Design of thermal process controller by using Bodé plots of open loop frequency characteristics

The literature, dealing with automatic control systems, describes the application of Bodé plots of open loop frequency characteristics to the controller parameter synthesis as the trial and error method. The procedure suggested is the one for controller parameter determining according to the given phase margin of the open-loop system frequency characteristics. The procedure is repeated until the required closed-loop response overshoot determined by means of the computer simulation is achieved. This paper describes the application of Bodé plots of open-loop frequency characteristics to the controller parameter synthesis with respect to the given closed-loop system response overshoot where controller parameters are determined by one iteration procedure only. In order to make the synthesis of PI controller parameters, approximate relationships for determination phase margin from the given closed-loop response overshoot are used while compensating the biggest time constant and symmetric frequency characteristics. Bodé plots of open-loop frequency characteristics is applied to the parameter synthesis of thermal process controller by compensating the biggest time constant and symmetric frequency characteristics as well as different values of the given closed-loop system response overshoot. This paper gives closed-loop system responses with regard to reference and disturbance signals obtained by means of the computer simulation.