PEMCWebLab - Distance and Virtual Laboratories in Electrical

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					             PEMCWebLab - Distance and Virtual
            Laboratories in Electrical Engineering –
                  Development and Trends
                                   Pavol Bauer*, Viliam Fedák†, Otto Rompelman*
                *   Delft University of Technology, Delft, The Netherlands, e-mail: P.Bauer@TUDelft.NL
                       †
                         Technical University, Košice, Slovak Republic, e-mail: viliam.fedak@tuke.sk


  Abstract—The paper deals with basic philosophy and               An overview of some typical solutions is presented in
structure    of    remote    controlled    laboratory   for     the reference [1]. Within the PEMCWebLab a more
experimentation in Electrical Engineering. The laboratory       complex system of virtual laboratories is developed
collects experiments from fields of Power Electronics,          containing not only single experiments but the whole set
Electrical Machines, Electro-Mechanical and Motion              of the experiments [2] that are distributed across Europe
Control Systems. The workbenches in the real laboratory         (Fig.1) and the experiments allocated there cover basic
are used over internet. The real experiments of the remote      fields of electrical engineering. They are placed in
controlled laboratory are placed at various universities. A     different laboratories at universities. The system to be
special care is devoted to preparation of the learners to       developed presents an open system enabling later
experimentation, including examining their knowledge            expansion. The virtual (distance) laboratories are not any
before joining to the experiment. To have a feeling of          web-based simulation. They present real electro-technical
participation in the experiment, except of the measurement      experiments conducted in the laboratory, but they are
data, also the signal from web camera is transferred to a       remotely controlled and monitored by web-based tools
distance operator.                                              with visualization of measuring apparatus, electronic
                                                                components and many more factors.
  Keywords— e-learning, remote controlled experiments,
engineering education.                                             Design of such a system except of technical solutions
                                                                dealing with access and sharing of remote experiments
                                                                requires solving number of other tasks that is pointed out
                    I. INTRODUCTION                             in the following.
   Although modelling and dynamic simulation are basic
tools for understanding and verifying theoretical subjects,                   II. REMOTE PEMCWEBLAB,
the experimentation with a real system plays a                            ITS FUNCTIONALITY AND SUBSYSTEMS
fundamental role that cannot be replaced. Analysis of              To support distance learning in electrical engineering a
these tools from view of modern education is given in [1].      set of remotely controlled real experiments from fields of
   Practical education needs to be based understanding          electrical engineering mainly from Power Electronics and
phenomena that occur in real systems. Remote control of         Electrical Drives and motion control has been developed,
the experiments trough Internet comes as a solution to          so that they create the PEMCWebLab (Fig. 3). It can be
these problems, allowing students to control them, without      approached via webpage www.PEMCWebLab.com
leaving their normal workplace.                                 (Fig.2) where there is also a direct link to the booking
   Rapid development of ICT technologies since
beginning of 90ties enabled expansion of online distance
laboratories. Their utilisation presents the latest trends in
education – to get practical experience by experimentation
with measurements, verifying properties of complex
equipment and well as analysis of the equipment in
various operation points. Tacking advantage of the
internet and development of related technologies, an
increasing number of remote access solutions are being
developed. A remote hardware experiment are adapted in
such a way that it can also be accessed from the Web that
enables distance sharing of the experiment by other
individuals and/or institutions.
   Currently we can find numerous solutions for remote
controlled experiments in various fields of practical
education and also there are running numerous projects
focused to their developments that are presented at special                  Fig. 1. PEMCWebLab project partners.
conferences, e.g. in [3], [4] and special sessions of the
scientific conferences [1], [8], [9], [11], [13], [22], etc.
                                                                    • the objectives should be described in terms of
                                                                        knowledge and/or skills to be acquired by students,
                                                                    • the objectives should be realistic given the attributes
                                                                        of the target group (prior knowledge, skills) and the
                                                                        time available for the students (credit points),
                                                                    • the outcomes should be testable; if not, they should be
                                                                        left out or reformulated,
                                                                    • there is an ability to analyze the function and working
                                                                        of electrical power (electronic) systems,
                                                                    • there is an ability to design, implement and verify
                                                                        electrical power (electronic) systems.
                                                                       Since both analysis and synthesis are key competences
                                                                    of engineers, the main objectives of the project are highly
                                                                    appropriate in an engineering education environment. A
 Fig. 2. Web page of the PEMCWebLab (www.PEMCWebLab.com).           few remarks should be made with respect to these issues.
                                                                    Analyzing existing systems implies measurements. It is,
system and more information about the project,                      however, very important, that students learn to conceive
dissemination results and description of different modules          measurements as a means, rather than a goal.
(measurements).                                                     Measurements are a means to verify a hypothesis of the
   The PEMCWebLab creates an integrated learning                    functioning of the system under analysis. The modules
platform. Several learning issues are addressed such as:            should indeed be structured such, that this concept indeed
• Learning objectives                                               becomes clear. Therefore, it is proposed, that any
• Education                                                         measurement is embedded in the following structure of
• Animation                                                         consecutive steps:
• Simulation                                                        • Define the function of the system
• Experiment                                                        • Decompose into subsystems with sub- functions
   In the first part the learning objectives of each                • Formulate hypotheses on characteristics of subsystems
experiment are addressed. In the part education a                   • Voltages, currents
theoretical background of the each individual experiment            • Design measurements for verification of hypotheses
is given. Interactive animations developed in the previous          • Carry out measurements
project are addressed further. The last educational method          • Compare results with hypotheses
before experiment is the simulation.                                • Evaluate learning
                                                                       As far as synthesis is concerned, all modules will lead
A. Learning objectives                                              to a common design methodological approach for the
  The experiments are not only analysis oriented (to                student.
measure and see the results) but also synthesis oriented.              The main function of PEMCWebLab is to provide a
They should involve a design aspect. Therefore the                  web-based remote control for designed experiments. The
measurements are designed as a project with educational             learning process includes several, specially designed,
philosophy.                                                         experimental tasks. However, for safety reasons no one
  The learning objectives for each single experiment are            will be allowed to perform any experiment until he, or
defined with the goal that:                                         she, has shown adequate knowledge of the experiment.




