This work has been submitted to the IEEE for possible publication. Abstract-- We present a novel approach to localizing radioactive material by cooperating Micro Aerial V ehicles (MA Vs). The detector's exceptionally low weight (40 g) opens up new possibilities of radiation detection by a team of cooperating agile MA Vs. We propose a new fundamental concept of fusing the Compton camera measurements to estimate the position of the radiation source in real time even from extremely sparse measurements. The data readout and processing are performed directly onboard and the results are used in a dynamic feedback to drive the motion of the vehicles. The MA Vs are stabilized in a tightly cooperating swarm to maximize the information gained by the Compton cameras, rapidly locate the radiation source, and even track a moving radiation source. I. INTRODUCTION Nuclear environments represent a domain particularly well suited for the deployment of mobile robots [1]-[3]. The primary driving force is to reduce human exposure to harmful radiation, and to facilitate access to areas that are difficult to reach by conventional means.

--Deployment of robots into hazardous environments typically involves a "Human-Robot T eaming" (HRT) paradigm, in which a human supervisor interacts with a remotely operating robot inside the hazardous zone. Situational A wareness (SA) is vital for enabling HRT, to support navigation, planning, and decision-making. This paper explores issues of higher-level "semantic" information and understanding in SA. In semi-autonomous, or variable-autonomy paradigms, different types of semantic information may be important, in different ways, for both the human operator and an autonomous agent controlling the robot. We propose a generalizable framework for acquiring and combining multiple modalities of semantic-level SA during remote deployments of mobile robots. We demonstrate the framework with an example application of search and rescue (SAR) in disaster response robotics. We propose a set of "environment semantic indicators" that can reflect a variety of different types of semantic information, e.g. Based on these indicators, we propose a metric to describe the overall situation of the environment called "Situational Semantic Richness (SSR)". This metric combines multiple semantic indicators to summarise the overall situation. The SSR indicates if an information-rich and complex situation has been encountered, which may require advanced reasoning for robots and humans and hence the attention of the expert human operator . The framework is tested on a Jackal robot in a mock-up disaster response environment. Experimental results demonstrate that the proposed semantic indicators are sensitive to changes in different modalities of semantic information in different scenes, and the SSR metric reflects overall semantic changes in the situations encountered. Situational A wareness (SA) is vital for robots deployed in the field to function with sufficient autonomy, resiliency, and robustness.

A novel method for autonomous localization of multiple sources of gamma radiation using a group of Micro Aerial Vehicles (MAVs) is presented in this paper. The method utilizes an extremely lightweight (44 g) Compton camera MiniPIX TPX3. The compact size of the detector allows for deployment onboard safe and agile small-scale Unmanned Aerial Vehicles (UAVs). The proposed radiation mapping approach fuses measurements from multiple distributed Compton camera sensors to accurately estimate the positions of multiple radioactive sources in real time. Unlike commonly used intensity-based detectors, the Compton camera reconstructs the set of possible directions towards a radiation source from just a single ionizing particle. Therefore, the proposed approach can localize radiation sources without having to estimate the gradient of a radiation field or contour lines, which require longer measurements. The instant estimation is able to fully exploit the potential of highly mobile MAVs. The radiation mapping method is combined with an active search strategy, which coordinates the future actions of the MAVs in order to improve the quality of the estimate of the sources' positions, as well as to explore the area of interest faster. The proposed solution is evaluated in simulation and real world experiments with multiple Cesium-137 radiation sources.

This paper describes a novel semi-autonomous mobile robot system designed to assist search and rescue (SAR) first responders in disaster scenarios. While robots offer significant potential in SAR missions, current solutions are limited in their ability to handle a diverse range of tasks. This gap is addressed by presenting a system capable of (1) autonomous navigation and mapping, allowing the robot to autonomously explore and map areas affected by catastrophic events, (2) radiation mapping, enabling the system to triangulate a radiation map from discrete radiation measurements to aid in identifying hazardous areas, (3) semi-autonomous substance sampling, allowing the robot to collect samples of suspicious substances and analyze them onboard with immediate classification, and (4) valve manipulation, enabling teleoperated closing of valves that control hazardous material flow. This semi-autonomous approach balances human control over critical tasks like substance sampling with efficient robot navigation in low-risk areas. The system is evaluated during three trials that simulate possible disaster scenarios, two of which have been recorded during the European Robotics Hackathon (EnRicH). Furthermore, we provide recorded sensor data as well as the implemented software system as supplemental material through a GitHub repository: https://github.com/TW-Robotics/search-and-rescue-robot-IROS2024.

Abstract-- A system and testing rig were designed and built to simulate the use of an eversion robot equipped with a radiation sensor to characterise an irradiated pipe prior to decommissioning. The magnets were used as dummy radiation sources which were detected by a hall effect sensor mounted in the interior of the robot. The robot successfully navigated a simple structure with sharp 45 and 90 swept bends as well as constrictions that were used to model partial blockages. Most caps are made from rigid materials spaces is one such area for which robotic solutions and fully encase the tip [4, 5], limiting the size of the have been developed [1]. However, the deployment of in-situ aperture they can fit through and undermining the eversion inspection solutions to the pipes and ducts that riddle these robot's ability to squeeze through spaces smaller than itself. Their A soft, fabric solution exists [6], but that can have difficulties uses ranged from ventilation to waste drainage and many are remaining in place while the robot retracts.

In recent years, radiation mapping has attracted widespread research attention and increased public concerns on environmental monitoring. In terms of both materials and their configurations, radiation detectors have been developed to locate the directions and positions of the radiation sources. In this process, algorithm is essential in converting detector signals to radiation source information. However, due to the complex mechanisms of radiation-matter interaction and the current limitation of data collection, high-performance, low-cost radiation mapping is still challenging. Here we present a computational framework using Tetris-inspired detector pixels and machine learning for radiation mapping. Using inter-pixel padding to increase the contrast between pixels and neural network to analyze the detector readings, a detector with as few as four pixels can achieve high-resolution directional mapping. By further imposing Maximum a Posteriori (MAP) with a moving detector, further radiation position localization is achieved. Non-square, Tetris-shaped detector can further improve performance beyond the conventional grid-shaped detector. Our framework offers a new avenue for high quality radiation mapping with least number of detector pixels possible, and is anticipated to be capable to deploy for real-world radiation detection with moderate validation.

Prostate cancer is the most common form of cancer in men. Every year about 13,000 Dutch men are diagnosed with this disease. According to the Prostate Cancer Foundation, about 1 in 10 men suffers from prostate cancer at some point in their lives. When an all-male TU Delft student team started working with PhD researcher Martijn de Vries to design a robot that can precisely place a radiation source in your body with a steerable needle, it took a while for these statistics to sink in. But once that happened, motivation shot up.