Development of a web-based laboratory for control experiments on a coupled tank apparatus

The Internet provides a new environment for developing a variety of applications for educational and research purposes. This paper presents the implementation of a web-based laboratory experiment on a coupled tank apparatus, a multi-input-multi-output (MIMO) system. The web-based laboratory has been developed to serve students and staff in the Department of Electrical Engineering at the National University of Singapore (NUS). The laboratory is an educational tool for teaching students the basic principles and methodology in performing a series of experiments on a coupled tank apparatus at any time and from any location through the Internet. With the capability to implement strategies for manual, proportional integral derivative (PID), general state-space, and fuzzy logic control, the laboratory also provides a platform for research staff to test control algorithms. Video conferencing has been used to provide audio and video feedback, with a camera mounted on a movable platform so that the user can control both the zooming and viewing angle.

I. Introduction

The concept of a web-based laboratory is not new. Shor and Bhandari [2] developed a distance learning application that allowed a user to remotely conduct experiments in the Control Engineering Laboratory at Oregon State University. The application permitted the experiments to be run via the World Wide Web (WWW). Only a basic web browser that ran Java is needed to gain access and a robot experiment was developed for demonstration. Bytronic Process Control unit [3], referred to as the process rig in the Process Control and Automation Laboratory at Case Western Reserve University, can be accessed remotely via the Internet. Using a web browser, the user can log on and post the parameters from a remote client to a Laboratory Virtual Instrument Engineering Workbench (LabVIEW, from National Instruments [6]) web server that is connected to a process rig via a programmable logic control (PLC) module. The image is generated by a program and refreshed on the client side using server push technology. A remote laboratory called VLAB Fig. 1. Laboratory setup of the equipment. [1] on an oscilloscope experiment was recently set up in the Department of Electrical Engineering, National University of Singapore (NUS). These remote laboratories are actual laboratory experiments that are run remotely via a web interface, and are well suited to distance learning courses where students need not be physically present on campus. They also facilitate the sharing of expensive instruments and equipment, and represent the next important step in remote distance learning.