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Matteo Fumagalli

Publications and source records attributed to Matteo Fumagalli.

17 recordsLinked to original sources

Event-based Civil Infrastructure Visual Defect Detection: ev-CIVIL Dataset and Benchmark

Small unmanned aerial vehicle (UAV)-based visual inspections are a more efficient alternative to manual methods for examining civil structural defects, offering safe access to hazardous areas and significant cost savings by reducing labor requirements. However, traditional frame-based cameras, widely used in UAV-based inspections, often struggle to capture defects under low or dynamic lighting conditions. In contrast, dynamic vision sensors (DVS), or event-based cameras, excel in such scenarios by minimizing motion blur, enhancing power efficiency, and maintaining high-quality imaging across diverse lighting conditions without saturation or information loss. Despite these advantages, existing research lacks studies exploring the feasibility of using DVS for detecting civil structural defects. Moreover, there is no dedicated event-based dataset tailored for this purpose. Addressing this gap, this study introduces the first event-based civil infrastructure defect detection dataset, capturing defective surfaces as a spatio-temporal event stream using DVS. In addition to event-based data, the dataset includes grayscale intensity image frames captured simultaneously using an active pixel sensor (APS). Both data types were collected using the DAVIS346 camera, which integrates DVS and APS sensors. The dataset focuses on two types of defects: cracks and spalling, and includes data from both field and laboratory environments. The field dataset comprises 318 recording sequences, documenting 458 distinct cracks and 121 distinct spalling instances. The laboratory dataset includes 362 recording sequences, covering 220 distinct cracks and 308 spalling instances. We evaluated the dataset using four real-time object detection models.The results demonstrate the applicability of DVS cameras for robust detection of civil infrastructure defects under challenging lighting conditions.

cs.CV

Real-Time Frame- and Event-based Object Detection with Spiking Neural Networks on Edge Neuromorphic Hardware: Design, Deployment and Benchmark

Real-time object detection on energy-constrained platforms is critical for applications such as UAV-based inspection, autonomous navigation, and mobile robotics. Spiking neural networks (SNNs) on neuromorphic hardware are believed to be significantly more energy-efficient than conventional artificial neural networks (ANNs). In this work, we present a comprehensive methodology for designing general SNN detection architectures targeting neuromorphic platforms, along with the engineering adaptations required to deploy them on the state-of-the-art Neuromorphic processor, Intel Loihi 2. We benchmark SNN-based object detection on Loihi 2 using both frame-based and event-based datasets, comparing performance with ANN-based detection on the NVIDIA Jetson Orin Nano, NVIDIA Jetson Nano B01, and the Apple M2 CPU. Our results show that SNNs on Loihi 2 can perform real-time detection while achieving the lowest per-inference dynamic energy among all platforms. Also, Loihi 2 outperforms the other platforms in terms of power consumption, though ANNs on Jetson Orin Nano achieve higher inference rates. Furthermore, our ANN-to-SNN distillation-aware training enables SNNs to recover 87-100% of the detection accuracy of their ANN counterparts while maintaining lower inference latency; without distillation, SNNs exhibit an 11-27% accuracy drop. These results highlight the potential of neuromorphic systems for energy-efficient, real-time object detection at the edge.

cs.CV

Integration of a Variable Stiffness Link for Long-Reach Aerial Manipulation

This paper presents the integration of a Variable Stiffness Link (VSL) for long-reach aerial manipulation, enabling adaptable mechanical coupling between an aerial multirotor platform and a dual-arm manipulator. Conventional long-reach manipulation systems rely on rigid or cable connections, which limit precision or transmit disturbances to the aerial vehicle. The proposed VSL introduces an adjustable stiffness mechanism that allows the link to behave either as a flexible rope or as a rigid rod, depending on task requirements. The system is mounted on a quadrotor equipped with the LiCAS dual-arm manipulator and evaluated through teleoperated experiments, involving external disturbances and parcel transportation tasks. Results demonstrate that varying the link stiffness significantly modifies the dynamic interaction between the UAV and the payload. The flexible configuration attenuates external impacts and aerodynamic perturbations, while the rigid configuration improves positional accuracy during manipulation phases. These results confirm that VSL enhances versatility and safety, providing a controllable trade-off between compliance and precision. Future work will focus on autonomous stiffness regulation, multi-rope configurations, cooperative aerial manipulation and user studies to further assess its impact on teleoperated and semi-autonomous aerial tasks.

