Date: Feb 6, 2013 4:31 AM
Author: Ahmed Hakim
Subject: DC Motor PID control

Hello

I am trying to bulid a DC motor model with PID controller

I already build the model and when I tried to design the PID controller using MATLAB 2012 PID tune I got a PID controller with 4 paramters

P I D and N
with the following formula 
P (1 + I(1/s) + D (N /1+N/S))


I run the simulation with the PID (tuned by MATLAB) and it gives uper results

but
when I used this formula P (1 + I(1/s) + D (N /1+N/S)) and implement  it by myself as a model with P I D and N gains (tuned)
I got strange results

can anybody help?

why different results?
Do MATLAB uses something else not only this formula with these paramters