4776 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 56, NO. 12, DECEMBER 2009
Integrating Mixed-Reality Remote Experiments IntoVirtual Learning Environments Using
Interchangeable ComponentsFrederico Menine Schaf and Carlos Eduardo Pereira
AbstractThis paper presents a proposal to integrate mixed-reality remote experiments into virtual learning environments(VLEs) using the concept of interchangeable components, whichcan represent either real or virtual devices or software in in-dustrial automation systems. Combinations of real and virtualtechnical plants and automation systems are used in differentlearning scenarios for teaching control and automation concepts.Configurations of interchangeable components can be dynami-cally created via a VLE by configuring database parameters. Theproposed system includes a remote Web interface that follows athin client strategy and is designed to be compatible with Webbrowsers, including basic Java support. As the architecture thatsupports the integration of virtual and real components is locatedon the server side, remote students/users are only concerned withthe experiment and do not need to be aware of the system thatprovides this integration and flexibility. In the current version,interchangeable components are integrated via an Object Linkingand Embedding for Process Control interface, which is a widelyadopted standard in the control and automation area. The pro-posed approach also provides practical and theoretical supportfor experiments within a collaborative virtual environment. Thispaper includes a description of four experiments developed usingthe proposed environment and concepts.
Index TermsCollaborative work, computer-aided engineer-ing, educational technology, learning systems.
ENGINEERING education has become a crucial aspect formost countries since it has been recognized that skilledengineers are one of the main components for the developmentof innovative products and services, as well as for the opti-mization of production processes to ensure high productivityand quality. Considering education on control and automationsystems, a key issue is the reduction of the gap between clas-sical theoretical courses and real industrial practice. Hence, itis important to allow students to operate with devices, systems,and techniques that are as close as possible to those that theywill confront in industrial settings. Unfortunately, reproducing
Manuscript received August 15, 2007; revised June 18, 2009. First publishedJune 30, 2009; current version published November 6, 2009. This work wassupported in part by the Brazilian research agencies Coordenao de Aper-feioamento de Pessoal de Nvel Superior (CAPES), Financiadora de Estudos eProjetos (FINEP), and Conselho Nacional de Pesquisa (CNPq), by the Germanexchange agency Deutscher Akademischer Austauschdienst (DAAD), and bythe Servio Nacional de Aprendizagem Industrial (SENAI) in Brazil.
The authors are with the Federal University of Rio Grande do Sul (UFRGS),Porto Alegre 90040-060, Brazil (e-mail: firstname.lastname@example.org;email@example.com).
Digital Object Identifier 10.1109/TIE.2009.2026369
a real industrial plant in an academic environment is not an easytask. Industrial equipment is, in general, very expensive (bothin terms of acquisition and maintenance costs). Furthermore,safety constraints should also be taken into account. Suchfactors restrict the use of real industrial devices in academiclaboratories, which, in general, are then structured as small-scale experiments with little connection to industrial reality.Within this context, an industrial laboratory facility that isavailable via the Web and, therefore, accessible at flexible timesto a larger number of individuals helps to improve the overallcost effectiveness of such solution.
The Internet growth has brought new paradigms and pos-sibilities in technological education. In particular, it allowsthe remote use of experimental facilities that can be used toillustrate concepts that are handled in a classroom and servesas an enabling and powerful technology for distance teaching.Through its worldwide connectivity, the Internet also allowshaving learning materials available to a much larger audience ofstudents. Web-accessible laboratories with remote experimentshave become an attractive economical solution for the increas-ing number of students . They represent a second-best-of-being-there (SBBT)  solution for students and laboratorieswith expensive equipment. Following this trend, many institu-tions around the world have been engaged in the development ofWeb-based experimental settings. Systems aiming at teachingand research in several different areas have been proposed, suchas digital process control , proportionalintegralderivative(PID) control , embedded communication systems , su-pervisory control , robot and other systems teleoperation, and real-time video and voice applications. Mostly,these experiments utilize customized devices and software tomake small-scale textbook-like experiments remotely available.
