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A Debris Clearance Robot for Extreme Environments
Abstract
The need for nuclear decommissioning is increasing globally, as power stations and other facilities utilising nuclear reaches the end of their operational life. Currently the majority of decommissioning tasks are carried out by workers in protective air fed suits, which is slow, expensive and dangerous. The work presented here is the early stages in the development of a flexible mobile manipulator platform, combining a Clearpath Husky, a Universal UR5 manipulator and various sensors. The system will be used for research specifically in the area of exploration of contaminated environments, map building to aid in task planning, and also to investigate manipulation for waste sorting. The aim is to develop a system that can, in the short term, be used in real world tasks but longer term function as a research platform to allow continued research and development. As well as developing a hardware platform, a detailed simulation model is also being developed to allow testing of algorithms in simulation before being deployed on hardware. The use of the simulation model for operator training is also an area that will be investigated in the future. This article focuses on the planned work for developing the system, as well as discussing the progress on the simulation model.
... The nuclear industry is responsible for many legacy facilities that are in the process of being decommissioned. These facilities range from research and development laboratories built in the 1940s, to more recent plants, which have come to the end of their design life (Lee et al., 2020;West et al., 2019;Zhang et al., 2020). Nuclear decommissioning is an expensive and time consuming process, mainly due to the hazardous nature of the work (Sato et al., 2019), which is compounded by uncertainties in the nuclear materials that may be present and the integrity and layout of facilities (Bandala et al., 2019). ...
... Power was provided to the robot via a tether system that used a bank of lead acid batteries to save mass and increase ease of transportation, when compared to the petrol generator system the robot was initially designed to use. West et al. (2019), proposed a tether management system to prevent their tether from tangling in the robot's drive mechanism and snagging in the environment, which was stated to be a significant risk in their work, and could potentially cause the robot to become stuck and have to be abandoned. ...
... Whilst consideration was taken in some cases to ensure that the robots could be decontaminated (wheels/ tracks removed and disposed of, chassis washed with detergent and pressure washer Guzman et al., 2016;Kawatsuma et al., 2017), this still required operators to physically clean the robot, which introduces risk, and this necessity had to be taken into account during the design phase (such as ensuring the robot was water tight). All of the reviewed works featured some kind of robotic manipulator, however, in the specific applications that were being addressed there was no evidence presented that showed a requirement that the payload needed to be 5 kg or more (with the exception of West et al's work; West et al., 2019), with many tasks in radioactive environments, such as gathering small samples or taking surface swab samples for later chemical analysis, typically possible with a much lower payload capacity. ...
This paper presents the Vega robot, which is a small, low cost, potentially disposable ground robot designed for nuclear decommissioning. Vega has been developed specifically to support characterization and inspection operations, such as 2D and 3D mapping, radiation scans and sample retrieval. The design and construction methodology that was followed to develop the robot is described and its capabilities detailed. Vega was designed to provide flexibility, both in software and hardware, is controlled via tele-operation, although it can be extended to semi and full autonomy, and can be used in either tethered or untethered configurations. A version of the tethered robot was designed for extreme radiation tolerance, utilizing relay electronics and removing active electronic systems. Vega can be outfitted with a multitude of sensors and actuators, including gamma spectrometers, alpha/beta radiation sensors, LiDARs and robotic arms. To demonstrate its flexibility, a 5 degree-of-freedom manipulator has been successfully integrated onto Vega, facilitating deployments where handling is required. To assess the tolerance of Vega to the levels of ionizing radiation that may be found in decommissioning environments, its individual components were irradiated, allowing estimates to be made of the length of time Vega would be able to continue to operate in nuclear environments. Vega has been successfully deployed in an active environment at the Dounreay nuclear site in the UK, deployed in nonactive environments at the Atomic Weapons Establishment, and demonstrated to many other organizations in the UK nuclear industry including Sellafield Ltd, with the goal of moving to active deployments in the future.
