Designing a Cruise Control System Controller with Root Locus Method | Coursework

[CEL]

Does that mean that the terms risetime, settling time and overshoot etc have no meaning at all for a pure derivative controller ? But when I think again I get confused that there should be some settling time formula or for overshoot etc. If yes then what is it ?

So what is going to be steady state value in case of pure derivative controller ? Zero, always ?

The settling time is zero.
The ss value can be obtained from the final value theorem. The settling time is the time when response attains 1% or 2% of its final value. In a negative exponent exponential, what is the time when this happens?

 

[CEL]

And what about PID controller how do I find rise time etc for a PID controller...It has to has some...

Obtain the time response and verify how long does it take from 10% to 90% of ss.

 

[Altairs]

In a negative exponent exponential, what is the time when this happens?

Indefinite ?

 

[CEL]

Indefinite ?

When is$$Ke^{-\alpha t}$$ equal to 0.01K or 0.02K?

 

[Altairs]

When is$$Ke^{-\alpha t}$$ equal to 0.01K or 0.02K?

$$\frac{-ln(0.01)}{\alpha}$$

 

[Altairs]

Obtain the time response and verify how long does it take from 10% to 90% of ss.

I have got the steady state value but how do I get the time response ? Laplace Transform ? Isn't there some shorter method ? This is because I have got a zero as well in the PI controller so the general formulae doesn't work..Any approximation ? I don't want to go for any tedious method...

 

[CEL]

I have got the steady state value but how do I get the time response ? Laplace Transform ? Isn't there some shorter method ? This is because I have got a zero as well in the PI controller so the general formulae doesn't work..Any approximation ? I don't want to go for any tedious method...

You must take the inverse tarnsform of the response Y(s). Don't forget that the transform of the step is 1/s, so the s in the denominator cancels the s in the numerator.