Characterizing the Resilience and Sensitivity of Polyurethane Vision-Based Tactile Sensors
This work addresses durability issues in tactile sensors for robots in rugged, high-load applications, but it is incremental as it focuses on material substitution rather than a fundamental breakthrough.
The study tackled the problem of vision-based tactile sensors (VBTSs) using silicone gels that deteriorate easily under load, by testing polyurethane rubber as an alternative material for improved resilience, finding that polyurethane yields a more robust sensor with increased effective force range, though it sacrifices sensitivity at low forces.
Vision-based tactile sensors (VBTSs) are a promising technology for robots, providing them with dense signals that can be translated into a multi-faceted understanding of contact. However, existing VBTS tactile surfaces make use of silicone gels, which provide high sensitivity but easily deteriorate from loading and surface wear. We propose that polyurethane rubber, a typically harder material used for high-load applications like shoe soles, rubber wheels, and industrial gaskets, may provide improved physical gel resilience, potentially at the cost of sensitivity. To compare the resilience and sensitivity of two polyurethane gel formulations against a common silicone baseline, we propose a series of repeatable characterization protocols. Our resilience tests assess sensor durability across normal loading, shear loading, and abrasion. For sensitivity, we introduce learning-free assessments of force and spatial sensitivity to directly measure the physical capabilities of each gel without effects introduced from data and model quality. We also include a bottle cap loosening and tightening demonstration to validate the results of our controlled tests with a real-world example. Our results show that polyurethane yields a more robust sensor. While it sacrifices sensitivity at low forces, the effective force range is largely increased, revealing the utility of polyurethane VBTSs over silicone versions in more rugged, high-load applications.