A Study on Mobility and Control of the SELENE-2 Lunar Rover

Paper number

IAC-08.A3.2.B5

Author

Dr. Shin-ichiro Nishida, Japan Aerospace Exploration Agency (JAXA), Japan

Coauthor

Ms. Sachiko Wakabayashi, Japan Aerospace Exploration Agency (JAXA), Japan

Year

2008

Abstract

JAXA is carrying out research and development of a mobile robot (rover) aimed at technology demonstration and searching for rocks and soils on the lunar surface. The target areas for manned base construction and lunar exploration are mainly in mountainous zones, and the moon's surface is covered by regolith. Achieving a steady run on such irregular terrain is the big technical problem for rovers. A newly developed lightweight crawler mechanism is good for driving on such irregular terrain because of its low contact force with the ground. This was determined considering the mass and expected payload of the rover. 
Determination of own position using signals from earth orbiting GPS satellite is difficult on the moon, and since the sun may not be visible over much of a path over the moon's surface, heading direction measurement cannot depend on a sun sensor. Dead reckoning based on the odometeric information from the traction system would not be sufficiently accurate due to errors from sliding over the regolith. Using a radio emitter or optical reference on the lander or star tracker and a sensor on the rover is effective for position determination but relies on an optical or radio line of sight being available. Therefore, determining changes in position by reference to geographical features, using for example range finding and/or stereo image sensors, in considered essential.Equipping the rover with a stereo imaging sensor is seen as essential, and since there are many domains in shadow, LED or flash lighting will be required for it to operate. Obstacles can also be directly detected using a laser rangefinder, and equipping the rover with a small laser rangefinder to enable three-dimensional measurements is desirable. From these considerations, the rover course measurement / control system will ideally have a fiber optical gyro, a star tracker, a stereo camera, a wide field camera and a laser range finder, although resource restrictions may force some items to be omitted. This paper describes composition of the rover designed for Japanese first lunar surface exploration , and presents the results of study into methods of dynamics testing and analysis which are needed in its development. This paper also gives an overview of the SELENE-2 lunar exploration rover and the composition of its mobility, navigation and control system.

Abstract document

IAC-08.A3.2.B5.pdf

Manuscript document

IAC-08.A3.2.B5.pdf (🔒 authorized access only).

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