High accuracy temperature control research on charge stable colloidal crystals

Abstract

Colloidal crystal phase dynamics is one of the hotspots on Condensed Matter Physics. Kossel-line diffraction method is an important way to measure the inner structure of colloidal crystal. The research on the model of colloidal crystal phase dynamics changing as the temperature will provide scientific basis to the preparation of colloidal crystal materials, especially in the condition of microgravity. Achieving high accuracy temperature control on the suspension of colloid crystal is a key work on the research of colloidal crystal phase dynamics. A proportional-integral-derivative (PID) control method based on pulse-width modulation (PWM) is proposed. Then, system identification on the heating system of the sample solution is used to get transfer function, and Hooke-Jeeves pattern search method is used to get optimal parameters of the PID controller. We obtain best temperature control accuracy (±0.1°C) as well as simulation results, after actual temperature control system uses the optimal parameters. © 2012 Springer-Verlag GmbH.