Control of integral processes with dead-time. 2. Quantitative analysis

Several different control schemes for integral processes with dead time resulted in the same disturbance response. Moreover, it has already been shown that such a response is subideal. Hence, it is quite necessary to quantitatively analyze the achievable specifications and the robust stability regions. This paper is devoted to do so. As a result, the control parameter can be quantitatively determined with compromise between the disturbance response and the robustness. Four specifications — (normalized) maximal dynamic error, maximal decay rate, (normalized) control action bound and approximate recovery time — are given to characterize the step-disturbance response. It shows that any attempt to obtain a (normalized) dynamic error less than is impossible and a sufficient condition on the (relative) gain-uncertainty bound is . Index Terms: Dead-time compensator, robustness, integral processes with dead time, disturbance observer, Smith predictor