Seiga Kiribayashi

Collaborative mapping of an earthquake-damaged building via ground and aerial robots

We report recent results from field experiments conducted with a team of ground and aerial robots engaged in the collaborative mapping of an earthquake-damaged building. The goal of the experimental exercise is the generation of three-dimensional maps that capture the layout of a multifloor environment. The experiments took place in the top three floors of a structurally compromised building at Tohoku University in Sendai, Japan that was damaged during the 2011 Tohoku earthquake. We provide details of the approach to the collaborative mapping and report results from the experiments in the form of maps generated by the individual robots and as a team. We conclude by discussing observations from the experiments and future research topics.

Redesign of rescue mobile robot Quince

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.

Gamma-ray irradiation test of electric components of rescue mobile robot Quince

On March 11, 2011, a massive earthquake and tsunami hit eastern Japan, particularly the Tohoku area. Since then, the Fukushima Daiichi Nuclear Power Station has been facing a crisis. To respond to this situation, we began a project to redesign our mobile robots for disaster response missions. A key issue to be addressed was to check the radiation hardness of the electric components of our robot. Initially, no information was available in this regard. Therefore, we conducted gamma-ray irradiation tests for the electric components using cobalt-60. In this paper, we introduce the procedure for the irradiation test and report the results of the test.

Multirobot exploration for search and rescue missions: A report on map building in RoboCupRescue 2009

Mobile robots may be able to aid rescue crews in dangerous environments during search and rescue missions after natural or man-made disasters. In 2006, we began a research project to realize mobile robots that can gather information rapidly at the first stage of a disaster. 3D mapping, which can be an important aid for rescue crews in strategizing rescue missions, is one of our important objectives. Some fundamental elements to enable 3D mapping have been developed. We attended RoboCupRescue 2009 to validate our integrated autonomous 3D mapping system. We demonstrated our mapping system using multiple-robots on the RoboCupRescue field. In this paper, we introduce our mapping system and report the results from the RoboCupRescue competition.

Volcanic ash observation in active volcano areas using teleoperated mobile robots - Introduction to our robotic-volcano-observation project and field experiments

Observation of an active volcano is very important to determine a strategy for estimating its eruptive activity and providing residents with an evacuation warning. However, it is too dangerous for humans to install cameras during eruptive activity to determine the status of a volcano. Furthermore, permanently installed cameras might be damaged by eruptions, and craters can emerge in unanticipated positions. To handle this situation, we proposed robotic observations in a volcanic area after an eruption using a multi-rotor UAV (unmanned aerial vehicle) and a small ground robot. Field experiments are effective at promoting this type of research and development. Therefore, we performed several field experiments at Mt. Asama. In this paper, we introduce our robotic observation project, and report on the field experiments conducted with teleoperated mobile robots in October 2012 at Mt. Asama.

Multi-robot exploration for search and rescue missions: A report of map building in RoboCupRescue 2009

Mobile robots may be able to aid rescue crews in dangerous environments during search and rescue missions after natural or man-made disasters. In 2006, we began a research project to realize mobile robots that can gather information rapidly at the first stage of a disaster. 3D mapping, which can be an important aid for rescue crews in strategizing rescue missions, is one of our important objectives. Some fundamental elements to enable 3D mapping have been developed. We attended RoboCupRescue 2009 to validate our integrated autonomous 3D mapping system. We demonstrated our mapping system using multiple-robots on the RoboCupRescue field. In this paper, we introduce our mapping system and report the results from the RoboCupRescue competition.

Modeling and design of tether powered multicopter

Recently, micro unmanned aerial vehicles (MUAVs), particularly multicopters, are expected to be used for rescue missions and investigations all over the world. However, their operating time for conducting actual missions is currently quite short, typically 20 minutes or less. To extend the flight time, and to prevent the multicopter from leaving the flight area caused by incorrect operations, it is proposed to use an electrical cable as a tether to supply electric power for to the multicopter. To realize such a system, the cable selection is critical. Therefore, in this research, we model the electrical devices (motors and ESCs) on the multicopter, and discuss the optimal cable selection. In this paper, we propose our cable selection method, and introduce our power-feeding tether system that can be carried by unmanned ground vehicles.

Field Report: UAV-Based Volcano Observation System for Debris Flow Evacuation Alarm

Once a volcano erupts, molten rocks, ash, pyroclastic flow, and debris flow can cause disasters. Debris flows can cause enormous damage over large areas. Therefore, a debris-flow simulation is an effective means of determining whether to issue an evacuation call for area residents. However, for safety purposes, restricted areas are set up around a volcano when it erupts. In these restricted areas, it is difficult to gather information such as the amount and permeability of the ash; this information is necessary for precise debris-flow simulations. To address this problem, we have developed an unmanned observation system for use in restricted areas around volcanoes. Our system is based on a multirotor micro unmanned aerial vehicle (MUAV); this system can be used to perform field tests in actual volcanic areas. In this paper, we report the field tests conducted at Mt. Unzen-Fugen during November 2016. The field tests included a demonstration of an unmanned surface flow measurement device and the deployment and retrieval of a small ground vehicle and a drop-down-type ash-depth measurement scale using an MUAV. In addition, we discuss some of the lessons learned.

Design and Development of Tether-Powered Multirotor Micro Unmanned Aerial Vehicle System for Remote-Controlled Construction Machine

In Japan, several types of natural disasters such as floods, earthquakes, and volcanic eruptions have occurred and will likely occur in the future. Therefore, civil engineering works are required for restoration after such natural disasters, and teleoperated construction machines have been developed to facilitate such works. During the operation of teleoperated construction machines, images from various viewpoints e.g., an image from the perspective of the machines or that from the side of the bucket is essential for carrying out tasks efficiently. However, in the case of the initial response to natural disasters, it is difficult to use dedicated, conventional camera-equipped vehicles and fixed cameras on external towers to obtain such perspective images, particularly within a month after the disaster. Therefore, in this research, we propose a tether-powered multirotor micro unmanned aerial vehicle (MUAV) system to obtain images from various perspectives for the operator of a teleoperated construction machine. The features of the proposed system are (1) high voltage for transmitting electric power through thin tether, (2) tension control of the tether in vibration and inclined conditions, and (3) wired VDSL communication between the MUAV and the helipad. In this paper, we introduce the design and implementation of the proposed system. In addition, we report the results of the field test of the tethered MUAV mounted on a construction machine.

Position estimation of tethered micro unmanned aerial vehicle by observing the slack tether

At disaster sites, the use of Micro Unmanned Aerial Vehicles (MUAVs) is expected for human safety. One application is to support first-phase emergency restoration work conducted by teleoperated construction machines. To extend the operation time of a MUAV, the authors proposed a powerfeeding tethered MUAV to provide an overhead view of the site to operators. The target application is to be used outdoors, so a robust and simple position estimation method for the MUAV is required. Therefore, in this paper, the authors propose a position estimation method for the MUAV by observing the slack tether instead of using the Global Positioning System (GPS), vision sensors, or a laser rangefinder. The tether shape is assumed to be a catenary curve that can be estimated by measuring the tethers length, tension, and outlet direction. To evaluate the proposed method, the authors developed a prototype of a helipad with a tether winding mechanism for the tethered MUAV, which contains a measurement function of the tether status. Some indoor experimental results proved the feasibility of the proposed method.