The Arm2u biomedical engineering team from the Barcelona School of Industrial Engineering (ETSEIB) of the Universitat Politècnica de Catalunya designed and constructed a configurable transradial prosthesis that responds to the user's nerve impulses using 3D printing technology.

As stated in the release, UPC bachelor's and master's degree students started off improving a prosthesis for people with disabilities using assistive technologies. 

Arm2u is a prosthesis that can replace a missing arm below the elbow. It can be controlled with myoelectric control, which means that it is controlled by the natural electrical signals produced by muscle contraction.

Following the development of the first prosthesis last year, the team has advanced by producing a second prototype – a fully functional robotic arm – that allows for the opening and closing of the hand and forearm rotation.

It is based on EMG sensors, which gather the instructions from a patient's muscle contraction and convert these electrical impulses into a signal that the microcontroller can comprehend and use.

Costs less than similar prostheses

The prosthesis is 3D printed with PLA plastic, so it can be produced at a low cost, as explained by Lluís Bonet Ortuño, one of the team leaders:

“One of our main goals when developing the prosthesis was to make a prototype with affordable technologies so that it could be produced and modified constantly without a high cost. Using 3D printing, we have created a prosthesis at a much lower cost than similar prostheses on the market.” 

The prototype, which was entirely created by the Arm2u team, consists of four key components that work together to enable mobility:

• The socket, which securely fastens the device to the limb;
• The prono, which stores the majority of the electronics and houses the prosthesis' control and status information components;
• The gripper, a clamp-shaped component to manipulate objects;
• The electronic component uses an Arduino Uno microcontroller to connect the sensors, motors, and other components.

The second model has a number of enhancements, including an inbuilt LCD screen that continuously updates information about the prosthesis' state, including its battery life, the effort required by the fingertips, interior temperature, and more. 

The new design is also lighter overall than the previous generation, which makes it more comfortable, and has improved adaptability that enables adjusting to the user's arm size.

All thanks to teamwork

"The team aims to develop new prostheses to help people in everyday life and continue research in biomedical engineering. We want to become a leading university team for all students who want to learn about this area, and we are open to working with anyone who shares our concerns,” says team leader Aleix Ricou.

The team is divided into three departments with the goal of pushing the boundaries of the prosthetics industry: mechanics, electronics, and management.

The mechanics' department is in charge of creating a conceptual CAD model, both kinetic and static simulations, choosing materials, and researching manufacturing systems. The electronics department is also in charge of controlling the multiple actuators in the prosthesis and the acquisition of myoelectric signals.