Servo system, basic

In our examples, we will take Gm = Ga = 1, and use a servo system with L = 0 to highlight the basic ideas. The algebra tends to be more tractable in this simplified unity feedback system with only Gc and Gp (Fig. 5.6), and the closed-loop transfer function is... 

Significant technological development and research on accuracy and waste disposal make today s ECM technique a better choice than many other nonconventional as well as conventional techniques. Control of ECM process is improving all the time, with more sophisticated servo systems. However, there is still a need for basic information on electrode phenomenon at both high current densities and electrolyte flow rates [2]. Some of the improvements in ECM process have mentioned below ... 

To obtain rapid and accurate motion control, servo systems employ the same basic principle just outlined, the principle of feedback. By measuring the output (usually the position or velocity of the motor) and feeding it back to the input, the performance can be improved. This output measurement is often subtracted... 

There are two basic types of specifications commonly used in the frequency domain. The first type, phase margin and gain margin, specifies how near the openloop GM iu)Gc ia)) polar plot is to the critical (- 1,0) point. The second type, maximum closedloop log modulus, specifies the height of the resonant peak on the log modulus Bode plot of the closedloop servo transfer function. So keep the apples and the oranges straight. We make openloop transfer function plots and look at the (- 1, 0) point. We make closedloop servo transfer function plots and look at the peak in the log modulus curve (indicating an underdamped system). But in both cases we are concerned with closedloop stability. 

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