A fuzzy expert organizer/robust control strategy for moving base robotic assembly operations

In this paper, three analytical tasks, stability analysis, robust control, and fuzzy intelligent organizer for a moving base robot are introduced. These tools are necessary for a mobile robot to perform complex assembly or manufacturing tasks in an unstructured environment. A stability envelope based on the relations between the system´s mechanical energy and the stability relation is derived. A robust control algorithm is applied to the moving base robot that accounts for the dynamics of the composite system. A fuzzy intelligent organizing control strategy, based on a fuzzy rule-base and derived from measured force/moment data, for a robotic device performing quasi-static assembly tasks is presented. A modified distance metric is employed to measure the uncertainty (fuzziness) as it is related to specific control actions. A learning algorithm based on the probability of a fuzzy event is introduced. Experimental results show the effectiveness of the proposed approach. Finally, a hierarchical controller which consists of a higher level fuzzy expert organizer coordinating with a lower level robust controller is proposed.