Simulation Environment for Manufacturing Cell to Support Full Production Performance at Product Launch

Proc. EUROSIM 2007 (B. Zupančič, R. Karba, S. Blažič) 9-13 Sept. 2007, Ljubljana, Slovenia

SIMULATION ENVIRONMENT FOR MANUFACTURING CELL TO SUPPORT FULL PRODUCTION PERFORMANCE AT PRODUCT LAUNCH

Hironori Hibino

Technical Research Institute of JSPMI (Japan Society for the Promotion of Machine Industry), 1-1-12 Hachiman-cho, Higashikurume-city, Tokyo, Japan, 203-0042 [email protected]

Abstract

It is now important to reduce lead-time from the manufacturing system design stage to the manufacturing system implementation stage and support full production performance at the product launch, because manufacturing industries face various problems such as shorter product life cycle. Before a manufacturing system is implemented, it is difficult to complete all the facility control programs for several pieces of equipment used in the manufacturing system currently. Before the real manufacturing system runs, methods to confirm implementation of production management applications, which need to evaluate and improve manufacturing systems at the product launch such as a facility behaviours record application, have not been developed. These difficulties stopped precise and rapid support of a manufacturing engineering process. In order to solve these difficulties, it is necessary to develop a method to mix and synchronize real equipment, virtual factory models on the computers, and production management applications. In our research, in order to reduce the lead-time from the design stage to the implementation stage, a manufacturing engineering environment (MEE) is proposed. MEE consists of a manufacturing cell simulation environment (MCSE) and a distributed simulation environment (DSE). MCSE, which is used to create and evaluate facility control programs while mixing and synchronizing real equipment, virtual factory models, and production management applications before manufacturing systems are implemented, is emphatically proposed in detail. MCSE consists of a manufacturing cell simulator, a soft- wiring system, and ORiN. The manufacturing cell simulator simulates facility behaviours by using data from the soft-wiring system. The soft-wiring system connects real world data, simulation world data on the manufacturing cell simulator, and data on manufacturing management applications without hard- wiring. The soft-wiring system also connects manufacturing cell and production management applications. ORiN is a standard distributed network system for manufacturing systems. Finally the case was carried out to evaluate MCSE.

Keywords: Manufacturing cell, simulation, PLC, robot, production launch. Author’s biography Dr. Eng. HIRONORI HIBINO is a Senior Researcher of the Technical Re- search Institute of Japan Society for the Promotion of Machine Industry (JSPMI), which is an affiliate of the Ministry of Economy, Trade and Industry in Japan. He is a guest professor at the Tokyo University of Agriculture and Technology concur- rently. His research fields are distributed simulation, manufacturing system design using simulation, manufacturing cell simulation for combinations of real world and simulation world. He is an academic member of JSME, JIMA, and JSPE. He is also a director of the Scheduling Society of Japan.

