Performance analysis of the sliding mode—based analog differentiator and dynamical compensator
The SM principle can be used to derive the input signal of a certain relatively low-order dynamical system from its output. This operation is equivalent to applying the reciprocal of the transfer function of this dynamical system to the output, which can be viewed as the transfer function “inversion.” This is closely related to the problems of state observation and signal differentiation. In that respect, we analyze two devices: the SM differentiator and the SM compensator of sensor dynamics.
Obtaining the derivative of a signal is done with devices called differentiators which can be implemented either in hardware or software. Signal differentiation is a very important practical problem, since using a differentiator is normally a much cheaper option than using a sensor or a transmitter for obtaining variables such as velocity and rate of change. However, practical realizations of various differentiators reveal some fundamental limitations and drawbacks, such as the presence of time delay (or lag) and sensitivity to noise. Most of the efforts by designers of differentiators are aimed at mitigating these drawbacks.
KeywordsTransfer Function Equivalent Control Sensor Dynamic Utility Boiler Important Practical Problem
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