However, our experience has shown that the availabilityof remote experiments is not a sufficient condition to ensuresuccess in the learning process of control and automation engi-neers. Remote laboratory experiments offered as stand-alonesettings, without connection to adequate learning materials(explaining the topics that are to be learned in the experiment),usually lead students to the use of a trial-and-error strategy,which has a lower learning impact than originally expected.Moreover, remote laboratories are available 24/7 for a largeaudience of students, increasing the demand in the numberof faculty members and tutors that are necessary to provideonline guidance to students. To alleviate these problems,remote experiments can be integrated into virtual learning
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SCHAF AND PEREIRA: INTEGRATING MIXED-REALITY EXPERIMENTS INTO VIRTUAL LEARNING 4777
environments (VLEs)  that manage and provideguidance via learning materials before, during, and afterthe experimentation. This paper proposes such an integratedlearning environment on which mixed-reality laboratoryexperiments and student guidance tools are combined forcontrol and automation education. Mixed-reality experiments, on which simulated components can be combined to realequipment, are used to illustrate different learning situationsaccording to the knowledge level of remote students.
The proposed environment has been developed with thecontext of the RExNet Consortium . This Alfa II financedproject, funded by the European Community, had mainly threegoals: 1) to share; 2) to harmonize; and 3) to spread currentskills on remote experimentation. The first goal directly ad-dresses the essence of the ALFA program (financial support),namely, it calls for the cooperation among the consortiumpartners. Harmonization is a direct consequence of havinguniversities from distinct countries with different languages andcultures. Each university participating in the RExNet projectacts as a disseminating party within its own country, i.e.,spreading access to remote experiments to other surroundinguniversities. Results of the RExNet project can be seen in ,, and .
This paper is divided as follows. Section II describesDistance Education Environment of the Automation, Roboticsand Control Systems Group (GCAR-EAD), a VLE for con-trol and automation engineering education developed at ouruniversity. Sections III and IV describe experiment scenarios,which exploit different combinations of real and simulatedautomation-system modules. Section V compares the GCAR-EAD with other similar systems presented in the literature.Section VI discusses the results achieved when using theGCAR-EAD in undergraduate and graduate courses. Finally, inSection VII, conclusions are drawn and future work is discussed.
Our experience in applying remote experiments for controland automation started in 2002 with the construction of aremote laboratory with a Foundation Fieldbus (FF) pilot plant. That system enabled students to learn PID tuning controltechniques and industrial communication protocols by workingwith a hypertext-based learning material and by remotely ac-cessing the pilot plant.
A. FF Pilot Plant
The FF pilot plant consists of three interconnected tanks,four ac pumps (two of which are driven by vector-controldrivers), and five control valves to control the liquid flow inthe system. It is, therefore, possible to configure many differentsingle-variable and multivariable control loops, involving tanklevel and liquid flow as process variables, with various choicesof control inputs. All sensors and actuators in the plant arenetworked smart devices, which communicate using the FFprotocol.
The use of a highly innovative industrial-oriented technology brings a very strong perspective to research andteaching. Practical interest is raised in the students, as the
experiments become visually and conceptually closer to theprofessional practice. Also, a wider variety of concepts canbe illustrated, and several levels of difficulty and complexity/challenge can be explored.
The pilot-plant architecture  is based on Object Linkingand Embedding for Process Control (OPC) and Web servicestechnologies to provide remote accessibility. Tools like theElipse SCADA1 software (supervisory system) and the Sysconsoftware and PCI302 FF network card2 (SMAR commercialproducts) were employed in the development and operation ofthe industrial pilot plant. The FF devices are responsible for thecontrol that is not affected by Internet connection delays.
The communication between the supervisory and the Webserver is based on a client/server structure, which allows anybrowser (client) to access the screens of the supervisory system(server). The plant monitoring (visualization) is implementedby means of Java Applets. The user interacts with the browser,sending parameters to the plant via PHPMySQL functions.The information is processed by the supervisory system in theserver, and an answer is sent back to the user, closing the cycle.