... Limited by this, the options for mobile robots are to either return to a base station for charging, have its battery replaced manually, or operate with a tether. The first two options result in downtime for the robot while the third option presents additional challenges such as tether crossovers, limited bending around obstacles, reduce in the robot payload from the tether system, all of which limit the mobility and performance of the robot [8]. ...
... Both wheel and legged robots of medium (ANYmal and Husky) and small (Jackal and Corin) scale have been included for ground-based robots as these platforms have gained significant interest in the industry and research community due to their availability or capability that previous platforms have not been capable of achieving [8,14,15]. The AVEXIS and BlueROV represent the mini-and small autonomous underwater vehicle (AUV) scale robot which is more suitable for the hazardous environment [16]. ...
Advances in technology have seen mobile robots becoming a viable solution to many global challenges. A key limitation for tetherless operation, however, is the energy density of batteries. Whilst significant research is being undertaken into new battery technologies, wireless power transfer may be an alternative solution. The majority of the available technologies are not targeted toward the medium power requirements of mobile robots; they are either for low powers (a few Watts) or very large powers (kW). This paper reviews existing wireless power transfer technologies and their applications on mobile robots. The challenges of using these technologies on mobile robots include delivering the power required, system efficiency, human safety, transmission medium, and distance, all of which are analyzed for robots operating in a hazardous environment. The limitations of current wireless power technologies to meet the challenges for mobile robots are discussed and scenarios which current wireless power technologies can be used on mobile robots are presented.
... As an example, for dry storage facilities, Cheah et al. [3] proposed a re-configurable robotic platform that crosses a small access point and inspects an extreme environment. Another example of robotic solutions for the extreme environment was proposed in [4], where a robotic solution was utilised to clean up decommissioning sites. In the case of underwater storage facilities, several robotic solutions were developed [5][6][7][8]. ...
Swarm robotics is a decentralised mechanism used to coordinate a large group of simple robots. An exploration task means fully scanning an unknown area using a large number of robotic swarms. It has great potential for use in many real-world applications, such as monitoring extreme environments. Although there are many research studies on swarm exploration, the real-world scenarios of the swarm algorithm have not been fully investigated. This paper proposes a new application scenario for swarm exploration to monitor nuclear waste storage facilities. To coordinate the robotic swarm, the active elastic sheet model was utilised, which is a bio-inspired collective motion mechanism. We implemented the exploration scenario in a wet storage facility using a swarm of low-cost autonomous micro-surface robots, Bubbles. We developed a realistic kinematic model of the Bubble platform and implemented the exploration scenario using large swarm sizes. This paper showed the feasibility of using a low-cost robotic platform for this new application, although the accuracy of the path planning was not very high.KeywordsSwarm roboticsExplorationCollective motionExtreme environments
... More recently, the emergence and growth of care robotics, advancements in prosthetics limbs and associated research [2,3] renewed attention on this topic due to the need for closing the distance between platforms and users. New materials and advancements in tactile systems contributed to the flourishing of new studies, areas of interests, and applications, for example, the rising need for robots to take over complex and risky [4,5] tasks in hazardous environments to safeguard human lives. Tasks in radioactive or corrosive environments require spatial awareness and sensory feedback to be performed effectively. ...
This work introduces an array prototype based on a Frequency Modulation (FM) encoding architecture to transfer multiple sensor signals on a single wire. The use case presented adopts Hall-effect sensors as an example to represent a much larger range of sensor types (e.g., proximity and temperature). This work aims to contribute to large area artificial skin systems which are a key element to enhance robotic platforms. Artificial skin will allow robotic platforms to have spatial awareness which will make interaction with objects and users safe. The FM-based architecture has been developed to address limitations in large-scale artificial skin scalability. Scalability issues include power requirements; number of wires needed; as well as frequency, density, and sensitivity bottlenecks. In this work, eight sensor signals are simultaneously acquired, transferred on a single wire and decoded in real-time. The overall taxel array current consumption is 36 mA. The work experimentally validates and demonstrates that different input signals can be effectively transferred using this approach minimizing wiring and power consumption of the taxel array. Four different tests using single as well as multiple stimuli are presented. Observations on performances, noise, and taxel array behaviour are reported. The results show that the taxel array is reliable and effective in detecting the applied stimuli.
