The amount of leftover moisture in a grain drying conveyor process can be controlled by varying the conveyor’s motor speed (Mansor, 2011). Although the process is highly variable, the transfer function at one of the operating points has been found to be

A unity feedback system will be built around this plant such as the one shown in Figure P11.1 to maintain grain moisture at specified levels. The specifications are: e_ss = 0 for a unit-step input; e_ss is half that of the uncompensated system for a ramp input; settling time = 500 seconds, and %OS = 13%. 

Since the system is Type 0, it must be augmented to a Type 1 using an integrator in order to achieve e_ss = 0 for a step input. In addition, a phase lead-lag compensator will be required to achieve the specifications. Simulate your design using a computer program.

0.0169s + 0.03558 -27s G(s) %3D 3.368s + 3.762s2 + 32.19s + 1