Development of a robot skin with Human finger like softness capable of object location sensing and slip phase isolating

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The study concern development of a robot skin which is capable of accurately sensing the contact location of an object as well as securely isolating slip phases of an object in contact with the skin surface, taking advantage of the soft skin surface made of silicon gel and rubber. In the first study of contact object location sensing, we propose the structure of the robot skin with 25 of tiny reflector chips arranged in a matrix form on the skin surface, the principle of the location sensing ; both optically detecting the positions of the reflector chips which corresponds to the deformation of the skin surface of gel being pressed by an object and fitting the planes of the object from the deformation data assuming the object to be a convex polygon. The robot skin is characterized by that the skin surface is low cost and easily replacable, and the sensing performance is robust against any electromagnetic disturbance. We conducted some experiments for verifying the above principles as we … More ll as accurately detecting the position of the relfector chip from which the covariance matrix of detection errors was computer, and sensing the location of a wedge-shaped object. For evaluating the accuracy of the location sensing, we compared two methods of fitting both each object plane independently and all planes simultaneously using a Lagrangian multiplier under geometrical constraints. The second Lagrangian fitting method exhibited more accurate estimation results.On the other hand, the second part of the study concerns a vibrotactile sensor capable of generating impulsive high-frequency signals for exclusively distinguishing a slip phase from various other contact phases. We propose the structure of the vibotactile sensor with surface ridges and after analyzing the slip signals, conclude that the output signal originates in the free vibration of the ridge. By using a two-fingered robot hand with the sensor attached to its compliant endtips, we verify that the vibrotactile sensor has a slip phase isolating function and demonstrate object regrip control in real time.Finally, we made an attempt to integrating the above two sensing schemes on a soft robot skin made of gel material which both sensor structures were mounted on. Less