Development of Nontactile Compact Slip Sensor Using Grating Image

The problem of slip detection has to be explored so that an industrial robot may certainly grasp objects with the appropriate grasping force. Slip Sensors must be able to detect fine slip to be used for controlling grasping force. Slip sensors are classified into two types; tactile slip sensors and nontactile slip sensors. The tactile slip sensors must be pressed against the object surface. If the sensor is pressed with an insufficient force, it can't detect slip correctly. If the sensor is pressed with an excessive force, the object may be damaged. A method of nontactile slip detection have been proposed before. In this method, the sensor detects intensity of scattered light from an object surface at the position of fringes of the phenomenon of two-beam interference. In this paper, we describe development of a nontactile slip sensor using the method above mentioned. The slip sensor has features as follows; 1. NonTactile, 2. The fine slip can be detected by projecting a grating image on the object surface, 3. The sensor is miniaturized by using semiconductor laser and by assembling components of the sensor in one case.