Practical Relative Degree in SMC systems: Frequency Domain Approach
Por:
Rosales A., Fridman L., Shtessel Y.
Publicada:
1 ene 2014
Resumen:
A variety of output regulation problems can be addressed via sliding
mode control when system's relative degree is known. The difficulties in
the implementation of sliding mode controllers emerge when the relative
degree is unknown. On the other hand, practical systems controlled by
sliding mode algorithms always work under tolerance limits, which are
frequently known. This behavior is called real sliding motion. In this
work, the concept of practical relative degree in
single-input-single-output systems controlled by sliding mode
controllers is revisited from the view point of frequency analysis.
Practical relative degree is understood as the smallest order of the
sliding mode controller that satisfies the tolerance limits. Also, the
notion of practical relative degree is analyzed in terms of the
definitions of performance margins. The usefulness of the proposed
concept is the way to design sliding mode controllers for systems that
can be considered a black-box. The practical relative degree is studied
and illustrated via examples and simulations.
Filiaciones:
Deparment of Control and Robotics, Faculty of Engineering, National Autonomus University of Mexico, 4510 Mexico City, Mexico
Electrical and Computer Engineering Dept., University of Alabama in Huntsville, Huntsville, AL 35899, United States
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