Nyquist stability criterion
E36214
The Nyquist stability criterion is a graphical frequency-domain method in control theory used to determine the stability of feedback systems by analyzing how their open-loop transfer function encircles a critical point in the complex plane.
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
control theory concept
→
frequency-domain method → stability criterion → |
| analyzes |
open-loop transfer function
→
|
| appliedIn |
aerospace engineering
→
chemical process control → communication systems → electrical engineering → mechanical engineering → |
| appliesTo |
feedback control systems
→
linear time-invariant systems → |
| assumes |
system is linear
→
system is time-invariant → transfer function is rational → |
| basedOn |
Nyquist plot
→
|
| canDetermine |
marginal stability
→
|
| canHandle |
systems with right-half-plane poles
→
systems with time delay → |
| category |
feedback stability methods
→
graphical analysis techniques in control → |
| comparedWith |
Bode stability criterion
→
Routh–Hurwitz stability criterion → |
| coreConcept |
encirclement of the critical point -1+0j in the complex plane
→
relationship between open-loop poles and closed-loop stability → |
| determines |
absolute stability
→
|
| domain |
frequency domain
→
|
| field |
control theory
→
systems engineering → |
| historicalPeriod |
20th century
→
|
| input |
open-loop frequency response
→
|
| namedAfter |
Harry Nyquist
→
|
| output |
stability conclusion
→
|
| relatedConcept |
closed-loop pole locations
→
root locus method → small-gain theorem → |
| relatedTo |
Bode plot
→
closed-loop characteristic equation → gain margin → phase margin → |
| relates |
number of encirclements to right-half-plane poles
→
|
| requires |
Nyquist contour in the complex plane
→
|
| teachingContext |
graduate control theory courses
→
undergraduate control systems courses → |
| usedFor |
determining closed-loop stability from open-loop data
→
stability analysis of feedback systems → |
| uses |
argument principle from complex analysis
→
mapping of contours under a complex function → |
| visualizedBy |
Nyquist diagram
→
|
Referenced by (2)
| Subject (surface form when different) | Predicate |
|---|---|
|
Harry Nyquist
→
|
notableWork |
|
negative feedback amplifier
→
|
usesConcept |