A fuzzy system for real-time control of tissue temperature during laser heating

Author

Ding, Yongsheng ; Ying, Hao ; Shao, Shihuang

Author_Institution

Biomed. Eng. Center, Univ. of Texas Med. Branch, Galveston, TX, USA

fYear

1998

fDate

20-21 Aug 1998

Firstpage

5

Lastpage

9

Abstract

A real-time fuzzy control laser system to control tissue temperature during hyperthermia in fresh pig liver samples is presented in this paper. The technical difficulties of this study lie in two facts: laser tissue heating is a highly nonlinear time-varying dynamic process; and the output power of the 810 nm diode laser that we used is not adjustable during operation. We have overcome the difficulties by regulating the laser via variable ON-OFF signal sequence, which is computed at each sampling time, by our novel nonlinear time-varying fuzzy controller. The structure of the fuzzy controller is analytically analyzed and the result is related to the PD controller. The average of the absolute values of the maximum temperature derivations for six hyperthermia experiments using the fuzzy control system is 0.44°C. These satisfactory results indicate that our fuzzy control system could be useful for clinical applications

Keywords

fuzzy control; heating; hyperthermia; laser applications in medicine; nonlinear control systems; real-time systems; temperature control; time-varying systems; two-term control; PD controller; clinical applications; fuzzy system; hyperthermia; laser heating; nonlinear time-varying dynamic process; nonlinear time-varying fuzzy control; pig liver samples; real-time control; tissue temperature control; variable ON-OFF signal sequence; Control systems; Fuzzy control; Fuzzy systems; Heating; Hyperthermia; Liver; Optical control; Power lasers; Real time systems; Temperature control;

fLanguage

English

Publisher

ieee

Conference_Titel

Fuzzy Information Processing Society - NAFIPS, 1998 Conference of the North American

Conference_Location

Pensacola Beach, FL

Print_ISBN

0-7803-4453-7

Type

conf

DOI

10.1109/NAFIPS.1998.715512

Filename

715512