A computational technique for the robust root locus

In this paper, the authors present a modified method for generating multiparameter root loci of both continuous and discrete time systems. A more practical computational method for plotting the robust root locus is developed. The graph of the locations of the poles of the transfer function of the closed-loop system corresponding to each gain can be plotted readily and accurately with this method. The sensitivity of poles to the coefficients of the characteristic polynomial can thus be examined, and the appropriate tuning gain selected to achieve a better robustness. Also, a stricter bound of the zeros of the characteristic polynomial is given to further reduce the complexity of the computation of the robust root locus. The technique is applied to the design of robotic manipulators. Simulations of controller design for the PUMA 762 robot disk grinding process are included