SLIDING MODE THERMAL CONTROL-SYSTEM FOR SPACE STATION FURNACE FACILITY

This paper addresses the decoupled control of the nonlinear, multiinpu t-multioutput, and highly coupled space station furnace facility (SSFF ) thermal control system. Sliding mode control theory, a subset of var iable-structure control theory, is employed to increase the performanc e, robustness, and reliability of the SSFF's currently designed contro l system. This paper presents the nonlinear thermal control system des cription and develops the sliding mode controllers that cause the inte rconnect-edw subsystems to operate in their local sliding modes, resul ting in control system invariance to plant uncertainties and external and interaction disturbances. The desired decoupled flow-rate tracking is achieved by optimization of the local linear sliding mode equation s, The controllers are implemented digitally and extensive simulation results are presented to show the flowrate tracking robustness and inv ariance to plant uncertainties, nonlinearities, external disturbances, and variations of the system pressure supplied to the controlled subs ystems.