A Novel Calibration Device for Large-Deformation Six-Axis Force Sensors and Evaluation of Error Factors

In fields such as medical rehabilitation and wearable devices, large-deformation six-axis force sensors have received more and more attention. Meanwhile, calibration devices suitable for large-deformation six-axis force sensors have yet to be reported. This study proposed a calibration device suitable for large-deformation six-axis force sensors, with the loading position automatically adjusted during the calibration process when there is a large deformation, ensuring that the calibration sensor's loading direction and the force arm remain unchanged. The coupling generated by the loading force may be eliminated. The impacts of error sources such as force application direction deviation, rope weight, bearing friction, and weight mass on calibration accuracy and crosstalk error are evaluated. When compared to the existing calibration device suitable for high-stiffness six-axis force sensors, the proposed calibration device reduces type I (static nonlinearity rate) and type II (static coupling rate) errors by 61.61% and 87.71%, respectively. This study addresses the challenges of accurate calibrating large deformation six-axis force sensors.