A Tactile Sensor With Slippage Prediction by Unequal-Height Dome Array

Tactile sensors are essential to enable manipulators to perform complex tasks like human hands. Slippage prediction helps manipulators avoid dropping grasped objects. Here, we present a vision-based tactile sensor with an unequal-height dome array (UHDA) to predict slippage without the slippage occurring. The sum of each shading area and the sum of each area center displacements in the image are linear to the applied normal force and tangential force, respectively. The resolutions of the normal force and the tangential force can both reach 10 mN with maximum relative uncertainties of approximately 5.47% and 4.78%. Under a certain normal force, the small dome will be applied a smaller tangential force due to a more minor normal force component, causing them to slip earlier. The sliding time difference between the large and small domes can be utilized to realize slippage prediction subtly. Hence, this sensor is expected to help robots ensure safe contact and move objects safely in case of a possible collision.