Gridding discretization-based multiple stability switching delay search algorithm: The movement of a human being on a controlled swaying bow

PLoS One. 2017 Jun 8;12(6):e0178950. doi: 10.1371/journal.pone.0178950. eCollection 2017.

Abstract

Delay represents a significant phenomenon in the dynamics of many human-related systems-including biological ones. It has i.a. a decisive impact on system stability, and the study of this influence is often mathematically demanding. This paper presents a computationally simple numerical gridding algorithm for the determination of stability margin delay values in multiple-delay linear systems. The characteristic quasi-polynomial-the roots of which decide about stability-is subjected to iterative discretization by means of pre-warped bilinear transformation. Then, a linear and a quadratic interpolation are applied to obtain the associated characteristic polynomial with integer powers. The roots of the associated characteristic polynomial are closely related to the estimation of roots of the original characteristic quasi-polynomial which agrees with the system's eigenvalues. Since the stability border is crossed by the leading one, the switching root locus is enhanced using the Regula Falsi interpolation method. Our methodology is implemented on-and verified by-a numerical bio-cybernetic example of the stabilization of a human-being's movement on a controlled swaying bow. The advantage of the proposed novel algorithm lies in the possibility of the rapid computation of polynomial zeros by means of standard programs for technical computing; in the low level of mathematical knowledge required; and, in the sufficiently high precision of the roots loci estimation. The relationship to the direct search QuasiPolynomial (mapping) Rootfinder algorithm and computational complexity are discussed as well. This algorithm is also applicable for systems with non-commensurate delays.

MeSH terms

  • Algorithms*
  • Humans
  • Movement / physiology*

Grants and funding

The work was supported by the Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme project no. LO1303 (MSMT-7778/2014), https://www.isvav.cz/projectDetail.do?rowId=LO1303. This work was supported by the European Regional Development Fund under the project CEBIA‐Tech Instrumentation No. CZ.1.05/2.1.00/19.0376, http://www.risy.cz/cs/vyhledavace/projekty-eu/detail?id=141580. The authors are members of the team that received the funding but they are not responsible persons. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.