Virtual CIM System: A Reality in CIM Training Tan Hock Soon Lecturer Mechatronics, School of Engineering Temasek Polytechnic 21 Tampines Avenue 1 Singapore 529757 Tel: (65)780 -5481 Fax: (65)787-4958 Email:
[email protected]
Mark Ward Curriculum & Software Development Adviser Denford Limited Birds Royd, Brighouse West Yorkshire HD6 1NB England Tel: 01484-712264 Fax: 01484-712264 Email:
[email protected]
Abstract Virtual Reality (VR) technologies have transformed the landscape of intelligent computer based instruction and offer unique new viewpoints on the core goals of education and training. What distinguishes VR from all preceding technology is the sense of immediacy and control created by the immersion process: the feeling of “being there”. Over the last ten years, Singapore manufacturing industries have shifted towards producing high quality, high value-added products for export to the world market. Products manufactured would have to compete with other countries in terms of delivery, quality and cost. Computer Integrated Manufacturing (CIM) is known to be one of the enabling techniques to achieve this objective. This paper presents the features and use of the VR CIM System currently used as part of the CIM training curriculum in Temasek Polytechnic. The VR environment allows students to operate a fully automated factory from the basic level of programming machines such as robots, AS/RS, etc. all the way to cell control, scheduling, and order generation in production planning. Various scenarios in terms of control complexities are possible, so that students can gradually progress from running a simple system to one that is highly complex. Because the environment exists only in the virtual world, students can choose to work on the exercise at their own pace without supervision and also without the fear of damaging the equipment or causing harm to themselves. Keywords: Virtual CIM, VR in Training/Education
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Introduction to VR and CIM
Movement of technology between industry and the home is not always in the same direction. Computers, for instance, started off very much in industry. Virtual Reality (VR) has very definitely achieved its initial success in the entertainment arena and is only just beginning to be accepted by industry. Despite use in military applications, in particular training, applications in the medical sector and some industrial initiatives, the technology is still very much seen in terms of its leisure success. These applications are however, usually written on high end workstations. In recent years, technological advancement in computer technology have made it possible for VR applications to be ported down to personal computer platforms and hence the possibility of harnessing VR in technical training.
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The concept of Computer Integrated Manufacturing (CIM) has been around since 1973 when it was coined by Dr. Joseph Harrington in a book published under the same name. However, until the early 1980s, CIM did not become a commonly known acronym as it exists today. CIM promulgates a fundamental strategy of integrating manufacturing facilities and systems in an enterprise through computers and their peripherals (Lin 1997). Effective integration requires an in-depth understanding of all the technologies and comprehensive knowledge of all activities in all functional units of a company. Over the last ten years, Singapore manufacturing industries have shifted towards producing high quality, high valueadded products for export to the world market. Products manufactured would have to compete with other countries in terms of delivery, quality and cost. Computer Integrated Manufacturing (CIM) is known to be one of the enabling techniques to achieve this objective. It is essential hence, that graduates from university and polytechnic level need to have a sound base in CIM. The VR system developed is not meant to replace a physical CIM system in the training but to augment CIM training; giving the students multiple scenarios; the ability to run machines without danger to students and damage to expensive equipment; enabling comprehension through exploration and the ability to let students learn at their own pace. This paper will attempt to review work done in the area of VR training systems and discuss how VR is implemented in CIM training in Temasek Polytechnic.
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Review of VR Systems in Training
The engagement and excitement that is part of the VR phenomenon is an obvious candidate for exploitation in education and training (Bricken and Byrne, 1993). The motivation and mindful engagement (Salamon, Perkins, and Globerson, 1991) that comes from this environment stems not only from the novelty but from the challenge, interactivity, realism, fantasy, cooperation and immersion that is a natural extension to the benefits of games and simulations (Malone and Lepper, 1987). Parts of this engagement come from the thrill of new technologies, but there is a more enduring and valuable component as well: VR is an empowerment technique that opens many new paths for learning (Pantelidis, 1993). Gay and Santiago (1994) report that high schools have effectively used VR to stimulate interest in algebra, geometry, science and the humanities. This was done using only the crudest equipment. In their studies on VR as training instruments, Tan and Francis (1997) showed that it is possible to use VR as a training tool for training students in the use of complicated and potentially dangerous equipment. Their experiments focused on constructing a Robot model and using the virtual model to augment robot training. Johnson (1994) conducted research which required soldiers to use VR technology for terrain familiarisation training. The soldiers trained on the heliport VR unerringly guided him to points he requested in the real world. In other words, they were able to learn external
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terrain information from self-guided exploration of a virtual environment and transfer this knowledge to the actual, physical environment being modelled. Under the criteria established in this experiment, virtual environment technology has been shown to be a valid medium for the transmission of terrain knowledge for navigation. One of the applications covered by Grigson (1995) in her article on VR applications in the industry features Motorola’s VR robotic assembly line which is used to train workers on operating the line. The line is used to assembly pagers and consists of a conveyor system, three robotic cells, a machine vision system and a laser marking system. The above review has shown the wide spectrum is which VR has been implemented as training tools from the training of high school students to military applications to training in the use of machines to operator training in factories. From the above examples, it is seen that the use of VR technology in the world of training is becoming more common. 3.
