Publications

2025

1. RA-L

   

   Collaborative Exploration with a Marsupial Ground-Aerial Robot Team through Task-Driven Map Compression

   Angelos Zacharia, Mihir Dharmadhikari, and Kostas Alexis

   IEEE Robotics and Automation Letters, 2025

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   Efficient exploration of unknown environments is crucial for autonomous robots, especially in confined and large-scale scenarios with limited communication. To address this challenge, we propose a collaborative exploration framework for a marsupial ground-aerial robot team that leverages the complementary capabilities of both platforms. The framework employs a graph-based path planning algorithm to guide exploration and deploy the aerial robot in areas where its expected gain significantly exceeds that of the ground robot, such as large open spaces or regions inaccessible to the ground platform, thereby maximizing coverage and efficiency. To facilitate large-scale spatial information sharing, we introduce a bandwidth-efficient, task-driven map compression strategy. This method enables each robot to reconstruct resolution-specific volumetric maps while preserving exploration-critical details, even at high compression rates. By selectively compressing and sharing key data, communication overhead is minimized, ensuring effective map integration for collaborative path planning. Simulation and real-world experiments validate the proposed approach, demonstrating its effectiveness in improving exploration efficiency while significantly reducing data transmission.

2. RA-M

   

   Cooperative Aerial Robot Inspection Challenge: A Benchmark for Heterogeneous Multi-Uncrewed-Aerial-Vehicle Planning and Lessons Learned

   Muqing Cao, Thien-Minh Nguyen, Shenghai Yuan, Andreas Anastasiou, Angelos Zacharia, Savvas Papaioannou, and 9 more authors

   IEEE Robotics & Automation Magazine, 2025

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   We propose the Cooperative Aerial Robot Inspection Challenge (CARIC), a simulation-based benchmark for motion planning algorithms in heterogeneous multi-uncrewed-aerial-vehicle (UAV) systems. CARIC features UAV teams with complementary sensors, realistic constraints, and evaluation metrics prioritizing inspection quality and efficiency. It offers a ready-to-use perception-control software stack and diverse scenarios to support the development and evaluation of task allocation and motion planning algorithms. Competitions using CARIC were held at the 2023 IEEE Conference on Decision and Control (CDC) and the IROS 2024 Workshop on Multi-Robot Perception and Navigation, attracting innovative solutions from research teams worldwide. This article examines the top three teams from CDC 2023, analyzing their exploration, inspection, and task allocation strategies while drawing insights into their performance across scenarios. The results highlight the task’s complexity and suggest promising research directions in cooperative multi-UAV systems. The simulation framework, including the source code and detailed instructions, is publicly available at https://ntu-aris.github.io/caric.

2024

1. ICUAS

   

   Automated Real-Time Inspection in Indoor and Outdoor 3D Environments with Cooperative Aerial Robots

   Andreas Anastasiou, Angelos Zacharia, Savvas Papaioannou, Panayiotis Kolios, Christos G. Panayiotou, and Marios M. Polycarpou

   In 2024 International Conference on Unmanned Aircraft Systems (ICUAS), 2024

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   This work introduces a cooperative inspection system designed to efficiently control and coordinate a team of distributed heterogeneous UAV agents for the inspection of 3D structures in cluttered, unknown spaces. Our proposed approach employs a two-stage innovative methodology. Initially, it leverages the complementary sensing capabilities of the robots to cooperatively map the unknown environment. It then generates optimized, collision-free inspection paths, thereby ensuring comprehensive coverage of the structure’s surface area. The effectiveness of our system is demonstrated through qualitative and quantitative results from extensive Gazebo-based simulations that closely replicate real-world inspection scenarios, highlighting its ability to thoroughly inspect real-world-like 3D structures

2023

1. MED

   

   Distributed Control for 3D Inspection using Multi-UAV Systems

   Angelos Zacharia, Savvas Papaioannou, Panayiotis Kolios, and Christos Panayiotou

   In 2023 31st Mediterranean Conference on Control and Automation (MED), 2023

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   Cooperative control of multi-UAV systems has attracted substantial research attention due to its significance in various application sectors such as emergency response, search and rescue missions, and critical infrastructure inspection. This paper proposes a distributed control algorithm to generate collision-free trajectories that drive the multi-UAV system to completely inspect a set of 3D points on the surface of an object of interest. The objective of the UAVs is to cooperatively inspect the object of interest in the minimum amount of time. Extensive numerical simulations for a team of quadrotor UAVs inspecting a real 3D structure illustrate the validity and effectiveness of the proposed approach.

2021

1. ICUAS

   

   ICARUS: Automatic Autonomous Power Infrastructure Inspection with UAVs

   Antonis Savva, Angelos Zacharia, Rafael Makrigiorgis, Antreas Anastasiou, Christos Kyrkou, Panayiotis Kolios, and 2 more authors

   In 2021 International Conference on Unmanned Aircraft Systems (ICUAS), 2021

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   Power transmission and distribution networks mostly span across harsh environments and thus, frequent faults and failures are observed, increasing the maintenance costs, pressing the authorities to provide electricity continuously and uninterruptedly. To this end, thorough field inspections with skilled personnel are regularly conducted, which are labor-intensive, costly and slow, whereby efficiency and staff safety cannot be always ensured. UAVs stem as a promising solution for power infrastructure inspection; however, their use is mostly limited by the fact that a remote pilot is in control of flight and mission processes, rendering reliable data acquisition in short time interval a tedious task. Despite research efforts for automating inspection procedures, these have not been widely adopted. In this study, we address this challenge by developing a Power Distribution Network Inspection Platform Using UAVs (ICARUS), based on a vision-based artificial intelligence toolkit, that integrates multiple sensors and automates many tasks, such as detection, tracking and identification of infrastructure components, gathering reliable spatial/time data associated to these components autonomously, safely and fast.

2020

1. ICUAS

   

   HorizonBlock: Implementation of an Autonomous Counter-Drone System

   Nicolas Souli, Rafael Makrigiorgis, Antreas Anastasiou, Angelos Zacharia, Petros Petrides, Alexandros Lazanas, and 3 more authors

   In 2020 International Conference on Unmanned Aircraft Systems (ICUAS), 2020

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   Unmanned Aircraft Systems (UASs) are techno-logically advancing at such a rapid pace that domain experts are now highly concerned of the potential misuse of the technology that can be used for unlawful actions with detrimental effects. The most effective measure to counteract the operation of rogue drones are electronic anti-drone systems that in one way or another intercept the normal operation of a rogue agent. In this work we develop an intelligent pursuer drone that implements novel lightweight functions to meet all necessary interception steps (i.e., detection, tracking and interception) in addition to self-localizing using signals of opportunity in order to maintain perception when performing wireless jamming against a rogue drone.