Robots will have hairy hands

Artificial skin was provided with sensitive hairs

Ekaterina Zhdanova, N+1

Scientists from China has created a prototype of artificial "skin with hair" – a highly sensitive sensor that allows you to feel a wide range of influences and has increased mechanical resistance. The results of the study are published in the journal Applied Materials & Interfaces (Zhang et al., Biomimic Hairy Skin Tactile Sensor Based on Ferromagnetic Microwaves).

The sensory characteristics of human skin in the language of devices can be formulated as follows: high sensitivity, a wide range of force detection, durability, abrasion resistance and the ability to determine the stiffness of the affected material. The hairs on the skin are responsible for most of these characteristics.

Sensors that combine all the "necessary" characteristics have not yet been created, and competing prototypes are either insufficiently sensitive, or have a narrow range of "perception", or are complex and expensive nanocomponent devices. In addition, existing prototypes are either artificial skin or hair-like sensors.

Chinese researchers have proposed combining "skin" and "hair" into a simple design. Two arrays of ferromagnetic micro-wires were crossed and mounted in a silicone "skin". The sensory effect of such "hairs" is based on the Barkhausen effect and electromagnetic induction. Arrays of micro-wires are inductors. An alternating current is supplied to the left, which, due to mutual induction, induces an alternating magnetic field in the second trap. The Barkhausen effect manifests itself in the generation of voltage by the second "coil" under mechanical action on it, and the value and type of dependence of the generated voltage on the applied effort allows us to judge what kind of impact it was.

Cobalt-based glass-coated microcircuits used in the work have not only magnetic sensory properties, but also good mechanical ones. According to scientists, these properties resemble human hair – they are thin, able to "distinguish" mechanical effects, and also quite "elastic" – do not tie into knots and do not break off under pressure.

Image of a cobalt-based wire in a scanning microscope
(here and below are the drawings from the article in Applied Materials & Interfaces).

Testing the capabilities of the prototype showed that the sensor has a high sensitivity and a wide range of detection of the impact force. The sensor can sense from one ten-thousandth of a newton to 25 newtons, that is, such an artificial skin will distinguish a fly that has landed on the surface and a load of two kilograms. According to the test results, the robot-like hand was able to "feel" the sliding of the object and friction with the help of the prototype.

(a) The concept of "skin hair" based on the analogy of the properties of cobalt wires and human skin hair, (b) sensor design – two clusters of "hair" are combined and "inserted" into a silicone "skin", the entire structure is installed on an electronic printed circuit board.

The method of production of the proposed sensor and its simple structure allows you to create a scalable production, and its design provides competitive sensitivity and range of perception in comparison with existing analogues. High mechanical stability makes such a sensor applicable in the improvement of robot hands and artificial prostheses.

Portal "Eternal youth" http://vechnayamolodost.ru  20.12.2016