Tele-operated laboratory for teaching logistics operations

The link between academia, government, and business to improve the development and appropriation of knowledge in certain topics, such as logistics, is being promoted in Colombia. One of the key issues of teaching logistics is try to bring to actual work contexts, problems that can be handled by people who do not have experience. The incorporation of Information and Communications Technologies (ICT) in academic environments supports the training of professionals in different fields. The tele-operated laboratory for logistics operations called Internet2 way [TELEOPLOGIS] is a project focused on the development and implementation of a remote laboratory where an integrated and didactic manufacturing cell, some robot manipulators, and specific pieces of software are used for the teaching of logistics operations. This laboratory includes the development of guidelines and academic workshops with two approaches: teleoperation systems for discrete events, and manufacturing cells that transform the cell nodes into elements of logistics operations. We achieved acceptable results in both remote operations and in practices that currently are in progress.


I. Introduction
In Colombia, several approaches have been developed to include the use of Information and Communication Technologies [ICT] in higher education. This topic is a novel proposal, since only 25% of the Colombian population has access to college. Some private and public institutions are driving these kinds of project. As an example we have the National Direction of Virtual Academic Services [DNSAV: Dirección Nacional de Servicios Académicos Virtuales] -known as UN Virtual. UN Virtual is a dependency of the Universidad Nacional de Colombia in charge of providing the tools and necessary support for the construction, execution, and management of academic training supported in Learning Management Systems [LMS]. It is important to note that, nowadays, UN Virtual offers academic programs for the entire college community (DNIA, 2014). The National Research and Education Networks [NREN], like the National Academic Network of Advanced Technology [RENATA: Red Nacional Académica de Tecnología Avanzada], try to enhance the development of several educative schemes through modernization, upgrading, and research in ICT, defining and executing policies, plans, and programs to improve some projects of pedagogic innovation.
Despite the fact that some researchers have worked on topics related with the control of manufacturing cells, e.g. Rodríguez, Hernández, Foyo, andLoa (2011), andDuque et al. (2011), they relate their job with the control and operation of a manufacturing cell through RENATA. Consequently, there is a significant difference between these projects and the one described in this document. This is because the objective of our proposal is to develop a remote laboratory where the development of the practices involves students with an interest in discrete event control and supply chain management, assessing the features of remote connections. We propose some changes in the functional nodes of the manufacturing cell over logistics operations elements. These modifications can be simple, but they are not trivial since the practices must be in accordance with the reality of the companies and their particular logistics.
A remote laboratory is defined as a person with a computer, which remotely controls an experiment in a specific location. The rise in its utilization, especially in the education field, is linked with the increase in bandwidth available for users, together with the reduction of the connection costs, and the ease of buying computers (Calvo, Zulueta, Gangoi-

I. Introducción
En Colombia ya se han adelantado pasos para involucrar el uso de las Tecnologías de la Información y las Comunicaciones [TIC] en la educación superior. Esta solución se empezó a considerar dado que en Colombia solo el 25% de la población puede acceder a la universidad.
Although, a priori, the reader might think that the construction of remote laboratories is not as complicated as the implementation of traditional ones, this is not an absolute truth. This is because remote labs still have the issues of the design of experiments and the set-up of the equipment used during the execution of the experiment, that are common in traditional laboratories. Besides, remote labs require the construction of a friendly and easy-to-configure infrastructure for the access (Calvo et al., 2008).
Virtual laboratories have evolved into remote ones as a result of the inclusion of more complex practices (additional to the development of the computational tasks). Moreover, remote labs are systems based on real laboratory equipment, which allow students to perform hands-on activities, either face-to-face or remote practices, transferring the information between the process and the students in a unidirectional or bidirectional way, respectively. Students use and control the available resources of the lab through work stations in a local network. The difference between the virtual and the remote laboratories resides in the type of computation used and the treatment of the materials. For example, in the remote labs, students use real laboratory instruments such as data acquisition cards, measurement instruments, connections in diverse interfaces, data communication, etc. On the other hand, virtual labs only use computational processes based on simulations, e.g., executable programs in the cloud, Flash programs, or Java applets.
