Sensitivity of robust systems controlling first order objects

The study investigates controlled objects with a first order transfer function, which are known to be the most common for further obtainment of controllers in closed loop automatic systems. The transfer functions of compensating and non-compensating robust regulators with the first and second order of astatism were obtained in the work by means of the method of polynomial equations. Then the analysis of closed loop systems with controllers was carried out by the analytical method of coefficient estimates by a characteristic polynomial of the closed loop control system. The principle of the method lies in the obtainment of pattern indexes and further analysis of change of these coefficients under variations of parameters of the controlled object. The study results are presented graphically by means of the areas allowing to determine a way of alteration of transient processes in the closed loop control system under a variation of process parameters. The comparison of robust controllers with traditional ones was performed. The study results were proved through the modeling of the closed loop control systems under the influence of parametric disturbances of the controlled object, which results in alteration of a tangible controlled object gain coefficient. © Published under licence by IOP Publishing Ltd