Internet-mediated automation of a cascade control system-an Engineering laboratory experiment

Abstract

The paper aims to enhance the controllability of a standalone cascade control system with Internet architecture and promote the system to be accessible by remote students. The user interactive web page is developed by using platform independent ASP.NET language and enabled with both monitoring and controlling functionalities. The Internet transmission time delays that are associated with both feed-forward and feedback channels are compensated by using model predictive controller. The performance of cascade control system with and without compensation is validated by measuring indices, such as rise time, peak time and settling time, and also integral square error and integral absolute error. Access privileges among web page users have been added to ensure simultaneous operations as well as security. The cascade control system is an engineering laboratory experiment interfaced with a dedicated computer by using MODBUS protocol and it is made available to the remote students. The user perception analysis is carried out by using a set of questionnaire that observes 85% of positive feedback.