Faculty Profiles - NAKAJIMA Shuro

A leg-wheel robot has mechanically separated four legs and two wheels, and it performs high mobility and stability on rough terrains. In this paper, we propose gait algorithms for trot and pace gaits, and velocity limitation method, which allow continuous locomotion of a leg-wheel robot under random velocity commands. The gait algorithms which are based on the predictive event driven method determine the leg lifting timing to avoid the legs reaching the border of the work space. The velocity limitation method limits the velocity command when it exceeds the mechanical specifications of the robot. Combined the velocity limitation method with the gait algorithms, the proposed method ensures the continuity of locomotion on trot and pace gaits. It is evaluated by simulations and experiments.

DOI

The Set Up Method of Legs' Compliance for Crawl Gait of a Leg-wheel Robot

Shuro Nakajima, Eiji Nakano, Takayuki Takahashi （Part： Lead author )

Journal of the Robotics Society of Japan ( The Robotics Society of Japan ) vol.22 ( no.8 ) 1061 - 1069 2004.11 [Refereed]

A leg-wheel robot, Chariot II, has been developed for the purpose of moving on an unknown unexplored rough terrain without using many sensors such as visual and tactile/force sensors that need accurate and complex control and heavy calculations. The robot equips with mechanically separated wheels and legs, which allows to utilize the advantages of two mechanisms. This paper presents a set up method for legs' compliance of the leg-wheel robot to decrease the pitching and rolling movement of its body when moving on unknown unexplored rough terrains. Using the proposed method, the leg's basic compliance is adjusted in proportion to the roughness of the surface when a phase of leg changes from returning phase to supporting phase. The effectiveness of this method is confirmed by simulation and experiments.

DOI

The Motion Control Method for a Leg-wheel Robot on Unexplored Rough Terrains

Shuro Nakajima, Eiji Nakano, Takayuki Takahashi （Part： Lead author )

Journal of the Robotics Society of Japan ( The Robotics Society of Japan ) vol.22 ( no.8 ) 1082 - 1092 2004.11 [Refereed]

A leg-wheel robot, which has mechanically separated four legs and two wheels, performs high mobility and stability on rough terrain. In this paper, we propose a basic control method for the leg-wheel robot moving on unexplored rough terrains. When moving on a rough terrain, the compliance values and the trajectories of legs are set up in proportion to the environment without using external sensors. And the step axis mechanism that we have developed realizes the stable rolling movement of the robot. The proposed method is evaluated by simulations and experiments. Using this method combined with the predictive event driven gaits, the leg-wheel robot can move on rough terrains in arbitrary directions.

DOI

A Simplified Cooperational Motion Control Method of a Leg-Wheel Robot for an Unexplored Rough Terrain Environment

E.Nakano, T.Takahashi, Z.Wang, Y.Dai, S.Nakajima

Proceedings of The 4th World Multiconference on Systems, Cybernetics and Informatics vol.XII 234 - 239 2000.01 [Refereed]

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Published Papers - NAKAJIMA Shuro