... Previous use of physics simulators and video game engines to recreate nuclear environments has largely been separated into two sub categories. There have been efforts to model radiation fields, predominantly for dosimetry training [43] and dose estimation of radiation workers, or to model robot deployment into mock nuclear facilities [44,45]. The former contains inverse square distance estimations of radiation exposure rate but not robot interaction, whereas the latter has simulated robot systems without radiation field estimations. ...
The utilisation of robots in hazardous nuclear environments has potential to reduce risk to humans. However, historical use has been largely limited to specific missions rather than broader industry-wide adoption. Testing and verification of robotics in realistic scenarios is key to gaining stakeholder confidence but hindered by limited access to facilities that contain radioactive materials. Simulations offer an alternative to testing with actual radioactive sources, provided they can readily describe the behaviour of robotic systems and ionising radiation within the same environment. This work presents a quick and easy way to generate simulated but realistic deployment scenarios and environments which include ionising radiation, developed to work within the popular robot operating system compatible Gazebo physics simulator. Generated environments can be evolved over time, randomly or user-defined, to simulate the effects of degradation, corrosion or to alter features of certain objects. Interaction of gamma radiation sources within the environment, as well as the response of simulated detectors attached to mobile robots, is verified against the MCNP6 Monte Carlo radiation transport code. The benefits these tools provide are highlighted by inclusion of three real-world nuclear sector environments, providing the robotics community with opportunities to assess the capabilities of robotic systems and autonomous functionalities.
... Currently, research and development in robotics and its applications is an actively growing field, including the development of robotics applications in assisting first responders in rescue missions, in which the main objective is to improve the search and rescue (SAR) operation to become faster and safer. A wide range of robotics design has been introduced and deployed for specifically performing SAR missions [4][5][6][7][8][9][10][11]. Most of these robots are designed to assist with some specific tasks that can be grouped into four general categories according to their purpose in the SAR response process, namely search, extraction, evacuation, and treatment [5]. ...
Despite the fact that a large number of research studies have been conducted in the field of search and rescue robotics, significantly little attention has been given to the development of rescue robots capable of performing physical rescue interventions, including loading and transporting victims to a safe zone—i.e., casualty extraction tasks. The aim of this study is to develop a mobile rescue robot that could assist first responders when saving casualties from a dangerous area by performing a casualty extraction procedure whilst ensuring that no additional injury is caused by the operation and no additional lives are put at risk. In this paper, we present a novel design of ResQbot 2.0—a mobile rescue robot designed for performing the casualty extraction task. This robot is a stretcher-type casualty extraction robot, which is a significantly improved version of the initial proof-of-concept prototype, ResQbot (retrospectively referred to as ResQbot 1.0), that has been developed in our previous work. The proposed designs and development of the mechanical system of ResQbot 2.0, as well as the method for safely loading a full-body casualty onto the robot’s ‘stretcher bed’, are described in detail based on the conducted literature review, evaluation of our previous work, and feedback provided by medical professionals. We perform simulation experiments in the Gazebo physics engine simulator to verify the proposed design and the casualty extraction procedure. The simulation results demonstrate the capability of ResQbot 2.0 to carry out safe casualty extractions successfully.
... 1 A mobile manipulator is composed of a robotic manipulator mounted on a mobile base, offering both mobility and dexterity. Many different professional and consumer service applications have been envisioned for mobile manipulators, mainly to perform manufacturing assistance in industrial environments [4,5], to execute domestic service tasks [3,6] and human assistance [7,8], to transport goods inside warehouses and stores [9,10] and to manipulate and transport objects in hazardous environments such as in search and rescue missions [11,12] or in areas with radioactive or toxic debris [13]. There has been a growing interest in the research community in developing autonomous mobile manipulators, ranging from wheeled-mobile robots [14,15] to humanoids [16], legged robots [17] and even aerial robots [18]. ...
