智能烘箱温度控制器设计-英文翻译(2)

the input of the error signal integral relationship. Of an automatic control system, if in the steady state error, there's system, called the control system. In order to eliminate the steady-state error, in the controller must be introduced to "integration". Depends on the time integral, integral study of error with the increase of time, integral will increase. Like this, even if the error is very small, integral item also increases with increasing over time, it pushed further increases the output of the controller makes the steady-state error is reduced, until it is equal to zero. Proportional plus integral (PI) controller, therefore, can make the system in the steady state after no steady-state error.

Differential control (D) in the differential control of controller output is proportional to the input of the error signal differential relations. Automatic control system in the process of overcoming the error adjustment may appear oscillation even instability. The reason is because there are large inertia link, is to inhibit the action of the error and its change is always behind the change of the error. Solution is to inhibit the action of the error change "advanced", namely the error close to zero, to inhibit the action of the error should be zero. That is to say, in the controller only introduced "ratio" is often not enough, the role of proportional error is only amplified amplitude, and the need to increase the "differential", it can predict error change trend, in this way, a proportional plus differential controller can make the inhibitory effect of error control in advance is equal to zero, even negative, avoiding being controlled amount of serious overshoot. So for controlled object with large inertia or lag,