Materials testing requires the design of control systems that can faithfully reproduce normal specimen operating environments over a range of specimen parameters [23]. From the control system design viewpoint, a materials-testing machine system can be considered a servomechanism in which we want to have the load waveform track the reference signal. The system is shown in Figure P10.13.
(a) Determine the phase margin of the system with Gc(s) = K, choosing K so that a phase margin of 50° is achieved. Determine the system bandwidth for this design.
(b) The additional requirement introduced is that the velocity constant Kr be equal to 2.0. Design a lag network so that the phase margin is 50° and Kv = 2.

Controller Process RUs) elerence -G,(s) - 4 s (s +s 2) waveform