This paper describes the implementation of an autonomous mobile manipulator to build outdoor structures consisting of heterogeneous brick patterns, finding applications in different industrial automation, manufacturing and civil construction scenarios. This system was developed for the Mohamed Bin Zayed International Robotics Challenge (MBZIRC) 2020, to demonstrate the novel real-world application of constructing structures using teams of robots, showcasing once again the role of major scientific competitions in advancing the state of the art towards exploring solutions to open problems. The paper presents in detail the hardware and software architectures of the developed mobile manipulator, integrating different research results and developments into a functional complex robot system, while proposing methods to detect, approach and manipulate differently sized/colored bricks to build a wall of predefined pattern given to the robot just before the building task starts.
Article Highlights
Full system description of an autonomous mobile manipulator for construction tasks tested in a realistic setting
Algorithms for detection, localization, picking and placement of heterogeneous building blocks to form large structures
Versatile service robot capable of smooth adaptation to other functions developed through scientific robot competitions
... However, the main limitation of mobile robots is the short battery lifetime. Therefore, while conducting remote jobs, mobile robots are required to return to a base station for charging, manually battery replacement or tethering [159]. However, these operations are time-consuming. ...
Robotic applications nowadays are widely adopted to enhance operational automation and performance of real-world Cyber-Physical Systems (CPSs) including Industry 4.0, agriculture, healthcare, and disaster management. These applications are composed of latency-sensitive, data-heavy, and compute-intensive tasks. The robots, however, are constrained in the computational power and storage capacity. The concept of multi-agent cloud robotics enables robot-to-robot cooperation and creates a complementary environment for the robots in executing large-scale applications with the capability to utilize the edge and cloud resources. However, in such a collaborative environment, the optimal resource allocation for robotic tasks is challenging to achieve. Heterogeneous energy consumption rates and application of execution costs associated with the robots and computing instances make it even more complex. In addition, the data transmission delay between local robots, edge nodes, and cloud data centres adversely affects the real-time interactions and impedes service performance guarantee. Taking all these issues into account, this paper comprehensively surveys the state-of-the-art on resource allocation and service provisioning in multi-agent cloud robotics. The paper presents the application domains of multi-agent cloud robotics through explicit comparison with the contemporary computing paradigms and identifies the specific research challenges. A complete taxonomy on resource allocation is presented for the first time, together with the discussion of resource pooling, computation offloading, and task scheduling for efficient service provisioning. Furthermore, we highlight the research gaps from the learned lessons, and present future directions deemed beneficial to further advance this emerging field.
An integral part of the global task of increasing the efficiency of movement processes and performing specified technological operations by a mobile robot is the choice of a movement path from the initial (starting) to the final (target) point. At the same time, a preliminary assessment of the proposed route of movement is an important stage in the development of a program for its movement. In this paper, we consider the problem of finding the shortest path for moving the mobile robot in a multilevel environment, taking into account the features of transitions between levels, restrictions, the presence or absence of obstacles along the way. An information system for calculating the shortest route from the starting point to the target point is proposed based on the NavMesh navigation system in the Unity virtual environment. The results of computer simulation of robot movement in a multilevel environment show that the system successfully finds the shortest route for various scenarios.
