Consider the second-order system
+2ζωn+ωn
2
with initial conditions y(0) = y0,
(0) = 0. Introduce state variables x1=y, x2=. Phase plots for an underdamped (ζ = 0.25), critically damped (ζ = 1), and overdamped (ζ = 2) case with ωn
= 1 rad/s and y0
= 1 are shown in Figure:
a. Plot a histogram for the distance from the initial point x1(0) = 1, x2(0) = 0 to the steadystate equilibrium point x1(∞) = 0, x2(∞) = 0 along the trajectories in state space if the damping ratio is uniformly distributed between 0 and 2. Note that the distance from the initial point (1,0) to the point [x1(t), x2(t)] along the trajectory is given by
(i) Repeat part (a) for the case where ζ = 0.25, and the natural frequency ωn
is uniformly distributed between 0 and 100 rad/s.
(ii) Repeat part (a) for the case where ζ = 1, and the natural frequency ωn is uniformly distributed between 0 and 12.5 rad/s.
(iii) Repeat part (a) for the case where ζ ~ U(0, 2), ωn
~ U(0, 100), and y0
~ U(0, 1).