Steady-state response

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In electrical engineering, a steady-state response is the electrical response of a system at equilibrium. The steady-state response does not necessarily mean the response is a fixed value. An AC power supply has no fixed voltage on the output but the output is steady (a voltage of a fixed frequency and amplitude).

The steady-state response follows the transient response. It is also sometimes referred to as the forced response in systems involving damping, though this is not an entirely accurate description. The forced response of a system has both transient and steady-state components.

The two classical ways of decomposing the systems are as described by these equations:

Complete Response = Natural Response + Forced Response

Complete Response = Transient Response + Steady-state Response

In aerospace engineering the steady-state response is used in conjunction with the theory governing aircraft flight controls as well as for topics such as aeroacoustics, vibrations, and nonlinear dynamics.

In flight control theory, for example, the steady-state response of a system can be thought of in terms of deflections of the aerodynamic control surfaces: ailerons, elevators, rudders, etc... The response is exactly what it sounds like -- the reaction of the control system to a pilot input.

For example, if a pilot were to pull back on the yoke to pitch the aircraft up (by deflecting the elevators down) the response would be a plot of the aircraft's pitch as a function of time. This plot typically looks sinusoidal damping to a constant value. This constant value is the steady-state response -- it is the response of the aircraft after a long period of time has passed (mathematically at infinity) such that the transient response (the initial oscillations after the input) no longer has an effect.

[edit] See also

• Sinusoidal response
• Steady state (electronics)
• Transient response