Journal of Advanced Manufacturing Technology manuscript No. (will be inserted by the editor) Task Planning for Cooperating Self-Reconfigurable Mobile Fixtures Wlodzimierz Kasprzak · Dimiter Zlatanov · Wojciech Szynkiewicz · Teresa Zieli´ nska Received: date / Accepted: date Abstract The work solves the problem of task and motion planning of a self-reconfigurable fixture system. A feasible solution is a key requirement for the viability of such systems, which have raised hopes of overcoming the deficiencies that more traditional fixtures are rec- ognized to have in the dynamic conditions of modern manufacturing, with its increasing emphasis on flexibil- ity, adaptability, and automation. The paper proposes an application-independent approach for the generation of a time-relevant action plan for the locomotion, re- configuration, and positioning of two or more mobile robotic fixtures. The fixture agents need to provide lo- cal support for a large workpiece during machining. The path planning problem is converted into a constraint satisfaction problem (CSP). The proposed approach is called Triple-CSP, as it applies an incremental state search to solve three hierarchical path planning tasks W. Kasprzak Institute of Control and Computation Engineering, Warsaw University of Technology, ul.Nowowiejska 15/19, 00-665 Warszawa, Poland Tel.: +48-22-8250995, Fax: +48-22-8253719 E-mail: W.Kasprzak@elka.pw.edu.pl D. Zlatanov PMAR Laboratory, DIMEC, University of Genoa, Via all’Opera Pia 15a, 16145 Genoa, Italy E-mail: zlatanov@dimec.unige.it W. Szynkiewicz Institute of Control and Computation Engineering, Warsaw University of Technology, ul.Nowowiejska 15/19, 00-665 Warszawa, Poland E-mail: W.Szynkiewicz@elka.pw.edu.pl T. Zieli´ nska Institute of Aeronautics and Applied Mechanics, War- saw University of Technology, ul.Nowowiejska 24, 00-665 Warszawa, Poland E-mail: teresaz@meil.pw.edu.pl for the three components of each mobile fixture agent: a supporting head, a mobile base, and a parallel ma- nipulator, respectively. A final time-related trajectory (time scaling of actions) for the agents’ entire task exe- cution is obtained. Thus, the planner takes into account all the relevant physical, geometrical, and time-related constraints. Keywords active supports · agent system · constraint satisfaction · hole drilling · milling · mobile fixtures · robotized machining · task planning 1 Introduction A fixture is a device for locating, constraining, and ad- equately supporting a deformable workpiece during a manufacturing operation [1–3]. Components made of thin metallic or composite sheets are ubiquitous in au- tomotive and aircraft manufacturing. For both aesthetic and economic reasons they are becoming increasingly common in other sectors. The fixtures traditionally used in the manufacturing of thin-sheet metal parts are large moulds reproducing the shape of the skin to be sup- ported, but this type of fixture is part-specific and not reconfigurable. Modular flexible fixture systems (MFFSs), and single structure flexible fixture systems (SSFFS) are intended to make retooling easer by providing lim- ited reconfigurability. However, most FFSs still require some human intervention to reconfigure and few are suitable for thin sheets [4–6]. One attempt to automate reconfiguration is the use of an SSFFS of the pin-bed type, with a matrix of supports, which provides support comparable to a mould-like fixture. The main disadvan- tages are the high cost, as well as a reduced ability to adapt easily and efficiently to parts of different sizes, drawbacks in part linked to a lack of modularity.