Recovery System Based on Exploration-Biased Genetic Algorithm for Stuck Rover in Planetary Exploration

Contributing toward continuous planetary surface exploration by a rover (i.e., a space probe), this paper proposes (1) an adaptive learning mechanism as the software system, based on an exploration-biased genetic algorithm (EGA), which intends to explore several behaviors, and (2) a recovery system as the hardware system, which helps a rover exit stuck areas, a kind of immobilized situation, by testing the explored behaviors. We develop a rover-type space probe, which has a stabilizer with two movable joints like an arm, and learns how to use them by employing EGA.

To evaluate the effectiveness of the recovery system based on the EGA, the following two field experiments are conducted with the proposed rover: (i) a small field test, including a stuck area created artificially in a park; and (ii) a large field test, including several stuck areas in Black Rock Desert, USA, as an analog experiment for planetary exploration. The experimental results reveal the following implications: (1) the recovery system based on the EGA enables our rover to exit stuck areas by an appropriate sequence of motions of the two movable joints; and (2) the success rate of getting out of stuck areas is 95% during planetary exploration.

Percussive Rock Surface Remover Driven by Solenoid with Planer Motion for Lunar Exploration

This paper deals with a percussive rock surface crusher driven with a solenoid to smoothen the sample surface by a 2-axis planar motion. The weathered rock surface should be removed and smoothened before analyzing its structure and composition precisely. The solenoid, which generates a large vibration amplitude and a large impulsive force, was used to vibrate a tool bit with engineered 1-mm pyramids made of tungsten carbide. The tool bit was fixed parallel to the feed direction or with a skew. A rock sample was moved by a stage with movable ranges for the machining of 10 mm and 20 mm in the x- and y-directions, respectively. The sample paths were randomly generated in 1 or 2 directions. In the comparisons of the surface roughness, the 2-axis motion and tool skew not only allowed isotropic and small roughness but also the removal of more amount due to the removed debris. The roughness reached several tens of micrometers without a certain special frequency component. This level allows for component analysis by X-ray fluorescence or laser-induced breakdown spectrometer.

Vision-Based Behavior Planning for Lunar or Planetary Exploration Rover on Flat Surface

Lunar or planetary exploration rovers are expected to have the ability to move across an area as wide as possible in an unknown environment during a limited mission period. Hence, they need an efficient navigation method. Most of the surface of the moon or planets consists of flat ground, sand, and scattered rocks. In a simple flat sandy terrain with some rocks, rough route planning is sufficient for a lunar or planetary rover to avoid obstacles and reach an assigned point. This paper proposes an efficient vision-based planning scheme for exploration rovers on a flat surface with scattered obstacles. In the proposed scheme, dangerous areas are robustly extracted by processing image data, and the degree of danger is defined. A rough routing plan and sensing plan are simultaneously constructed based on the dangerous-area extraction results. The effectiveness of the proposed scheme is discussed based on the results of some simulations and simple experiments.

Satellite, Planetary or Terrestrial Subsurface Explorer Robot Based on Earthworm Locomotion

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00260005/17.jpg"" width=""150"" />

Subsurface explorer robot</div> We have developed a small, unmanned explorer robot to investigate the undergrounds of satellites and planets. This paper describes the developed excavation robot, which is based on earthworm locomotion. The robot demonstrates excavation activity at 1/6 of its own weight, mimicking the light gravity conditions of the Moon. We conclude that the robot is suitable for future excavation missions. </span>