area, wherein calculating, by the controller, the BI value of the working area using the BRs of the predecessor and the successor includes calculating the BI value of the intermediate working area using the following equation: in: BI is the BI value of the intermediate working area; BR pred is a single predecessor BR of the intermediate working area; and BR succ It is the single successor BR of the intermediate working area.

3. The method according to claim 1, wherein: The work area includes an assembly work area, the predecessor includes a predecessor immediately in front of the assembly work area, and the successor includes a single successor immediately behind the assembly work area, so that the assembly work area has the predecessor and the single successor.

4. The method according to claim 3, wherein: Calculating, by the controller, the BI value of the working region using the predecessor and successor BRs includes calculating the BI value of the assembled working region using the following equation: ； in: BI is the BI value of the assembly workspace; Min(BR pred ) is the BR of one of the plurality of predecessors having the lowest value; and BR succ It is the single successor BR of the assembly workspace.

5. The method according to claim 1, wherein: The work area includes a disassembly work area, the predecessor includes a single predecessor immediately in front of the disassembly work area, and the successor includes a plurality of successors immediately behind the disassembly work area, so that the disassembly work area has the single predecessor and the plurality of successors.

6. The method according to claim 5, wherein: Calculating, by the controller, the BI value of the working area using the predecessor and successor BRs includes calculating the BI value of the disassembly working area using the following equation: ； in: BI is the BI value of the disassembly work area; BR pred is a single front-wheel drive BR; and Max(BR succ ) is the BR of the one with the highest value among multiple predecessors.

7. The method according to claim 1, wherein: The working area includes a merged working area, and calculating, by the controller, a BI value of the merged working area using the predecessor and the successor BRs includes calculating the BI value of the merged working area using the following equation: ； in: BI is the BI value of the merged workspace; PartCntWtdAvg(BR pred ) is the weighted average of the part counts of the predecessors immediately preceding the merged workspace; and BR succ is the single successor BR of the workspace.

8. The method according to claim 7, wherein: The working area includes a split working area, and calculating, by the controller, a BI value of the split working area using the predecessor and the successor BRs includes calculating the BI value of the split working area using the following equation: ； in: BI is the BI value of the split working area; BR pred is a single predecessor BR of the workspace; and PartCntWtdAvg(BR succ ) is the weighted average of the subsequent part counts immediately following the segmented workspace.

9. The method according to claim 1, wherein: Calculating, by the controller, the BRs of the predecessor and the successor previously identified by the controller includes calculating the BR of the station using the following equation: ， in: Block% is the percentage of time that the station is blocked during the observation time, and Starve% is the percentage of time that the station is starved during the observation time, where: BR is the block rate of the station.

10. The method according to claim 1, wherein: Calculating, by the controller, the BRs of the predecessor and the successor previously identified by the controller includes calculating the BR of the predecessor at the beginning of the flowchart using the following equation: ， in: BR pred is the BR preceding the beginning of the flowchart; and Block% is the percentage of time that the predecessor at the beginning of the flow graph is blocked within a predetermined observation time.

11. The method according to claim 1, wherein: Calculating, by the controller, the BRs of the predecessor and the successor previously identified by the controller includes calculating the BR of the successor at the end of the flowchart using the following equation: ； in: BR succ is the subsequent BR at the end of said flowchart; and Starve% is the percentage of time that the successor at the end of the flow chart is starved during a predetermined observation time.

12. The method according to claim 1, wherein: A subject predecessor includes a plurality of successors immediately following the predecessor, and calculating, by the controller, the BR of a predecessor previously identified by the controller includes calculating the BR of the subject predecessor using the following equation: ； in: BR pred is the block rate of the predecessor of the subject; BR MinPredSucc is the minimum block rate of multiple topic predecessors and successors; and BR MaxPredSucc It is the maximum block rate of multiple topic predecessors and successors.

13. The method according to claim 1, wherein: The subject successor includes a plurality of predecessors immediately preceding the successor, and calculating, by the controller, a BR of a successor previously identified by the controller includes calculating the BR of the subject successor using the following equation: ； in: BR succ is the block rate of the subject successor; BR MinSuccPred is the minimum block rate of multiple topic successors and predecessors; and BR MaxSuccPred is the maximum block rate of multiple topic successors and predecessors.

14. The method according to claim 1, wherein: The predecessor includes a subject predecessor of the workspace without the predecessor itself because it is at the beginning of the flowchart, and calculating by the controller the BR of that predecessor previously identified by the controller includes calculating the BR of the subject predecessor using the following formula: ； in: BR pred is a BR that is a predecessor of the subject; and BR succ is the successor BR.

15. The method according to claim 1, wherein: The successor comprises a subject successor without a successor itself, and calculating, by the controller, a BR of the successor previously identified by the controller comprises calculating the BR of the subject successor using the following formula: ； in: BR succ is the block rate of the successor to the subject; and B pred is the BR of the front drive.

16. A control system comprising: A controller configured to communicate with a manufacturing system, wherein the controller is programmed to: creating a flow chart showing how parts travel through the manufacturing system, wherein the manufacturing system includes stations and buffers; Identifying a work area in the flowchart to be analyzed; identifying a predecessor and a successor for each of the workspaces in the flow chart, wherein each of the predecessor and the successor is at least one of the station or the buffer of the manufacturing system; receiving buffer usage and station blocking / starvation data of the manufacturing system; collecting the buffer usage and station blocking / starvation data for the predecessor and the successor previously identified by the controller; calculating a block rate (BR) of the predecessor and the successor previously identified by the controller; Calculating a bottleneck index (BI) value of the work area using the predecessor and successor BRs; listing the BI values ​​from highest to lowest to identify a top bottleneck operating area among the operating areas, wherein the top bottleneck operating area has the highest value among the BI values; and controlling the manufacturing system taking into account the top bottleneck work area to maximize the throughput of the manufacturing system, Wherein, calculating, by the controller, the BRs of the predecessor and the successor previously identified by the controller comprises calculating the BR of the buffer using the following equation: ； in: BR is the block rate of the buffer; BufferFullRatio is the buffer fullness ratio; and Exp Factor is the exponential factor; Here, the buffer fill rate is calculated using the following equation: ； in: AveragePartCount is the average number of parts observed in the buffer during the observation time; Minimum Threshold is the minimum threshold of jobs that the buffer must have to prevent starvation of downstream systems; and Maximum Threshold is the maximum number of jobs that can be stored in the buffer before upstream blocking occurs. Calculating the BR of the buffer zone includes calculating the exponential factor using the following formula: ； in: Exp Factor is the exponential factor; Min Threshold is the minimum threshold of jobs that the buffer has to prevent downstream starvation; Max Threshold is the maximum number of jobs that the buffer can store before blocking upstream; and Flatness is equal to 2.

17. The control system according to claim 16, wherein: The operating region includes an intermediate operating region, the predecessor includes a single predecessor of the intermediate operating region, and the successor includes a single successor of the intermediate operating region, such that the intermediate operating region has a single predecessor immediately preceding the intermediate operating region and a single successor immediately following the intermediate operating region, wherein the controller is programmed to calculate the BI value of the operating region using the following equation: in: BI is the BI value of the intermediate working area; BR pred is a single predecessor BR of the intermediate working area; and BR succ It is the single successor BR of the intermediate working area.

18. The control system according to claim 16, wherein: The work area includes an assembly work area, the predecessor includes a predecessor immediately in front of the assembly work area, and the successor includes a single successor immediately behind the assembly work area, so that the assembly work area has the predecessor and the single successor.

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