Automatica, Vol.95, 433-445, 2018
A behavioral approach to inversion-based control
A new simplified behavior theory is proposed to address inversion-based control for linear, nonminimum-phase SISO systems. The chosen space of signals is the set of piecewise C-infinity-functions and input-output pairs (as weak solutions) satisfy a differential-integral equation with additional smoothness requirements. A related key result is the output-input (or inverse) representation of the behavior set that leads to the solution of a general stable inversion problem where polynomially unbounded, noncausal desired outputs are allowed. It is shown that this problem has a solution if and only if the smoothness degree of the desired output is greater than or equal to the system relative degree minus one. When this straightforward condition is satisfied, a closed-form expression provides the inverse input. Then, an analysis on preaction and postaction control follows. Two examples are included showing the relevance of output signal design in control applications. (C) 2018 Elsevier Ltd. All rights reserved.
Keywords:Inversion-based control;Feedforward;Behavioral approach;Stable inversion;Nonminimum-phase systems;Linear systems