SciELO - Scientific Electronic Library Online

vol.48 issue6Fabricación de niobato de litio periódicamente polarizado para óptica no linealThe Wigner function in paraxial optics I: Matrix methods in Fourier optics author indexsubject indexsearch form
Home Pagealphabetic serial listing  

Services on Demand




Related links

  • Have no similar articlesSimilars in SciELO


Revista mexicana de física

Print version ISSN 0035-001X


CYWIAK, M.  and  CASTRO, M.. Simple technique for root locus plotting. Rev. mex. fis. [online]. 2002, vol.48, n.6, pp.556-564. ISSN 0035-001X.

We present a simple technique for calculating and plotting the root locus of a linear control system. Although several programs are commercially available for this purpose, and remarks on this subject can be found in dedicated texts, a complete description ofthe program code is desirable to provide the designer with versatility and deeper insight. This report describes our technique and includes complete program codes. In this technique, the roots of the system's characteristic function are found by providing a single, unique guess value to be used in a first derivative search algorithm in order to calculate the unknown set of roots. Similarly to other techniques, the root locus is found by calculating the system's set of roots as the gain varies in the range of interest. The resolution obtained depends on the sampling rate of the gain parameter. The technique is suitable for any programming language and there is basically no limit on the root order of the system. To illustrate the technique a four-pole order system is analyzed. Then, to improve the response of the system a lead compensation network is added.. The usefulness of the technique is illustrated by comparing the time response of the compensated network over the uncompensated one.

Keywords : Linear control system; root locus; stability.

        · abstract in Spanish     · text in English     · English ( pdf )


Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License