Contact prediction and reasoning for compliant robot motions

A method for interpreting the measured contact forces during compliant robot motions using kinematic screws is presented. Domain-specific rules combined with partial a priori knowledge of mating parts geometry and interpreted force signals are used to reason and make inferences about the initial contact configuration. The likely contact surfaces are predicted and point(s) or line(s) of contact are fully defined. These surfaces are idealized and represented by quadratic equations or polyhedral surfaces. The geometric properties of surfaces at the contact location are used to select the contact configuration when multiple solutions exist. The developed methodology has been validated experimentally using a 6R manipulator, six-axis force sensor, and host computer