The experiment accessibility is controlled through an accesscontrol tool that has the following objectives: user validation,experiment scheduling, monitoring a sessions duration, para-meterization of experiments, and experiment initialization.
B. GCAR-EAD: Embedding Remote Laboratories Into VLEs
Experiences using the FF pilot plant showed that due to thefact that the learning material was loosely coupled with theremote experiment, students were not able to identify whichtopics to review in case they could not get the proposed experi-ments adequately done.
To overcome those drawbacks, a system called GCAR-EADwas proposed, which supports mixed-reality remote experimen-tation. The GCAR-EAD has a more complex architecture (seeFig. 1) that additionally integrates learning-material manager(also called VLEs), educational materials, remote experimentswith mixed reality , , , interchangeable componentsstrategy , experiment analysis, and simple student guid-ance tools. The proposed architecture has five main modules:a learning-material manager, a student guidance system (orguide), experiment booking, experiment analysis (or analyzer),and experiment manager/interface. Each of these modules is re-sponsible for controlling a specific functionality of the GCAR-EAD. The interaction with each module is transparent, i.e.,students interact directly only with the VLE interface.
A central database is the main communication channelamong modules (see Fig. 1). In the sequence, each of themodules is further described.
1) Learning-Material Manager: This module containsall learning materials. All users are identified viausername/password, and, depending on the users category (incase of students, their knowledge level), distinct operationsare allowed when accessing an available learning material.Distinct learning modes are supported: active learning ,
1Elipse SCADA. See http://www.elipse.com.br.2SMAR PCI302; FF Process Control Interface. See https://www.smar.com/
4778 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 56, NO. 12, DECEMBER 2009
Fig. 1. GCAR-EAD high-level architecture.
, distributed learning , and team learning . Active-learning skills are justified since, via environment interactions,students can self-learn (or self-teach). Distributed-learningskill is obviously linked to the spatial flexibility characteristicoffered by VLEs Web accessibility. The most important skillis, however, related to collaborative interaction, i.e., studentteams (or users, in general) may work together, increasing theknowledge transfer in a common environment. In traditionalcourses, it is assumed that teachers were the only source ofknowledge, and they centralized all courses information. Thecollaborative learning skill is mostly associated with the socialconstructionist pedagogic line .
The learning-material manager plays the most meaningfulrole in the GCAR-EAD architecture since this system wasdeveloped to supply an educational (learning) environmentattached to remote experiments for the students.
2) Experiment Booking Module: This module is responsi-ble for controlling students access to experiments. Since realexperiments are not replicable with no cost, booking systemsare necessary to organize the use of the real equipment (orentire real experiments) by students. Only signed VLE userscan book/access experiments and select the available time slotsfor running their experiments in a calendar-type Web page.
3) Experiment Interface/Manager Module: The experimentmanager provides a link among the remote experiments andthe VLE and must ensure that the right remote experimentinterface is available according to VLE setup parameters. Thatmeans that the experiment manager receives from the VLE areference to the experiment to be executed and constructsthe experiment, providing also a Java Applet interface for datavisualization.
This module is also responsible for implementing the inter-changeable components strategy  by linking and combiningreal and virtual components in a learning scenario.
4) Experiment Analysis: The experiment analysis modulecomprises tools to evaluate the results of a conducted experi-ment and determine some metrics derived from the experimentresults (for instance, in the PID tuning experiment, usual met-rics are overshoot, rise time, settling time, etc.). The experimentdata are supplied by the experiment manager and the VLE in aform of reports or are directly stored in the central database.
Experiment feedback characteristics are also stored in thecentral database and are available for further visualizationand/or manipulation by the VLE and other modules.
5) Student Guidance Module: The last module of theGCAR-EAD architecture is responsible for providing studentguidance, which means that...