Transfer Function: U(s) to Y(s): 2 Plants, D(s) Disturbance

[khedira]

U(s) is my input, Y(s) is the output. I have two plants, G1(s) and G2(s). Between these two plants, i have a disturbance input, D(s).

Am i right to say Y(s) = U(s)G1(s)G2(s) + G2(s)D(s)?

If that is the case, how can i get the overall transfer function Y(s)/U(s)? Please advise. Thank you.

 

[rock.freak667]

I believe if you move D(s) to the left, you will now have D(s)/G₁(s) in parallel with G₁(s) and G₂(s).

 

[khedira]

I believe if you move D(s) to the left, you will now have D(s)/G₁(s) in parallel with G₁(s) and G₂(s).

Hi rock.freak667,

sorry i don't get you. do you mean shift the disturbance D(s) to the left of G1(s) as in in the block diagram?

or do you mean the equation Y(s) - G2(s)D(s) = U(s)G1(s)G2(s)?

please advise. thank you.

 

[rock.freak667]

Hi rock.freak667,

sorry i don't get you. do you mean shift the disturbance D(s) to the left of G1(s) as in in the block diagram?.

Sorry I was not clearer, I meant shift the disturbance to the left of G₁(s) in the block diagram.