A first-order system G(s) = 10/(s + 5) receives a step input of size 10 at t = 0, starting from rest. Find the final value y(∞) of the output.
Step response worksheet with answers
A step is applied to a first-order process at t = 0. The output starts at 0 and settles at 5. At t = 10 s it reads 4.5. Find the time constant τ.
A system has the transfer function G(s) = 50/(s² + 6s + 25) and receives a unit step input. Find the 2 % settling time ts of the step response, using ts ≈ 4/(ζωₙ).
A system has the transfer function G(s) = 69/(s² + 13s + 69) and receives a unit step input. Find the damping ratio ζ.
A mass m = 8 kg hangs on a spring k = 200 N/m with a viscous damper c = 24 N·s/m (m·x″ + c·x′ + k·x = F). At rest in equilibrium, a constant force F = 25 N is suddenly applied. Find the largest displacement xmax in mm.
A unity negative feedback loop has G(s) = 200/(s(s + 20)). Find the 2 % settling time ts of the closed-loop step response, using ts ≈ 4/(ζωₙ).
Answer key
- 1. y(∞) = 20
- 2. τ = 4.343 s
- 3. ts = 1.333 s
- 4. ζ = 0.7825
- 5. xmax = 171.5 mm
- 6. ts = 0.4 s
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