Robot Tactile Sensing: Vision Based Tactile Sensor for Force Perception

Abstract

Tactile sensing is important for both humans and robots especially about force sensing. Although recently some successful tactile sensors have been designed, robot's is still underdeveloped, particularly about sensing multi-modal tactile information and reducing its price. There is a great demand for developing tactile sensors. When a robot exploring perform a complicated manipulation task such as grasping some fragile things, sensing of multi-axis force is important. In this paper, focusing on force sensing, we first develop a stereo vision based optical multi-modal sensor. This sensor consists of a soft skin with markers inserting it, and two RGB cameras. When external force applied to the sensor, the soft layer's deformation would cause movement of markers. A markers tracking algorithm is developed to get the displacement of the markers. A contact force field will be estimated by tracking markers in the soft skin. This sensor could be made with off-the-shelf materials. We make a prototype of this sensor and demonstrate its usefulness in force estimation.