A first-order system G(s) = 1/(s + 1) receives a step input of size 1 at t = 0, starting from rest. Find the final value y(∞) of the output.
Step response worksheet with answers
1.Easy
G(s) = 1/(s + 1)U = 1
y(∞) =
2.Easy
A first-order system G(s) = 0.5/(s + 1) receives a step input of size 5 at t = 0, starting from rest. Find the final value y(∞) of the output.
G(s) = 0.5/(s + 1)U = 5
y(∞) =
3.Medium
A system has the transfer function G(s) = 2.5/(s² + 2s + 5) and receives a unit step input. Find the percent overshoot %OS of the step response.
G(s) = 2.5/(s² + 2s + 5)
%OS = %
4.Medium
A system has the transfer function G(s) = 36/(s² + 8s + 72) and receives a unit step input. Find the peak time tp of the step response.
G(s) = 36/(s² + 8s + 72)
tp = s
5.Hard
A second-order system without zeros must have a step response with 50 % overshoot. Find the damping ratio ζ.
%OS = 50 %
ζ =
6.Hard
A unity negative feedback loop has G(s) = 155/(s(s + 4)). Find the 2 % settling time ts of the closed-loop step response, using ts ≈ 4/(ζωₙ).
G(s) = 155/(s(s + 4))
ts = s
Answer key
- 1. y(∞) = 1
- 2. y(∞) = 2.5
- 3. %OS = 20.79 %
- 4. tp = 0.4198 s
- 5. ζ = 0.2155
- 6. ts = 2 s
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