A numerical path-controlled machine turret lathe is an interesting problem in attaining sufficient accuracy [2, 23]. A block diagram of a turret lathe control system is shown in Figure P10.8. The gear ratio is n = 0.1. J - 10-3, and b - 10-2. It is necessary to attain an accuracy of 5 x 10-4 in., and therefore a steady-state position accuracy of 2.5% is specified for a ramp input. Design a cascade compensator to be inserted before the silicon-controlled rectifiers in order to provide a response to a step command with an overshoot of less than 5%. A suitable damping ratio for this system is 0.7. The gain of the silicon-controlled rectifiers is KR = 5. Design a suitable lag compensator by using the (a) Bode diagram method and (b) s-plane method.
