By: Puttiphong Jaroonsiriphan
Advisor: Dr. Timothy Chang
Department of Electrical and Computer Engineering

Time: 2:00 PM, Friday, April 22nd, 2005
Place: Room 202, ECE Center, New Jersey Institute of Technology (NJIT), Newark NJ. Directions

Abstract

With the increase in bandwidth through high speed and Integrated Services Digital Network (ISDN) data lines, real-time web-based distance experiments and control systems can play a significant role in supporting collaborative research and education processes by providing a 24/7 laboratory with real-time information exchange. However, real-time web-based control systems may encounter a range of web-specific problems such as communication time-delays, synchronization errors, and connection failure. The existence of such web-specific problems is frequently a source of the system instability and performance degradation. The stabilization and control problems for the real-time web-based control systems are being investigated by time domain and frequency-response analyses to produce existence conditions as well as stability margin with respect to time-delay and finite sampling rate. It is a primary objective of this work to determine existence conditions of the stabilization and control problems based upon limited plant information such as the DC gain matrix. The conditions and synthesis parameters may be calculated from state space model or directly derived from input-output measurement.

Two categories of experiments are considered in this work: virtual and physical experiments. Web-based identification of first and second order dynamic systems is one such real-time virtual experiment, which allows clients access the simulation data continuously from remote sites. Web-based physical experiments include the control of a two-degree-of-freedom (DOF) monolithic piezoelectric actuator, shaping control of an Adept Cobra 600 robot, and DC motor control.

For this work, the LabVIEW/DataSocket package is chosen to support the implementation of the web-based real-time experiments. DataSocket Transfer Protocol (dstp) is used to communicate and exchange real-time data between server and multi-client components. DataSocket is an ActiveX control which is used in Visual Basic to design client component while server component is created by using LabVIEW-Graphical Programming Language. Three modes of client operations under the DataSocket setup are introduced in this work: 1. LabVIEW based client program, 2. Web-based client plug-in program, and 3. Web-based client logged-in by URL.

Future consideration of this work will extend the stability margin analysis of the closed loop control system to higher order plants encountering large communication time-delays (exceeding one sampling period) and to multivariable plants with multi-input-multi-output configuration. Existence conditions and stability margin estimation due to time-delay and finite sampling rate will be derived using the DC gain block decentralized matrix.

Committee Members:

Prof. Timothy Chang, Advisor, NJIT
Prof. Andrew Meyer, NJIT
Prof. Bernard Friedland, NJIT
Prof. Edwin Hou, NJIT
Prof. Zhengfang Chen, Motorola