Robust tuning of a dead-time compensator

In this paper, the design of a dead-time (DT) controller is presented to control a nonlinear and long dead-time heating tunnel plant. The new control design uses the Smith predictor (SP) to compensate the dead-time, the PID control law as a primary controller and a filter. Both, PID and filter parameters, may be changed to improve robustness aspects of the closed-loop system. Due to the nonlinear characteristic of the plant, the combination of slow and fast models is used for modeling purposes of the process in the SP design. The relay feedback method is implemented to tune the primary PID controller. According to experiments, on a heating tunnel, the SP control system provides an efficient solution to deal with long dead-time plants even if the plant is modeled by a high-order transfer function.