The Remote Access to Laboratories - a Fully Open Integrated System.pdf

IFAC PapersOnLine 52-9 (2019) 121–126
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10.1016/j.ifacol.2019.08.135
© 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
The Remote Access to Laboratories: a Fully Open Integrated System
R. Sanchez-Herrera*, A. Mejías**, M.A. Márquez***, J.M. Andújar****
*Huelva University, Huelva 21819 Spain (e-mail: reyes.sanchez@die.uhu.es).
** Huelva University, Huelva 21819 Spain (e-mail: mjias@uhu.es).
*** Huelva University, Huelva 21819 Spain (e-mail: marcoa@iesppg.net).
*** Huelva University, Huelva 21819 Spain (e-mail: andujar@uhu.es).
Abstract: An existing lab experience can be made remotely accessible in a relatively easy way. The
problem is with the design of a tool which allows any kind of experience to be made remotely accessible.
The complexity of this tool is out of discussion. Several universities have been working on it for years. In
fact, the Huelva University presented the work “A Complete Solution for Developing Remote Labs” in
the 10th IFAC Symposium on Advances in Control Education (2013). Such complete solution was the
result of those universities working together. Since then, the joint-work has continued and improvements
have also been achieved. Hereafter, a fully open integrated system is presented whose scope is greater
than that of 2013. It offers a way to easily implement cloud services for managing the configuration and
access to all type of sensors, actuators and controllers (the devices base of the any remote lab). The
access proposed is secure, controlled, organized and collaborative.
Keywords: Remote access, instrumentation, remote sensor, remote pilot plant.
1. INTRODUCTION
Among others, in areas such as automation, robotic or
electronics, different approaches for remote laboratories (RL)
are emerging, which allows access to different kinds of
didactic or professional materials. For example, in (Indrusiak
et al., 2007) the reader can get a general overview of RL for
digital systems design. Andújar et al. (2011) presents an
example of this kind of lab, which allows programming and
interacting with a Field Programmable Gate Array (FPGA)
development board. (Al-Hadithi, B.M. et al., 2016; Chacon et
al., 2017; Ruano Ruano, I. et al., 2016) show RL devoted to
automatic control. In addition, in the last work a comparative
of the most outstanding RL of this kind is included. An
example of RL applied to engineering measurement can be
seen in (Restivo et al., 2009). (Nayak, S. et al., 2014) and
(Mejías Borrero and Andújar Márquez, 2012) present
different RL devoted to teaching robotics.
In (Rojko et al., 2010) a power engineering and motion
control RL is presented, which offers 18 complete online
courses with remote experiments and their corresponding
documentation. Within the electrical engineering, there are
some other remote platforms, (Callaghan et al., 2013;
Cardoso et al., 2015).
With respect to photovoltaic systems, there are multiple
studies into the use of remote transmission systems to
monitor them such as (Chao and Chen, 2017) and (Koklu and
Kilinç, 2016), among others. Within the educational field, the
virtual lab possibilities have been explored (Cotfas et al.,
2013), and RL, (Blanchard et al., 2014; Freeman et al., 2012;
Schauer et al., 2012).
However, in all those RL cited above and many other
approaches found in the Literature, the designed solutions to
develop RL can be considered specific. Each of them solves,
in its own way, the different aspects involved in RL
development.
In this paper, a fully open integrated system is proposed,
which offers a way to easily implement cloud services for
managing the configuration and access to all type of sensors,
actuators and controllers (the devices base of the any remote
lab). The access proposed is secure, controlled, organized and
collaborative.
The main improvements of the present work with respect to
the previous version of 2013 are the next:
- The procedure proposed in 2013 was based on Java
and the new one on software supported by the new
generation of browsers.
- The new procedure can join a set of RL connected to
different LANs.
- With the new procedure, the RL is accessible as a
cloud service.
2. DESCRIPTION OF THE SYSTEM
Several issues must be clarified before exhibiting the fully
integrated tool.
- First, the meaning of “open”. To be open, the system
must be able to support devices from different
manufacturers whose software does not have to be
12th IFAC Symposium on Advances in Control Education
July 7-9, 2019. Philadelphia, PA, USA
Copyright © 2019 IFAC 126
1. INTRODUCTION
development.
collaborative.
different LANs.
cloud service.
integrated tool.
1. INTRODUCTION
development.
collaborative.
different LANs.
cloud service.
integrated tool.
1. INTRODUCTION
development.
collaborative.
different LANs.
cloud service.
integrated tool.
