Identifying Impulse Response Function from State Equations

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The discussion revolves around identifying the impulse response function from state equations represented as x(dot) = Ax + Bu and y = Cx. A participant questions whether the impulse response function is correctly expressed as C(e^(At))B, seeking clarification on the notation used. Confusion arises regarding the variables, specifically the meaning of "u" and whether it should be "y." The original poster clarifies that x is the state variable, u is the input, and y is the output, affirming the general representation of state space equations. The conversation emphasizes the need for precise notation in discussing system dynamics.
khedira
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Hi,

given the state equations of a system,

x(dot) = Ax + Bu
y = Cx

is the impulse response function of this system C(e^(At))B? If not, how can i identify the impulse response from a given state equations? Please advise. Thank you.
 
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khedira said:
Hi,

given the state equations of a system,

x(dot) = Ax + Bu
y = Cx

is the impulse response function of this system C(e^(At))B? If not, how can i identify the impulse response from a given state equations? Please advise. Thank you.
What you have written makes no sense. I recognize that "x(dot)" is the derivative of x with respect to t but do you mean to have a "dot" next to the y in the next line? And what is "u"? Was that supposed to be y?

That is, is the problem really
\frac{dx}{dt}= Ax+ By
\frac{dy}{dt}= Cx
?
 
HallsofIvy said:
What you have written makes no sense. I recognize that "x(dot)" is the derivative of x with respect to t but do you mean to have a "dot" next to the y in the next line? And what is "u"? Was that supposed to be y?

That is, is the problem really
\frac{dx}{dt}= Ax+ By
\frac{dy}{dt}= Cx
?

Oh so sorry, i thought what i have given is the general representation of a state space equation, where x is the state variable, u is the input and y is the output. and yes, "x(dot)" is the derivative of x with respect to t but y is just y.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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