Transfer Function & Unity Negative Feedback Control System

[boabby1]

Hi there. I'm wondering if anyone can help. I've got a few past papers I'm working on at the moment and there are a few questions I don't even know where to start with. Here's one:

a. Write down the transfer function for a time delay and then evaluate its corresponding frequency response as a magnitude and phase shift.

b. A unity negative feedback control system that can be modeled as a pure time delay in series with an integrator is controlled using proportional control. After a small change in setpoint is made a sustained oscillation occurs which has a period of 120 seconds. Determine:

i. The value of the controller gain
ii. The magnitude of the processor dead time.

Thanks again in advance

 

[CEL]

You must show some work before we can help you.

 

[boabby1]

CEL, that's the whole point of the sentence in my post that contains the phrase 'I don't even know where to start'!

 

[CEL]

CEL, that's the whole point of the sentence in my post that contains the phrase 'I don't even know where to start'!

I suggest that you look for information on some book. Modern Control Engineering, by Ogata, is a good option.

 

[boabby1]

Thanks CEL. Does that have exam type questions in it? That's really what I'm after for practice. My notes have examples in but nothing even remotely like the type of questions which have been set in the exam papers I've seen.

 

[CEL]

I have no idea what type are exam questions, but the book has lots of examples.