1. INTRODUCTION
development.
collaborative.
different LANs.
cloud service.
integrated tool.
1. INTRODUCTION
development.
collaborative.
different LANs.
cloud service.
integrated tool.
1. INTRODUCTION
development.
collaborative.
different LANs.
cloud service.
integrated tool.

122 R. Sanchez-Herrera et al. / IFAC PapersOnLine 52-9 (2019) 121–126
compatible, connected to different local area
networks (LAN) through the internet.
- Second, the scope of the system. The experimental
plant which is to be made remotely accessible must
be controllable from a computer. This characteristic
is referred as convergent from now on; and, so, the
experimental plant becomes a convergent
experimental plant (CEP). In addition, the
application designed for the user to control his/her
experience (user interface, UI) depends on the user’s
experience. Thus, both the CEP and UI have to be
out of the fully open integrated system (FOIS)
proposed to implement the RL.
Therefore, according to Fig. 1, the FOIS must include the
following (into the blue box):
- An associated PC (personal computer) (2 in Fig. 1),
or simply a single-board computer (SBC).
- A camera (3) that is directly connected to the
University LAN by means of an ethernet switch (4)
or the PC.
- A communication system (5). The corresponding to
the FOIS is a specific software designed to
automatically generate the necessary communication
channels (tunnel) to facilitate transparent access to
the CEP via the internet. This communications
system, denominated SARLAB (an acronym
corresponding to its Spanish name, Sistema de
Acceso Remoto a LABoratorios, or remote
laboratory access system in English), has been
designed and developed by the authors of this paper.
- A learning management system (LMS), where the
access to the CEP is integrated to optimally solve
the academic issues. For example, and of particular
importance in the case of RL, the LMS includes a
reservation system (developed by the UNED,
Spanish acronym for Universidad Nacional de
Educación a Distancia) that allows for orderly user
access 24 hours a day, 7 days a week. Moreover, the
proposed solution also facilitates concurrent access.
From the LMS, the user access to the UI (7) (out of the FOIS
scope), which runs in the user’s computer. It provides the
user with all necessary commands and records to monitor and
control the CEP as well as the required safety controls. Thus,
the UI includes the following elements:
- Live video stream from the camera located at the
CEP.
- Augmented reality features, (Andujar et al., 2011),
synchronized with the live video stream to enhance
the UI.
- Monitorisation and control of the CEP
actuators/sensors.
- Required safety features for ensuring correct
operation of the CEP.
Although the CEP and the UI are out of the FOIS scope, the
authors of this paper also propose a general method to make
convergent an experimental plant and other general methods
to develop the UI, which could be considered as part of the
FOIS.
Regarding the CEP, the FOIS develops a general
conditioning/signal processing/communication architecture
that can also be considered part of the FOIS. In fact, in order
to make convergent an experimental plant, the first step is
considering it as a black box with the required number of
inputs/outputs. Outputs are sent from the sensors and inputs
are received by the actuators. All signals (analogue or digital)
must be normalised to standard formats: 0/5 V, 0/3.3 V,
PWM and so on (signal conditioning stage). The
hardware/software solutions to implement the signal
conditioning stage and the A/D and D/A conversion stage
may be different in each case, but the purpose of these stages
remains the same. Once the experimental plant is completely
monitored, the rest of the process does not absolutely depend
on its nature. It may be chemical, mechanic, electric or
whatever the nature. Thus, the data processing/computing
stage is carried out by an associated PC or SBC which
connects the experimental plant to the LAN through the
network interface.
Fig. 1. General scheme of FOIS.
Regarding the UI, a free authoring tool written in Java
(although compatible with the constraints of the new
generation of browsers) can be created using EJS (easy Java
simulations), (“EJS,” n.d.), which facilitates interactive
simulations, and overcomes the limitations of the proprietary
software used by applications such as Matlab or LabView.
EJS has been created by the Murcia University. UNED and
Huelva University have also worked with EJS to include the
tools necessary to develop the UI and to make convergent the
experimental plants.
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R. Sanchez-Herrera et al. / IFAC PapersOnLine 52-9 (2019) 121–126 123
The core of FOIS is the communication system whose
characteristics are the basis of the FOIS openness. In fact,
SARLAB allows the following goals to be met:
- Internet access to devices connected to different
LANs.
- Access control by means of different user profiles,
including concurrent access.
- Unification of the access control to devices with
different access protocols.