The Computer Integrated Manufacturing (CIM) Environment
A typical CIM environment will consists of the following modules: • • • • • • • •
CAD/CAM Process Planning Machine Level Programming (eg. Robots, AGVs, Cell Sequencing) Production Planning Scheduling Inventory Databases etc.
which are integrated together using computers and networks. Activities in these modules have to take place before a product can be manufactured and product changes (in design and manufacture) can be made very quickly in a CIM system because of the integration between modules. Hence the environment is very suitable for small runs of batches of products. 4.
The Virtual CIM Training System
The requirement of the system in broad terms were: • • • • •
to use VR as a platform for modelling of the factory machines to have multiple scenarios (different combination of machines, type of machines) to enable machine programming to enable users to see the whole manufacturing process from individual machine programming, cell control, dispatching, scheduling, routing, process planning Must be a PC based application
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The are at present five scenarios in Room1, Room2 …..to Room5 with different machines and levels of complexity. Some examples are shown in figures 1 to 3.
Figure 1: VR CIM - Room 1 (1 Robot, 1 CNC Lathe)
Figure 2: VR CIM - Room4 (2 Robots, 1 Conveyor, 1 Vision System, 1 CNC Lathe, 1 CNC Miller, 1 AS/RS)
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Figure 3: VR CIM - Room5 ( 3 Robots, 1 Conveyor, 1 Vision System, 1 CNC Lathe, 1 CNC Miller, 1 AS/RS, 1 CMM, 1 AGV) The structure of the system is shown in figure 4. It basically consist of three core modules. These are:
HOST CONTROL MODULE Process Plan Routing Scheduling Dispatching etc. VR LINKER
VR ENVIRONMENT
Figure 4: VR CIM System a. The CIM Host Control which is the CIM supervisor, is positioned at the top of the shop floor control hierarchy. It communicates directly with all of the cells but is unaware of particular machine. The Host acts as the interface between the user and the entire manufacturing process. In the context of the hierarchical architecture, it is the function of the host to initialise, control and monitor the set
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of cells in the layer beneath it. Sub-modules in the host control module includes process planner, shopfloor configurator, router, scheduler, dispatcher, etc. b. The VR Linker is the interface between the CIM Host Module and the VR Environment. c. The VR Environment consists of worlds containing different machines and their behaviour. Because the system mimics a true factory environment, the user can choose to start from any two points in the system. He could choose to start from the VR environment where his role would be to a machine programmer he will have to program the machines and the cell sequence or he could choose to start from the Host Control Module where he his role would be a production planner in which case, he plans the process and schedules. By going through these processes and learning from his mistakes, the user will quickly understand the entire process of the new generation of automated manufacturing.
START
SHOPFLOOR CONFIGURATOR BILL OF PARTS/ PROCESS
SELECT SCENARIO
ROUTER
SCHEDULER
DISPATCHER MACHINE TEACH POINTS MACHINE PROGRAMMING
VR ENVIRONMENT
CELL SEQUENCE PROGRAMMING
Figure 5: The VR CIM Environment Figure 6 shows an example of how the machines are programmed in the VR environment. In this example, a teach pendent (an exact replica of the one use in robot teaching) is used to teach the robot. As in the real robot, the teach pendent can be used to store teach points as well as programs for robot movements. Figure 7 shows a screen capture of one of the planning environment, in this case the scheduler.
