Kenji Nagaoka

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Future planetary rovers are expected to probe over steep sandy slopes, such as crater rims, where wheel slippage can be a critical issue. One solution to this issue is to mount redundant actuators on the locomotion mechanisms of the rovers such that they can actively reconfigurate themselves to adapt to the driven terrain. In this study, we propose a(More)
Rovers that are used to explore craters on the Moon or Mars require the mobility to negotiate sandy slopes, on which slippage can easily occur. Such slippage can be reduced by actively readjusting the attitude of the rovers. By changing attitude, rovers can modify the position of their center of gravity and the wheel-soil contact angle. In this study, we(More)
Subsurface exploration on the Moon is a significant mission for future space developments. The authors have studied an autonomous robotic explorer which can burrow into the soils. This paper focuses especially on the excavation mechanism of a burrowing robot for near-future lunar subsurface exploration. The main objective of the proposed robot is to bury a(More)
This paper presents a mobile robotic system designed to perform deep soil sampling for lunar or planetary subsurface exploration in the near future. Drilling robots have to carry the excavated fine sand, regolith backward because of the high density. Therefore a new scheme is proposed, to move forward under the soil by making use of reactive force caused by(More)
Locomotion capabilities form the basis for accomplishing robotic exploration by a rover on an asteroid. While traditional locomotion gears, such as wheels and tracks, are promising candidates for traversing extrater-restrial terrains, their capabilities lower in such an environment due to its micro-gravity. Here, we propose a new idea of ciliary(More)
The wheels of planetary rovers typically have grousers (i.e., lugs, cleats) on their surface to provide grip for climbing in loose soil. However, from the viewpoint of designing wheels, there exist few theoretical methods or models for determining the grouser interval for a wheel. The goal of this study is to provide a fundamental guideline for determining(More)
As space exploration progresses, renewed attention has been given to advanced Lunar exploration technologies. The main objective is to address many open questions about the Moon, such as its origin or chemical components, as most of the current hypotheses are just inferences based on limited evidences. Unmanned subsurface investigation technologies for the(More)
This paper discusses a vibration suppression control method for a space robot with a rigid manipulator and flexible appendage. A suitable dynamic model that considers the coupling between the manipulator and flexible appendage was developed for the controller to accomplish the vibration suppression control of the flexible appendage. The flexible appendage(More)
The surfaces of both the Moon and Mars are covered with loose soil, with numerous steep slopes along their crater rims. Therefore, one of the most important requirements imposed on planetary rovers is their ability to minimize slippage while climbing steep slopes, i.e., the ability to generate a drawbar pull with only a small amount of slippage. To this(More)