A Study of Graspless Manipulation

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In this research, we propose 'graspless manipulation, ' a new concept of robot manipulation. In human manipulation, you don't grasp an object rigidly. You move the object dexterously by pushing, tumbling, and so on. In this manipulation, an environment, like a table or a floor, supports almost all weight of the object. We apply such a dexterous manipulation to robot manipulation.1.Introduction of graspless manipulationFirst, we define a graspless manipulation as a manipulation using a contact with an environment. Then we show that, in the view of the contact status with environment, graspless manipulation is divided to three types, pushing, tumbling, and pivoting. These three graspless manipulation method have various different characteristics. For example, in movement speed, or, moving minute distance, etc. Then, you can combine three types to achieve various manipulation tasks.2.Graspless manipulation referring to human methodThere exists a closed loop link mechanism, 'manipulator--object--environment' in graspless manipulation. To cope with this loop, we don't use a force control method, but propose two position control based method refering to human method. One is a method using free joint to absorb position error. The other is a method using a movable space of a geometric constraint by rigid fingers and environment.3.Graspless manipulation with visual feedbackIn graspless manipulation, manipulator doesn't grasp an oject rigidly. Then the position and posture of the object can't be calculated from that of the manipulator, and the object can't move acorrding to estimation because of uncertainty of friction. We use a hand-eye system to counter these problems. We use visual observation to tracking the object and to recognize a behavior of the object to classify some events. And then we have experiment with this hand-eye system to manipulate an object only by one finger.