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Rapid information gathering during the initial stage of investigation is an important process in case of disasters. However this task could be very risky for human rescue crews, when the infrastructure of the building has been compromised or the environment contaminated by nuclear, biological, or chemical weapons. To be able to develop robots that can go inside the site instead of humans, several...
Planetary rovers play a significant role in surface explorations on the Moon and/or Mars. However, because of wheel slippage, the wheels of planetary rovers can get stuck in loose soil, and the exploration mission may fail because of this situation. To avoid slippage and increase the wheels' drawbar pull, the wheels of planetary rovers typically have parallel fins called lugs on their surface. In...
In disaster scenarios, mobile robots that have the capability to explore in dangerous environments can offer significant assistance in search and rescue missions instead of rescue crews. The realization of such robot systems is depending on many technologies. One important future technology is autonomous navigation to replace the currently used teleoperation technology. To develop a 3-D path planning...
This paper describes the development of a sensing device that can be used to estimate the position of mobile robots on slippery terrains. The device consists of an optical sensor designed for a computer mouse and dual laser light sources for generating a laser speckle pattern. It detects the motion of a moving surface at a large distance from the surface, from 80 mm to 300 mm, by tracking the laser...
This paper describes various configurations of two connected unit crawlers. By changing the relative position of the two connected vehicle units, the overall robot comprising such a mechanism can automatically adapt to surface obstacles on the field, including complicated structures such as disaster-generated debris. In addition, we analyzed the effect of axis arrangements in order to simplify the...
In the case of disasters such as earthquakes or Nuclear/Biological/Chemical(NBC) terrorist attacks, mobile robots, called “rescue robots,” that can work in dangerous environments instead of rescue crews in rescue missions, can be of great help. However, realizing such robot systems requires many types of technologies. In particular, path planning is an important technology that provides a mobile robot...
In this paper, a new category of wheel-leg hybrid robot inspired by retracting configuration of the armadillo is presented. The proposed mechanism can compose large wheel diameter compared with the previous hybrid robot to realize high ability to climb obstacles. A prototype model of one wheel-leg module of the proposed robot mechanism has been developed to illustrate the concept. Actual design and...
Mobile rescue robots used in search and rescue missions must be able to navigate in unknown environments and map these environments. In such situations, three-dimensional (3D) data obtained by a laser range finder is very useful for supporting teleoperation of robots to locate victims and aid rescue crews in devising rescue strategies. However, when using conventional scanning systems to obtain such...
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...
The authors attempted to create a 3-D map of an underground mall and subway station using a tracked vehicle. This paper is a field report of the 3-D mapping of the Sendai subway station by the tracked vehicle in Dec. 2007. From the ticket barriers to the platform, the Sendai subway station consists of three floors. For the 3-D mapping, we developed a tracked vehicle named ??Kenaf??, a small and light-weight...
The wheel slip ratio is an important state variable in terramechanics research and the control of planetary rovers. Definitions of the slip ratio for a wheel with lugs and methods of estimating it for all wheels onboard have seldom been attempted. This paper presents several definitions for the slip ratio of a lugged wheel, which can be interconverted by altering the shearing radius. Equations for...
Identifying planetary soil parameters is not only an important scientific goal, but also necessary for exploration rover to optimize its control strategy and realize high-fidelity simulation. An improved wheel-soil interaction mechanics model is introduced, and it is then simplified by linearizing the normal stress and shearing stress to derive closed-form analytical equations. Eight unknown soil...
In this paper, the basic running performance of the cylindrical tracked vehicle with sideways mobility is presented. The crawler mechanism is of circular cross-section and has active rolling axes at the center of the circles. Conventional crawler mechanisms can support massive loads, but cannot produce sideways motion. Additionally, previous crawler edges sink undesirably on soft ground, particularly...
In this paper, a tetrahedral mobile robot with central axis for transformation to the flat vehicle is presented. The throwable robot with the function of going into narrow spaces when its in the flat-vehicle mode is explained in detail. A prototype has been developed to illustrate the concept. Motion experiments confirm the novel properties of this mechanism: mode changing function and omnidirectional...
The wheels of planetary rovers that are used in space explorations sometimes slip or lose contact with the ground while traversing a sandy terrain. In order to estimate the behavior of these rovers moving on loose soil, it is very important to accurately estimate the drawbar pull of their wheels. Some wheel-soil interaction models based on terramechanics have been proposed for the estimation of the...
For tracked vehicles moving over rough terrain, it is important to avoid rollovers and rapid motion. To realize smooth locomotion on rough terrain, some tracked vehicles are equipped with ??active flippers.?? Such flippers increase the traversability and stability of tracked vehicles. However, their control increases the operator workload, especially in the case of teleoperation. To eliminate this...
In this paper, the authors present a path planing system for autonomous navigation of lunar/planetary rover. In the path planner, candidate paths are generated and evaluated by multiple criteria including occlusion index, terrain roughness/inclination indices. The proposed system considers the occlusion effect produced by obstacles present in the inspected environment and the features of the environment...
Localization and mapping are essential elements in the design of mobile robots used for search and rescue mission. Localization is a key-function of remote control and mapping in an unstructured environment. However, in general, odometry in tracked vehicles is ambiguous because of the track slippage. To solve this problem, we developed a three-dimensional gyro-based odometry that considers the compensation...
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