Different Types of Stability

Different Types of Stability

1. ¿What's Stability?

   • A system is stable if the system's response to impulse tends to zero when time tends to infinity.
     • If the system tends to a finite value other than zero, it can be said that the system is critically or marginally stable.
       • An infinite magnitude makes the system unstable.
     • If all the poles of the transfer function are on the left side of the plane, then the system is stable.
       • A system is critically stable if one or more poles are on the imaginary axis of the plane.
         • In the stability study only the poles of the transfer function are important, the zeros are irrelevant.
           • The poles of a system are the roots obtained from the denominator of the transfer function when equalized to zero. Characteristic polynomial.
             • The concept of stability is applied to closed loop or open loop systems.

2. Types

   • Absolutely Stable System
     • An open loop control system is absolutely stable if all the poles of the transfer function are present on the left of the S plane. The same criteria is used for the closed loop systems
   • Marginally Stable System
     • A system is marginally stable by producing an output signal with constant amplitude and constant frequency of oscillations for bounded input. We can say an open loop system is marginally stable if any two poles of the transfer function is present on the imaginary axis and the same criteria is used for the closed loop systems.
   • Conditionally Stable System
     • When the System is stable only for a certain range of system component values

3. Absolute stability Refers to the condition of a system of being stable or not

4. Relative stability It refers to the degree of Estabilida of the system. If a system is stable, then its degree of stability or relative stability can be determined.

5. In that form there are two equations, the denominator equation is called characteristic equation and to study the stability of a system, we need to find the roots of this equation.

6. Owen Nicolás Aranda Pérez

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