A low-cost voltage-to-current calibration technique for multiple-sensor systems

Systems with multiple sensors pose a problem of heterogeneity, i.e., different sensors have different outputs subject to the same excitation. To tackle this problem, this paper presents a calibration technique for multiple-sensor applications. An array of voltage-to-current converters, followed by a summing inverter, is employed to aggregate the responses of the system, which originated from heterogeneous sensors. The calibration method aims to normalize the output from each independent sensor, so that heterogeneity of the system, like positional error, could be reduced. The performance of the calibration technique had been tested by a prototype with multiple sensors, and the results were found to be satisfactory, which indicates that a reduction from 2% to 0.2% in positional error can be achieved. The proposed method can be implemented by adding only a minimal of passive components, which is suitable for cost-sensitive mass-production-type products.