This paper explores the design and development of a folding robot required to survey and characterize nuclear facilities only accessible via 125 mm diameter entry ducts. The enclosed legacy facilities at old nuclear sites like Sellafield in the UK have limited access. The condition, radioactive characteristics and accessibility of the enclosed environments is unknown and for decommissioning to take place, these environments must be mapped and characterised. For a robot to carry out this task, one of the key requirements is the ability of the robot to traverse rough terrain and obstacles that could be found inside the facility. To accommodate this, while fitting through the entry duct, the chosen design utilizes morphing whegs (wheel-legs), for locomotion. These are shape-changing wheels that can open out into a set of legs that rotate around an axle, allowing greater traction, diameter, and object traversal ability than wheels alone. The design and morphology of a folding morphing-wheg robot for nuclear characterisation, as well as the manufacture and testing of a prototype is discussed in this paper. A preliminary evaluation of the robot has shown it is capable of climbing up a maximum step height of 150 mm, while having a wheel diameter of 100 mm and being able to fit through a 125 mm duct.KeywordsFolding RobotMorphing WhegNuclear Decommissioning
Recent times are witnessing the emergence of indoor sites with extenuating circumstances that place a strict time constraint on mobile robots to reach a target while covering a given area. This has created a global demand to equip mobile robots with the ability to autonomously plan a coverage path to reach the static target effectively and efficiently. The current approaches to achieve such tasks, however, are either time-consuming or human-operator dependent. To this end, an offline-online strategy is proposed to meet the speeding-up challenge by efficiently modelling the environment using a priori information. In the ‘offline’ stage of the strategy, the layout of the environment is segmented into a set of regions. The corners and dead-ends are identified based on the spatial mobility of the regions. The global path is then computed by deriving a graph-structured, road map using the segmented regions. In the ‘online’ stage, the global path is traversed by selecting frontiers which concurrently minimizes the covered area and time. In case the path is obstructed, a re-planning strategy is deployed. The proposed strategy is evaluated by various experiments against two baseline search approaches in three simulated environments. The results manifest a significant reduction in time to reach the goal and coverage area which caters to the strict time constraint for mobile robots
The perception of different visual motion cues is crucial for autonomous mobile robots to react to or interact with the dynamic visual world. It is still a great challenge for a micro mobile robot to cope with dynamic environments due to the restricted computational resources and the limited functionalities of its visual systems. In this study, we propose a compound visual neural system to automatically extract and fuse different visual motion cues in real-time using the extremely constrained computation power of micro mobile robots. The proposed visual system contains multiple bio-inspired visual motion perceptive neurons each with a unique role, for example to extract collision visual cues, darker collision cue and directional motion cues. In the embedded system, these multiple visual neurons share a similar presynaptic network to minimise the consumption of computation resources. In the postsynaptic part of the system, visual cues pass results to corresponding action neurons using lateral inhibition mechanism. The translational motion cues, which are identified by comparing pairs of directional cues, are given the highest priority, followed by the darker colliding cues and approaching cues. Systematic experiments with both virtual visual stimuli and real-world scenarios have been carried out to validate the system’s functionality and reliability. The proposed methods have demonstrated that (1) with extremely limited computation power, it is still possible for a micro mobile robot to extract multiple visual motion cues robustly in a complex dynamic environment; (2) the cues extracted can be fused with a lateral inhibited postsynaptic network, thus enabling the micro robots to respond effectively with different actions, accordingly to different states, in real-time. The proposed embedded visual system has been modularised and can be easily implemented in other autonomous mobile platforms for real-time applications. The system could also be used by neurophysiologists to test new hypotheses pertaining to biological visual neural systems.
The use of ground-based robotic systems for the characterization of nuclear environments is reviewed. Almost since the dawn of the nuclear energy industry, man has somewhat inadvertently created environments in which access has been constrained primarily due to the risk posed by extreme levels of radiation exposure but also due to space constraints, and because of toxic and combustible atmospheres. Robotic systems pose an ideal solution to some of these difficulties, removing the need for humans to access such places and frequently providing data on the state of such places that would not otherwise be available. However, each of these requirements are often very different in terms of the specification of a given robot, and the detailed characteristics of a given harsh environment can pose significant challenges even for the most robust of platforms. Furthermore, such developments can be expensive in terms of cost and development time. These issues notwithstanding, robotic solutions to nuclear challenges are reaching a level of maturity where their use is destined to add significant value. This paper considers the salient developments in ground-based solutions from the era preceding the Three Mile Island accident, through Chernobyl and on to the present day and, in particular, the needs of Fukushima Daiichi as attentions turn to this complex robotic suite of challenges. [OPEN ACCESS]
In this paper, the characteristics and performance of three open-source simulators for robotics, V-REP, Gazebo and ARGoS, are thoroughly analysed and compared. While they all allow for programming in C++, they also represent clear alternatives when it comes to the trade-off between complexity and performance. Attention is given to their built-in features, robot libraries, programming methods and the usability of their user interfaces. Benchmark test results are reported in order to identify how well the simulators can cope with environments of varying complexity. The richness of features of V-REP and the strong performance of Gazebo and ARGoS in complex scenes are highlighted. Various usability issues of Gazebo are also noted.
