Visualization of robust stability condition in an alternative form (9)–the plant model (23) with controller (24) (dashed curve), (25) (dotted curve) or (26) (solid curve).

<p>Visualization of robust stability condition in an alternative form (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181078#pone.0181078.e009" target="_blank">9</a>)–the plant model (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181078#pone.0181078.e023" target="_blank">23</a>) with controller (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181078#pone.0181078.e024" target="_blank">24</a>) (dashed curve), (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181078#pone.0181078.e025" target="_blank">25</a>) (dotted curve) or (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181078#pone.0181078.e026" target="_blank">26</a>) (solid curve).