Analyzing control system robustness

D. Simon
2002 IEEE potentials  
When an engineer designs a control system, the design is usually based on some mathematical model for the system to be controlled. However, the system model is only an approximation. In reality the system may behave di®erently than the model indicates, or the system parameters may vary with time. In practice, though, control systems that are designed on the basis of some system model often work quite well. A control system designer (and the designer's manager and customer) may have nagging
more » ... s about how much the real system can depart from the model before the control system performance fails to meet its requirements or even becomes unstable. The Nyquist stability test was developed in 1932 as a graphical method of determining the stability of a linear single-input-single-
doi:10.1109/45.985322 fatcat:pi56knltq5ekdoylcftysvafcy