Identification of Hysteresis And Relaxation Parameters in Stretch Sensor TM

Stretch SensorTM developed by Images Scientific Instruments Inc, USA, is a unique polymer component that changes resistance when stretched. When sensor is stretched and released it exhibits hysteresis and large relaxation time. For identification of hysteresis and relaxation, Preisach model is a very well-known method. Experiments are carried out using tension tester and the experimental data is used for identification. Modified Preisach model is used for relaxation identification and the experimental data is discretized for analysis of relaxation. Identification is based on first reversal curve of major hysteresis loop and noise error of sensor. It has been observed that if sensor is used in pre-stretch conditions, relaxation time is reduced. Also more the iterations of stretch, hysteresis is reduced and sensor output error is also reduced. Hysteresis and relaxation time cannot be eliminated because they are inherent properties of polymer but can be compensated under specific conditions. Compensation is useful for calibration of the sensor