Determine the frequency at which the gain has unit magnitude and compute the phase angle at that frequency:
In Problems 9 and 10, consider the feedback system in Figure 8.55 with the loop transfer function
Problems 9
Sketch the logarithmic-magnitude versus phase angle curves for the transfer functions (a) and (b) of Problem P8.1.
Problem P8.1
Sketch the polar plot of the frequency response for the following loop transfer functions:
Problems 10
A linear actuator is used in the system shown in Figure P8.10 to position a mass M. The actual position of the mass is measured by a slide wire resistor, and thus H(s) = 1.0. The amplifier gain is selected so that the steady-state error of the system is less than 1 % of the magnitude of the position reference R(s). The actuator has a field coil with a resistance Rf = 0.1 Ω.
