Please help me with a root locus calculation. What is the easiest method to determine where the root locus crosses a given damping ration line and the gain at that point?

Thank you

Question

Please help me with a root locus calculation.  What is the easiest method to determine where the root locus crosses a given damping ration line and the gain at that point?

Thank you

osprey · Answer

this sounds like a complex plane/argand diagram control theory question. the problems come, I think, when the transfer functions start to become above FIRST ORDER, into second and third order and good old OSCILLATIONS can start. If the feedback in a control system is such that the input and the feedback signal are in phase (two phase shifts of 180 degrees) then oscillations can start. http://perendis.webs.com

osprey · Answer

Closed questions are hard to find. See pptx for very rough sketch