Remote laboratories present considerable advantages in relation to virtual ones, since the first provide higher interactivity levels. Consequently, students stay in touch with the real equipment, instead of doing it through simulated programs. From the didactic point of view, remote labs are a novel innovation in the field of education, and research related to their design, advantages and disadvantages is required.
The architecture of a remote laboratory is based on the client-server model and it requires a minimum of two applications for its correct operation. On the server side, we have the application that concedes access to the physical device, running the data collection (either analog or digital) of the variables to control. Alternatively, the client side presents the application with a Graphical User Interface. This app is the one the user remotely manipulates and the data is sent to the server, feeding the signal (variable to control) in a bidirectional way (Calvo et al., 2008).
Remote laboratories, also called controlled labs via web or WebLabs, provide remote access to the real laboratory equipment and instruments in real time. As Rosado and Herreros (2005) and Coquard, Guillemot, Leleve, Noterman, and Benmohamed (2008) mention, some advantages of We-bLabs are the ability to take advantage of human resources and the materials of the laboratories. This is enabled by the integration of the necessary instruments for the execution of the practices in a single workstation; so, the savings in laboratory material are considerable. Therefore, the remote laboratory enhances the time availability for the students in their learning experience.
Working in the laboratory through the implementation of WebLabs is not limited either by the physical space or by the available time of the personnel, since they contribute to the structuring of the experiments. This is used by the students to increase their development of skills related with observation, problem resolution, and results analysis. Their main disadvantage is the lack of direct control, since the visualization of the system is through web cameras; hence, external devices like the mice of keyboards handle the tools of the remote system. Real-time experimentation demands relatively small sampling times, in addition to which it is necessary to provide real-time operating systems. Both hardware and software have to be robust enough to reduce potential failures whilst they are being operated by the students, providing a comfortable user experience for them.
One of the topics of growing interest is the role of logistics in higher education research laboratories, one example of which is the creation of a conference focused on these studies and called Impact of Virtual, Remote and Real Logistics Labs [ImViReLL] (Uckelmann, 2012), the objective of which is to assess the impact of the research labs based on logistics. The conference tackles research, from the point of view of the logistics, in a wide variety of knowledge areas such as engineering, computer science, and research in distributed education, among others. Some of the open topics for discussion are LMS focused on research, remote virtualization environments, existing research environments, logistics in the life of the laboratories, and end-user participation.
The case of supply chains is even more critical because each sector has a particular technique to handle logistics. One of the key advantages of a WebLab is the possibility to suggest several cases, diversifying the experience in representative economic sectors. For instance, the manufacturing process optimization laboratory of São Paulo University has modern manufacturing systems, which add the use of ad-mohamed (2008), las ventajas de un WebLab es que permite aprovechar los recursos humanos y materiales de los laboratorios tradicionales, al integrar, en un único computador, los instrumentos necesarios para la ejecución de las prácticas; el ahorro en material de laboratorio es considerable, unido a la realidad con que trabaja el alumno. De otro lado, el laboratorio remoto amplía la oferta horaria al alumno en su proceso de aprendizaje, convirtiéndose en un recurso beneficioso en su formación.
El trabajo en laboratorio por medio de la implementación de laboratorios remotos no se ve limitado por el espacio físico o el tiempo de disponibilidad del personal del centro, ya que contribuye a la estructuración de los experimentos que puede aprovecharse para incorporar el desarrollo de las habilidades de los estudiantes en cuanto a la observación detallada, la resolución de problemas y el análisis e interpretación de resultados. Su principal inconveniente es la falta de control directo, ya que el sistema se visualiza mediante cámaras Web y las herramientas del sistema remoto se manejan por medios externos, como el ratón o teclado. La experimentación en tiempo real exige periodos de muestreo relativamente pequeños y disponer de sistemas operativos de tiempo real. Tanto el hardware, como el software, han de ser suficientemente robustos para que no presenten fallas mientras el alumno los está utilizando, de manera que responda y mantenga las expectativas con que este se acerca a las prácticas. vanced network functions for the control and monitoring of the machines as an important feature of the supply chain management. Given the concept of the system in the supply chain, the distribution of the manufacturing is in several places. In these cases, the development of products and fabrication control functions can be scattered through the users of the system. This schematic opens the possibility of sharing the use of fixed manufacturing facilities with basic technology between the users of the system.
