Week 07

Root Locus

I follow the saved course materials and calculations from modeling through stability, root locus, and frequency response.

Automatic Control course visual
Course visual for this study sequence.

What I connect in this unit

A root locus traces closed-loop poles from open-loop poles toward zeros or infinity as loop gain changes. Branch count, asymptotes, and breakaway points establish the geometry; the angle condition selects the valid path before gain is chosen.

Concept map

  1. Branches and asymptotes
  2. Breakaway points
  3. Angle condition
  4. Gain selection

Technical anchor

From 1+KG(s)H(s)=0, only points satisfying angle G(s)H(s)=(2q+1)180° lie on the locus. Real-axis breakaway candidates follow from dK/ds=0 applied to K(s)=-1/[G(s)H(s)].

How I review it

Overlay the desired damping-ratio line and natural-frequency circle on the s-plane, compute gain from the magnitude condition at their intersection, and inspect every remaining pole.

Connection to the full course

Unit 7 of 12. Unit numbers organize the concepts found in the materials and do not reproduce an attendance schedule.

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