Abstract
This paper is concerned with a design method of robust PID controllers for first-order lag with dead time. PID controllers have been widely used as they are easy to be tuned up. Ziegler-Nichols rule gives the parameters of a PID controller simply from the time constant, the dead time and the gain of the given plant. Although the rule is well-known and widely used, designed PID controllers does not attain the satisfactory performance even with the given nominal plant. This paper proposes a simple design method of robust PID controllers based on partial model matching. The proposed method gives the time constant of the closed-loop systems simply from the time constant and the dead time of the given plant.