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The main objective of this thesis is to design third-order
transfer functions satisfying non-overshoot step response.
Furt- her, the process of analysis can be used to design
third-order transfer functions with monotone-increasing step
response.Simul- taneously, by obeying a simple non-undershoot
rule, the results could be adopted in the general model of
PID control DC motors and other third-order linear systems. In
the analytical process, the transfer functions are classi- fied
in five cases of poles, which are real, complex or multiple-
order poles. In view of time domain, the conditions, the
necessa- ry and sufficient conditions or only the
sufficient ones, for non-overshoot systems are discussed.
Finally the conditions are described in terms of the
coefficients of the numerator of tran- sfer functions. Using
these conditions to determine the range of the coefficients
bounded by the combination of stright-lines and second-order
curves, a suitable design can be achieved. For the sake of
simplicity and the consideration about the capacities of the
sufficient conditions, we substitute the coeff- icients of the
numerator for the zeros of transfer functions as the
controlled parameters of the transient perfermance index. By
the characteristics of the non-overshoot step response curve
and the monotone-increasing one, the sufficient conditions
can be easily improved to contain.
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