Application of PID Controller for Controlling Paddy Temperature in Hot Air Pneumatic Drying Process

This research aims to implement Ziegler-Nichols' method in tuning a PID controller for regulating the temperature of paddy during the drying process, referred to as the paddy temperature-controlled drying method (PTC method). The PTC performance and the quality of the dried paddy were compared with those of the air temperature-controlled drying method (ATC method). In the PTC method, the paddy temperature was consistently maintained at 42 °C, while in the ATC method, the paddy was dried using hot air at constant temperatures of 60 °C, 80 ° C, and 100 °C, respectively. It was found that the PID controller can effectively compensate for process errors. Although the maximum overshooting was 7.14%, the system was able to reach a settling time of 43 minutes, and process errors decreased with process duration. When comparing the PTC and ATC method at 60 °C of hot air temperature, the PTC method exhibited a higher drying rate and superior rice quality compared to ATC method by 15.21% and 6%, respectively. However, the specific energy consumption was found to be similar.