1 Introduction simulator simulates facility behavior by using data from the soft-wiring system. The soft-wiring system connects Recently, manufacturing industries face various prob- real world data, simulation world data on the lems such as shorter product life cycle, more diversified [1] manufacturing cell simulator, and data on manufacturing customer needs . It is now important to reduce the lead- management applications without hard-wiring. The soft- time from the manufacturing system design stage to the wiring system also connects manufacturing cell and manufacturing system implementation stage. A manu- production management applications. ORiN is a standard facturing system simulator plays an important role in distributed network system for manufacturing systems. designing and evaluating manufacturing systems by Finally, evaluation of the performance of cooperative using a virtual factory model at the manufacturing sys- work is shown. tem design stage[2][3][4]. At the manufacturing system implementation stage, it is important to make and evaluate facility control programs for a manufacturing cell, 2. Manufacturing Engineering Environment such as ladder programs for programmable logical con- A manufacturing system is defined as a CIM refer- [8] trollers (PLCs) rapidly[5]. ence model in ISO standards . The manufacturing system is classified into six layers in the model. Figure 1 Ordinarily the facility control programs not only illustrates the typical system structure. In general, the control a single piece of equipment such as a robot and sequence controller means a PLC, and the motion con- a sensor, but often control several pieces of equipment (6] troller means a robot controller or a single axis controller. simultaneously . Therefore contents of the programs And simulation is mainly used at the design stage of are usually complicated. It is thus very important to each layer. evaluate the programs before executing the programs The manufacturing engineering procedure is usually using real equipment. Concerning the facility control based on the waterfall model. Although the original pur- programs for a single piece of equipment such as parts pose of the waterfall model is to reduce the waste of of a robot program and a NC program, it is now possible [7] loop-back and re-doing, still there are many loop-backs to evaluate the programs on computers . for each manufacturing engineering process. Without However, before a manufacturing system is reducing these loop-backs, shortening manufacturing implemented, it is difficult to complete all the facility system development time is difficult. The development control programs for several pieces of equipment used stage is composed of the design stage and the imple- in the manufacturing system. Although it is essential mentation stage, and its development time is defined by for completing the facility control programs to get real data from the real equipment with precise timing, it is the following equation. not possible to get the data before the manufacturing Development time = Loop frequency × Average loop system is implemented. Before real manufacturing time system runs, methods to confirm implementation of Therefore, it is necessary to reduce the loop production management applications, which need to frequency or to shorten the loop time for development evaluate and improve manufacturing systems at the time reduction. product launch such as a facility behavior record To reduce the loop frequency, the upper-layered application, have not been developed. These difficulties design process should be highly precise. Current stopped precise and rapid support of a manufacturing simulators on the market such as a manufacturing line engineering process. Consequently the lead-time to get simulator are designed for special purposes. In order to full production performance at the product launch is design and implement the manufacturing system, many- not reduced. To solve these difficulties, it is necessary faceted evaluation is required. To realize this, it is to develop a method to mix and synchronize real necessary to collaborate with several simulators, or to equipment, virtual factory models on the computers, and collaborate with the simulators and real equipment. The production management applications. collaborations lead to the wide-use of the simulator at In our research, in order to reduce the lead-time from the implementation stage that was difficult so far. the design stage to the implementation stage, a Consequently, the average of loop time also can be manufacturing engineering environment (MEE) is reduced because of quick loop-backs in the simulation. proposed. MEE consists of a manufacturing cell However the simulators on the market are not considered simulation environment (MCSE) and a distributed the above usages. simulation environment (DSE), where ‘environment’ Therefore we propose a manufacturing engineering means a tool-set like an integrated development environment (MEE) to connect the design stage and environment (IDE). MCSE, which is used to create and the implementation stage. MEE consists of two sub- evaluate facility control programs while mixing and environments. One sub-environment is a manufacturing synchronizing real equipment, virtual factory models, cell simulation environment (MCSE). The main role of and production management applications before MCSE is to make and evaluate facility control programs manufacturing systems are implemented, is emphatically for a manufacturing cell while mixing and synchronizing proposed in detail. real equipment, virtual factory models, and production MCSE consists of a manufacturing cell simulator, a management applications. soft-wiring system, and ORiN. The manufacturing cell

Another sub-environment is a distributed simulation emulators of real controller, the following functions are environment (DSE). The main role of DSE is to connect necessary. MCSE and manufacturing system simulators at the 1. A simulation function to simulate manufacturing design stage. Distributed simulation is defined as the cell behaviors by using data from a real world execution of a simulation while connecting and which consists of the real controller and the emu- synchronizing several different simulators. In the past, lators of real controller. we have researched the distributed simulation 2. A wiring function to logically wire the real world technologies for manufacturing systems evaluation. The data, the simulation world data on a simulation distributed simulation technologies are applied in DSE, world implemented the simulation function, and and the two environments are mutually connected by a data on manufacturing management applications. gateway system[2][3][9][10]. 3. A transmission function to transmit the signals Figure 2 shows an outline of MEE, where ‘emulator’ means software simply imitating the existing equipment. ISO CIM Reference Model ・・・ On the other hand, ‘simulator’ means software which 6. Enterprise has an extended function to the real world such as time 5. Facility/Plant management. In this paper, we propose MCSE in the 4. Area Area 3. Cell Mfg. following chapters in detail. Simulator Cell 2. Station PLC R/C 3. Manufacturing Cell Simulation Environ- 1. Equipment B/R C/P Rb ment Mfg. Sys. Design Stage Mfg. Sys. Execution Stage To realize the manufacturing cell simulation environment (MCSE) which simulates manufacturing cell Fig.1 Manufacturing system structures and a usage behaviors by synchronizing the real controllers and the range of the simulation in the CIM reference model.

Product’s Design Mfg. Sys. Design Mfg. Sys. Implementation

Manufacturing Engineering Environment Distributed Simulation Specification Design Manufacturing Cell Environment Simulation Environment Transfer Line 3D Mfg. Cell Simulator Drafting Layout Design Manufacturing Adapter

締付ボルト１種上ハウジング２０ ×２種 Fastening Bolt Upper Housing Assembly Line PLC(ladder) ブラケット５０種 Bracket 取付ボルト１種

Setting Bolt Rotor Line Stator Line ORiN-HLA Gateway ロータ２種 Logistics System Rotor Warehouse Shipping Area ベアリング１種×２ヶ Bearing ステータ２種 Upper Housing Line Stator Assembly Line Under Housing Line

下ハウジング２種 Under Housing

Manufacturing Adapter Real Device, Real I/F Machining Line Prod. Management Appli. Manufacturing Adapter HLA(High Level Architecture) Level HLA(High Interface for the Network) the Interface for ORiN(Open Resource

Dis tribu te d S i mulation Manufacturing Cell 6.Enterprise Envir onment Simulati on Environment

5.Plant Mfg. Simulator A Simulator Mfg. B Simulator Mfg. Mfg. Simulator N Simulator Mfg.

