Building Tensile Structures with Flying Machines

Flying machines offer a number of advantages compared to traditional construction machines. Specifically, they can reach any point in space and fly in or around existing objects. However, they also have drawbacks, such as limited payload and accuracy. Tensile structures fit very well this combination of characteristics and constraints, and were subject of preliminary research in [2,3].

Eventually, a rope bridge that can support the crossing of a person was assembled by quadrocopters. The rope bridge acts as a demonstrator, showing for the ﬁrst time that small ﬂying machines are capable of autonomously realizing load-bearing structures at full-scale and proceeding a step further towards real-world scenarios. Except for the required anchor points at both ends of the structure, the bridge consists exclusively of tensile elements and its connections and links are entirely realized by ﬂying machines. Spanning 7.4 m between two scaffolding structures, the bridge consists of nine rope segments for a total rope length of about 120 m and is composed of different elements, such as knots, links, and braid [4].

The vehicles are equipped with a motorized spool that allows them to control the tension acting on the rope during deployment. A plastic tube guides the rope to the release point located between two propellers. The external forces and torques exerted on the quadrocopter by the rope during deployment are estimated and taken into account to achieve compliant ﬂight behavior [5]. The rope used for these experiments is made out of Dyneema, a material with a low weight-to-strength ratio and thus suitable for aerial construction.