- Access to several commercial devices with
proprietary software as well as to devices whose
access procedure is implemented in open platforms
with low cost software.
- Abstraction of the complexity inherent in
communication programming for the RL designer
and user.
- Overcoming of limitations associated with the new
generation of browsers, whereby their capacity for
interaction with the physical system on which they
run can be restricted or even eliminated.
Three of the RL functioning in the Huelva University and
made remotely accessible using FOIS are presented in the
following three sections of this paper. The first is
denominated electric machines RL (EMRL). The second is
the photovoltaic RL (PRL). The third is the automatization
RL (ARL). Although these plants are relatively simple to the
potential solution, their particular characteristics allow
different technical details regarding implementation to be
illustrated. Indeed, our intention is to show the potential for
FOIS, rather than the complexity of the plants themselves. In
fact, the solution permits the inclusion of as many sensors
and actuators as necessary, regardless of the complexity of
the plant, as well as providing the procedure and tools for the
plant’s remote management.
3. THE ELECTRIC MACHINES REMOTE LAB
In this RL, the associated PC is directly connected to the
CEP. An axis camera has been used directly connected to the
ethernet switch. SARLAB resolves the communication
problems. The UI has been embedded in the LMS and runs
on the user’s computer during access. Access to the UI is
available 24/7 via the browser using the corresponding user
profile all year around.
The CEP core is an electric machine bench, involving a
synchronous generator driven by a DC (Direct Current)
machine. The nominal values of the generator are 360 W,
380/220 V AC (alternating current), 1500 rpm with a power
factor of 0.72. The DC machine nominal values are 440 W,
220 V DC and 1500 rpm. Both electric machines are coupled
to an analogue tachometer, which sends the rotational speed
signal to an I/O (input/output) board, (“PhidgetInterfaceKit
8/8/8 Mini-Format - 1010_0 at Phidgets,” n.d.), with
analogue inputs and digital outputs. This I/O board is directly
connected to an USB port in the associated PC. Its functions
are as follows:
• Rotation speed measurement.
• Field current measurement from the current source.
• Switching the current source on/off.
• Turning the RPP supply on/off according to the
orders received from the PC through a set of
optocoupled relays.
• Configuring the connections suitable for each test of
the synchronous generator (vacuum or short circuit
tests, among others) through several contactors.
Fig. 2 shows the developed UI with the tools presented in this
work. The central part of the display shows the video stream
enriched with augmented reality (AR) objects in the form of
interactive tabs providing useful explanatory information
about the nature and function of the plant. The pop-up
displayed when the user selects the DC machine tab is shown
at the top right of Fig. 2 while at the bottom right, a graph
illustrates the evolution of the actuators’ signals.
To appreciate the AR effect, the CEP in the lab is shown in
Fig. 3.
Fig. 2. UI of the EMRL.
In addition, in order to enhance the user's interaction with the
UI, the video stream is reinforced with an audio stream; since
the variations in rotational speed have a direct effect on the
sound produced by the electric machines. Hence, the
availability of audio boosts the feeling of being engaged with
physical elements, although remotely.
Finally, in the case of this RL, the UI incorporates the
required safety measures that are of particular relevance.
The constitution of this EMRL is the basis for designing the
lab class to be carried throughout a given topic. The possible
lab classes are related to the modelling of the asynchronous
machine to the reproduction of its functioning within
different conditions and, finally, to its control (Jesús Fraile
Mora, 2015).
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Fig. 3. The experimental plant of the EMRL.
4. THE PHOTOVOLTAIC REMOTE LAB
In this section, a remote experimental system is presented
constituted by two photovoltaic modules connected to a
variable load and lighted by a variable focus. It allows the
students to characteristically obtain different curves and
being able to compare them; for example, curves with several
irradiations and curves corresponding to one and/or two
modules connected in different ways (serial and parallel). In
the classroom, students manually switched on/off several
luminaries to simulate the variation of the solar irradiance, as
well as change the position of a variable resistor (as load) to
set the different work points of the photovoltaic panels. In
addition, the panels connection was also manually
configured.
All these manual activities required the lab class to include
the same number of automatic systems to be
managed/handled remotely.
In the case of the PRL, the need for energy has been
optimized by means of a Raspberry Pi board (a SBC which
functions as an associated PC). This switches the system on
when a user requires it and switches off when the user
finishes the work. In this same way as using open access
devices, the I/O boards are Arduino, (“Arduino - Home,”
n.d.). They are used to control the light power (variable
irradiance on the panels) and the variable load as well as to
measure monitored parameters.