cs.RO

Underground Multi-robot Systems at Work: a revolution in mining

The growing global demand for critical raw materials (CRMs) has highlighted the need to access difficult and hazardous environments such as abandoned underground mines. These sites pose significant challenges for conventional machinery and human operators due to confined spaces, structural instability, and lack of infrastructure. To address this, we propose a modular multi-robot system designed for autonomous operation in such environments, enabling sequential mineral extraction tasks. Unlike existing work that focuses primarily on mapping and inspection through global behavior or central control, our approach incorporates physical interaction capabilities using specialized robots coordinated through local high-level behavior control. Our proposed system utilizes Hierarchical Finite State Machine (HFSM) behaviors to structure complex task execution across heterogeneous robotic platforms. Each robot has its own HFSM behavior to perform sequential autonomy while maintaining overall system coordination, achieved by triggering behavior execution through inter-robot communication. This architecture effectively integrates software and hardware components to support collaborative, task-driven multi-robot operation in confined underground environments.

eess.SY

Advancing Manipulation Capabilities of a UAV Featuring Dynamic Center-of-Mass Displacement

As aerial robots gain traction in industrial applications, there is growing interest in enhancing their physical interaction capabilities. Pushing tasks performed by aerial manipulators have been successfully demonstrated in contact-based inspections. However, more complex industrial applications require these systems to support higher-DoF (Degree of Freedom) manipulators and generate larger forces while pushing (e.g., drilling, grinding). This paper builds on our previous work, where we introduced an aerial vehicle that can dynamically vary its CoM (Center of Mass) location to improve force exertion during interactions. We propose a novel approach to further enhance this system's force generation by optimizing its CoM location during interactions. Additionally, we study the case of this aerial vehicle equipped with a 2-DoF manipulation arm to extend the system's functionality in tool-based tasks. The effectiveness of the proposed methods is validated through simulations, demonstrating the potential of this system for advanced aerial manipulation in practical settings.

cs.RO

Assisted Physical Interaction: Autonomous Aerial Robots with Neural Network Detection, Navigation, and Safety Layers

The paper introduces a novel framework for safe and autonomous aerial physical interaction in industrial settings. It comprises two main components: a neural network-based target detection system enhanced with edge computing for reduced onboard computational load, and a control barrier function (CBF)-based controller for safe and precise maneuvering. The target detection system is trained on a dataset under challenging visual conditions and evaluated for accuracy across various unseen data with changing lighting conditions. Depth features are utilized for target pose estimation, with the entire detection framework offloaded into low-latency edge computing. The CBF-based controller enables the UAV to converge safely to the target for precise contact. Simulated evaluations of both the controller and target detection are presented, alongside an analysis of real-world detection performance.

cs.RO

Dynamic Center-of-Mass Displacement in Aerial Manipulation: An Innovative Platform Design

Aerial manipulators are increasingly used in contact-based industrial applications, where tasks like drilling and pushing require platforms to exert significant forces in multiple directions. To enhance force generation capabilities, various approaches, such as thrust vectoring and perching, have been explored. In this article, we introduce a novel approach by investigating the impact of varied CoM (Center of Mass) locations on an aerial manipulation system's force exertion. Our proposed platform features a design with a dynamically displacing CoM, enabling a smooth transition between free flight and high-force interactions supported by tilting back rotors. We provide detailed modeling and control strategies for this design and validate its feasibility through a series of physical experiments. In a pushing task, the proposed system, weighing 3.12kg, was able to stably exert over 28N of force on a work surface-nearly equivalent to its gravitational force-achieved solely through the tilting of its back rotors. Additionally, we introduce a new factor to evaluate the force generation capabilities of aerial platforms, allowing for a quantitative comparison with state-of-the-art systems, which demonstrates the advantages of our proposed approach.

cs.RO

Enhancing Sliding Performance with Aerial Robots: Analysis and Solutions for Non-Actuated Multi-Wheel Configurations

