A dynamic approach to high-precision parts mating

A method for the mating of tightly fitting parts in the presence of significant sensing, model, and control uncertainties is presented. Using this method randomly placed parts that were located using a three-dimensional laser range scanning system can be mated even when the clearance between them is only 0.001 in. The various sources of error introduced in the fine forced-guided motions used to execute assemblies are examined. Among these sources are noisy force/torque readings, mechanical vibrations, the presence of sliding and sticking frictions, and the possibility of eccentric oblique impacts. It is pointed out how most of these errors might be reduced or eliminated. Straight-line motion goals (SLMGs) are then processed by the basic building blocks of a dynamic planning strategy. By dynamically building an assembly plan out of SLMGs, it is possible to carry out robotic assemblies in the presence of sensing and model uncertainties while recognizing and recovering from errors introduced by control uncertainties. A specific instance of this approach is outlined