Autonomous drones are facing a tough efficiency challenge due to limitations on the utilized processing hardware units. Among these limitations is the tradeoff between fast computing and low power consumption; between functional complexity and flight time. Recent progressions point to FPGAs for accelerating heavy processing. In this work, we present the MPSoC4Drones Framework; a novel framework for organizing FPGA-design and OS build projects. The framework combines tools for creating bootable images for the Ultra96-V2 board.We show how MPSoC4Drones organizes the build, combining the latest well-known tools for research and industrial drone development, Ubuntu 20.04, PX4 autopilot, and ROS2 middleware. We validate the framework through a computationally intensive deep learning use case implemented in the MPSoC4Drones framework. We show the superior throughput and low power consumption of FPGA processing compared to classical CPU and GPU approaches. Finally, we offer the full framework as open-source.

Inspection of critical infrastructure with drones is experiencing an increasing uptake in the industry driven by a demand for reduced cost, time, and risk for inspectors. Early deployments of drone inspection services involve manual drone operations with a pilot and do not obtain the technological benefits concerning autonomy, coordination, and cooperation. In this paper, we study the design needed to handle the complexity of an Unmanned Aerial System (UAS) to support autonomous inspection of safety-critical infrastructure. We apply a constructive research approach to link innovation needs with concepts, designs, and validations that include simulation and demonstration of key design parts. Our design approach addresses the complexity of the UAS and provides a selection of technology components for drone and ground control hardware and software including algorithms for autonomous operation and interaction with cloud services. The paper presents a drone perception system with accelerated onboard computing, communication technologies of the UAS, as well as algorithms for swarm membership, formation flying, object detection, and fault detection with artificial intelligence. We find that the design of a cooperative drone swarm and its integration into a custom-built UAS for infrastructure inspection is highly feasible given the current state of the art in electronic components, software, and communication technology.

Inspecting overhead cables using autonomous Unmanned Aerial Vehicles (UAVs) is an affordable and promising future solution for providing a clear picture of the energy infrastructure. However, most of today's UAVs for powerline inspection are designed to use the Global Navigation Satellite System (GNSS) to follow the power pylons which compromises the detection accuracy. In this paper, we provide an overview of the current state-of-the-art in sensors that can be used to remotely detect power lines using UAVs. The work compares 20+ low-cost, low-power, and light-weight sensors. The performance of 6 different kinds of sensors is evaluated thoroughly in a real outdoor powerline test setup using a custom UAV. The sensor data is obtained and analyzed using Robot Operating System (ROS) and is provided openly.

Autonomous Unmanned Aerial Vehicle (UAV) interactions with powerlines, such as close-up inspections for fault detection or grasping and landing for recharging, require advanced onboard perception capabilities. To solve such tasks, the UAV must be equipped with perception abilities that allow it to navigate between powerlines and safely approach specific cables of interest. A perception system with such capabilities requires state-of-the-art sensor technologies and data processing while still being subject to the limited hardware and energy resources of the UAV. In this paper, we present an advanced embedded system based on the cutting-edge Multiprocessing System-on-Chip (MPSoC) for onboard UAV powerline perception. Our platform consists of a mmWave radar and an RGB camera with data processing carried out on the MPSoC, covering both CPU and Field-Programmable Gate Array (FPGA) computations. Following hardware-software co-design methodology, the heavy image processing tasks are accelerated in the FPGA and fused with computationally light mmWave data on the CPU, facilitating pose-estimation of the power lines. Utilizing the open-source autonomy frameworks PX4 and ROS2, we demonstrate integration of the system with onboard path planning based on the estimated cable positions. The robustness of the detection and pose-estimation methods have been demonstrated in several tests performed both in simulated and real-world powerline environments. The results show that our proposed perception system allows the UAV to safely navigate in close proximity to powerlines, by perceiving more individual cables at longer distances compared to previous work, while remaining lightweight, power-efficient, and low-cost.

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Recent research has pushed the applications of UAVs into domains such as infrastructure inspection and interaction. For UAVs to be able to safely and efficiently perform autonomous operations near the target infrastructure, they need to be aware of their surroundings while exposing navigation API to the application software. For powerline inspection UAVs, this yields a requirement for knowledge of the powerline cable positions and a set of actions facilitating specific flight operations in this environment. This work presents a hardware/software system solving these requirements. A framework is shown which allows application software to autonomously fly the UAV to any of the perceived cables, to fly the UAV along a cable, and to land on and takeoff from a cable. The system relies on an abstract representation of the identified and tracked cables, while solving the flight maneuvers using an MPC based trajectory planning routine. The system is tested in a real powerline environment featuring four cables stretched between two pylons. A GUI application is developed for triggering the actions remotely from a ground control station while providing a visual representation of the perceived cables and planned trajectories.

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