VOA常速英语2015--德国科学家发明新的仿生手（在线收听）

德国科学家发明新的仿生手

Artificial limbs, including the most complex of them – the human hand – are getting more life-like and useful due to constant advances in tiny hydraulic, pneumatic and electric motors called actuators. But now scientists in Germany say the future of the prosthetic hand may be not in motors, but in wires that can ‘remember’ their shape.

The human hand is one of the most mechanically complex systems in nature, so making an artificial replica is a daunting task. An ideal prosthesis should be light and flexible, with a reasonably powerful grip and controlled by the owner’s mind.

人手是自然界最复杂的机械系统之一，所以制造假手是很艰难的任务。理想的假肢应该轻便又灵活，握力适当，且能被主人用意念控制。

Presently, prosthetics rely on relatively heavy hydraulic, electric or pneumatic actuators to flex artificial fingers, but scientists at Germany's Saarland University are experimenting with much lighter fibers made of a nickel-titanium alloy that change shape when connected to a source of electricity.

目前，假肢要依赖于重液压、电力或气动制动器来让假肢上的手指弯曲，但德国萨尔兰大学的科学家们在试验一种由镍钛合金制成的更轻便纤维，能在连接到电源后改变形状。

“The movement of the hand is done by the wire. This wire, when activated, they contract. And we are able to exploit this contraction to make the finger move. And we can move each phalanx independently,” said Filomena Simone, a PhD engineering student.

“手部的运动是由线路完成的，这种线路在被激活时会收缩，我们就能利用这种收缩来让手指运动，还能让每个指骨独立活动。”

Artificial muscles, tendons

Bundles of memory wires could form more powerful yet lightweight artificial muscles and tendons. Their flexing can be controlled independently by measuring the electrical resistance of the wires.

一束束的记忆线路能组成更强大但轻型的人造肌肉和腱，可以通过测量线路的电阻来独立控制它们的屈伸动作。

“We can monitor the position of the finger without adding any other sensor; only exploiting this embedded feature of the wire,” said Simone.

“我们可以无需添加其他感应器就能监控手指的位置，只需利用线路的这种内在特点即可。”

Scientists believe that with further advances of so-called shape memory alloys, it will be possible to build more natural-looking prosthetic hands.

科学家认为，随着这种形状记忆合金的进一步发展，我们就可能制造出具备更自然外观的假手。

“If you look down the road to future prostheses generations, you'd like to see this integrated with the human body in a way that you can actually sense the nerve stimuli and then can feed that into a micro-controller which there will be translated to a corresponding signal to activate the muscle," said Stefan Seelecke at Saarland University.

“如果展望下未来的假肢，就能看到它们将会与人体融为一体，能感知神经刺激，然后将这种刺激信号传给微控制器，然后转换成相应的信号来激活肌肉。”

Saarland University scientists are now looking into how natural patterns of hand movements could be applied to memory alloy muscles.

萨尔兰大学的科学家们现在在研究如何将手部运动的自然模式应用到记忆合金肌肉中。