4.Area

3.Cell Cell

Robot 2.Station PLC Controler Barcode Control Robot Virtual 1.Equipment Reader Panel Virtual Mfg. Sys. Design Mfg. Sys. Implementation Real Fig. 2 An outline of our proposed manufacturing engineering environment.

and the data between the simulation world and and so on. In order to simulate manufacturing cell the real world without considering the differences behaviors using signals and data from a real world, it is between the real controllers and the emulators. necessary to transform data on the real world (or a 4. A network interface function to connect the real simulation world) into utilizable data on the simulation controller and the emulators with a standard man- world (or the real world). The real world means that a ner. world consists of real equipment. The simulation world means that a world consists of equipment emulators and manufacturing cell simulation models. Therefore the In order to realize these functions, we propose a soft-wiring system realizes to logically wire the real world manufacturing cell simulator to accomplish the simulation data and the simulation world data which are modeled function 1, and a soft-wiring system to perform the wiring on a simulation world. The system mainly needs to have function 2. The manufacturing cell simulator simulates the following functions for step 3. mechanical behavior in accordance with signals from 1. A function to logically wire data between the real the soft-wiring system. world and the simulation world while transform- The function 3 and 4 are achieved by ORiN. ORiN (Open Resource interface for the Network / Open Robot ISO/CIM Reference Model interface for the Network) is a middle-ware based on an Manufacturing Cell Simulator Mfg. Management appl. [11] 3. Cell object oriented technology . It provides a standard Soft-wiring System access method to various controllers. ORiN ORiN consists of two parts, an engine and a provider. 2. Station Bar Code Operation Panel Robot Provider PLC Provider The ORiN engine provides the application interfaces and Provider ・・・ Provider some sophisticated common functions. An ORiN application operates abstracted equipment. This means 1. Equip. that the real equipment is capsuled by the engine. The Real Equipment or Emulators abstracted equipment model is defined by the ORiN specification. And the ORiN provider absorbs the Fig. 3 An outline of manufacturing cell simulation envi- differences between abstracted equipment and real ronment. ISO/CIM Reference Model equipment. For example, a request from the engine (originally from an application such as the soft-wiring Manufacturing Management Applications system) is converted into a dedicated protocol of the Ex. Working Monitoring real equipment such as a PLC and a robot in the provider. The soft-wiring system and the manufacturing cell 3.Cell simulator are running on ORiN. Using ORiN, the Production proposed systems can become more general because of Control Soft-wiring Mfg. Cell the independence from the equipment’s specifications. appl. System Simulator Figure 3 shows an outline of MCSE. Figure 4 shows ORiN information flows of manufacturing cell simulation 2.Station environment. Figure 5 presents an outline of ORiN. Robot PLC Bar-code OP-Panel provider provider provider provider 1. 4. Soft-wiring System Equipment In real manufacturing systems, wiring between Real equipment or Emulator controllers is usually used hard-wiring. As MCSE is used Information flow at the implementation stage. before manufacturing systems are implemented, we need Information flow at the execution stage. to evaluate the facility control programs of the controller without hard-wiring. Therefore the soft-wiring system, Fig. 4 Information flows of manufacturing cell simula- which logically wires the real world data, the simulation tion environment. world data, and data on manufacturing management applications, is necessary. This system executes the FDC

Application Internet following steps for each controller asynchronously and (Area layer Cell layer Application based on In ISO) App. App. App. OPC UPnP FDML independently. other standards. X Y Z Step 1. Making connection to real equipment or its Application IF emulator through ORiN. Abstract Dev. Engine Device B ORiN Step 2. Observing the item value of the equipment Device IF

continuously. Provider Step 3. Propagating the value to linked item whenever A Co. B Co. C Co. D Co.

it detects the change of value. Device (Station layer Equipment layer Machine tool In ISO) C/P(Control panel) PLC However there are many types of data on the Rb(Robot) Barcode Reader controller such as integer type, real type, character type Fig. 5 An outline of ORiN.

ing and propagating data in response to data Process Flow: types. Step 1: Make a connection to the real world or the simulation world logically. Step 2: Observe the item value of the device continuously. 2. A function to perform the data conversions such Step 3: Propagate the value to linked item whenever the value is changed. as BCD (Binary Coded Decimal) data conversion, Soft-wiring System Data types: data masking, data type conversion such as Integer, BCD, Real, String, ‘String to Integer’, data calculation and so on. Array, etc.

