Transient response
From Wikipedia, the free encyclopedia
In electrical engineering, a transient response or natural response is the electrical response of a system to a change from equilibrium. A simple example would be the output of a 5 volt DC power supply when it is turned on: the transient response is from the time the switch is turned on and the output is a steady 5 volts. At this point the power supply reaches its steady-state response of a constant 5 volts.
The transient response is not necessarily tied to "on/off" events but to any event that affects the equilibrium of the system. If in an RC circuit the resistor or capacitor is replaced with a variable resistor or variable capacitor (or both) then the transient response is the response to a change in the resistor or capacitor.
The impulse response and step response are transient responses to a specific input (an impulse and a step, respectively).
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[edit] Damping
The response can be classified as one of three types of damping that describes the output in relation to the steady-state value.
[edit] Underdamped
An underdamped response is one that oscillates within a decaying envelope. The more underdamped the system, the more oscillations and longer it takes to reach steady-state.
[edit] Critically damped
A critically damped response is the response that reaches the steady-state value the fastest without being underdamped. It is related to critical points in the sense that it straddles the boundary of underdamped and overdamped responses.
[edit] Overdamped
An overdamped response is the response that does not oscillate about the steady-state value but takes longer to reach than the critically damped case.
[edit] Properties
[edit] Rise time
Time required for system response to rise from:
0% to 90% (Overdamped); 5% to 95%; 0% to 100% (Underdamped)
of the final steady state value of the desired response.
[edit] Overshoot
Maximum Overshoot is the maximum peak value of the response curve measured from the desired response of the system.
[edit] Settling time
Time required for response to reach and stay within 2% of final value.but in the same time it can
[edit] Steady-state error
The steady state error of a system is the difference between the input and output of the system in the limit as time goes to infinity, i.e. when the transient response reaches a steady state. With no overshoot the steady state error is eliminated when the steady state velocity of the vehicle reaches the desired velocity.
