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

Several different control schemes for integral processes with dead time resulted in the same disturbance response. It has already been shown that such a response is subideal. Hence, it is necessary to quantitatively analyse the achievable specifications and the robust stability regions. The control parameter can be quantitatively determined with a compromise between the disturbance response and the robustness. Four specifications: (normalised) maximum dynamic error, maximum decay rate, (normalised) control action bound and approximate recovery time are used to characterise the step-disturbance response. It is shown that any attempt to obtain a (normalised) dynamic error less than tau(m) is impossible and a sufficient condition on the (relative) gain-uncertainty bound is root(3)/2.