Transfer Function from Difference Equations
Transfer Function from Difference Equations
(OP)
If you had a difference equation model of say x(k+1) = 0.2x(k)+u(k) and y(k+1)=-0.4y(k)+x(k)+u(k-1), how would you develop a transfer function in the discrete time domain.
Likewise, working backwards, if you were given a transfer function in the continous domain of say (s+3)/(s^2+4s+16), sampled every 0.05s, how would you find a set of difference equations.
Thanks for your time.
Likewise, working backwards, if you were given a transfer function in the continous domain of say (s+3)/(s^2+4s+16), sampled every 0.05s, how would you find a set of difference equations.
Thanks for your time.
RE: Transfer Function from Difference Equations
This is for what kind of application because it doesn't make much sense.
I looks like you just made this up.
Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com
http://forum.deltamotion.com/
RE: Transfer Function from Difference Equations
I did not make this up.
RE: Transfer Function from Difference Equations
Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com
http://forum.deltamotion.com/
RE: Transfer Function from Difference Equations
RE: Transfer Function from Difference Equations
For instance a digital PID controller can be implemented as
u(n)=u(n-1)+K0*e(n)+K1*e(n-1)+K2*e(n-2)
where
K0=Ki*T+Kp+Kd/T
K1=-Kp-2*Kd/T
K2=Kd/T
So if I know K0,K1,K2 and T I can calculate Ki, Kp and Kd but why? Usually one starts with Ki,Kp, and Kd then calculates K0, K1, K2.
Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com
http://forum.deltamotion.com/
RE: Transfer Function from Difference Equations
RE: Transfer Function from Difference Equations