F-TOUCH Sensor for Three-Axis Forces Measurement and Geometry Observation

We present an innovative concept for a sensor design that can simultaneously measure multi-axis force information and acquire geometry information with the use of a vision-based technique. The sensor is named F-TOUCH (force and tactile optically unified coherent haptics) which is originally inspired by the GelSight tactile sensor. However, the GelSight tactile sensor uses numerous markers painted between the coating layer and the elastomer base, and it can not well generalize the force-related information from the GelSight images [1]. The F-TOUCH sensor is enhanced with a three-axis force measurement capability by virtue of an internal elastic structure placed underneath the entire elastomer layer, as well as using a conventional force sensor calibration method. The proposed sensor uses a camera to concurrently record the mechanical deformation of the elastic structure (for normal and shear forces measurement) and the surface distortion of the elastomer layer (for geometry observation). Results show that the F-TOUCH sensor is effective in generalizing the force-related information from the images and performing brilliant multi-axis force measurements (comparing with a commercial force sensor), as well as capturing the object's geometry at the same time.