Multi-directional aerial platforms can fly in almost any orientation and direction, often maneuvering in ways their underactuated counterparts cannot match. A subset of multidirectional platforms is fully-actuated multirotors, where all six degrees of freedom are independently controlled without redundancies. Fully-actuated multirotors possess much greater freedom of movement than conventional multirotor drones, allowing them to perform complex sensing and manipulation tasks. While there has been comprehensive research on multi-directional multirotor control systems, the spectrum of hardware designs remains fragmented. This paper sets out the hardware design architecture of a fully-actuated quadrotor and its associated control framework. Following the novel platform design, a prototype was built to validate the control scheme and characterize the flight performance. The resulting quadrotor was shown in operation to be capable of holding a stationary hover at 30°incline, and track position commands by thrust vectoring [Video attachment: https://youtu.be/8HOQl 77CVg].
Additive manufacturing methods 1-4 using static and mobile robots are being developed for both on-site construction 5-8 and off-site prefabrication 9, 10 . Here we introduce a new method of additive manufacturing, referred to as Aerial Additive Manufacturing (Aerial-AM), that utilizes a team of aerial robots inspired by natural builders 11 such as wasps who use collective building methods 12, 13 . We present a scalable multi-robot 3D printing and path planning framework that enables robot tasks and population size to be adapted to variations in print geometry throughout a building mission. The multi-robot manufacturing framework allows for autonomous 3D printing under human supervision, real-time assessment of printed geometry and robot behavioural adaptation. To validate autonomous Aerial-AM based on the framework, we develop BuilDrones for depositing materials during flight and ScanDrones for measuring print quality, and integrate a generic real-time model-predictive-control scheme with the Aerial-AM robots. In addition, we integrate a dynamically self-aligning delta manipulator with the BuilDrone to further improve manufacturing accuracy to 5mm for printing geometry with precise trajectory requirements, and develop four cementitious-polymeric composite mixtures suitable for continuous material deposition. We demonstrate proof-of-concept prints including a cylinder of 2.05m with a rapid curing insulation foam material and a cylinder of 0.18m with structural pseudoplastic cementitious material, a light-trail virtual print of a dome-like geometry, and multi-robot simulations.
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