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3D scanner technologies for ergonomic exoskeletons

3D scanner technologies are now used to develop ergonomic exoskeletons. A technological revolution in the health sector: in Belgium, a research group develops the capacities of electrical exoskeletons by adapting their design with the help of the 3D scanner Artec Eva

Kevin Langlois, researcher at the Université Libre de Bruxelles and member of the Robotics & Multibody Mechanics Research Group), whose main interest is portable robotics, such as exoskeletons, believes that robotic assistance technology is one of the most major technologies that can help keep health costs under control.

Indeed, these technologies help people to stay mobile, less dependent on care and reduce the risk of side effects of immobility.

Although remarkable progress has been made in the field of research, a major problem remains to be solved: how to achieve the perfect interaction between a human being and his robotic exoskeleton?

At the mechanical level, this question comes down to how to get a perfect adhesion between the two entities? The answer to this question is not easy to find, knowing that each person is unique anthropometrically (the dimensions of its members and their abilities) and biomechanically (the way the person walks). This suggests that one needs a tailor-made solution for each individual.

Use a 3D scanner to capture individual anatomy

Scan the individual anatomy of the subject and design an orthosis that would copy it easily is the goal. Specifically, the physical interfaces of the exoskeleton are scanned in 3D since they are the mechanical connections between the human and the robot. In this way, it is possible to obtain a stronger adhesion and improve the robustness of the exoskeleton without compromising user comfort. To this end, the group has acquired a high precision 3D scanner Artec Eva

“Research in this area is currently rare. So far, the majority of research has focused on the fundamentals of these machines, actuation and control. Now is the time to integrate humans into these systems, “says Kevin. “That’s why, in the R & MM laboratory, we decided to use 3D scanning technology to develop innovative solutions. “Now we use Artec Eva and help design and produce individualized orthotics that have advantages over adjustable orthoses,” says Kevin. “The Eva scanner offers a scan process that is fast (less than 5mn) and accurate for compiling a digital image of the patient. Using this 3D scanning device to produce orthotics takes less time and effort than using a plaster mold. “

Based on the biomechanical literature, we can estimate the torques, or forces, that must be transferred to the subject’s joints (ankle, knee and hip) to be able to offer help during the walk, since the MIRAD exoskeleton activates the hip joints, knees and ankle for both legs. With this information and knowledge about the pain pressure threshold (PPT), which is the maximum pressure a human can endure on a specific anatomical region before feeling pain, an orthic prototype can be designed.

A key function of the actuator is the use of an adjustable elastic element – a spring with variable pretension – in series with an electric transmission. Its characteristics are well adapted to electrical exoskeletons: energy storage, increased maximum power output, tolerance to impact loads and low output impedance. Unlike “hard” or “hard” actuators – such as gear transmissions – this flexible actuator naturally allows for deviations from the target position when external forces are applied by the user.

“The Artec Eva 3D scanner allows us to incorporate all these parameters into a compact and ergonomic orthosis,” says Kevin.

To make a custom orthosis, Kevin first selects the areas that need to be captured, for example, the hock. He then selects one or more subjects on which the orthosis will be tested. These subjects are scanned, and the data is processed in the 3D software Artec Studio

“The generation of a file. STL since scans is a simple process in Artec Studio, “says Kevin. “The critical point is to gather high-quality scans, not to leave a hole in the model, and to facilitate the alignment of the scans. The Fusion Fine tool will precisely merge the scans together and generate the final model.

After the postprocessing, the file. STL is exported to CAD software, where a finely tuned ortho device is designed. The final step is to produce an orthosis using additive manufacturing. After 3D printing of the orthosis, it is reinforced with carbon fibers and an epoxy compound.

The use of 3D scanning and 3D printing is particularly beneficial compared to the use of a plaster mold, because it allows the subject to fully integrate the human design robot. It also allows more freedom on the production or manufacturing options of the orthosis, allowing the use of CAM (Computer Aided Manufacturing) techniques, such as 3D printing. This in turn can potentially reduce costs and improve the quality and applicability of products.

Experiments are currently underway to identify the benefits of this design.

“The purpose of these experiments is to demonstrate the effectiveness of individualized orthotics based on constructing a digital recording of the subject,” says Kevin. “And one day, the goal will be to allow humans to wear an exoskeleton that will be almost invisible to others and, to some degree, to the wearer himself! 3D scanning technology is a promising tool to achieve that. “

About Artec 3D

An international group headquartered in Luxembourg, Artec 3D is a global leader in portable 3D scanners, at the forefront of innovative 3D technologies since 2007. Artec 3D develops and manufactures high-quality, easy-to-use 3D scanners, software User-friendly 3D and an SDK that offers the best integration possibilities, whatever the application. With a worldwide presence and a large number of customers around the world, we provide 3D technologies for different sectors such as industry, health, design, art, science, historical preservation, and manufacturing.

For more information, visit: https://www.artec3d.com

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