Design and implementation of a multi-sensor robot system for printed circuit board insertion

The authors present the design and implementation of a robot system equipped with multiple sensors. The robotic assembly system couples the task sequence of the robot with information from different sensors, enabling the system to handle uncertainties encountered during task execution. The target task involves the insertion of a printed circuit board into a card cage. The sensors used are an overhead three-dimensional vision system, a fingertip cross-fire sensor, and a six-degree-of-freedom force/torque sensor. The vision system is used to locate the printed circuit boards and the insertion slots. Information provided by the cross-fire sensor is used to complement the information from the vision system in order to obtain a proper grasping location on the printed circuit board. A fuzzy-logic-based system is used to interpret the forces and torques generated by the force/torque sensor during the insertion process. Using a fuzzy controller, an experiment is presented which successfully inserts printed circuit boards into target insertion slots. The repeated success of this assembly task over many trials verifies the modeling and controller assumptions made by fuzzy set theory