High accuracy temperature control system for charged colloidal crystals

The charged colloidal crystal is one of the hotspots on the condensed physics research. The main reason forming the charged colloidal crystal is that the charged colloidal particles achieve a balance and long orderly arrangement because of the static repelling force between particles and granular Brownian movement. However, the slight fluctuations temperature will cause the strength of Brownian motion changes and then influence the crystallization of colloidal crystal state and crystallization process. This paper solves a key work on the research of colloidal crystal phase dynamics: colloidal crystal solution of high precision low volatility temperature control system. 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.