| 摘要 |
PURPOSE:To discriminate the instability of a process control applicable to the adaptive control, by utilizing poles of the oscillation of a process variable and an operation variable, the oscillating period and the attenuation factor of the amplitude of oscillation. CONSTITUTION:The three poles X1-X3 and their generated times tX1-tX3 are obtained from the timewise change of the process variable X, the three poles Y1-Y3 and their generated times tY1-tY3 are obtained from the operating variable similarly, the period (tX3-tX1) of the waveform X and the period (tY3- tY1) of the waveform Y are compared and whether the ratio of both is close to the unity in a certain range or not is discriminated. Further, whether the attenuation factor of the amplitude of the waveform X is larger than a prescribed attenuation factor or not is discriminated according to the formula of discrimination. Similarly, the same is performed for the amplitude of the waveform Y. When the three conditions are established, it is discriminated that the control operation is instable and hunting takes place. |
