جبران هوشمند اثرات تغيير دما بر سنسورهاي اختلاف فشار خازني

چكيده انگليسي :

Intelligent Compensation of Temperature Influences on Capacitive Differential Pressure Sensors Amin Salighehdar salighehdar@ec iut ac ir Date of Submission May 5 2009 Department of Electrical and computer engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisors Jafar Ghaisari ghaisari@cc iut ac irAbstractSensors are widely used in industrial processes automobiles robotics avionics and othersystems to monitor and control the system behavior Besides the use of precise accurateand low power sensors has recently emerged in many sensor network applications Capacitive Sensors because of their high sensitivity and low power consumption areextensively used in various applications to measure pressure force position speed acceleration liquid level dielectric properties and flow of material However one of thedrawbacks of capacitive sensor is the relative small change in capacitance of the sensordue to applied pressure is small compared to the offset capacitance and its responsecharacteristics is highly nonlinear Another problem associated in general with allsensors is that their response characteristics are influenced by the disturbingenvironmental parameters e g temperature humidity and pollution For example in thecase of capacitive pressure sensor CPS its response depends not only on the appliedpressure that also on the environmental temperature This problem becomes severe especially when the capacitive sensor is operated in a harsh environment wheretemperature variation is large Usually an exact mathematical model of a sensor showingthe relationship between the measured and its response and the dependency of sensoroutput on environmental parameters is not available Furthermore since most sensorsexhibit some degrees of nonlinear response characteristics and the environmentalparameters influence the sensor behavior nonlinearly the problem of obtaining anaccurate readout and its calibration becomes highly complex Some of the ideal propertiesof a sensor include linear response characteristics auto correction for the adverse effectsof nonlinear environmental parameters high sensitivity and accuracy and low powerconsumption However in practical situation it is not easy to achieve ideal sensorcharacteristics especially when the sensor is operating in a harsh environment The mainobjective of this research is to design an intelligent compensator which is capable ofcompensating adverse effect of environment temperature on cps for this purpose in thisresearch we design a benchmark which models the real condition that cps operates in Thetemperature of this system in varied in each constant temperature a differential pressureis applied to cps and out pit of cps is recorded This process is being kept on for eachseparate temperature By gathering these data an artificial neural network is being trainedto learn dependency of cps behavior to ambient temperature After that this compensatoris able to provide true differential pressure Besides in this research we proposed anintelligent compensator by using look up table based on adaptive neural fuzzy systems The effectiveness of these methods is tested by extensive simulations

سليقه دار، امين

جبران هوشمند اثرات تغيير دما بر سنسورهاي اختلاف فشار خازني

استنتاج عصبي فازي , شبكه هاي عصبي , شبكه تطبيقي