Novel Calibration Methodologies for Compliant, Multiaxis, Fiber-Optic-Based Force/Torque Sensors

In this article, we present a number of novel calibration methodologies for compliant, multiaxis, fiber-optic-based force/torque sensors and evaluate the performance of these methods in real-time experiments with our custom-designed sensors. These methods address the challenges arising from the complex dynamic behavior of a compliant sensor and the nonlinearities in the force-deflection relationship. This article also investigates compliant sensor performance against its response characteristics, such as the impact of compliance on the sensor's bandwidth using dynamic modeling and identification process. A powerful hysteresis compensation solution using a dynamic estimation model is also presented. Furthermore, we propose and apply a new calibration strategy building on the combination of a linear dynamic model combined with a static nonlinear model. This includes a state space (SS) model with Gaussian Process Regression (GPR) model named SSGPR. The results achieved from the proposed calibration method have revealed an improvement from an R-squared value of 93.86%-100% when compared to data obtained using a linear dynamic model.