摘要
The general form of the dynamic response of a controlled process is shown in Fig. 1, where E is the deviation of the controlled variable U from its set-point value U<sub>0</sub> （i. e. E= U<sub>0</sub>-U）. For convenience in discussing, we transform the curve in Fig. 1 into that in Fig. 2 a t-domain curve of |E|. Now, we discuss a certain period of variation of the curve in Fig. 2, e.g. a time interval between to and t<sub>4</sub>.We partition this period of variation into four subintervals: t<sub>0</sub>—t<sub>1</sub>, t<sub>1</sub>—t<sub>2</sub>, t<sub>2</sub>—t<sub>3</sub> and t<sub>3</sub>—t<sub>4</sub>. It is easily seen that, in the first and the third subintervals, the rate of change