We developed a research project for the design and operation of a remote laboratory for network logistic operations and supported by a communications platform, which allows the remote operation and supervision of a flexible-didactic manufacturing cell. The partial results of the system performance are summarized in this article. The described WebLab is located in the laboratories of the Universidad Autónoma de Occidente [UAO] in Cali, Colombia, and its basis is the Internet2 technology. The methodology used is detailed in section 2, the results and their respectively discussion are presented in section 3, and section 4 presents conclusions and future work.

II. Method
The methodology employed for the execution of the project had an explorative, descriptive, and correlational scope. This is because it was necessary to enhance the knowledge by searching for updated information about remote labs and their technical aspects, their application in logistics considering the academic point of view, and the pedagogic strategies for their inclusion in undergraduate and postgraduate studies.
Within the first phase of the project, we focused on setting up each laboratory component as the manufacturing cell, the Bosh Cartesian coordinate robot (from now on, we refer to this as a linear robot), and Scara ER-14 robot (Figure 1 exhibits a photo of the lab). The update included components such as the engines and controllers of the Scara robot and the adaptation of the Festo transporting band. The development of the control stage of the main components of the transporting band and the linear robot was in the Lab-View ® software. Afterwards, we performed some bidirectional remote operation tests between the equipment in the UAO and that present in the Monterrey Superior Studies and Technological Institute [ITESM: Instituto Tecnológico y de Estudios Superiores de Monterrey] in Mexico. These tests were supported by the infrastructure of RENATA in Colombia and the University Corporation for the Development of se puede distribuir en varios sitios diferentes. En estos casos, el desarrollo de productos y las funciones de control de fabricación, pueden ser distribuidos a través de los usuarios de los sistemas. Este esquema abre la posibilidad de compartir, entre los usuarios del sistema, el uso de instalaciones fijas de fabricación con tecnología básica.
En la primera fase del proyecto se destinó tiempo y recursos para la puesta a punto de los componentes del laboratorio: celda de manufactura, robot cartesiano y robot Scara (la Figura 1 presenta una fotografía del laboratorio). La actualización incluyó componentes como los motores y controladores del robot Scara ER-14 y la adecuación de la cinta transportadora Festo, la etapa de control de los componentes principales de la cinta transportadora y del robot cartesiano Bosh se desarrolló en el software Lab-View©. Posteriormente se procedió a realizar pruebas de tele-operación de forma bidireccional entre los equipos de los laboratorios de la UAO y el Instituto En la segunda fase, una vez establecidos los requerimientos técnicos acordes con las características y posibilidades de los equipos dispuestos en ambas instituciones académicas, se procedió a diseñar el proceso productivo que se representaría en la celda de manufactura de la UAO; se realizó una simulación en el software ProModel© que sirve para ilustrar el proceso que se desea ejecutar con el laboratorio. Este material se utilizará como material didáctico para los cursos de logística, simulación y gestión de operaciones, en pregrado, y de simulación y In the second phase, as soon as the technical requirements based on the features of the equipment present in both academic institutions were established, we designed the production process to represent in the UAO manufacturing cell. We ran a simulation in the ProModel ® software, which allows an illustration of the processes executed in the lab. The results of this research can be used as didactic material for the courses in logistics, applied logistics operations management, simulation and logistics information models, and applied logistics operation management. Furthermore, these results contribute to acquaint the support and development engineers with the desired use to the components of the remote laboratories.

III. Developed Practices
Currently, we have two simulated practices in the test phase in the tele-operated laboratory.

