A step is applied to a first-order process at t = 0. The output starts at 0 and settles at 20. At t = 10 s it reads 16. Find the time constant τ.
Step response worksheet with answers
A first-order system G(s) = 1/(0.2s + 1) receives a step input of size 20 at t = 0, starting from rest. Find the final value y(∞) of the output.
A system has the transfer function G(s) = 116/(s² + 12s + 58) 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) = 24/(s² + 3s + 24) and receives a unit step input. Find the natural frequency ωn in rad/s.
A mass m = 10 kg hangs on a spring k = 100 N/m with a viscous damper c = 38 N·s/m (m·x″ + c·x′ + k·x = F). At rest in equilibrium, a constant force F = 100 N is suddenly applied. Find the largest displacement xmax in mm.
The step response of a second-order system without zeros shows 15 % overshoot, and the first peak occurs at t = 0.5 s. Find the natural frequency ωn.
Answer key
- 1. τ = 6.213 s
- 2. y(∞) = 20
- 3. ts = 0.6667 s
- 4. ωn = 4.899 rad/s
- 5. xmax = 1094 mm
- 6. ωn = 7.34 rad/s
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