TIME-OPTIMAL EXTENSION AND RETRACTION OF ROBOTS - NUMERICAL-ANALYSIS OF THE SWITCHING STRUCTURE

The problem of the time-optimal control of robot manipulators is of im portance because of its potential for increasing the productivity of a ssembly lines. This work is part of a series of papers by the authors on this topic using direct and indirect methods of optimization. A cyl indrical robot or a spherical polar robot constrained to the horizonta l plane is considered, and optimal solutions for radial maneuvers are generated. Indirect methods are employed in order to establish the swi tching structure of the solutions. The results show that even such app arently simple maneuvers as extension or retraction of a robot with a prismatic joint can produce very complex optimal solutions. Time-optim al retraction can exhibit ten different switching structures with eigh t switching points and two singular arcs.