Hybrid fuzzy-pid controller integrated with anti windup strategy for small-medium industry scale steam distillation plant

The current demand for essential oil is in explosive growth due to the interest of usage in major end-use industries such as; food and beverage, pharmaceuticals, cosmetics, and aromatherapy. Essential oils can be extracted via various extraction methods ranging from classical to modern techniques. However, the most common and famous technique approach in essential oil extraction technology is the steam distillation technique. There are common influencing parameters affecting the quality of the essential oils in all extraction process of essential oils with temperature being the most influential parameter. Hence, the study solely focusses on controlling the temperature. Regulating temperature is simple, but the process is much more complicated because many low molecular weight volatile compounds break down when exposed to high temperatures due to their instability. Unfortunately, in most studies, essential oils are extracted under minimal or without supervision when it comes to temperature control. The control strategy integration is crucial and necessary as an elevation of several degrees in temperature can affect the chemical structure composition of essential oils. However, the effort to regulate the system at the desired set-point is very challenging due to non-linearities in dynamic behaviour. Most practitioners and engineers still rely on conventional PID control method to control applications. Conventional PID controller is the famous controller in many applications due to its simple structure which is easy to develop. Unfortunately, numerous researchers claimed that PID has some weaknesses for certain applications. The main drawback of conventional PID comes from the control variable; which is delay in corrective action to drive to the desired set-point. This is inadequate and not capable of regulating a non-linear system. In addition, the integral action is unable to improve the system once the control signal exceeding the physical operating range of the actuator. Consequently, the wind-up phenomenon occurs due to actuator limitation and non-linearities of the system. The phenomenon contributes to high overshoot and long settling time. Hence, the implementation of an advanced controller such as the Fuzzy controller will enhance the set point tracking performance. Several type controllers such as PID controller, PID Anti-Wind-up (PIDAW) controller, Hybrid Fuzzy-PID (HFPID) controller, and Hybrid Fuzzy-PID Controller with Integrated Anti-Wind-Up Strategy (HFPIDAW) were proposed to control steam temperature in Small-Medium Industry Steam Distillation Plants (SMISDs). These controller performances were evaluated based on their steady state response and transient response. The qualitative analysis were performed by applying rise time, settling time, percentage of overshoot, RMSE, ISE, IAE, and ITAE in simulation and real-time studies. The evaluation on the performance of these controllers were evaluated and the finding reveals that; HFPIDAW controller achieved better performance in terms of transient response and steady state response compared to other PID, PIDAW and HFPID based controllers. The HFPIDAW controller tuned by smallest of Tracking Time Constant, Td value successfully managed to contribute better performance since it exhibited better performance in rise time and settling time as well as producing small percentage of overshoot and lower readings for RMSE, IAE, ISE and ITAE.