Sock sensor

A sensitive sock was created for prosthetics

Nikolay Vorontsov, N+1

Researchers from the University of Applied Sciences of Upper Austria have developed a prototype of a feedback sock for lower limb prostheses. Scientists presented a report at the UIST (User Interface Software and Technology) 2016 conference.

Some modern models of prosthetics for hands and feet are already equipped with feedback systems, but the cost of such smart prostheses can reach several tens of thousands of dollars. At the same time, prostheses wear out over time and require replacement every few years, which significantly limits the number of people who can afford high-tech artificial limbs. At the same time, conventional prostheses often have a minimal set of functions, and the cheapest versions of lower limb prostheses are a passive support at all. Such simple artificial limbs do not allow their owner to perform many operations familiar to most people – for example, to fully use pedals or ride a bicycle.

In order to expand the functionality of basic prostheses, Austrian scientists decided to develop an additional non-invasive feedback system that is not tied to a specific artificial limb. Researchers have developed a prototype of a smart sock that can detect pressure in different areas of the foot and transmit this information to the user using vibration. According to the developers, such a sock can be used for several prostheses and different activities, since the device can use different sets of settings.

The sock consists of three layers of fabric sewn together. The middle layer is made of piezoresistive fabric, and the inner and outer layers contain conductive strips. At the same time, the sock is sewn in such a way that the strips of these two layers are arranged perpendicular – thus, the sock is an elastic matrix that allows you to determine the pressure in six different zones of the foot. Data on the force of pressure, bending or touching in any area of the foot is transmitted to a sling-bracelet with six vibration motors, one motor for each zone. The user with the help of "Velcro" can attach a vibrating strap to the arm, torso, or other more convenient part of the body, and the motors vibrate with different strength, which depends on the signal transmitted by the matrix.

The matrix allows you to set the zones that respond to pressing (figures from the article by Leong et al.
proCover: Sensory Augmentation of Prosthetic Limbs Using Smart Textile Covers – VM)

The user can configure the necessary zones via the smartphone app.

The authors note that the matrix allows you to adjust the sensitivity zones of the sock in different ways - out of eight interviewed people with amputated lower limbs, all volunteers identified the foot zones that need sensitivity in different ways. At the same time, more than half of the volunteers agreed with the statement that a feedback system that reports the touch of the prosthesis to something will facilitate the performance of everyday tasks.

There are other projects that solve the problem of feedback in an artificial limb. For example, there are experimental prostheses that provide fine sensitivity of the finger, warning about a burn by an electric shock, as well as a neurointerface that allows you to control individual fingers of the prosthesis. In addition, American scientists have developed a neurointerface that allowed a completely paralyzed person to touch objects with a prosthesis.

Portal "Eternal youth" http://vechnayamolodost.ru  28.10.2016