Automated design for robust PID controllers

The paper presents a method for the automated design of robust PID controllers in continuous and discrete time. In the continuous case it systematically improves the settling time, i.e. the real parts of all closed loop eigenvalues are smaller than γ0. In the discrete case also the damping is improved.For fixed KP the stable region in the (KD, KI)-plane consists of convex polygons. For several representive operation conditions of the plant the intersection of such polygons represents the set of all simultaneously stabilizing controllers. For a grid on KP the centers of gravity of the polygons and the corresponding γ0-values are computed. The best γ0 from this list is a feasible specification for the next design iteration in a transformed coordinate system. Application to a complex track guided bus problem shows good performance after a few automatic iterations.