A study on numerical measurement of stability in feedback control systems by DKA method and their controlled output efficiency

The stability of control systems is an important issue and its evaluation can be realized by the Routh or Hurwitz method. In this paper, the authors treat the numerical stability and its evaluation in feedback control systems. Adachi proposed that the stability evaluation in feedback control systems could be realized by the Bairstow-Hichkock method. We use the DKA method which is an effective way for deriving the solutions of n-th ordered polynominal equations, just like the characteristic equations in feedback control systems. In the DKA method, the solutions obtained are approximate solutions. The authors investigate the following issues: (1) methods of presenting initial values efficiently; (2) comparisons of the result among traditional methods, Adachi's method and our method with numerical example; and (3) results on the controlled output efficiency in feedback control systems.