A step is applied to a first-order process at t = 0. The output starts at 0 and settles at 20. At t = 3 s it reads 12. Find the time constant τ.
Step response worksheet with answers
A first-order system G(s) = 2/(0.8s + 1) receives a step input of size 1 at t = 0, starting from rest. Find the final value y(∞) of the output.
A system has the transfer function G(s) = 15.5/(s² + 5s + 31) and receives a unit step input. Find the peak time tp of the step response.
A system has the transfer function G(s) = 15/(s² + 5s + 15) and receives a unit step input. The poles are s = σ ± jωd. Find the real part σ.
A series RLC circuit with R = 41 Ω, L = 500 mH and C = 47 µF is connected to a 5 V step at t = 0. The capacitor is uncharged and no current flows before the step. Find the time tp of the first voltage peak, in ms.
A mass m = 20 kg hangs on a spring k = 2000 N/m with a viscous damper c = 240 N·s/m (m·x″ + c·x′ + k·x = F). At rest in equilibrium, a constant force F = 50 N is suddenly applied. Find the damping ratio ζ.
Answer key
- 1. τ = 3.274 s
- 2. y(∞) = 2
- 3. tp = 0.6315 s
- 4. σ = −2.5
- 5. tp = 15.54 ms
- 6. ζ = 0.6
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