                                 Fig. 3. Principal structure of the PEMCWebLab distance laboratory.
   Entering wrong input parameters, due to insufficient         B. Teachers
knowledge of the experiment, may also lead to improper             The document for teachers is aimed at understanding
operation of the experiment. Therefore, a learning routine      the different (technical) functions available in the module
is designed for learners to gain the prerequisite knowledge     and enabling the creation of an educational environment
which is required before attempting the experiment.             for students. The document should at least contain the
   After completion of the online experiment, the learners      following items (chapters, sections):
are given an opportunity to take a simple questionnaire or           1) Goal of the module: the educational objectives
alternatively to submit their report through the available                as envisaged by the developers of the module.
feedback subsystem for its final evaluation (depending on
the requirement enforced by the instructor). All learning            2) How to create experiments for the students.
procedures are recorded for future reference and analysis.           3) How to create assignments.
                                                                     4) Suggestions for assessment.
                      III. MANUALS                                   5) How to create a structure for communication
   The quality of a product is largely determined by the                  with students.
quality and completeness of accompanying documents.                  6) How to communicate suggestions for
Documents are meant for communication. It can be very                     improvements to the developers and/or their
helpful to contemplate on the four main issues of                         successors.
communication. These issues can be expressed as
questions, viz:                                                 C. Technical staff responsible for maintenance
     1) What do I want to tell it?                                 As everything in life, things need maintenance. This
     2) Why do I want to tell it?                               holds for the PEMCWebLab - modules as well. Though
     3) To whom to I want to tell it?                           initially the maintenance may be taken care of by the
                                                                developers of the modules, after some time the attention
     4) Once these questions are adequately answered,           of these developers will be deviated to other issues, and
          the answer to the final question can be               the maintenance will be left to other people or
          formulated:                                           disregarded. Unfortunately, the latter is more often a rule
     5) How do I tell it?                                       rather than an exception. An analysis afterwards of this
   The order in which the questions are answered, it is a       undesired development usually leads to the conclusion,
logical one, if we start from scratch. In the PEMCWebLab        that things were not sufficiently documented.
project we have already chosen for an educational                  The contents of the document(s) for maintenance are
structure and the overall goals are clear: better and easier    largely dependant on the form of the modules. It should
learning of complex matters in electrical power                 contain at least:
engineering. Therefore let us start with the third question:         1) Functional block diagrams,
To whom do I want to tell it? The answer immediately
leads to the so called target groups. If we turn to the first        2) Input and output specifications of different
questions in somewhat more detail, it will be clear, that                 modules,
the target groups will need different information.                   3) Detailed diagrams of individual blocks including
Furthermore, the same information may be presented in                     key measurement points with their normal
different ways for the different target groups.                           voltages, waveforms etc.,
   The main target groups are:                                       4) Structural diagrams of software modules (source
     A. Students                                                          codes only on CD-ROM or DVD).
     B. Teachers                                                           IV. EXPERIMENT ADMINISTRATION
     C. Technical staff responsible for maintenance
                                                                   A central booking system is available at the project
A. Students                                                     page PEMCWebLab.com Booking system is provided
                                                                through Moodle software. Layout of the Moodle pages for
   The goal of the document is to make students familiar        all experiments is uniform. This page will contain menu
with the educational objectives of the module. It should        with the following submenus:
provide them with sufficient information to work with the
module. It should be clear what students are expected to             1) Learning objectives
do and how their results will be assessed. In order to               2) Education
achieve this, the document could contain the following               3) Animation
items (chapters, sections):                                          4) Simulation
                                                                     5) Experiment
   1) Educational objectives
                                                                   All the submenus at the booking system are to be
   2) Assumed entrance competencies                             accessed without restriction of number of students. The
   3) Structure of the module (block diagrams)                  actual booking is provided in the submenu Experiment.
   4) Instructions how to use the module                        The experiments can be booked one week ahead, the
   5) Assignments/tasks                                         length of the offered time window for the experiment
                                                                varies from 5 to 30 min. Before the experiment becomes
   6) Instructions how to communicate with teachers             available online, it should be tested to verify the
       and fellow students                                      correctness of the experiment results as well as the
   7) How to communicate suggestions for                        stability of the experimental set-up. The power to some
       improvements                                             experiment is available 24 hours a day; some experiments
                                                                are available for safety reasons in the working hours only.
   An administrator of each experiment can restrict the use    • The guidelines for project oriented measurements
if the experiment for his purposes during some days or             with the learning objectives for distance and /or
hours only. Supervisors have to routinely check the status         virtual practical education,
of each experiment to make sure that each of them is           • Synthesis oriented experimental measurements,
functionally correct and is available for use.
                                                               • Technology and technical documentation for distance
   Several clients can connect to PEMCWebLab.com                   practical education and measurements via the Internet,
simultaneously. However, Internet bandwidth becomes
extremely limited when too many remote users request to        • Different designed measurements each with its own
use this system. Several concurrent, remote users are              philosophy.
allowed via an Internet connection for each experiment.        The outputs from the project will present:
However, each experiment in the PEMCWebLab can be              • teaching material (in electronic form; guidelines,
operated only by a single remote user at a time. The               manuals, documentation in English and other
system thus considers each experiment as a “resource”,             languages),
and remote users who wish to operate a specific
experiment should first get permission to operate the          • distance and virtual laboratories approached via web,
experiment. Once the resource is in use, other remote          • vizualization and layout of the measured system, and
users cannot access that resource, because it is then          • measurement results obtained via Internet.
marked as “locked.” All the remote users without access           The following modules are proposed (Table 1, grouped
permission can see only the online, real-time video of that    into sets of modules) in such a way that they cover
experiment.                                                    fundamentals and basic applications of the EE and
Server Site Administration                                     advance topics including the application “as well”.
   As already said every experiment has its own server
and it is located at the different location. Remote users
first logged onto a main booking server, after which they
will be directed to the specific server for actually
performing the experiment get into the page of the
experiment itself.

