Competition in all sectors requires companies to be increasingly flexible to market changes and the assembly industry is no exception. The impact of this work concerns aircraft production, as well as other fields. The main focus is on modelling and control techniques to carry out assembly tasks involving deformable parts, by exploiting a multi-robot system. Specifically, two robot arms are used to move a light and deformable part in order to adapt its shape for an assembly operation. A vision system is used, assisted by markers. Furthermore, the stability of the proposed controller is analyzed and experimental results are given.