This paper presents an algorithm that generates collision-free trajectories in three dimensions for multiple vehicles within seconds. The problem is cast as a non-convex optimization problem, which is iteratively solved using sequential convex programming that approximates non-convex constraints by using convex ones. The method generates trajectories that account for simple dynamics constraints and is thus independent of the vehicle's type. An extensive a posteriori vehicle-specific feasibility check is included in the algorithm. The algorithm is applied to a quadrocopter fleet. Experimental results are shown.

This paper takes a first step in characterizing a novel field of architectural research - aerial robotic construction (ARC) - where aerial robotics is used not only for construction, but as a guiding principle in the design and fabrication process. Featuring autonomous flying vehicles that lift small building elements and position them according to a precise digital blueprint, ARC offers a comprehensive new approach to architecture research and technology. Developed by the research groups of Gramazio & Kohler and Raffaello D'Andrea at ETH Zurich, ARC offers unique advantages over traditional approaches to building: it does not require scaffolding, it is easily scalable, and it offers digital integration and informational oversight across the entire design and building process. This paper considers 1) research parameters for the individual components of ARC (such as module design, connection methodologies, vehicle cooperation, and construction sequencing/synchronization), and 2) the architectural implications of integrating these discrete components into a systemic, unifying process at the earliest stages of design. Fidelity between the design concept and the full-scale construction is of particular concern.

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This paper presents the building of lightweight tensile structures with quadrocopters. The construction elements (such as ropes, cables, and wires) in this kind of structure are subject to tension forces. This paper identifies the basic building elements (nodes, links) required for the construction of tensile structures, and translates them into meaningful trajectories for quadrocopters. The use of a library of building elements is suggested. Hybrid force-position control strategies based on admittance control are exploited. Prototypical tensile structures are built by quadrocopters to validate the proposed approach. An accompanying video shows the building process.

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