by Christine Azevedo Coste (Inria) and Roger Pissard-Gibollet (Inria)
A model of a frugal, replicable and open-source technological innovation approach to improve the quality of life of people with disabilities by developing technical aids for an individual and making them accessible to the greatest number.
Humanlab Inria (HLI)
Humanlabs are collaborative digital fabrication spaces. The operating principle is similar to that of Fab Labs, a concept created at MIT by Neil Gershenfeld in the late 1990s: places of learning and innovation that offer access to an environment, skills and technologies to enable the manufacture of technical objects.
Humanlabs are Fab Labs dedicated to people with disabilities to help them realise a project related to their situation and to enable them to appropriate technology for their own use. These are not medical equipment centres, and the developed homemade prototypes are not medical devices. It is a complementary approach to complete or customise commercial devices at the margin. For simple needs, it can also replace expensive or non-existent devices. The realised devices can be, for example, a new joystick for an electric wheelchair or a motorised thumb orthosis with a control unit. The disabled person becomes a project leader by expressing his or her needs or ideas for realisation.
The first Humanlab, MyHumanKit, was created in 2017 in France [L1]. Inria joined the Humanlab network in 2021 [L2, L3] to help meet the needs expressed by people with disabilities. The Humanlab Inria (HLI) action is part of a frugal, reproducible and open-source innovation approach that aims to implement the scientific and technological know-how of Inria to meet specific needs. Unlike other Humanlabs, HLI does not receive any visitors but contributes to the development of projects for its partners.
Humanlabs regularly organise Hackathon-type days, where multidisciplinary teams are formed around the project owner and work for several days on a project. MyHumanKit has organised several events of this type (Fabrikariums) with the company Ariane Group. Employees of the company with disabilities propose the projects [L4].
We propose to illustrate our approach and our activity around a flagship project: Exofinger, a motorised finger orthosis for Bastien, who suffers from tetraplegia and has difficulty holding objects. His thumb has little strength but has active extension. Bastien chose a simple task for the project, which was to hold a pen to sign a document. This was one of the Fabrikarium 2020 projects, to which MyHumanKit, Inria, Humanlab Saint Pierre [L5] and ArianeGroup contributed.
After discussion and exploration of several hypotheses, the retained principle was that of a glove guiding cables pulled by a motor located on the forearm to apply the pulp of the thumb on the lateral edge of the index finger (key grip) to clamp an object [L6].
The HLI Inria team worked from the prototype produced at Fabrikarium 2020 to propose an advanced version of the device. A control unit positioned on the arm, containing the motor with reduction gearbox and an Adafruit feather nrf52840 microcontroller, pulls a cable that runs inside a glove. The cable is wound and unwound on a spool. We also developed a wireless button using another Adafruit feather that communicates with the control unit via Bluetooth Low Energy (BLE). This wireless button activates the motor and winds the cable to bring the thumb closer to the rest of the hand. The button is also used to stop the motor, allowing the thumb to return to its resting position (see Figure 1).
Figure 1: Use of the Exofinger system by a user with tetraplegia.
The glove is based on the principle of protecting the hands when propelling a wheelchair, by which the user can put the glove on independently by wrapping it around the hand instead of slipping it on.
A glove pattern generator has been developed to enable adaptation to individual morphology. All that is required is to enter a few characteristic dimensions of the hand and fingers to generate a printable pattern necessary for the production of the glove (leather cutting and sewing).
A phone app has been developed to trigger the activation of the motor in the same way as the wireless button. It also allows the user to obtain the battery status of the motor housing and to set the clamping range.
An experimental validation will be carried out in the coming months to assess the interest of the solution to various user profiles who have difficulty grasping objects.
In order to be reproducible by the general public, we use open-source design software, for example Kicad for electronics or Freecad for mechanics. The machines used for manufacturing are found in common Fab Labs and include 3D printers, laser-cutting machines, sewing machines, etc. The chosen hardware is also accessible, e.g., Arduino or RaspberryPi for controllers. Sensors and actuators can be connected to these controllers to interact with the environment.
What guides us
In the Humanlab approach, the process of realisation is as important, if not more important, than the realisation of the object itself. By guiding the whole realisation process, the project owner becomes familiar with the custom-made technical aid developed. This is fundamental to Humanlabs’ ways for two main reasons: to be able to understand the functioning of the technical aid in order to fix it or make it evolve if necessary, and to see his or her own disability and technical aid differently. A Humanlab project is made up of different people: disabled, volunteers, technical or medical specialists, who collaborate to create a device. It is a space of socialisation and reappropriation of the stakes of the handicap. To facilitate this, the objects must be duplicable, modifiable and reusable; one way to ensure this is the open-source approach.
For G. Simondon, a French philosopher, the alienation of humans from technical objects is due to the misunderstanding of the mode of existence of technical objects  and of their internal functioning. This idea leads to proposals made by the author in the sense of a pedagogy and technical culture, and of a democratisation of technical knowledge. This is what drives HLI.
We are also convinced that meeting individual needs with less-complex devices must generate new research problems. From a simple homemade system, we can try to generalise it to answer a class of needs, to measure its technical and clinical effectiveness. Moreover, it allows us to think about the tension between the complexity of a device and the degree of satisfaction of a need; In a way, we are in the low-tech movement [L6] where simple technology is opposed to the obsession of high technology.
 G. Simondon: “Du mode d’existence des objets techniques”, Paris, Aubier, 1958.
Christine Azevedo Coste, Inria, France
Roger Pissard-Gibollet, Inria, France