3. A function to filter out data which are over a limi- … … … ...... ORiN tation value as a dead band function. Data processing: 4. A function to record a data transition log to evalu- ・・・・・ Convert, Calc, Filter, etc. ate a timing chart of an action sequence. Real equipment or Emulator The soft-wiring system which includes four functions was developed in C++ program language. Figure 6 shows Rb(Robot) Machine tool PLC C/P(Control panel) an outline of the soft-wiring system. Fig. 6 An outline of soft-wiring system.

Manufacturing Cell Simulator 5. Manufacturing Cell Simulator 3D Animation Motion Design Soft-wiring System In real manufacturing systems, it is possible to evaluate facility control programs by producing materials with flow while synchronizing real equipment. As MCSE is used before manufacturing systems are implemented, it is impossible to evaluate the facility control programs XML XML XML by the same way. Therefore we need to have a world to (XVL) (EMU) (CSQ) simulate producing materials with flow while mixing and 3D Graphic Model Equipment Behavior Model Soft-wiring Model Manufacturing Cell Simulator synchronizing real equipment, its emulators and virtual All models are described in XML. factory models. We propose the manufacturing cell simu- Simulation Model lator to realize the world. Figure 7 shows an outline of Fig. 7 An outline of manufacturing cell simulator. the simulator. The manufacturing cell simulator simulates manufacturing cell behaviors using signals and data from the real A link node 2) can refer the real world data through world through the soft-wiring system. The manufactur- the soft-wiring system. Then the manufacturing cell simu- ing cell simulator needs to have mainly following func- lation model in the simulation world is behaved in re- tions. sponse to the referred data. The node also can output data to the real world data through the soft-wiring sys- 1. A definition function to define behaviors for tem. Then the equipment in the real world executes pro- manufacturing cell simulation models. cesses in response to the output data. That is, the links 2. An animation function to visualize 3D manufac- are bi-directional connection. For instance, when a cyl- turing cell simulation models by synchronizing inder reaches the terminal point, the cell simulator can with the results of manufacturing cell behaviors. output a signal to the soft-wiring system; it means that 3. A connection function to link the simulation world the system can output a signal to both real equipment data to the real world data through the soft-wir- and an emulator. And then the equipment which received ing system. a signal can continue to execute a program by the signal. We propose that the behaviors are expressed by a tree structure. One task of computer processes is de- 6. Case Study fined on one node of the tree structure. Complex tasks can be defined by combining several nodes. And there A case study was carried out using a hypothetical case of small size of a manufacturing cell which consists are main four types of nodes. of a robot, a tester, a palettizer and a conveyor. This 1) Flow control nodes such as branch, join, and trig- case study consists of a robot controller, a bar-code ger. reader and a palate as real equipment. And a PLC emulator 2) A link node to link data on the simulator to the and operation panel emulator are also connected. On soft-wiring system the other hand, there are four systems, production 3) An animation control node to execute the anima- control system, manufacturing cell simulator, soft-wiring tion function system, and working monitoring system. The production 4) A script node to define the details of behavior. control system and the working monitoring system are real systems running in the real manufacturing system. All nodes of the tree are executed in series or in paral- Figure 8 shows the case study models on the lel. The vertical direction is executed sequentially, and manufacturing cell simulator. the horizontal direction is executed in parallel.

A typical procedure in this case study shows the the tester by the robot. These behaviors are con- followings. Figure 9 presents one of the typical trolled by the PLC and the robot controller via procedures in this case study. Figure 10 shows the ORiN. system structure of this case study. Figure 11 presents 7. The assigned product is investigated by the one of the working monitoring applications windows tester in the simulator. which are monitored the manufacturing cell in this case 8. Results of this investigation in the simulator are study. informed to the PLC via the soft-wiring system. 1. The barcode reader receives production order information by a KANBAN. 2. The production control system receives the pro- Procedure System behaviors in the case study duction order information via ORiN. STEP1 3. The production control system indicates to in- KANBAN Bar Code Reader vestigate the quantity of a product along the pro- Production Control duction order information toward the PLC via the STEP2 Application soft-wiring system. 4. The assigned product is picked up and moved to STEP3 PLC the conveyor by the palettizer in the simulator. These behaviors are controlled by the PLC via the soft-wiring system. STEP4 5. The assigned product is translated in front of the robot by the conveyor in the simulator. This behavior is controlled by the PLC via the soft-wir- STEP5 ing system. 6. The assigned product is picked up and moved to STEP6 STEP7 TESTER Control ROBOT Panel

