Old spec 4.6 exerciseExercise sheetCurrent spec2:28 min

ENGR202 (old spec) Control 4.6 Derivative and Velocity, exercise

Draw the block diagram for velocity feedback (instead of derivative action) applied to the second order plant, and use the block diagram to derive the Closed Loop Transfer Function.

X(s)=ωn2s2+2ζωns+ωn2U(s)u(t)=d(t)−kvdx(t)dtX(s) = \frac{\omega_n^2}{s^2 + 2\zeta\omega_n s + \omega_n^2}U(s) \qquad u(t) = d(t) - k_v\frac{dx(t)}{dt}

Formulas you may need
  • Negative feedback rule: G11+G1G2\dfrac{G_1}{1 + G_1 G_2} (learn this)
  • Velocity feedback: u(t)=d(t)−kvdxdtu(t) = d(t) - k_v\dfrac{dx}{dt}, i.e. U=D−kvsXU = D - k_v sX (given in the question)
  • Generalised second order form s2+2ζωns+ωn2s^2 + 2\zeta\omega_n s + \omega_n^2 (learn this)