Supply chain
We started with a production process consisting of the assembly of two parts, represented by Lego ® pieces in four different colors. The model incorporates stock management and it allows up to 16 combinations/references. The four storage stations of the Lego ® pieces (raw material) are in the work area of the Scara robot. They are also located in the outside part of the transporting band. The assembly station is located inside the band, next to the robot; this allows the arm to hold the first piece of the corresponding station, put it it in the assembly area, and take the second piece. The students can program both the delay and the assembly time. Finally, the model puts the two assembled pieces -the endl product-on the transporting band, where they are transported into the storage station, managed by the linear robot (see Figure 2).
In the storage station, composed of the linear robot and a shelf, the system receives the raw material and the final product. The robot is capable of carrying the individual Lego ® pieces towards the band, given certain necessities. It also picks up the assembled pairs for their storage The configurable parameters of the process are: • The quantity of each of the 16 possible references to produce -demand; • the minimal stock in the stations next to the assembly area -security stock; • the speed of the transporting band; • the size of the production and transport lots; and • the type of process -which can be push (produce the total amount of each of the references) or pull (produce one reference at the time).

Port operations
This cell configuration represents the loading up and offloading of four container types, considering that the shelves in the warehouse represent the container ship, whilst the linear robot takes the role of the gantry crane. The Scara robot is responsible for the location of the containers offloaded from the ship into the respective storage areas -where the identification is carried out using a bar code Figure 2. Simulation in ProModel® of practice 1, associated with supply chain management / Simulación en ProModel de la práctica 1, asociada a la gestión de la cadena de suministros cias posibles -demanda-; • los inventarios mínimos en las estaciones adjuntas al área de ensamble -stock de seguridad-; • la velocidad de la banda transportadora; • el tamaño de lote de producción y transporte; y • el tipo de proceso -que puede ser push (producir la totalidad de cada una de las referencias) o pull (producir una referencia a la vez).
Esta encuesta se ha distribuido principalmente entre es-scanner and an IEEE 1494 vision camera located in the manufacturing cell-and also for the dispatching of the containers in the ship (see Figure 3).
In parallel, at this point of the project development, and with the purpose of identifying the technical possibilities of the objective user accessing virtual platforms, we have decided to offer in the project website (http://teleoplogis.net/) a survey related to the use of technological resources such as computers, tablets, and smartphones. Other questions are related to topics in the field of operations management, logistics, and simulation; ending with questions to measure the experience and contribution of the practices imparted at the UAO. This study is currently in execution and it precedes the implementation of the practices in the remote lab. This questionnaire has been presented to candidates for the Master in Integral Logistics and to undergraduate students taking the stochastic process simulation subject of Industrial Engineering. We expect to gather information from students in other subjects. In the case of the first year students, we only considered data related to the use of technological resources.
It is important to note that, in the first quarter of 2014, the number of connections to broadband internet (fixed and mobile) wase 8.8 million, which represents an increase of 33.9% relative to the first quarter of 2013 (Mora, 2014). As a notable datum, 4G LTE mobile connections grew by up to 63.8% in the same period. For this reason, internet penetration, together with a broader availability of mobile devices at lower prices, guarantees a constant increase in users with the capacity to access online services. In consequence, new training strategies need to be developed to take advantage of ICT services for remote labs. tudiantes de la Maestría en Logística Integral y de la asignatura Simulación de Procesos Estocásticos de Ingeniería Industrial. Se espera recopilar información con estudiantes de otras asignaturas. Para el caso de los estudiantes de primer año (Introducción a la Ingeniería), solo se recopilaron datos relacionados con el uso de recursos tecnológicos.
