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Paredes-Vallés, Federico (author), Hagenaars, J.J. (author), Dupeyroux, J.J.G. (author), Stroobants, S. (author), Xu, Y. (author), de Croon, G.C.H.E. (author)Biological sensing and processing is asynchronous and sparse, leading to low-latency and energy-efficient perception and action. In robotics, neuromorphic hardware for event-based vision and spiking neural networks promises to exhibit similar characteristics. However, robotic implementations have been limited to basic tasks with low-dimensional...journal article 2024
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Ferede, R. (author), de Croon, G.C.H.E. (author), de Wagter, C. (author), Izzo, Dario (author)Developing optimal controllers for aggressive high-speed quadcopter flight poses significant challenges in robotics. Recent trends in the field involve utilizing neural network controllers trained through supervised or reinforcement learning. However, the sim-to-real transfer introduces a reality gap, requiring the use of robust inner loop...journal article 2024
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Xu, Y. (author), de Croon, G.C.H.E. (author)In this paper, we propose a learning-based lightweight visual-inertial odometry (VIO) based on an uncertainty-aware pose network and an extended Kalman filter (EKF). The pose network serving as the VIO vision front-end predicts the relative motion of the camera between consecutive image frames and estimates the prediction uncertainty. The...conference paper 2023
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Meester, R.S. (author), van Dijk, Tom (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)Obstacle avoidance is an important capability for flying robots. But for robots with limited resources, such as small drones this becomes particularly challenging. Bug algorithms have been proposed to solve path planning with only minimal resources. And stereo vision provides a rich description of the world for limited weight but typically has a...conference paper 2023
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Pfeiffer, S.U. (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)Moving Horizon Estimation (MHE) offers multiple advantages over Kalman Filters when it comes to the localization of drones. However, due to the high computational cost, they can not be used on Micro Air Vehicles (MAVs) with limited computational power. We have previously shown, that with a few assumptions and simplifications, MHE can be made...conference paper 2023
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Xu, Y. (author), de Croon, G.C.H.E. (author)When deployed onboard micro air vehicles (MAVs) with limited processing power, visual ego-motion estimation solutions face an efficiency-accuracy trade-off. This paper proposes an aerodynamic-model-aided approach that emphasizes time efficiency over estimation accuracy. A linear drag force model of propellers guarantees bounded estimation errors...conference paper 2023
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King, Andrew J. (author), Portugal, Steven J. (author), Strömbom, Daniel (author), Mann, Richard P. (author), Carrillo, José A. (author), Kalise, Dante (author), de Croon, G.C.H.E. (author), Barnett, Heather (author), Scerri, Paul (author)A single sheepdog can bring together and manoeuvre hundreds of sheep from one location to another. Engineers and ecologists are fascinated by this sheepdog herding because of the potential it provides for ‘bio-herding’: a biologically inspired herding of animal groups by robots. Although many herding algorithms have been proposed, most are...journal article 2023
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Liu, C. (author), van Kampen, E. (author), de Croon, G.C.H.E. (author)Enabling the capability of assessing risk and making risk-aware decisions is essential to applying reinforcement learning to safety-critical robots like drones. In this paper, we investigate a specific case where a nano quadcopter robot learns to navigate an apriori-unknown cluttered environment under partial observability. We present a...conference paper 2023
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Liu, C. (author), Xu, Y. (author), van Kampen, E. (author), de Croon, G.C.H.E. (author)In this paper, we propose an obstacle avoidance solution for a 34-gram quadcopter equipped with a monocular camera. The perception of obstacles is tackled by a lightweight convolutional neural network predicting a dense depth map from a captured grey-scale image. The depth network performs self-supervised learning and thus requires no ground...journal article 2023
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Yu, H.Y. (author), de Croon, G.C.H.E. (author), de Wagter, C. (author)Obstacle avoidance is an essential topic in the field of autonomous drone research. When choosing an avoidance algorithm, many different options are available, each with their advantages and disadvantages. As there is currently no consensus on testing methods, it is quite challenging to compare the performance between algorithms. In this...conference paper 2023
