Internet-based supervisory control and stability analysis for time delay

The main objective of this research is to demonstrate experimentally the feasibility of using the Internet for distributed real-time control. A magnetic ball levitation system was developed as a test bed for the experimental verification of the real-time supervisory control scheme via the Internet. This supervisory control is based on the client/server architecture. With CGI (common gateway interface) and HTML (hypertext markup language) codes, it has been shown that a client can change the position commands, modify the control parameters, and receive the experimental results in real time. We propose a methodology of using timeout and sensor data estimation along with the controller to stabilize the system with bounded sporadic time delay in the Internet. The algorithm increased the mean allowable time delay following a uniform distribution from 90 μs to 836 μs. This algorithm also ensures the system stability at a sampling frequency of 333.3 Hz in the presence of bounded sporadic surges in time delays.