  In this paper, we propose a object detection method expressed as rotated
bounding box to solve grasping challenge in the scenes where rigid objects and
soft objects are mixed together. Compared with traditional detection methods,
this method can output the angle information of rotated objects and thus can
guarantee that within each rotated bounding box, there is a single instance.
This technology is especially useful in the case of pile of objects with
different orientations. In our method, when uncategorized objects with specific
geometry shapes (rectangle or cylinder) are detected, the program will conclude
that some rigid objects are covered by the towels. If no covered objects are
detected, the grasp planning is based on 3D point cloud obtained from the
mapping between 2D object detection result and its corresponding 3D point
cloud. Based on the information provided by the 3D bounding box covering the
object, grasping strategy for multiple cluttered rigid objects, collision
avoidance strategy are proposed. The proposed method is verified by the
experiment in which rigid objects and towels are mixed together.