Sliding tasks performed by aerial robots are valuable for inspection and simple maintenance tasks at height, such as non-destructive testing and painting. Although various end-effector designs have been used for such tasks, non-actuated wheel configurations are more frequently applied thanks to their rolling capability for sliding motion, mechanical simplicity, and lightweight design. Moreover, a non-actuated multi-wheel (more than one wheel) configuration in the end-effector design allows the placement of additional equipment e.g., sensors and tools in the center of the end-effector tip for applications. However, there is still a lack of studies on crucial contact conditions during sliding using aerial robots with such an end-effector design. In this article, we investigate the key challenges associated with sliding operations using aerial robots equipped with multiple non-actuated wheels through in-depth analysis grounded in physical experiments. The experimental data is used to create a simulator that closely captures real-world conditions. We propose solutions from both mechanical design and control perspectives to improve the sliding performance of aerial robots. From a mechanical standpoint, design guidelines are derived from experimental data. From a control perspective, we introduce a novel pressure-sensing-based control framework that ensures reliable task execution, even during sliding maneuvers. The effectiveness and robustness of the proposed approaches are then validated and compared using the built simulator, particularly in high-risk scenarios.

cs.RO

AEROBULL: A Center-of-Mass Displacing Aerial Vehicle Enabling Efficient High-Force Interaction

In various industrial sectors, inspection and maintenance tasks using UAV (Unmanned Aerial Vehicle) require substantial force application to ensure effective adherence and stable contact, posing significant challenges to existing solutions. This paper addresses these industrial needs by introducing a novel lightweight aerial platform (3.12kg) designed to exert high pushing forces on non-horizontal surfaces. To increase maneuverability, the proposed platform incorporates tiltable rotors with 5-DoF (Degree of Freedom) actuation. Moreover, it has an innovative shifting-mass mechanism that dynamically adjusts the system's CoM (Center of Mass) during contact-based task execution. A compliant EE (End-Effector) is applied to ensure a smooth interaction with the work surface. We provide a detailed study of the UAV's overall system design, hardware integration of the developed physical prototype, and software architecture of the proposed control algorithm. Physical experiments were conducted to validate the control design and explore the force generation capability of the designed platform via a pushing task. With a total mass of 3.12kg, the UAV exerted a maximum pushing force of above 28N being almost equal to its gravity force. Furthermore, the experiments illustrated the benefits of having displaced CoM by benchmarking with a fixed CoM configuration.

cs.RO

Distributed Planning for Rigid Robot Formations with Probabilistic Collision Avoidance

This paper presents a distributed method for robots moving in rigid formations while ensuring probabilistic collision avoidance between the robots. The formation is parametrised through the transformation of a base configuration. The robots map their desired velocities into a corresponding desired change in the formation parameters and apply a consensus step to reach agreement on the desired formation and a constraint satisfaction step to ensure collision avoidance within the formation. The constraint set is found such that the probability of collision remains below an upper bound. The method was demonstrated in a manual teleoperation scenario both in simulation and a real-world experiment.

cs.RO

Optimal Distributed Multi-Robot Communication-Aware Trajectory Planning using Alternating Direction Method of Multipliers

This paper presents a distributed, optimal, communication-aware trajectory planning algorithm for multi-robot systems. Building on prior work, it addresses the multi-robot communication-aware trajectory planning problem using a general optimisation framework that imposes linear constraints on changes in robot positions to ensure communication performance and collision avoidance. In this paper, the optimisation problem is solved distributively by separating the communication performance constraint through an economic approach. Here, the current communication budget is distributed equally among the robots, and the robots are allowed to trade parts of their budgets with each other. The separated optimisation problem is then solved using the consensus alternating direction method of multipliers. The method was verified through simulation in an inspection task problem.

cs.RO

Optimal Multi-Robot Communication-Aware Trajectory Planning by Constraining the Fiedler Value

The paper present a novel approach for the solution of the Multi-Robot Communication-Aware Trajectory Planning, which builds on a general optimisation framework where the changes in robots positions are used as decision variable, and linear constraints on the trajectories of the robots are introduced to ensure communication performance and collision avoidance. The Fiedler value is adopted as communication performance metric. The validity of the method in computing both feasible and optimal trajectories for the robots is demonstrated both in simulation and experimentally. Results show that the constraint on the Fiedler value ensures that the robot network fulfils its objective while maintaining communication connectivity at all times. Further, the paper shows that the introduction of approximations for the constraints enables a significant improvement in the computational time of the solution, which remain very close to the optimal solution.

cs.RO

Passive Aligning Physical Interaction of Fully-Actuated Aerial Vehicles for Pushing Tasks