This tutorial chapter aims to teach the main theoretical concepts and explain the use of ROS Navigation Stack. This is a powerful toolbox to path planning and Simultaneous localization and mapping (SLAM) but its application is not trivial due to lack of comprehension of the related concepts. This chapter will present the theory inside this stack and explain in an easy way how to perform SLAM in any robot. Step by step guides, example codes explained (line by line) and also both simulated and real robot testing will be available. We will present the requisites and the how-to's that will make the readers able to set the odometry, stablish reference frames and its transformations, configure perception sensors, tune the navigation controllers and plan the path on their own virtual or real robots.
Recently, Rao-Blackwellized particle filters (RBPF) have been introduced as an effective means to solve the simultaneous localization and mapping problem. This approach uses a particle filter in which each particle carries an individual map of the environment. Accordingly, a key question is how to reduce the number of particles. In this paper, we present adaptive techniques for reducing this number in a RBPF for learning grid maps. We propose an approach to compute an accurate proposal distribution, taking into account not only the movement of the robot, but also the most recent observation. This drastically decreases the uncertainty about the robot's pose in the prediction step of the filter. Furthermore, we present an approach to selectively carry out resampling operations, which seriously reduces the problem of particle depletion. Experimental results carried out with real mobile robots in large-scale indoor, as well as outdoor, environments illustrate the advantages of our methods over previous approaches
Decommissioning nuclear facilities is a relatively new field, which has developed rapidly in the last ten years. It involves materials that may be highly radioactive and therefore require sophisticated methods of containment and remote handling. The wastes arising from decommissioning are hazardous and have to be stored or disposed of safely in order to protect the environment and future generations. Nuclear decommissioning work must be carried out to the highest possible standards to protect workers, the general public and the environment. This book describes the techniques used for dismantling redundant nuclear facilities, the safe storage of radioactive wastes and the restoration of nuclear licensed sites. * Describes the techniques used for dismantling nuclear facilities, safe storage of radioactive wastes, and the restoration of nuclear licensed facilities. * Provides the reader with decommissioning experience accumulated over 15 years by UKAEA. * Contains valuable information to personnel new to decommissioning and waste management.
In this paper we investigate the problem of navigation for a planar mobile robot tethered to a base by a flexible cable of length L. Obstacles present in the environment, coupled with the cable length constraint, makes the problem highly non-trivial. We adopt a topological approach along with graph search-based techniques to solve this problem, wherein we use the notion of a homotopy augmented graph to capture the information about the homotopy class of the cable. This lets us plan traversable optimal trajectories from an initial robot position and cable configuration to a final position of the robot. We demonstrate the algorithm by planning trajectories in several cluttered environments and with different cable lengths. As a demonstration of practical applicability, using a dynamic simulation testbed we simulate a robot-cable system following a planned trajectory.
On March 11 2011, a huge earthquake and tsunami hit eastern Japan, and four reactors in the Fukushima Daiichi Nuclear Power Plant were seriously damaged. Because of high radiation levels around the damaged reactor buildings, robotic surveillance were demanded to respond to the accident. On June 20, we delivered our rescue robot named Quince which is a tracked vehicle with four sub-tracks, to Tokyo Electric Power Company (TEPCO) for damage inspection missions in the reactor buildings. Quince needed some enhancements such as a dosimeter, additional cameras, and a cable communication system for these missions. Furthermore, stair climbing ability and user interface was implemented for easy operation for novice operators. Quince have conducted six missions in the damaged reactor building. In the sixth mission on October 20, it reached to the topmost floor of the reactor building of unit 2. However, the communication cable was damaged on the way back, and Quince was left on the third floor of the reactor building. Therefore, an alternative Quince is requested recently. In this paper, we report the situation of the missions for Quince, and introduce enhancements of the next Quince for future missions.
