Practical motion planning with visual constraints

The success of an autonomous assembly task relies on a motion planning system to generate a plan to accomplish the task, and on a sensor-based robot control system to ensure successful execution of the plan. The decoupling of sensor-based robot control from motion planning may yield undesirable motion plans that do not utilize the sensing effectively or consider sensor constraints. For example, a feasible collision-free path may be hard to traverse in practice because of inadequate sensor feedback in certain regions under uncertainty and sensor limitations. In this paper we consider an approach for motion planning that incorporates visual servoing constraints into the computation of the motion plans. The approach extends the notion of configuration space to include the corresponding sensor values. We propose a hierarchical representation of the high dimensional planning space involved, and a multistrategic heuristics search. This results in a practical motion planning scheme that is proven to be resolution-complete. Performance results are described for several robot manipulators with up to 6-DOF and under various sensing constraints.