DESIGN AND IMPLEMENTATION OF A REMOTE LABORATORY BASED ON AN INDUCTION MOTOR FOR THE TEACHING OF DIFFERENT CONTROL ALGORITHMS
Remote laboratories provide access to hardware devices through the Internet 24 h a day. These laboratories are a valuable educational tool that provides to students a better understanding of the behaviour of real processes without having to be physically in front of the equipment. This paper focuses on the design and development of a remote laboratory that illustrates the control of Electrical Machines. There are very nice tools available for building remote laboratories, however, most of them require that the instructors have to be skilled in IT. In this paper a very straightforward procedure has been followed to create a simple but powerful laboratory over which students may perform different experiments with an electrical machine
The proposed remote laboratory is composed by the following devices:
A. Plant under control
The plant used in the experiments consists of an induction motor
B. DSP controller
A MCK2812 board is used to test diverse motion control algorithms in a quick and flexible way. This board is based on a TMS320F2812 chip (a 150 MHz DSP by Texas Instruments) which will execute the program that generates the control signal for the motion of the motor.
C. Server Station
The Server Station will be a PC that will keep the necessary software for creating the binary code that the DSP board will execute as well as the communications software. This software consists of the following packages:
a) Matlab/Simulink: Simulink provides a graphical interface that may be used to model and simulate the behaviour of physical plants. In this case, Simulink is used by the remote students to design the appropriate control algorithm.
b) Matlab/Real-Time Workshop: Once a controller has been chosen and simulated, the code of the DSP board must be generated. This stage is going to be a two-stage process. Firstly, the source code will be generated with Matlab/Real-Time Workshop (RTW), from the controller designed with Simulink.
c) DMCD-Pro MCK2812: The source code generated with RTW must be compiled, linked and assembled for a TMS320F2812 DSP. This stage is carried out with the DMCD-Pro software which is a fully integrated cross-over IDE supplied by the manufacturer. This tool allows remote users to generate the binary code and download it into the DSP board via a RS-232 interface as well as cross-over debugging and monitoring of the process variables.
d) LogMeIn: LogMeIn Free is a free remote desktop tool that allows instant access to one PC from anywhere with an Internet connection. Even though there are other tools available, this one has several advantages like Web integration, HTML encapsulated traffic, etc.
An Axis 214 PTZ camera was used. This is a camera used in surveillance applications. In fact it is an independent HTTP video and audio server.
Remote computers will only require an Internet connection and an Internet Browser in order to act as a container for LogMeIn. Thus, by using the URL provided by the instructors, they will establish a connection with the Server Station to use remotely the software installed on it as if it were installed in their own computer. Moreover, as everything will be executed within a Web browser students neither will have to install any software nor buy any license. The control of the sessions will be made from the LogMeIn server where remote connections will be allowed or denied.