Aspects of Pole Placement Technique in Symmetrical Optimum Method for Pid Controller Design

The paper presents an analytical approach to the design of PID controllers by combining pole placement with symmetrical optimum method, for the integration plus first-order plant model. The desired closed-loop transfer function (c.l.t.f.) contains a second-order oscillating system and a lead-delay compensator. It is shown that the zero value of c.l.t.f. depends on the real-pole value of c.l.t.f. and in addition, there is only one pole value, which satisfies the assumptions of symmetrical optimum method. In these conditions, the analytical expressions of the controller parameters can be simplified. The method is applied to design a PID autopilot for heading control of a ship with firstorder Nomoto model. Copyright  2005 IFAC