Fuzzy incremental control algorithm of loop heat pipe cooling system for spacecraft applications

Reliable and high precision thermal control technologies are essential for the safe flight of advanced spacecraft. A fuzzy incremental control strategy is proposed for control of an LHP space cooling system comprising a loop heat pipe and a variable emittance radiator with MEMS louver. The generating and performing algorithm of the fuzzy control rules is provided with an analytical form based on the understanding of dynamics and control mechanisms of the space cooling system. This paper also presents a novel integrated mathematical model for the dynamic analysis of the LHP space cooling system and a numerical evaluation of the investigated control schemes. Numerical simulation results on the closed loop control effects suggest that the proposed control strategy takes advantage of no steady error, small overshoots and short settling times; thus benefiting safe, highly accurate and reliable operation of the entire space cooling system. The overshoots of the most important operating parameters (T-ob, Q(r), and P) under the proposed fuzzy incremental control have been reduced to 16.3%, 17.6% and 18.6% of the compared PID control's, while the respective settling times have been shortened to 33.9%, 42.3% and 30.5% of the reference values. (C) 2012 Elsevier Ltd. All rights reserved.