A skilled and intelligent paper roll manipulator

A general description of a control system for a prototype of an intelligent and skilled paper roll manipulator (PRM) is given. The elementary operations related to both manipulations and environment observations are described, and integrating these with a hierarchically organized planning-executing-monitoring architecture (PEM) is discussed. The kernel of PEM architecture is a goal-oriented module consisting of these three principal parts. The motion control of the paper roll manipulator is divided into free motion (gross motion) and force-constrained motion (fine motion) phases. Gross motion control takes the paper roll from the starting position to the vicinity of the goal position, whereas the fine motion control is used in placing the paper roll against other paper rolls and the support. For coarse recognition of the environment a 3D laser device is used. The accurate position of paper rolls in the picking phases is measured with the aid of an ultrasonic sensor system, and the final force constrained placement is carried out with force sensing based on measurements of hydraulic pressures of the manipulator system.