Drying Temperature Precision Control System Based on Improved Neural Network PID Controller and Variable-Temperature...

Area of Science:

• Food Engineering
• Control Systems Engineering
• Materials Science

Background:

• Precise temperature control is crucial for optimizing drying processes.
• Variable-temperature drying offers potential advantages over traditional constant-temperature methods.
• Existing control systems may lack the accuracy needed for advanced drying techniques.

Purpose of the Study:

• To develop and validate an improved neural network (INN) proportional-integral-derivative (PID) controller for precise drying temperature control.
• To evaluate the performance of the INN-PID controller against traditional PID and neural network PID (NN-PID) controllers.
• To compare the effectiveness of linear variable-temperature (LVT) drying with constant-temperature drying for cantaloupe slices.

Main Methods:

• Simulation of PID, NN-PID, and INN-PID controllers using MATLAB with unit step signals.
• Experimental validation of the controllers in an air impingement dryer.
• Drying experiments using LVT and constant-temperature methods on cantaloupe slices.
• Comprehensive evaluation of drying quality using brightness, color difference, vitamin C, chewiness, drying time, and energy consumption.

Main Results:

• The INN-PID controller demonstrated superior control accuracy and faster regulation time compared to PID and NN-PID controllers.
• Experimental results showed the INN-PID controller effectively regulated drying temperature with minimal overshoot (4.74%).
• LVT drying significantly reduced drying time and energy consumption while preserving cantaloupe quality compared to constant-temperature drying.

Conclusions:

• The developed drying temperature precision control system, utilizing the INN-PID controller, meets the stringent requirements of variable-temperature drying.
• Variable-temperature drying, specifically LVT, is a more effective and efficient drying mode than constant-temperature drying for cantaloupe slices.
• The study provides a robust technical foundation for further research and application of variable-temperature drying processes.