Abstract
Cooperating multiple robots may experience slips between their end-effectors and the object when they make no rigid grasps, as is the case of manipulating fingers. Consequently, these slips make the system unable to execute a job properly and can even cause a failure of control. Slip can be avoided by defining multiple constraints of grasping forces and usable workspace, but these constraints limit the use of a robotic system. Research on finger grasps have assumed no slip but, in contrast, this paper takes it as the main topic. The slip phenomenon is analyzed and generalized for a planar multiple robot system, manipulating a geometrically regular-shaped object. Different slip configurations are introduced and methods for their detection are proposed. This detection considers no sensors for the object's posture, but rather uses only finger-tip position information. Consequently, it is possible to realize exact manipulation of an object and stability of control with minimal sensors. (Author)