Ann based intelligent pressure sensor in noisy environment

Abstract

There are so many problems that arise due to nonlinearity, direct digital readout is one of them i.e. with the help of such devices taking the direct digital readout is not possible. Therefore we are bound to operate the instrument in their linear range of the characteristics only ,in other words we can say that the usable range of the instrument is getting restricted due to this problem. not only the usable range ,but also the accuracy of the instrument is affected if we are not able to use the full range of the instrument. One more factor important to mention is the variation of nonlinearity from instrument to instrument place to place and time to time ,sometimes it depends on some uncertain factors which are not possible to predict. Here capacitive pressure sensor(CPS) is the topic of discussion for adaptive linearization. We can introduce an intelligent inverse model in series with the nonlinear instrument or a sensor to reduce the nonlinearity present there. A switched capacitor circuit (SCC) is used to convert the change in capacitance of the CPS. Because of the change in applied pressure the capacitance of the CPS changes, this change in capacitance of the CPS due to applied pressure is converted into proportional voltage which can then be applied to an ANN model to estimate the pressure applied. This model gives satisfactory performance for wide temperature range (-20 to 70 ) and signal to noise ratio of 40 dB and above.