We study the problem of planning the shortest path for a polygonal robot anchored to a fixed base point by a finite tether translating among polygonal obstacles in the plane. Specifically, we preprocess the workspace to efficiently answer queries of the following type: Given a source location of the robot and an initial configuration of the tether, compute the shortest path to reach a target location while avoiding obstacles and adhering to the tether's constraints. Our work is an extension of the recent work by Kim et al. [1] who considered the problem for a point robot. Their algorithm relies on a discretization of the workspace and is optimal with respect to this discretization. We first replace their grid-based approach with a visibility-graph based approach. This allows to improve the running time of their algorithm by several orders of magnitude. Specifically, testing on a scenario similar to one presented by Kim et al., the running time is improved by a factor of more than 500. Moreover, our approach, which plans optimal paths, is applicable to polygonal (translating) robots and can be used to plan a shortest path while ensuring a predefined clearance from the obstacles. We report on our experimental results on a variety of scenarios. In all cases the preprocessing time is less than one second on a standard-commodity laptop, and a typical query takes several tens of miliseconds.
We consider the problem of finding the shortest path for a tethered robot in a planar environment with polygonal obstacles of n total vertices. The robot is attached to an anchor point by a tether of finite length. The robot can cross the tether; i.e., the tether can be self-intersecting. Neither the robot nor the tether may enter the interior of any obstacle. The initial tether configuration is given as a polyline of k vertices.
If the tether is automatically retracted and kept taut, we present an O(kn2logn) time algorithm to find the shortest path between the source and the destination point. This improves the previous O(lkn3) time algorithm [24], where l is the number of loops in the initial tether configuration. If the tether can only be retracted while the robot backtracks along the tether, we present an algorithm to find the shortest path in O((n+logk)logn) time.
From exploring planets to cleaning homes, the reach and versatility of robotics is vast. The integration of actuation, sensing and control makes robotics systems powerful, but complicates their simulation. This paper introduces a versatile, scalable, yet powerful general-purpose robot simulation framework called V-REP. The paper discusses the utility of a portable and flexible simulation framework that allows for direct incorporation of various control techniques. This renders simulations and simulation models more accessible to a general-public, by reducing the simulation model deployment complexity. It also increases productivity by offering built-in and ready-to-use functionalities, as well as a multitude of programming approaches. This allows for a multitude of applications including rapid algorithm development, system verification, rapid prototyping, and deployment for cases such as safety/remote monitoring, training and education, hardware control, and factory automation simulation.
On March 11, 2011, a massive earthquake and tsunami hit eastern Japan, particularly affecting the Tohoku area. Since then, the Fukushima Daiichi Nuclear Power Station has been facing a crisis. To respond to this crisis, we considered using our rescue robots for surveillance missions. Before delivering a robot to TEPCO (Tokyo Electric Power Company), we needed to solve some technical issues and add some functions to respond to this crisis. Therefore, we began a redesign project to equip the robot for disaster response missions. TEPCO gave us two specific missions. One was to explore the inside and outside of the reactor buildings to perform dose measurements. The other one was to sample contaminated water and install a water gauge in the basement of the reactor buildings. To succeed in the above two missions, we redesigned our mobile robot, Quince, and performed repeated operational test to improve it. Finally, one of the robots was delivered to the Fukushima Daiichi Nuclear Power Station on June 20, 2011. In this paper, we will introduce the requirements for the above two missions and report how we fulfilled them.
We consider the problem of planning shortest paths for a tethered
robot with a finite length tether in a 2D environment with polygonal
obstacles. We present an algorithm that runs in time O((k<sub>l</sub>+1)
<sup>2</sup>n<sup>4</sup>) and finds the shortest path or correctly
determines that none exists that obeys the constraints, where n is the
number obstacle vertices, and k<sub>l</sub> is the number loops in the
initial configuration of the tether. The robot may cross its tether but
nothing can cross obstacles, which cause the tether to bend. The
algorithm can also be applied to planning a shortest path for the free
end of an anchored cable
Robots compete in nuclear decommissioning challenge
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