Tag: 上海419论坛FQ

Sidewinder robots slither like snakes

first_img Sign up for our daily newsletter Get more great content like this delivered right to you! Country Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe Click to view the privacy policy. Required fields are indicated by an asterisk (*) Email The motion is peculiar and, supposedly, “if you look too long at [a sidewinder] you’ll go mad,” says Daniel Goldman, a physicist at the Georgia Institute of Technology in Atlanta. And that motion will enable a snake to go uphill. But to maintain a grip on an incline, the snake modifies its motion to keep more of its body touching the ground as it moves, he, Choset, and their colleagues report online today in Science.Those insights could lead to robots that do better on rough terrain than robots with wheels, such as a Mars rover. “We don’t presently have machines that can climb steeply inclined fragile ground, and this work suggests new ways to build machines that can,” says Daniel Koditschek, an engineer at the University of Pennsylvania who was not involved with this work but who develops legged robots for desert explorations. “The opportunities and benefits for robotics here are significant.”Goldman specializes in studying how animals manage to move through sand and other granular materials that tend to give way. Curious about snakes, he and Hamidreza Marvi, now at postdoctoral student at CMU, went to Zoo Atlanta, where they filmed and analyzed the movements of six sidewinder rattlesnakes climbing in an enclosure with an inclined floor covered with sand. They varied the angle of the floor with each test and also observed several vipers, snakes that are not sidewinders, try to ascend the incline.The vipers slipped and failed to move up the slope, whereas the sidewinders had no problem, the researchers report. As it moves, a sidewinder sends a horizontal wave down its body. At the same time, it undulates up and down. As a result, the parts of the body on the ground push off while the airborne loops reach upslope, where they then make contact to push off. Marvi found that on flat ground, at any moment the rattlers have 25% of their body in contact with the ground. But the snakes tune their motion to the terrain. On a slope of 10°, 40% of the body remains in contact with the ground. That fraction increases to 45% on a 30° slope.In making the adjustment, a snake has to balance two factors. Too much contact and the reptile can’t lift the other parts of the body high enough to reach up the slope. Too little contact, and the sand gives way under the snake’s weight. “Apparently, these animals have found a sweet spot,” Koditschek says.Choset’s group programmed the robot to move in a similar manner, then altered the waves to change how much of the robot’s body was in contact with the sand at any one time. It, too, made it up through the sand. In 2011, archaeologists needed to find out whether parts of ancient Egyptian boats were hidden in dangerously unstable humanmade caves by the Red Sea. Howie Choset, a roboticist at Carnegie Mellon University (CMU) in Pittsburgh, Pennsylvania, thought he had the perfect solution. He had built robotic snakes, so he outfitted one with a camera and sent it slithering through the cave’s narrow opening. But when the robot got inside, “we faced a challenge that we had not seen before,” Choset recalls. The robot couldn’t make its way up the cave’s sandy slope, and the exploration was a bust.Now, Choset has found a way to climb that mountain. By teaming up with researchers studying how live snakes move, he and his colleagues have determined what it takes to make snake robots go uphill, even on slippery, sandy slopes. These reptiles, real and robotic, are sidewinders—they move forward not by slithering, but rather by wriggling their bodies perpendicular to the direction of travel in a undulating S-shaped wave. And by tweaking the two waves, “we can make our snake robots do what the snake can’t do,” Choset says, such as turn on a dime. These attributes may lead to robots that can snake their way through rubble in disaster zones to find trapped people or that can inspect nuclear power plants.“I’m smitten with this paper,” says Adam Summers, a comparative biomechanist at the University of Washington Friday Harbor Laboratories who was not involved with the work. “The biology is informed by the engineering and vice versa.”Choset, too, is quite pleased. He doesn’t have the permits needed to go back to the Egyptian caves, but has now used the robot on another archaeological expedition. There, “we did much better,” he says. Things are looking up for robotic snakes.last_img read more

Read More Sidewinder robots slither like snakes