Tactile measurement with a GelSight sensor

Abstract

This thesis introduces a method of measuring contact force with GelSight. GelSight is an optical-based tactile sensor that uses a piece of coated elastomer as the contact medium. A camera records the distortion of the elastomer during contact. This sensor can obtain a high-resolution view of the contact surface geometry, which is a breakthrough for artificial tactile sensors. In this thesis, I will introduce my work on trying to measure the contact force with GelSight. This work is based on adding markers to the elastomer surface and using them to track the planar deformation field of the elastomer surface. I derive a quantitative relationship between the surface's planar deformation field and the external contact force. I describe the development of a finite element model of the elastomer as well as the experiments on a bench-top and a portable GelSight devices. The experiments show that the contact force and the deformation field are closely related, and indicate that the method is effective in inferring the contact state under realistic conditions.