Geometrical Data Extraction Using Interaction Between Objects and Robotic Fingers Equipped with Three-axis Tactile Sensors

摘要

If humans want to know geometrical information about certain objects, we can pick them up, push them, pull them or turn them to learn the distance and relationship between the objects and us. Although this tactic is very effective for robots working in unknown environments, it has not always been applied to them because it requires sophisticated tactile sensors to obtain data from the interaction between robotic hands and their environment. On the other hand, we developed a robotic finger equipped with optical three-axis tactile sensors, of which the sensing cell can separately detect normal and shearing forces. A robotic hand equipped with such fingers can explore geometrical data through pushing-pulling, turning and picking up-placing motions as follows. It can acquire the contour of an object with a corrugated shape through scanning the surface with two fingers; it can learn a curved line to fit a cap contour through turning it, even if input finger trajectories are rectangular; it can place an object on a specified location with unknown height (z-coordinate) after measuring the x-y position of the location because it can detect upward slippage occurring between the object and fingers when the object bottom touches the location.