题型:阅读理解 题类:模拟题 难易度:普通
安徽省定远县育才学校2020届高三英语5月模拟考试试卷
A dove rested on a telephone wire. Ready for takeoff, it raises its wings, springs into the air and flaps away. This series of actions is so common that you probably do not pay it much attention. But University of Manchester bioinechanical engineer Ben Parslew does. He is trying to design robots that can jump like birds.
Most conventional robots roll around on wheels, limiting mobility. There is a need for more agile robots that "can jump over obstacles in messy environments," Parslew says. To design such a machine, he turned to nature: "Birds are really good jumpers," he notes.
The trouble is, when birds start to take off, they lean so far forward that they should tip over and fall onto their beaks(喙). Yet that does not happen. Parslew and his team used computer modeling to discover how birds avoid this fate. They discovered that birds twist their bodies slightly towards the back while accelerating into a jump. They also have flexible legs and toe joints, which prevent them from taking off briefly and immediately crashing into the ground. The result were published last October in Royal Society Open Science.
Parslew thinks engineers can use this information to design robots that can not only jump well but also launch into flight more. efficiently. University of Southern California biomechanist Michael Habib, who was not involved in the study, says springs and levers(杠杆)enable more rapid acceleration-than wheels do. And many animals are masters of springs and levers.
"If you can understand how that works," Habib adds, "you can build a robot that's good at running around and good at flying, and it will also be good at taking off suddenly in all kinds of conditions and landing on a dime."Parslew is now designing such a robot, as an alternative to wheeled rovers for exploring other planets.
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