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

The correct measure of static and dynamic postures of patients is a fundamental element for dispensing correct rehabilitation procedures. Nowadays there are different sensors and transducers useful to reach the aim of measuring human postures, even in a non uncomfortable way, during normal activities of everyday life. Among all these sensors we selected the flex ones stand their cheapness an good performances in terms of reliability and stability of electrical signal they provide. It is possible to measure flex-extension of human joints simply laying the flex sensors on wrist, knee, elbow, ankle, etc. But a drawback is paid for these sensors, because of a non linear function of their electrical resistance variation vs. bending angle. The non linearity involves a time consuming calibration, more complexity of the conditioning electronics, more troubles for drift problems and the issue to establish the best fit algorithm. So here we propose methodologies and hints to linearise the sensor´s electrical function.