Finalizado 2014 los cuestionamientos asociados al uso de tecnología habían sido respondidos por 80 estudiantes. Entre los estudiantes de primer año se observó que el 63% posee computador de escritorio; 62%, equipo portátil; 97%, acceso a Internet; 80%, teléfono inteligente -46% sin plan de datos móviles, 22% con acceso solo a redes sociales y correo electrónico, y 32% con navegación completa-y solo By the end of 2014, 80 students answered the survey related with the use of technology. From these results, 63% of the first year students have a desktop computer; 62% have laptops; 97% have internet access; 80% have a smartphone -46% without data plan, 22% with limited internet access, and 32% with full navigation-and only 25% of these students have a tablet (22% Android ® ; 3% iPad ® ). Among the superior level students (latest semesters of industrial engineering) and postgraduate students (Master in Integral Logistics), we observed that 16% have a desktop computer, 42% have laptops, and 32% both. With regard to internet access, everyone mentioned having it; 84% of them have a smartphone, 16% with limited access and 37% with full navigation. Additionally, 47% of them have a tablet. Summarizing this data, Figure 4 presents the results about the survey respondent students who have had access to several traditional laboratory practices. From here, 16% consider that the activities offered do not serve to support the reinforcement of theoretical aspects, while 84% of them think they do serve as a support. In addition, 79% of the students believe that the laboratory practices expose them to real contexts by proposing situations or scenarios where theoretical knowledge is applied, whilst only 21% think these practices give them limited exposure. On the other hand, the acceptance of ICT is high: 95% of the survey respondents think ICT integration can increase the quality of their learning processes, while only 5% are not sure.
The results of this survey are a supply for the release of the remote laboratory and allow access for the students. Until now, we have carried out some tests in order to validate the practices and remote accessibility with some students registered in the platform.
Los resultados de este sondeo son un insumo para la liberación del laboratorio remoto y permitir acceso a los estudiantes; hasta el momento se han realizado pruebas para validar las prácticas y la accesibilidad remota con algunos estudiantes registrados en la plataforma para administración de usuarios.

IV. Resultados y discusión
Los resultados conseguidos hasta la fecha son evidentes, en el apartado anterior se describió el estado actual del proyecto, se ha logrado tener el laboratorio teleoperado en marcha y poner dos prácticas en funcionamiento, realizando pruebas de acceso remoto con resultado aceptables en cuanto a tiempo de respuesta y funcionalidad, con retardos de aproximadamente cuatro segundos. Estas pruebas se han realizado con conexión remota a una red local y con acceso intercampus con el TEC de Monterrey por medio de la red Clara.
En la etapa inicial del proyecto se identificaron inconvenientes relacionados con la capacidad técnica y de seguridad en las instituciones participantes, por lo que fue necesario gestionar la asignación de direcciones IP fijas y la liberación de algunos puertos para la conexión de cámaras y el acceso a la red de los campus universitarios desde el exterior; se compararon las características y flexibilidad del equipamiento dispuesto en los laboratorios, lo que hizo ne- project, where the tele-operated lab is operating flawlessly with two practices within it. We carried out remote access tests with acceptable results for response time and functionality, obtaining latency results of 4 seconds, approximately. We implemented these tests with a remote connection to a local network and with intercampus access with the ITESM through the CLARA network.
At the initial stage of the project, we identified some issues related to the technical capacity and security in the participating institutions. Therefore, it was necessary to manage the assignation of fixed IP addresses and to free up some ports for the connection of cameras and for remote access from external networks. We compared the features and flexibility of the equipment in the laboratories, where it was found necessary to execute some updates in the working stations, engines, sensors, actuators, and controllers, seeking for greater flexibility and agility in their operation.
We also formulated a detailed description of the hardware related to the control of the Festo manufacturing cell; in addition, we defined the communication protocols used for control of the devices conforming the flexible manufacturing system. Once we had finished the set-up of the physical platform, we developed the main interconnection program of the transporting band and the Scara robot, achieving the handling of the communication and synchronization mechanisms between the work station of the transporting band and the linear robot in the warehouse. In Figure 5, we present the development of practice 1 and the program controlling the Scara robot (C segment).
Likewise, we performed synchronization tests of every work station in an effort to achieve a correct communication and programming of the flexible manufacturing system.
También se realizó una descripción detallada del hardware relacionado con el control de la celda de manufactura Festo y se definieron los protocolos de comunicación utilizados para el control de los dispositivos que conforman el sistema flexible de manufactura. Una vez puesta a punto la plataforma física básica, se desarrolló el programa principal de interconexión de la banda transportadora y Robot SCARA, logrando la manipulación de los mecanismos de comunicación y sincronización entre la estación de trabajo de la banda transportadora y el robot cartesiano del almacén. En la Figura 5 se observa el desarrollo de la práctica 1 y el programa que controla el robot Scara (segmento C).
