Metholology to enlarge the workspace of parallel manipulators by means of non-singular transitions

Résumé

In this thesis the phenomenon known as assembly mode change is studied in depth. This phenomenon is related to the ability of some architectures of parallel manipulators to perform non-singular transitions between different solutions of the direct kinematic problem. Along these transitions the robot is able to move from one solution to another in a completely safe way. Knowing that one of the major drawbacks of parallel manipulators is their reduced workspace, it constitutes a desirable feature to have the capacity of changing between solutions, as the robot can enlarge its range of motion, resulting in a wider operational workspace.There exist different ways to accomplish these transitions. This thesis focuses mainly on those transitions that are performed when trajectories encircling cusp points of the singularity curves are made. The purpose is to exploit this cuspidality property such that the robot can move in the most effective manner. Moreover, a design procedure has been developed which includes the cuspidality property as one of the design criteria. The aim is to achieve a final design with an optimum operational workspace.