Technical session talks from ICRA 2012
TechTalks from event: Technical session talks from ICRA 2012
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Automatic Rock Recognition from Drilling Performance DataAutomated rock recognition is a key step for building a fully autonomous mine. When characterizing rock types from drill performance data, the main challenge is that there is not an obvious one-to-one correspondence between the two. In this paper, a hybrid rock recognition approach is proposed which combines Gaussian Process (GP) regression with clustering. Drill performance data is also known as Measurement While Drilling (MWD) data and a rock hardness measure - Adjusted Penetration Rate (APR) is extracted using the raw data in discrete drill holes. GP regression is then applied to create a more dense APR distribution, followed by clustering which produces discrete class labels. No initial labeling is needed. Comparisons are made with alternative measures of rock hardness from MWD data as well as state-of-the-art GP classification. Experimental results from an actual mine site show the effectiveness of our proposed approach.
Evaluation of the Reconfiguration Effects of Planetary Rovers on their Lateral Traversing of Sandy SlopesRovers 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 discuss the effects of attitude changes on downhill sideslip based on the slope failure mechanism and experiments on reconfiguring the rover attitude and wheel angles. We conducted slope-traversing experiments using a wheeled rover under various roll angles and wheel angles. The experimental results show that the contact angle between wheels and slopes has a dominant influence on sideslip when compared with that of readjusting the rover's center of gravity.
Evaluation of Influence of Surface Shape of Locomotion Mechanism on Traveling Performance of Planetary RoversThe 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 end, the wheels/tracks of planetary rovers typically have parallel fins called lugs (i.e., grousers) on their surface. Recent studies have reported that these lugs can substantially improve the traveling performances of planetary rovers. Therefore, in this study, we conducted experiments using lightweight two-wheeled and mono-tracked rovers to provide a quantitative confirmation regarding the influence of lugs on the traveling performances of planetary rovers. Based on our experimental results, we confirmed that, although an increase in the number of lugs contributes to the high traveling performance of wheeled rovers, it does not contribute much to that of tracked rovers. Furthermore, an increase in lug height improves the traveling performances of both types of rovers.
The Robonaut 2 Hand Designed to Do Work with ToolsThe second generation Robonaut hand has many advantages over its predecessor. This mechatronic device is more dexterous and has improved force control and sensing giving it the capability to grasp and actuate a wider range of tools. It can achieve higher peak forces at higher speeds than the original. Developed as part of a partnership between General Motors and NASA, the hand is designed to more closely approximate a human hand. Having a more anthropomorphic design allows the hand to attain a larger set of useful grasps for working with human interfaces. Key to the hands improved performance is the use of lower friction drive elements and a redistribution of components from the hand to the forearm, permitting more sensing in the fingers and palm where it is most important. The following describes the design, mechanical/electrical integration, and control features of the hand. Lessons learned during the development and initial operations along with planned refinements to make it more effective are presented.
Autonomous Detection of Volcanic Plumes on Outer Planetary BodiesWe experimentally evaluated the efficacy of var- ious autonomous supervised classification techniques for de- tecting transient geophysical phenomena. We demonstrated methods of detecting volcanic plumes on the planetary satellites Io and Enceladus using spacecraft images from the Voyager, Galileo, New Horizons, and Cassini missions. We successfully detected 73-95% of known plumes in images from all four mission datasets. We increased the detection rate by using a training subset. Additionally, we showed that the same tech- niques are applicable to differentiating geologic features, such as plumes and mountains, which exhibit similar appearances in images.
Gravity-Independent Mobility and Drilling on Natural Rock Using MicrospinesTo grip rocks on the surfaces of asteroids and comets, and to grip the cliff faces and lava tubes of Mars, a 250 mm diameter omni-directional anchor is presented that utilizes a hierarchical array of claws with suspension flexures, called microspines, to create fast, strong attachment. Prototypes have been demonstrated on vesicular basalt and aâ€˜a lava rock supporting forces in all directions away from the rock. Each anchor can support >160 N tangent, >150 N at 45, and >180 N normal to the surface of the rock. A two-actuator selectively-compliant ankle interfaces these anchors to the Lemur IIB robot for climbing trials. A rotary percussive drill was also integrated into the anchor, demonstrating self-contained rock coring regardless of gravitational orientation. As a harder-than-zero-g proof of concept, 20mm diameter boreholes were drilled 83 mm deep in vesicular basalt samples, retaining a 12 mm diameter rock core in 3-6 pieces while in an inverted configuration, literally drilling into the ceiling.