A step is applied to a first-order process at t = 0. The output starts at 0 and settles at 8. At t = 0.5 s it reads 5.6. Find the time constant τ.
Step response worksheet with answers
A first-order system G(s) = 4/(4s + 1) receives a step input of size 2 at t = 0, starting from rest. How long does the output take to reach 99 % of its final value? Find t.
A system has the transfer function G(s) = 146/(s² + 10s + 73) and receives a unit step input. The poles are s = σ ± jωd. Find the real part σ.
A system has the transfer function G(s) = 57/(s² + 9s + 57) and receives a unit step input. Find the peak time tp of the step response.
A unity negative feedback loop has G(s) = 85/(s(s + 8)). Find the 2 % settling time ts of the closed-loop step response, using ts ≈ 4/(ζωₙ).
The step response of a second-order system without zeros shows 20 % overshoot, and the first peak occurs at t = 0.1 s. Find the natural frequency ωn.
Answer key
- 1. τ = 0.4153 s
- 2. t = 18.42 s
- 3. σ = −5
- 4. tp = 0.5182 s
- 5. ts = 1 s
- 6. ωn = 35.3 rad/s
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