Fuzzy sliding mode controller with gain auto-tuning for un-symmetric input temperature control system

The temperature control system has nonlinear time-varying, slow response, time-delay and un-symmetric control input dynamic characteristics. It is difficult to accurately estimate the dynamic model and design a general purpose temperature controller for achieving good control performance. Here a model-free intelligent fuzzy sliding mode control strategy is employed to design a temperature controller with gain-scheduling scheme or auto gain-tuning algorithm for a heating input only closed chamber. The concept of gain scheduling is employed to adjust the mapping ranges of the input and output variables of fuzzy membership functions during the control process for improving the transient and steady-state control performances. The experimental results show that the steady state error of the step input response is always less than 0.2 degrees C without overshoot by using this control schemes.