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Figure 6: Robot Teach Pendent
Figure 7: The CIM Scheduler
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Current Status of CIM Training Facilities
The CIM elective in Temasek Polytechnic uses the most up to date equipment in CIM training. There is an Eshed Robotec CIM line which students use for training. A DNC (Direct Numerical Control) laboratory for learning about interfacing DNC connections, a Shopfloor Control Laboratory using Wonderware’s InTouch software and National PLCs where integration of PLCs, machines, sensors, and MMI (Man-Machine-Interface) are taught. On top of these laboratories, lecture notes can be accessed on-line from the internet. Every student has an individual account which he can use to log-in through the World Wide Web.
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In the environment, he can: i. ii. iii. iv.
Revise Lecture Materials Work on Extra Tutorials, have them graded and returned Take part in discussions on CIM topics in the CIM bulletin board Send Emails to Instructors, Lecturers, or classmates to clarify doubts in the learning process v. Read and Send Class Announcements vi. Takes Tests and have them graded
Figure 8: Samples of CIM OLE - Lessons Page
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With the addition of the VR CIM System to the training facilities, additional training aims set up at the beginning of the project were satisfied: • • • •
7.
to have multiple scenarios (different combination of machines, type of machines) to enable machine programming to enable users to see the whole manufacturing process from individual machine programming, cell control, dispatching, scheduling, routing, process planning Must be a PC based application
Further Development
The VR CIM system is only in its beta-release. Further work will be made in areas such as : • • • 8.
the virtual world the shopfloor configurator fine tuning of the system Conclusion
The beta-version of the system was commissioned and used in the CIM elective course from 23rd March 1998. Forty-eight students were given a chance to use the system. Key issues noted during the period of use were: • • • •
all students taught have hands-on individually students were able to learn at own time without supervision and also there was no danger to students and damage to equipment system provides learning through exploration and experimentation
Version 1.0 of the software was completed on 23rd April 1998. There are many potential high - payoff areas for research and development of VR technology for education and training. VR needs to be developed as an integral part of the educational and training process, implemented alongside other traditional and non-traditional tools. It can be used for exploration and for practical skills, technical skills, operations, maintenance and academic concerns. Regarding its use in the manufacturing arena, a survey of senior design engineers at more than 100 manufacturing sites in the UK forecasts an explosion in the use of the technology over the next five years. Sponsored by IBM and undertaken by Benchmark Research, the survey revealed that, currently only five percent of those surveyed are using VR. However, forty percent of respondents expect to adopt the technology by the end of the decade, and eighty percent expect VR to have an impact on engineering. (Grigson 1995).
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References: [Bricken, M. and Byrne, C. 1993], “Summer Students in VR: A pilot study on Educational applications in VR Technology”. In Wexelblat, A. (Ed.) (1993) Virtual Reality Applications and Explorations. Toronto: Academic Press Professional, pp. 199-217. [Gay, E.R. and Santiago, R. 1994], “VR Projects at Natrona County, Wyoming. Sci- VRApps bulletin, May 5, 1994. [Grigson, A. 1995], “Worlds of Virtue”, Manufacturing Engineer, Vol. 74, No. 5, October 1995, pp. 222 - 226. [Johnson, D. 1994], “Virtual Environments in Army Aviation Training. Proceedings of the 8 th Annual Training Technology Technical Group Meeting, Mountain View, CA, 1994 pp. 47-63. [Lin, G.C. 1997], “The Latest Research Trends in CIM”, Proceedings of the 4 th International Conference on Computer Integrated Manufacturing (ICCIM’97), Singapore 1997, Vol. 1, pp. 26 - 33. [Malone , T.W. and Lepper, M. 1987], “Making Learning Fun: A taxonomy of Intrinsic Motivations for Learning. In R.E. Snow and M.J. Farr (Eds.) Aptitude, learning, and instructions: III. Conative and Affective Process Analysis, 1987, pp. 223 - 253, Hillsdale, NJ: Erlbaum. [Pantelidis, V.S. 1993], “Virtual Reality in the Classroom”, Educational Technology, vol. 33, no. 4, April 1993, pp. 23-27. [Salamon, G., Perkins, D.N. and Globerson, T. 1991], “Partners in Cognition: Extending Human Intelligence with Intelligent Technologies”, Educational Researcher, 20(3), 1991, pp. 2-9. [Tan, H.S. and Francis, G.A. 1997], “Virtual Reality as a Training Instrument”, THEC project report, October 1997, Temasek Polytechnic.
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