STEP8

Patlite

STEP9

CONVEYOR

PALETTIZER STEP10

Fig. 8 Case study models on manufacturing cell simulator. Fig. 9 Typical procedure in this case study. Network

STEP 1,2,4, STEP 4,5,6, 5,6,7,9,10 7,9,10 PC4 PC3 PC2 PC1 Working Manufacturing Production Control STEP 3,4,5,6,7,8 Monitoring Cell simulator application Soft-wiring system STEP 2

CAOSQL ORiN

Patlite Bar-cord Robot OPC Provider Provider Provider Provider

Ladder PLC Control KANBAN Editer Emulater Panel RSLinx Patlite Robot PLC STEP 8 Bar-cord STEP 1 Reader STEP 6,9 STEP 3,4,5,6,7,8,9,10 STEP8 Fig. 10 System structure of this case study.

technologies. 2. To propose MCSE to realize making and evaluating facility control programs while mixing and synchronizing real equipment and virtual factory models before manufacturing systems are implemented. 3. To clarify necessary functions for a manufacturing cell simulator and a soft-wiring system in MCSE. 4. To confirm through a case study that a simulation world and a real world could be combined and synchronized using the manufacturing cell simulator and the soft-wiring system. Fig. 11 Working Monitor in this case study. 5. To confirm that verification of ladder programs could be confirmed by combination of the simu- Then the control panel displays the results via lation world and the real world before real manu- the PLC. The Patlite shows a kind of neon signs facturing cells are implemented. along the results via the PLC. 6. To confirm that practical usages of a working 9. The assigned product is picked up and moved monitoring application as manufacturing manage- from the tester to the conveyor by the robot. ment applications could be confirmed by combi- These behaviors are controlled by the PLC and nation of the simulation world and the real world the robot controller via ORiN. before real manufacturing cells are implemented. 10. The assigned product is translated to the end of 7. To confirm that MCSE is valid to carry to support conveyor by the conveyor in the simulator. This full production performance at product launch. behavior is controlled by the PLC via the soft- wiring system. 11. The assigned product is destroyed in the simu- Acknowledgements lator. This research is a part of the study on digital manufacturing research project of JSPMI. This project was supported by funding from the Japan Keirin We confirmed that the simulation world and the real Association. world could be combined and synchronized using the real equipment, the emulator, the virtual factory models and so on. We also confirmed that verification of the References facility control programs such as ladder program in the [1] Mehrabi, G., Ulsoy, G. and Koren, Y., PLC could be confirmed by combining and Reconfigurable manufacturing systems: key to synchronizing the simulation world and the real world. future manufacturing, Journal of the Intelligent We also confirmed that practical usages of Manufacturing, 11:403-419, 2000. manufacturing management applications such as [2] Hibino, H. and Fukuda, Y., A synchronization working monitoring application could be confirmed by mechanism without rollback function for combining and synchronizing the simulation world and distributed manufacturing simulation systems, the real world. Journal of the Japan Society of Mechanical Through this case study, we confirmed that MCSE Engineers, 68:2472-2478,2002. [in Japanese] could be used in the implementation stage. MCSE [3] Hibino, H. and Fukuda, Y., A user support system including the soft-wiring system and the manufacturing for manufacturing system design using distributed cell simulator and ORiN, is valid to carry out efficient simulation, Production Planning and Control, manufacturing system implementation at the 17:128-142, 2006. implementation stage. [4] Wohlke, G. and Schiller, E., Digital planning validation in automotive industry, Proceedings of the IFIP WG 5.7 Working Conference on Human 7. Conclusion Aspects in Production Management, 1:120-128, In this paper, the manufacturing engineering 2003. environment (MEE) to support manufacturing [5] Fukuda, Y., The state of the arts for digital engineering processes using simulation technologies engineering, Journal of the Japan Society of is proposed. The manufacturing cell simulation Mechanical Engineers, 106:230-233, 2003. [in environment (MCSE), which includes the soft-wiring Japanese] system and the manufacturing cell simulator and ORiN, [6] Pires, J. and Costa, J., Object-oriented and is proposed and developed. distributed approach for programming robot The results were: manufacturing cells, Robotics and Computer 1. To propose a concept of MEE to support manu- Integrated Manufacturing, 16:29-42, 2000. facturing engineering processes using simulation

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