Understanding PID
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Regarding PID, I have been reading some materials recently, and there are some aspects that I don’t quite understand. I hope that through this post, others can point out any misunderstandings I might have regarding PID control. Thank you! The larger the value of P, the smaller the steady-state error. However, once P reaches a certain level, oscillations can occur. The smaller the value of I, the stronger the integrating effect, which results in a faster response; conversely, a larger value of I leads to a slower response. A longer integration time increases the likelihood of overshoot. The integrating effect involves the accumulation of errors over time, which are then output all at once; therefore, a longer integration time reduces the stability of the system. Differentiation serves to respond in advance to overshoot, acting as a kind of lead time. If this value is too large, oscillations can also occur. Is there anyone who can provide some detailed additional information on PID control? Don’t be too theoretical
It seems to be the case; let’s see how the experts explain it
The shorter the integration time, the stronger the integrating effect; so isn’t the corresponding time also shorter?
It’s highly theoretical; take a look at control theory.
I don’t understand what you mean. The shorter the integration time, the greater its effect, right? In PID parameters, all three need to be used together: one parameter is used to enhance the effect, while the values of the other parameters should generally be reduced in order to avoid overshoot. In other words, the proportional action is enhanced, while the integral action generally requires adjustment in the direction of reducing its effect (by increasing the integration time); the same principle applies to the other aspects. It is sufficient to observe and make adjustments by taking into account the parameters of PV, SP, and OP
Put simply: P refers to the amplification factor of the output signal; for example, if the output is 1, the actuator amplifies the signal by that factor. I can be understood as the response time of the actuator after the output is generated, while D represents a lead time – in control systems where there is little lag, D can be omitted.
By practicing 100 control loops, you will understand it. There are some things that aren’t mentioned in the books, but what is written there is generally correct