(source: Science and technology daily)
Researchers from Saarland University in Germany recently created a equipped with shape memory alloy "muscle" artificial hand, it than the artificial hand more lithe. The hands of the "muscle fibers" by ultrafine nickel titanium alloy wire beam, can be bent, stretched, let the artificial hand can perform more accurate motion. This technique can be used in the future of industrial robots, but also produced a new prosthesis. The team will demonstrate the artificial hand in April 13th to 17 of the German Hannover industrial exhibition model.
According to Science Daily website reported, the research team from Saarland University and mechanical and electrical and automation technology center of Professor Stefan shillaker leadership. They will pull into shape memory nickel titanium alloy diameter and similar hair filaments, modelled on the structure of human muscle, the alloy wire bunches consist, with multi strand alloy wire connection joint of a finger, simulation of muscle fiber made finger positive flexor and back extensor and rapid contraction and relaxation.
Silec said, "the shape memory alloy" refers to the metal can "remember" their shape, can be restored to the original appearance after deformation. "This property of the nickel titanium alloy comes from the internal phase change. For example, when the alloy wire is warming, the material will change the lattice structure, make it shrink like a muscle."
At present, the artificial hand on the industrial production line depends on a lot of complex support technology and other equipment, such as electric motor or pneumatic device, become cumbersome and inflexible, noisy and expensive. "In contrast, the use of smart muscle manufacturing tools without additional equipment, light and flexible, adaptable and no noise, production costs are relatively low." Silec said, in all the known driving machinery, alloy wire energy density is the highest, can be strictly limited space to complete the high intensity of the movement."
The Engineer Firomona Simone said: "in a strong pulling force is applied, these alloys tow can rapid contraction and relaxation. The reason for this is because of the rapid cooling, because a large amount of metal wire surface area is larger, so that the heat can quickly spread. A very fine line of silk can withstand the force of contraction and stretching of the human muscle, so we can achieve fast and smooth movement of the fingers."
Shape memory alloy wire. Another effect of muscle, when the artificial hand is to perform a particular action, if blocked, it can in a very natural way to respond. This means that the human and artificial hand "hand in hand". The relative motion of the alloy wire is controlled by a semiconductor chip, can achieve precise motion. This system does not require sensor. The alloy wire material itself has sensing properties." Silec said, "the controller can identify resistance test data, so as to know the exact position of alloy wire at any moment, the hands and fingers can accurate activity."
The researchers hope to continue the study of hand motion model, exploration of shape memory alloy sensing properties, with the further development of artificial hand prototype, simulation and improvement of its manpower way. (Chang Lijun)