Abstract
A planning method for linear object manipulation including knotting/unknotting in the three-dimensional space is proposed. Firstly, topological states of a linear object are represented as sequences of crossing points including the crossing type at each crossing point. Secondly, transitions among crossing states are defined. They correspond to operations that change the number of crossing points or permute their sequence. Then, we can generate possible sequences of crossing state transitions, that is, possible manipulation processes from the initial state to a given objective state. Thirdly, a method for determination of actions, that is, grasping points and their moving direction, is proposed in order to realize derived manipulation processes. Furthermore, criteria for evaluation of manipulation processes are introduced in order to reduce the candidates of manipulation plans. Finally, it is demonstrated that our developed system based on the above method can generate and execute manipulation plans for untying an overhand knot.
