A Novel Nonlinear Plus Integral Controller With a Real-Time Application on Incubator Temperature Regulation

Abstract

A gel card incubator is an important clinical interface device that maintains gel cards at body temperature, completing the initial step in determining blood grouping. Achieving a much faster closed-loop response to shorten the warm-up period and maintaining a uniform temperature inside the incubator are crucial requirements for medical incubation devices. To accomplish incubator control requirements and deal with deadtime, this study proposes a novel nonlinear plus integral control (NPI) scheme coupled with a time-delay compensator using an incubator dynamic model. The NPI successfully shaped the control structure by utilizing a few nonlinear parameters. The control strategy, which promises a significant performance combining linear and nonlinear control actions, is easy to realize, simple to tune, and allows a smooth transition between control actions. Experiments were performed in a microprocessor-controlled gel card incubator using a computer interface to demonstrate the superiority of the proposed control technique. The comparative results prove that the proposed control scheme exhibits significantly faster and superior responses for transient and steady states. It also achieves successful disturbance rejection and less energy consumption than the Smith predictor-based PI control.