With disturbance D(s) Amplifier Coil Load R(s) Error V(s) K 1 Y(s) R+Ls s(Js+b) Sensor HS)=1 For unit step input: R(s)=1/s When D(s)=0 and H(s)=1 (S 1 R(s) 1+K,G(s)G2(s) Therefore me0=1中ka同With disturbance For unit step input: When and Therefore Rs s () 1  D s() 0  H s() 1  1 2 1 () () 1 () () a Es Rs KG sG s     0 1 2 1 1 lim lim 0 1 () () t s a et s   KG sG s s         