A Detection Error Correction Scheme Aiming at Gradient Nonlinear Problem in Cantilever Based Sensors

Gradient nonlinear problem is generated when cantilever based sensors are applied to the gradient field. The larger the amplitude of cantilever is (that is, the larger the positional change of the free end of cantilever in the gradient field is), the more serious gradient nonlinear problem is. As for a piezoelectric cantilever based current sensor, a higher sensitivity can be obtained by a greater amplitude which intensifies the gradient nonlinear problem that may decrease the detection accuracy. In this study, a detection error correction scheme aiming at gradient nonlinear problem is proposed for the first time. The distance between appliance and cantilever can be regarded as a variable with the scheme. The nonlinear error can be decreased to lower than 10% in the detection range from 2A to 7A based on a piezoelectric cantilever current sensor in the experiment results. Furthermore, the scheme is not only applicable to the gradient magnetic field, but also has implications for the nonlinear problems of other gradient fields and vibration structures.