Simulink/Differential Equation question with unit step inputs

Was wondering if I could get some help solving this HW question. Consider the following differential equation with 2 inputs (u1 and u2) and one output(y) y¨+ 2y˙ + y = 3u1 - u2 Set u1 to be a unit step input acting from t = 1 and u2 a unit step input acting from t = 2. Prepare a Simulink diagram to plot the response of y to these inputs for t = 0 to t = 5, starting with zero initial conditions (find a transfer function from v = 3u1 - u2 to y and use a summing node at the input.

I derived the transfer function as 1/s^2+2s+1 but how do I put it into simulink.

Answer 1

[Azzi Abdelmalek]

Use a transfer function block from simulink/continuous, and set Numerator and Denominator block:

 N=[1]
 D=[1 2 1]

If you want your step signal to start at 1 sec set it's step time at 1