Virtual and remote control laboratory using MATLAB.

Tarca, Radu ; Tarca, Ioan ; Popentiu-Vladicesu, Florin 等

1. INTRODUCTION

The accessibility of Information and Communication Technology (ICT) allowed the enhancement of the traditional learning methods. Nowadays, several universities have material and software facilities allowing students to perform laboratory experiments by simulation or with real equipment without any geographical or temporal limitations (Amadou, 2006).

The relationship between ICT and process control has reached a new stage, encouraging the creation of applications such as monitoring and control through the Internet, as well as teleworking, telemedicine, and telerobotics.

At this time, several e-learning laboratories have been developed. Two categories can be distinguished:

--remote distance-learning laboratories, which offer remote access to real laboratory equipment and instruments--figure 1;

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Based on the Internet, either a virtual learning laboratory (Schmid, 2001) or a remote distance-learning laboratory (Baccigalupi, 2006), (Callaghan, 2005), (Corter, 2004), (Ferrero, 2003), (Jimenez, 2007), (Khamis, 2003), (Sicker, 2005) are available for setting up a laboratory in a learning environment. A virtual laboratory allows continuous access to a simulated process on a computer. Remote distance-learning laboratories are an option halfway between traditional and virtual laboratories, allowing remote users to perform real experiments (Valera, 2005).

To implement virtual and remote laboratories, we have used one MATLAB-based software package, namely, MATLAB Web Server (by Mathworks).

2. THE VIRTUAL AND REMOTE CONTROL LABORATORY ARCHITECTURES

The scheme of the virtual and remote control architecture is shown in figure 3.

In the picture two main areas can be seen:

--local area in which the user works, and

--remote area where the whole physical system and control elements are located.

The elements of local and remote area are the following: For the local area:

--Computer with Internet connection and an HTTP 4.0 client application. The application is optimized for Internet Explorer 6 and Netscape 7.

For the remote area:

--High speed Internet Connection.

--Computer Server.

--Data acquisition system--the control unit of the physical system.

--Physical system to control.

--Images capture system and web video server: a CCD camera with MPEG-4 video compression streams.

--Http Server. This server allows the communication of the computers using the http protocol.

--MATLAB R2007 with SIMULINK.

--Real--Time Windows Target Toolbox V.2.1: this toolbox allows Simulink schemes to be executed in real time. For this purpose, it provides the necessary blocks for the interaction with the data acquisition system.

The Software part of the system consists of two modules:

1. Web application: this includes client-server communication using HTTP/HTML protocol, the user interface, user's access control, and the main CGI application. The Common Gateway Interface (CGI) is a standard for interfacing external applications with information servers, such as HTTP or Web servers.

2. Real-time application: this is a set of predefined Simulink control schemes and Matlab code, based on Real time Windows Target toolbox, which implements the real time execution of Simulink schemes over a specific physical system.

[FIGURE 3 OMITTED]

PHP is a popular script language that has been chosen as far as it is an open language widely supported by most web servers and O.S. platforms, and with an extensive library that supports every network protocol. PHP code runs on the web server so it shows a controlled environment for the programmer and can communicate with any other process running in the server (Matlab application in our case).

3. EXPERIMENTAL SYSTEMS

The experimental system is presented in figure 4. The system consists in:

--one DC servomotor;

--worm-gear transmission;

--two synchronous belt transmissions;

--an incremental rotation transducer.

Once the user has accessed the system, a page appears in which all needed data to perform the real-time execution is requested. User can choose the physical system (DC motor, worm gear transmission), the control model (speed or position feedback, space state feedback, identification), the type of execution (Simulation or Real-time execution) and Regulator type (PID, algebraic regulator, etc). After introducing all data, the experiment can be performed; when is finished, the output signal is shown on the screen. Moreover, the application allows to download a "*.mat" file with the values of the most significant signals (output, control action, etc.) in order to be analyzed by the user.

[FIGURE 4 OMITTED]

After the execution, a web page with the graph of the output signal is presented to the student (in this case the engine velocity). This page shows that the system allows the download of all the signals involved in the execution in order to be analyzed by the students.

During real-time execution the user has access to a compressed video stream showing the experiment. For this, a high bandwidth internet access is required.

4. CONCLUSION

This paper presents an experiment realised by our research team in the field of virtual and remote control laboratories. The advantage of the proposed system is that it helps the student to perform practice experiments remotely without a strict timetable. The tool developed, presented in this paper can also be used to test new control schemes over different physical equipments.

5. REFERENCES

Amadou, M. M. D.; Saad M.; Kenne, J. P.; Nerguizian V.; Virtual and remote laboratories, Proceedings of the 1st IEEE International Conference on E-Learning in Industrial Electronics, pp. 176-173, Dec. 2006, ISBN 1-4244-0324-3.

Baccigalupi, A.; De Capua, C.; Liccardo, A.; (2006) Overview on Development of Remote Teaching Laboratories: from LabVIEW to Web Services, IMTC 2006--Proceedings of the 23rd IEEE Instrumentation and Measurement Technology Conference, Sorrento, Italy 24-27 April 2006, pp. 992-997, ISBN 0-7803-9360-0.

Callaghan, J.M.; Harkin, J.; El Gueddari, M.; McGinnity, T.M.; Maguire, P.L.; (2005) Client-server architecture for collaborative remote experimentation, Proceedings of the Third International Conference on Information Technology and Applications (ICITA'05), Volume 2, 4-7 July 2005 pp. 125--129 vol.2, ISBN 0-7695-2316-1.

Corter, J. E.; Nickerson, J. V.; Esche, S. K.; Chassapis, C.; (2004) Remote versus hands-on labs: A comparative study. In Proceedings of the 34th ASEE/IEEE Frontiers in Education Conference. October 20--23, 2004, Savannah, GA, pp. F1G.17-F1G.21, ISBN 0-7803-8552-7.

Ferrero, A.; Salicone, S.; Bonora, C.; Parmigiani, M. (2003) ReMLab: a Java-based remote, didactic measurement laboratory, Instrumentation and Measurement, IEEE Transactions on Volume 52, Issue 3, June 2003, pp. 710-715, ISSN 0018-9456.

Jimenez, L.M.; Puerto, R.; Reinoso, O.; Neco, R.P.; Fernandez, C.; (2007) Remote Control Laboratory Using Matlab and Simulink, IEEE International Symposium on Industrial Electronics, 2007. ISIE 2007., 4-7 June 2007, pp. 2963-2967, Vigo, ISBN: 978-1-4244-0755-2.

Khamis, A.; Rivero, D.M.; Rodriguez, F.; Salichs, M.; (2003) Pattern-based Architecture for Building Mobile Robotics Remote Laboratories Proceedings of the 2003 IEEE Intsmatiooai Conrerenee on Robotics & Avtomntion Taipei, Taiwan, Sept. 2003, pp.3284-3289, ISBN 0-7803-7736-2.

Schmid, C. (2001) Virtual control laboratories and remote experimentation in control engineering, Proc 11th Annual Conference on Innovations in Education for Electrical and Information Engineering, pp. 213-218, 2001.

Sicker, D.C.; Lookabaugh, T.; Santos, J.; Barnes, F.; (2005) Assessing the Effectiveness of Remote Networking Laboratories, Proceedings 35th Annual Conference: Frontiers in Education, 2005. 19-22 Oct. 2005 pp. S3F-7-S3F-12, ISBN 0-7803-9077-6.

Valera, A.; Diez, J. L.; Valles, M.; Albertos P.; (2005) Virtual and Remote Control Laboratory Development, IEEE Control Systems Magazine, february 2005, pp. 35-39, ISSN 0272-1708.