Control strategies for fine positioning via tapping

There are many industrial tasks that require fine positioning, for example: parts feeding, subassembly alignment, and certain inspection tasks. In this paper, we describe an approach to positioning parts or subassemblies on a support surface by tapping them. We have built a "positioning cell" where an object placed in this cell is positioned and oriented by a number of "tapping actuators" placed about the perimeter. When fired, a tapping actuator strikes the object producing translational and rotational velocities. The object then slides and comes to rest due to friction. An overhead camera provides feedback on the part configuration. This paper presents a control strategy for this task, describes our hardware, and shows our experimental results.