  This paper develops a planner to find an optimal assembly sequence to
assemble several objects. The input to the planner is the mesh models of the
objects, the relative poses between the objects in the assembly, and the final
pose of the assembly. The output is an optimal assembly sequence, namely (1) in
which order should one assemble the objects, (2) from which directions should
the objects be dropped, and (3) candidate grasps of each object. The proposed
planner finds the optimal solution by automatically permuting, evaluating, and
searching the possible assembly sequences considering stability, graspability,
and assemblability qualities. It is expected to guide robots to do assembly
using translational motion. The output provides initial and goal configurations
to motion planning algorithms. It is ready to be used by robots and is
demonstrated using several simulations and real-world executions.
