A Hybrid Capacitive-Strain F/T Sensor With Integrated Thermal-Humidity Compensation

Six-axis force/torque (6-F/T) sensors are widely used in various applications. However, existing commercial sensors encounter two major bottlenecks hindering their widespread use: High costs due to difficult automated manufacturing and reduced accuracy from temperature-humidity (T-H) fluctuations. To tackle these challenges, the study develops a novel 6-F/T sensor by combining the merits of capacitive and strain sensing. Six capacitor units and eight strain gauge units were designed and strategically positioned to improve measurement accuracy and facilitate automated production. A segmented calibration method is proposed, with dedicated calibration matrices established at four T-H nodes to mitigate environmental influences. Experiments confirmed the effectiveness of the proposed sensor, with linearity errors ranging from 1.24% to 2.29% across the six axes. Stable performance was maintained in various environments, showing full-scale relative errors of 3.16% to 4.63%. This sensor design features low cost, ease of mass production, and strong environmental adaptability, providing a feasible solution for the widespread application of 6-F/T sensors.