A Novel 6-axis Force/Torque Sensor Using Inductance Sensors

TL;DR

This paper introduces a compact, non-contact six-axis force/torque sensor based on inductive sensing, featuring integrated high-speed signal processing, high accuracy, and suitability for precision robotic applications.

Contribution

It presents a novel inductive sensing-based F/T sensor with integrated PCB processing, achieving high accuracy, high resolution, and robust performance, surpassing conventional sensors.

Findings

Achieved a resolution of 0.03 N and over 55,000 quantization levels.

Demonstrated superior calibration accuracy with rational function fitting.

Validated low crosstalk and high sensitivity through experiments.

Abstract

This paper presents a novel six-axis force/torque (F/T) sensor based on inductive sensing technology. Unlike conventional strain gauge-based sensors that require direct contact and external amplification, the proposed sensor utilizes non-contact inductive measurements to estimate force via displacement of a conductive target. A compact, fully integrated architecture is achieved by incorporating a CAN-FD based signal processing module directly onto the PCB, enabling high-speed data acquisition at up to 4~kHz without external DAQ systems. The sensing mechanism is modeled and calibrated through a rational function fitting approach, which demonstrated superior performance in terms of root mean square error (RMSE), coefficient of determination ($R^2$), and linearity error compared to other nonlinear models. Static and repeatability experiments validate the sensor's accuracy, achieving a resolution of 0.03~N and quantization levels exceeding 55,000 steps, surpassing that of commercial sensors. The sensor also exhibits low crosstalk, high sensitivity, and robust noise characteristics. Its performance and structure make it suitable for precision robotic applications, especially in scenarios where compactness, non-contact operation, and integrated processing are essential.