ROBUST SPEED CONTROL OF A TWO-CONVEYOR WHEAT MIXING SYSTEM USING CONVENTIONAL PID AND PSO-OPTIMIZED PID UNDER MOTOR PARAMETER UNCERTAINTIES

This study presents an integrated control framework for a two-stream wheat conveying and mixing system driven by 4 kW induction motors. The proposed model couples the induction motor, indirect field-oriented control, conveyor dynamics, wheat mass flow, and mixing-ratio regulation within a unified simulation environment. Three operating strategies are investigated: a conventional uncontrolled system, a classically tuned proportional–integral–derivative (PID) controller, and a PID controller optimized using Particle Swarm Optimization (PSO). The PSO-based strategy is designed to improve control performance while considering variations in operating conditions. The robustness of the controllers is evaluated through independent variations of key electrical and mechanical parameters, including stator resistance, rotor resistance, mutual inductance, mechanical inertia, and load torque. The proposed strategies are further assessed for 50/50, 60/40, and 70/30 wheat mixing ratios. Performance is evaluated using speed and flow tracking, mixingratio error, root mean square error, integral absolute error, recovery time, total energy consumption, and specific energy consumption. The study also performs a sensitivity analysis to identify the parameters that most influence system behavior.