Output Feedback Disturbance Decoupling in Discrete-Time Nonlinear Systems

Disturbance decoupling of multi-input multi-output discrete-time nonlinear systems by static measurement feedback

“…The next step is to extend the results of [21] by addressing dynamic measurement feedback in the framework of differential forms for discrete-time systems. The results can then be compared with those by [15], which were obtained using the tools of the algebra of functions. In addition to the above theoretical problems, the functions in the Mathematica program have been developed for solving the DDP and integrated into the symbolic software package NLControl, developed in the Institute of Cybernetics at Tallinn University of Technology.…”

“…Few studies address the DDP for discrete-time nonlinear control systems using output feedback (e.g. [15,18,20], see also [13]), whereas only [18] treats explicitly the case of static measurement feedback, which is the topic of our paper. However, in [18] necessary and sufficient conditions are given only for single-input single-output (SISO) systems.…”

“…However, in [18] necessary and sufficient conditions are given only for single-input single-output (SISO) systems. Papers [15] and [20] focus on dynamic measurement feedback. In [20] the controlled output is a vector function of the measured output, having possibly less components than the measured output itself.…”

“…Therefore, the above solution may be considered only as a partial solution. Paper [15] provides a full algorithmic solution for the problem using dynamic feedback. In both papers the novel algebraic approach, called the algebra of functions (see [22]), is applied.…”