The light power that replaces the sun light must be controlled
by the corresponding circuit connected to an Arduino board.
In addition, the variable load must be controlled. It has also
been made by another circuit connected to another Arduino
board. There is still another circuit to change connections
(series or parallel) of the photovoltaic panels.
Furthermore, the experiment must be accessible from the
internet. Thus, the setup modification of working points must
be accessible from a TCP/IP network. To unify the method of
accessing all these devices through the net involves the
standard Modbus serial communications protocol. Modbus
allows for sending and receiving data between all the
involved devices with reliability and efficiency. In order to
achieve it, different devices in the lab are monitored by an
EJS element with Modbus master architecture, (Mejías et al.,
2017). In the same way, a Modbus slave must be included in
all the Arduino boards.
The UI of the PRL is composed of two parts, as illustrated in
Fig. 4. The video image shown at the top displays two
photovoltaic panels lit by a variable light source whose
irradiance change can be distinguished by the naked-eye by
means of the photographic image. In order to enrich the UI,
making it more intuitive and user-friendly, the load, I/V
meters and panel connection shown in the image are not the
real ones, but have instead been developed through AR to
provide the following advantages: firstly, AR connections
that are more user-friendly; secondly, from the user’s
perspective, the appearance (resistance) of the physical load
in the PRL operation remains unchanged, and, as such, the
values can vary (V1 to V8); voltmeter and ammeter
measurements have also been included as AR elements in the
UI (0.65 V and 46.08 mA respectively).
Fig. 4. UI of the PRL.
The second part of the UI, illustrated at the bottom of Fig. 4,
contains the control parameters that the user has to manage:
the irradiance received by the panel (depending on the
lighting power of the scenario, the focus power can be
modified continuously, although only four typical values can
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R. Sanchez-Herrera et al. / IFAC PapersOnLine 52-9 (2019) 121–126 125
be selected in the UI) (A); the load value (B); and the panels’
connections (individual, two in series or in parallel) (C).
5. THE REMOTE LAB AUTOMATIZATION
In this section, a RL is presented that is composed of an
industrial automation plant, which student can control
remotely and test the control programme implemented, also
remotely, into the corresponding PLC (programable logic
controller). The interface, designed in EJS framework, has
been "augmented" by 3D virtual objects that interact with the
real ones. The software used to programme the industrial
PLC is that proposed by the manufacture. The use of this
kind of software into the navigator framework is one of the
SARLAB’s indisputable advantages/strength.
Fig. 5 shows the UI, “augmented" by 3D virtual objects that
interact with the real ones. This figure may be compared with
Fig. 6, which shows the original video stream received from
the camera located in the University lab classroom.
Fig. 5. The UI of the ARL.
Fig. 6. The ARL experimental plant.
Fig. 7. Design tool (Unity Pro XL) used by the student to
programme the PLC.
In Fig. 6, the ARToolkit markers used to properly
superimpose the 3D virtual elements can be seen. Through its
computer interface, the student can remotely operate the
PLC, so that he/she can observe the evolution of the real
plant according to the schedule that he/she has sent to the
PLC.
The AR system transforms the conveyor belt in an automated
industrial plant that must place a plug and a label into the
bottle which is moved by the belt. In this case, real and
virtual elements interact with each other sharing the same
three-dimensional space. The PLC programming is
performed remotely using the design tool (Fig. 7) provided
by the PLC manufacturer. The PLC used is a Modicon M340
from Schneider ElectricTM, Schneider Electric (2013). This
software uses SARLAB to remotely access the PLC.
5. CONCLUSIONS
This paper presents a fully open integrated system to make
experimental plants accessible through the internet. The
experimental plant can be configured with elements from
different manufacturers, despite incompatibility. Thus, the
system is appropriated for any kind of experimental plants
and adaptable to different technologies.
Evidence of the effective potential of the proposed system is
the number of projects successfully utilising the technology;
three of which are outlined in this paper. These three
examples have been selected for they demonstrate the
adaptability of the system and allow including different
technical details such as innovative problem solving
techniques. The first RL example relates to the operation of
electric machines; the second deals with the management of
photovoltaic panels; and the last reproduces an automated
industrial plant.
The proposed fully open integrated system facilitates the
remote management of the labs via an internet browser,
through a friendly UI, 24 hours a day, 7 days a week, using
the corresponding user profile. Furthermore, it even switches
the power supply on when the RL is in use and shuts it off
otherwise.
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