Recently, the utilization of aerial manipulators for performing pushing tasks in non-destructive testing (NDT) applications has seen significant growth. Such operations entail physical interactions between the aerial robotic system and the environment. End-effectors with multiple contact points are often used for placing NDT sensors in contact with a surface to be inspected. Aligning the NDT sensor and the work surface while preserving contact, requires that all available contact points at the end-effector tip are in contact with the work surface. With a standard full-pose controller, attitude errors often occur due to perturbations caused by modeling uncertainties, sensor noise, and environmental uncertainties. Even small attitude errors can cause a loss of contact points between the end-effector tip and the work surface. To preserve full alignment amidst these uncertainties, we propose a control strategy which selectively deactivates angular motion control and enables direct force control in specific directions. In particular, we derive two essential conditions to be met, such that the robot can passively align with flat work surfaces achieving full alignment through the rotation along non-actively controlled axes. Additionally, these conditions serve as hardware design and control guidelines for effectively integrating the proposed control method for practical usage. Real world experiments are conducted to validate both the control design and the guidelines.

cs.RO

Safety-Conscious Pushing on Diverse Oriented Surfaces with Underactuated Aerial Vehicles

Pushing tasks performed by aerial manipulators can be used for contact-based industrial inspections. Underactuated aerial vehicles are widely employed in aerial manipulation due to their widespread availability and relatively low cost. Industrial infrastructures often consist of diverse oriented work surfaces. When interacting with such surfaces, the coupled gravity compensation and interaction force generation of underactuated aerial vehicles can present the potential challenge of near-saturation operations. The blind utilization of these platforms for such tasks can lead to instability and accidents, creating unsafe operating conditions and potentially damaging the platform. In order to ensure safe pushing on these surfaces while managing platform saturation, this work establishes a safety assessment process. This process involves the prediction of the saturation level of each actuator during pushing across variable surface orientations. Furthermore, the assessment results are used to plan and execute physical experiments, ensuring safe operations and preventing platform damage.

cs.RO

Versatile Airborne Ultrasonic NDT Technologies via Active Omni-Sliding with Over-Actuated Aerial Vehicles

This paper presents the utilization of advanced methodologies in aerial manipulation to address meaningful industrial applications and develop versatile ultrasonic Non-Destructive Testing (NDT) technologies with aerial robots. The primary objectives of this work are to enable multi-point measurements through sliding without re-approaching the work surface, and facilitate the representation of material thickness with B and C scans via dynamic scanning in arbitrary directions (i.e. omnidirections). To accomplish these objectives, a payload that can slide in omnidirections (here we call the omni-sliding payload) is designed for an over-actuated aerial vehicle, ensuring truly omnidirectional sliding mobility while exerting consistent forces in contact with a flat work surface. The omni-sliding payload is equipped with an omniwheel-based active end-effector and an Electro Magnetic Acoustic Transducer (EMAT). Furthermore, to ensure successful development of the designed payload and integration with the aerial vehicle, a comprehensive studying on contact conditions and system dynamics during active sliding is presented, and the derived system constraints are later used as guidelines for the hardware development and control setting. The proposed methods are validated through experiments, encompassing both the wall-sliding task and dynamic scanning for Ultrasonic Testing (UT), employing the aerial platform - Voliro T.

cs.RO

Distributed Planning for Rigid Robot Formations using Consensus on the Transformation of a Base Configuration

This paper presents a novel planning method that achieves navigation of multi-robot formations in cluttered environments, while maintaining the formation throughout the robots motion. The method utilises a decentralised approach to find feasible formation parameters that guarantees formation constraints for rigid formations. The method proves to be computationally efficient, making it relevant for reactive planning and control of multi-robot systems formation. The method has been tested in a simulation environment to prove feasibility and run-time efficiency.

cs.RO

Static-Equilibrium Oriented Interaction Force Modeling and Control of Aerial Manipulation with Uni-Directional Thrust Multirotors

This paper presents a static-equilibrium oriented interaction force modeling and control approach of aerial manipulation employing uni-directional thrust (UDT) multirotors interacting with variously defined environments. First, a simplified system model for a quadrotor-based aerial manipulator is introduced considering parameterized work surfaces under assumptions, and then a range of meaningful manipulation tasks are utilized to explore the system properties in a quasi-static equilibrium state. An explicit interaction force model in relation with the aerial manipulator pose configuration and the environment parameter is derived from the static equilibrium analysis, based on which singularity is pointed out. Then a hybrid attitude/force interaction control strategy is presented to verify the proposed interaction force model, which involves high gain attitude control and feedforward plus feedback force control. This paper represents preliminary results. We study the properties of UDT-based aerial manipulators via specific tasks, and propose a novel framework for interaction force modeling and control aiming at maximizing the commercial values of UDT platforms for aerial manipulation purpose.

cs.RO