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Mollie Holmberg takes crip lessons from philosopher Val Plumwood's experience of being prey to a crocodile, pointing toward strategies for collective pandemic survival and resistance to environmental violence.
The post Pandemics, Predation, and Crip Worldings appeared first on Edge Effects.
A new 3D-printed customized insole uses integrated sensors to measure the pressure on the sole of the foot directly in the shoe during various activities.
In elite sports, fractions of a second sometimes make the difference between victory and defeat. To optimize their performance, athletes use custom-made insoles. But people with musculoskeletal pain also turn to insoles to combat their discomfort.
Before specialists can accurately fit such insoles, they must first create a pressure profile of the feet. To this end, athletes or patients have to walk barefoot over pressure-sensitive mats, where they leave their individual footprints.
Based on this pressure profile, orthopedists then create customized insoles by hand. The problem with this approach is that optimizations and adjustments take time. Another disadvantage is that the pressure-sensitive mats allow measurements only in a confined space, but not during workouts or outdoor activities.
The new invention, described in the journal Scientific Reports, addresses these issues.
“You can tell from the pressure patterns detected whether someone is walking, running, climbing stairs, or even carrying a heavy load on their back—in which case the pressure shifts more to the heel,” explains co-project leader Gilberto Siqueira, senior assistant at Empa and at the ETH Zurich Complex Materials Laboratory. This makes tedious mat tests a thing of the past.
These insoles aren’t just easy to use, they’re also easy to make. They are produced in just one step—including the integrated sensors and conductors—using a single 3D printer, called an extruder.
For printing, the researchers use various inks developed specifically for this application. As the basis for the insole, the materials scientists use a mixture of silicone and cellulose nanoparticles.
Next, they print the conductors on this first layer using a conductive ink containing silver. They then print the sensors on the conductors in individual places using ink that contains carbon black. The sensors aren’t distributed at random: they are placed exactly where the foot sole pressure is greatest. To protect the sensors and conductors, the researchers coat them with another layer of silicone.
An initial difficulty was to achieve good adhesion between the different material layers. The researchers resolved this by treating the surface of the silicone layers with hot plasma.
As sensors for measuring normal and shear forces, they use piezo components, which convert mechanical pressure into electrical signals. In addition, the researchers have built an interface into the sole for reading out the generated data.
Tests showed the researchers that the additively manufactured insole works well.
“So with data analysis, we can actually identify different activities based on which sensors responded and how strong that response was,” Siqueira says.
At the moment, Siqueira and his colleagues still need a cable connection to read out the data; to this end, they have installed a contact on the side of the insole.
One of the next development steps, he says, will be to create a wireless connection. “However, reading out the data hasn’t been the main focus of our work so far.”
In the future, 3D-printed insoles with integrated sensors could be used by athletes or in physiotherapy, for example to measure training or therapy progress. Based on such measurement data, training plans can then be adjusted and permanent shoe insoles with different hard and soft zones can be produced using 3D printing.
Although Siqueira believes there is strong market potential for their product, especially in elite sports, his team hasn’t yet taken any steps towards commercialization.
Additional coauthors are from Lausanne University Hospital, the orthopedics company Numo, and ETH Zurich.
The ETH Domain’s Strategic Focus Areas program funded the project.
Source: ETH Zurich
The post 3D-printed insole measures foot pressure right in shoe appeared first on Futurity.
A new control algorithm could make ankle exoskeletons automatically adapt to individual users and tasks, say researchers.
Current exoskeletons are limited because they must be tailored to a single user performing a single task, like walking in a straight line. Any changes require a lengthy set of manual readjustments.
The new control algorithm demonstrates the ability to handle different speeds, as well as changes in gait between running and walking. It could pave the way for exoskeletons that are better able to handle the uncertainties of the real world.
“This particular type of ankle exoskeleton can be used to augment people who have limited mobility,” says Leia Stirling, associate professor of industrial and operations engineering and robotics at the University of Michigan and senior author of the study in PLOS ONE.
“That could be an older adult who wouldn’t normally be able to walk to the park with their grandkids. But wearing the system, they now have extra assistance that enables them to do more than they could before.”
The control algorithm directly measures how quickly muscle fibers are expanding and contracting to determine the amount of chemical energy the muscle is using while doing its work. Then, it compares that measurement with a biological model to determine the best way to assist.
Measuring muscle physiology directly is a key departure from current methods, which use broader measures of motion. Going straight to the source of motion could result in more accurate measurements over a larger range of movements with far less computing power required.
Stirling and first author Paul Pridham, senior research area specialist in industrial and operations engineering, zeroed in on the ankle because it plays a key role in mobility. Assisting the muscles in the ankle could have a dramatic impact on our ability to walk further and faster.
Since the research was done during COVID-19 restrictions, testing with human participants wasn’t possible. Instead, the team used data on existing ankle exoskeleton devices and muscle dynamics from previous studies to simulate, test, and adjust the algorithm to be more responsive to changes in speed and gait.
Human testing is an important next step, and will require the measurement of muscle fibers in real time using ultrasound. While much work and refinement remains, the researchers are confident that the new avenue of research will one day help people on the ground.
“This has the potential to help just about anyone,” Pridham says. “From someone who walks a lot for their job, to individuals in the military that perform tasks for long periods of time, to people with muscular disorders that need some extra assistance, and the elderly who need help day-to-day.”
The Under Secretary of Defense for Research and Engineering funded the work.
Source: Jessalyn Tamez for University of Michigan
The post Ankle exoskeleton algorithm adapts to speed and gait appeared first on Futurity.
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