            V. SET OF REMOTE EXPERIMENTS
   A Leonardo da Vinci EU project titled “E-learning
Distance Interactive Practical Education - EDIPE” [2] is
suggested and approved to create a full set of distance
laboratories. Twelve universities with the span across the
EU are participating in the project (Fig. 1).
The expected specific results of the project are:
• Learning objectives for the distance experimental
    education,
                                                                 Fig. 4. Remote experiment for three-phase space vector modulation.



                                                          TABLE 1
                           LIST OF MODULES WITH REMOTE CONTROLLED EXPERIMENTS IN THE EDIPE PROJECT

          Group      Group of specialized    Module
                                                                                 Module title
           N°             subjects            N°

                       Fundamentals of         1.1     Single Phase and Three Phase Rectifier Circuits
            1
                    Electrical Engineering     1.2     DC Circuit Measurements and Resonant AC Circuits
                                               2.1     Power Converters
                                               2.2     Power Factor Correction
                                               2.3     PWM Modulation
            2         Power Electronics        2.4     DC-DC Converter for Renewable Energy Sources and Microgrid
                                               2.5     Power Quality and Active Filters
                                               2.6     Power Quality and/or Electromagnetic Compatibility
                                               3.1     Basic Electrical Machinery – Synchronous Generator
                                               3.2     DC Machines
            3        Electrical Machines       3.3     Basic Electrical Machinery – DC Motor
                                               3.4     Basic Electrical Machinery – Asynchronous Motor
                                               4.1     Basic Elements of Internet based Tele-manipulation
                                               4.2     Mechatronics, HIL (Hardware in the Loop) Simulation
                   Electro-Mechanical and      4.3     High Dynamic Drives - Motion Control
            4                                  4.4     Automotive Electrical Drive
                   Motion Control Systems
                                               4.5     Complex Control of a Hoist Equipment by a SLC
                                               4.6     Intelligent Gate Control by a Small Logic Controller (SLC)
                                                                                    ACKNOWLEDGMENT
                                                                     This work has been performed within the project „E-
                                                                  learning Distance Interactive Practical Education
                                                                  (EDIPE)”,     (project    No      CZ/06/B/F/PP-168022)
                                                                  supported by the EC within framework of Leonardo da
                                                                  Vinci II programme and partly by the project No
                                                                  229930-CP-1-2006-1-RO-MINERVA-IDENTITY
                                                                  “Individualized Learning Enhanced by Virtual Reality”.
                                                                  The opinions expressed by the authors do not
                                                                  necessarily reflect the position of the EC, nor does it
                                                                  involve any responsibility on its part.

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