Adicionalmente se realizaron pruebas de sincronización de todas las estaciones de trabajo para la correcta comunicación y programación del Sistema Flexible de Manufactura.

V. Conclusiones y trabajo futuro
Se consiguió poner en funcionamiento la celda de manufactura Festo, el robot Scara y el robot Cartesiano, ubicados en el laboratorio de robótica de la UAO, de forma sincronizada, controlando su accionamiento con un programa desarrollado en Labview para la ejecución de prácticas con acceso remoto, con el cual se puede hacer seguimiento del accionamiento de los componentes por medio de cámaras web ubicadas en el laboratorio.
Se logró cambiar el concepto del tipo de prácticas a realizar en el laboratorio de robótica, con el desarrollo de ejercicios de laboratorio orientados a estudiantes de Ingeniería Industrial y afines, enfocados en gestión de operaciones y logística.
En la revisión del estado del arte de esta clase de laboratorios fue difícil encontrar prácticas diferentes al propio funcionamiento y a la programación del sistema flexible de manufactura, en los que se encuentran múltiples ejercicios Figure 5. Development of the practice associated with the supply chain management / Desarrollo de la práctica asociada a la gestión de la cadena de suministro A. B. C.
We were able to set up and run the Festo manufacturing cell, the Scara and the linear robots -located in the robotics laboratory of the UAO-in a synchronous way by controlling their actions with a program developed in LabVIEW for the execution of remotely accessed practices. Thanks to the functionality of this program, we were able to monitor the operation of the components through webcams located in the lab.
We were able to change the concept of the type of practice to execute in the robotics laboratory with the development of laboratory exercises oriented to industrial engineering students. We approached these exercises in operations management and logistics.
There were several difficulties to review of the state of the art to find practices different from the proper operation and programming of the manufacturing flexible system. In this research, we found multiple exercises aimed at students of mechatronics, electronics, and computer science engineering; these examples are associated with the programming of PLC, robot control, etc. Thus, the focus given to this type of laboratory in this project is a novel practice.
Within the development of the project, we included the execution of simulations of manufacturing processes with configurable options, so the users in their academic exercises could get the results of the process for subsequent work related to the analysis of the presented behavior. In this development, we used PHP programming and MySQL databases, to, afterwards, link these elements with the control module in LabVIEW.
As a future work, we propose the construction of an online platform to manage the registration and massive access of users to the system. For this task, it is necessary to either do previous several security tests or define the structure of a network exclusively for the robotics lab. In that structure, the network administrator can limit the manipulation of the manufacturing flexible system controls, in order to protect the security of the equipment.
We also propose the incorporation of new practices to the remote laboratory, mainly focused on routing and warehouse management, which are already being tested in simulators.

VI. Acknowledgements
This work is financed by the research project TELEOP-LOGIS -Tele-operated Laboratory for Logistics Operations-via Internet2 under the code 12INTER-180, and by the Universidad Autónoma de Occidente, through the resolution 6635 of June 5 of 2012. dirigidos a estudiantes de ingeniería mecatrónica, ingeniería electrónica e informática, asociados con la programación de PLC, control de robots, etc., por tanto el enfoque dado a este tipo de laboratorio en este proyecto ha sido novedoso.
En el desarrollo del proyecto se incluyó la realización de simulaciones virtuales de procesos de fabricación con opciones parametrizables, de tal manera que los usuarios -estudiantes-, en sus ejercicios académicos obtuvieran resultados del proceso para posteriores trabajos de análisis detallado del comportamiento presentado. En este desarrollo se empleó programación en PHP y bases de datos MyS-QL, que posteriormente serán enlazados con el módulo de control en Lab-View. Como trabajo futuro se propone la construcción de una plataforma en línea para gestionar el registro y acceso masivo de usuarios al sistema, para lo cual es necesario hacer varias pruebas previas de seguridad o definir la conformación de una red dedicada solamente al laboratorio de robótica, donde adicionalmente se limite la manipulación de los controles del sistema flexible de manufactura, con el fin de salvaguardar la seguridad de los equipos.