Fuzzy logic controller for low temperature application

Abstract

We describe the development of a new computer-based temperature controller using fuzzy logic algorithms. Fuzzy logic rules and reasoning are applied in-situ for determining PID controller parameters based on an error signal and its first derivative. This controller design will be used to stabilize several isothermal stages of a cryostat for studying thermodynamic properties near the3He liquid-gas critical point. Simulations of temperature control near the3He critical point (Tc=3.3 K) show that faster settling, smaller overshoot, and easier control can be achieved using the fuzzy logic temperature controller in comparison with the traditional PID controller.