Patent ID: 8255066

Claim:
A method of tuning a proportional-integral-derivative controller, further referred to as a PID controller, having a transfer function W c ⁡ ( s ) = K c ( 1 + 1 T ic ⁢ s + T dc ⁢ s ) , where s is a Laplace variable and K c , T ic , and T dc are tuning parameters, for a process in a feedback control system comprising the steps of: (a) selection of a desired gain margin γ m of the system for tuning for a gain margin specification or desired phase margin φ m , of the system for tuning for a phase margin specification; (b) determining the values of the parameters c 1 , c 2 , and c 3 that define optimal tuning rules of the PID controller from the desired gain margin γ m of the system for tuning for a gain margin specification or the desired phase margin φ m of the system for tuning for a phase margin specification selected at the previous step; (c) bringing the control system into symmetric self-excited oscillations of a frequency at which a phase response of the process is equal to the desired value equal to ψ−180°, where −90°<ψ<90°; (d) measurement of a frequency of the oscillations Ω 0 , and an amplitude of the oscillations α 0 ; (e) calculation of the tuning parameters of the PID controller in dependence on the measurements obtained at the previous step.