The PIROS Challenge is committed to deploy human-robot cooperative technologies in an application where robot collaboration is reckoned as a key competitive factor by the end user. The application is the high-skill preparation of complex pallets before/after machining in flexible manufacturing systems (FMS). Pallet preparation is critical for any CNC operation and it is the only manual task left in highly automated FMSs. Pallet setup involves hundreds of configurations, continuously changed for the production of small batches: mounting errors may generate substantial production losses. The introduction of robot technologies in pallet preparation will benefit the machine tool builders and, the machine tools customers in a variety of ultimate end-users businesses where machining is essential. In FMSs, parts to be machined are mounted on multi-fixturing devices, called pallets, depending on product demand and product mix. Pallets are assembled at a loading/unloading station (LUS), moved by an automatic transporter from/to general-purpose machine centers where they are machined. The number of pallet configurations, i.e. pallet mounting clamping systems/jigs and products, present at the same time into a FMS can be considerable. As a consequence, LUSs could substantially influence FMS performance in terms of final throughput because of 4 critical operations at LUS: pallet configurations are assembled, dissembled and checked before and after the machining. Very hard for humans. Although the pallet preparation task is always assigned to skilled operators, human can easily make errors during the pallet configuration. Very hard for robots. Adopting full robot automation has not been yet achieved, since human adaptability and dexterity is unique, e.g. for the insertion of screws in narrowed clearances. PIROS solution: collaborative as-needed robotics. Derived from the analysis of the problem by the end-user and the development team, the optimal solution for standard LUS layout and framework is a safe robot co-worker and information management tools, able to support a fast setup of new batches (i.e. easy programming) and the online redefinition of tasks (i.e. the possibility to exchange operations between human and robot).