Variational approach for singularity-free path-planning of parallel manipulators

This paper addresses the problem of singularity-free path-planning for parallel manipulators. Unlike in serial manipulators, where there are only boundary singularities, parallel manipulators also possess singular configurations within the workspace where the manipulators are uncontrollable. Therefore, it is imperative that the generated paths are singularity-free. In this paper, we use a variational approach for planning singularity-free paths for parallel manipulators, based on a Lagrangian incorporating both a kinetic energy term which keeps the path short, and a potential energy term which ensures that the obtained path is singularity-free and the actuator lengths remain within their prescribed limits. The approach is applied to several parallel manipulators to evaluate the performance of this method.