Methods and hints to linearise the resistance values vs. bending angle relationship of bend sensors

摘要

The correct measure of static and dynamic postures ofudpatients is a fundamental element for dispensing correctudrehabilitation procedures. Nowadays there are different sensorsudand transducers useful to reach the aim of measuring humanudpostures, even in a non uncomfortable way, during normaludactivities of everyday life. Among all these sensors we selected theudflex ones stand their cheapness an good performances in terms ofudreliability and stability of electrical signal they provide. It isudpossible to measure flex-extension of human joints simply layingudthe flex sensors on wrist, knee, elbow, ankle, etc. But a drawbackudis paid for these sensors, because of a non linear function of theirudelectrical resistance variation vs. bending angle. The non linearityudinvolves a time consuming calibration, more complexity of theudconditioning electronics, more troubles for drift problems andudthe issue to establish the best fit algorithm. So here we proposeudmethodologies and hints to linearise the sensor’s electricaludfunction.