Real time PID control for hydro-diffusion steam distillation essential oil extraction system using Gradient Descent tuning method

This paper present the implementation of real time PID controller for hydro-diffusion steam distillation essential oil extraction system based on comparison of Gradient Descent (GD) and Ziegler Nichols (ZN) tuning methods. The first order of Auto Regressive Exogenous (ARX) model was used to describe the behavior of the temperature system and will be use in the controller design. A PID controller is expected to execute a robust response towards parameters changes and better control of steam temperature during distillation process. The system had been evaluated based on rise time, % overshoot, settling time and root mean square error (RMSE). The temperature control was achieved by controlling the voltage fed to the heater ranging from 0V to 5V via digital-to-analogue converter (DAC). Robustness test of the PID controller are based on: i) introduce disturbance and ii) set-point tracking. From the result, the performance of PID controller using GD tuning method reveals that this controller can be adapt for the system because being sensitive to parameters changes and robust as the response can compensate the load disturbance and set point change.