A Bezier based state calibrating method for low-cost potentiometer with inherent nonlinearity

Abstract

The potentiometer is a widely used low-cost position sensor in robot and medical instruments. The measuring accuracy of the potentiometer could be greatly affected by its inherently nonlinearity due to the manufacturing error. In this study, a rational Bezier Calibration Method (BCM) and rational Bezier based State Calibrating Method (BSCM) have been presented for calibrating the inherent nonlinearity of the low-cost potentiometer. The effectiveness of the BCM and BSCM has been verified through experimental tests. Experimental results reveal that in calibrating the potentiometer’s inherent nonlinearity, the BCM have the advantage to reduce the calibration model order when compared with the most widely used polynomial calibration method (PCM). Lower ordered model could reduce the computing cost and benefit for the real time calibration stability. The BSCM could further reduce the error resulted by the reciprocating motion of the potentiometer during the measurements and achieve a better nonlinearity calibrating performance than BCM.