Page 507 - Mechanical Engineers' Handbook (Volume 2)

498 Closed-Loop Control System Analysis

Figure 49 Saturation.

5. Repetitive operation at high speed: Solutions can be generated to repeat hundreds of
times per second.
6. Outputs can be displayed on an oscilloscope or plotted on coordinate paper or on
continuous recording equipment.

All these features make an analog computer a highly useful tool for design of control sys-
tems.

8.2 Digital Computation

An analog computer simultaneously solves all of the differential equations that model a
physical system, and continuous voltage signals represent the variables of interest. This
enables the machine to operate in real time. Significant disadvantages of analog simulation
are the high cost of the computer due to the multiplicity of elements with demanding per-
formance specifications, difficulties with scaling to avoid overloading of amplifiers, and rel-

Figure 50 On–off controller.