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Suys, T. (author), Hwang, S. (author), de Croon, G.C.H.E. (author), Remes, B.D.W. (author)We present a novel controller for fixed-wing UAVs that enables autonomous soaring in an orographic wind field, extending flight endurance. Our method identifies soaring regions and addresses position control challenges by introducing a target gradient line (TGL) on which the UAV achieves an equilibrium soaring position, where sink rate and...conference paper 2023
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Bouwmeester, Rik J. (author), Paredes-Vallés, Federico (author), de Croon, G.C.H.E. (author)Nano quadcopters are small, agile, and cheap platforms that are well suited for deployment in narrow, cluttered environments. Due to their limited payload, these vehicles are highly constrained in processing power, rendering conventional vision-based methods for safe and autonomous navigation incompatible. Recent machine learning developments...conference paper 2023
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Mancinelli, A. (author), Remes, B.D.W. (author), de Croon, G.C.H.E. (author), Smeur, E.J.J. (author)Hybrid Unmanned Aerial Vehicles UAV are vehicles capable of take-off and landing vertically like helicopters while maintaining the long-range efficiency of fixed-wing aircraft. Unfortunately, due to their wing area, these vehicles are sensitive to wind gusts when hovering. One way to increase the hovering wind-rejection capabilities of hybrid...journal article 2023
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Altena, A. (author), Luesutthiviboon, S. (author), de Croon, G.C.H.E. (author), Snellen, M. (author), Voskuijl, M. (author)Due to technological advances in the drone industry, security threats induced by unmanned aerial vehicles (UAVs) are becoming more relevant. Fast and accurate localisation systems need to be designed. One approach is localisation of UAVs by their sound using acoustic techniques. So far, a systematic performance assessment of acoustic...conference paper 2023
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Smeur, E.J.J. (author), de Croon, G.C.H.E. (author), Chu, Q. P. (author)The authors regret to inform that an incorrect transfer function was included in Eq. (12). The correct transfer function is: [Formula Presented] The selected gains were [Formula Presented]. This leads to a real pole at 0.964 and two complex poles at 0.965 ± 0.0445i. The difference of the model compared to the measured step response has now...journal article 2023
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de Croon, G.C.H.E. (author), Hönig, W. (author), Theraulaz, G. (author), Vásárhelyi, G. (author)The idea of preparing a special issue of the Swarm Intelligence journal dedicated to the distributed control and adaptive collective behavior in swarms of drones has emerged after a workshop on this topic held in Toulouse on November 13–14, 2017. This workshop was intended to promote an interdisciplinary approach of collective behavior both in...contribution to periodical 2023
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Stroobants, S. (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)Neuromorphic processing promises high energy efficiency and rapid response rates, making it an ideal candidate for achieving autonomous flight of resource-constrained robots. It can be especially beneficial for complex neural networks as are used for high-level visual perception. However, fully neuromorphic solutions also need to tackle low...conference paper 2023
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- de Croon, G.C.H.E. (author) journal article 2023
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Harvey, Christina (author), de Croon, G.C.H.E. (author), Taylor, Graham K. (author), Bomphrey, Richard J. (author)Powered flight was once a capability limited only to animals, but by identifying useful attributes of animal flight and building on these with technological advances, engineers have pushed the frontiers of flight beyond our predecessors’ wildest imaginations. Yet, there remain many key characteristics of biological flight that elude current...journal article 2023
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Paredes-Vallés, Federico (author), Scheper, K.Y.W. (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)Event cameras have recently gained significant traction since they open up new avenues for low-latency and low-power solutions to complex computer vision problems. To unlock these solutions, it is necessary to develop algorithms that can leverage the unique nature of event data. However, the current state-of-the-art is still highly influenced...conference paper 2023