This research focuses on gain scheduling control of a dual duct system and its local loop interactions. To reach these objectives, experiments were conducted in a dual duct system. The test facility consists three control loops. (cold air temperature control, hot air temperature control, and mixed air temperature control). 
The steady state and dynamic characteristics of the dual duct system were studied. Two control strategies were employed to improve the system performance: (i) conventional PI control, and (ii) gain scheduling control. The experimental results subject to load disturbances (set-point changes and initial condition changes) showed that the performance of the gain scheduling controller is better than the conventional PI controller. However, it was found that the gain scheduling control method caused significant oscillations and took nearly 25 minutes to reach a stable final value under low load conditions. Therefore, an adaptive gain scheduling (AGS) controller was developed to improve the disturbance rejection properties of the controller. Experimental and simulation results show that the adaptive gain scheduling controller has dramatically increased controller performance under low load conditions. 
The prioritization of control loops due to loop interactions was evaluated and the gain scheduling-adaptive controller was applied to the entire system to minimize loop interactions. The experimental results showed that, compared to conventional PI controller, the dynamic responses of adaptive gain scheduling controller are better.