  Complex manipulation tasks require careful integration of symbolic reasoning
and motion planning. This problem, commonly referred to as Task and Motion
Planning (TAMP), is even more challenging if the workspace is non-static, e.g.
due to human interventions and perceived with noisy non-ideal sensors. This
work proposes an online approximated TAMP method that combines a geometric
reasoning module and a motion planner with a standard task planner in a
receding horizon fashion. Our approach iteratively solves a reduced planning
problem over a receding window of a limited number of future actions during the
implementation of the actions. Thus, only the first action of the horizon is
actually scheduled at each iteration, then the window is moved forward, and the
problem is solved again. This procedure allows to naturally take into account
potential changes in the scene while ensuring good runtime performance. We
validate our approach within extensive experiments in a simulated environment.
We showed that our approach is able to deal with unexpected changes in the
environment while ensuring comparable performance with respect to other recent
TAMP approaches in solving traditional static benchmarks. We release with this
paper the open-source implementation of our method.
