Design of a 3D printed exo-aid with integrated EMG electrodes

MSc assignment

The NWO "perspectief" program wearable robotics aims at developing technology to truly augment or restore human motor functions. The envisioned Exo-aids will allow for agile and versatile movements. The developed technology will be integrated in Exo-aids for three applications that have a high socio-economic impact:

  • to restore mobility in patients with a spinal cord injury;
  • to prevent progressive function loss in patients with muscular dystrophy; and
  • to prevent work-related musculoskeletal disorders in dynamic heavy lifting (industry workers) or static high-precision work (medical surgeons).


When designing parts for medical purposes such as in an exoskeleton, often customization is needed to guarantee a perfect fit for a specific user. With 3D printing it becomes easier to fabricate such customized parts. With multi-material 3D printing it also becomes possible to fabricate complex parts that increate sensing capabilities into the parts, reducing the amount of assembly required afterwards.


At the Robotics and Mechatronics (RAM) department, we have developed a multi-material fabrication process that can be used to 3D print up to 5 different materials in one part, ranging from very flexible to very stiff materials, using fused deposition modelling (FDM). One of these materials also is conductive and therefore it becomes possible to fabricate parts that have integrated Electromyography (EMG) electrodes [1].

Normally muscle activity (EMG) is measured using electrodes that use chloride gel to ensure a good connection to the skin. However because the 3D printed electrodes are dry electrodes, the readout of the bioelectrical signals is more challenging and requires higher input impedance amplifiers and AC leadoff detection. For this reason, a custom wireless amplifier module has been designed together with TMSi. This amplifier module will be integrated into the 3D printed parts and will obliviate the need for cables.

During this assignment, you will redesign the currently existing EMG band design such that it is more user-friendly, comfortable and gives better signals. To do so you will update the CAD design and then print it on the multi-material 3D printer at RAM (Diabase H-series). Afterwards you will design and perform experiments to evaluate the performance on user-friendliness, comfortability and signal quality. Due to the nature of 3D printing, it will be possible to go through several design iterations.

For the assignment affinity with 3D printing (FDM) is highly appreciated. Also, some basic knowledge of electronics and bioelectrical signals is needed. The assignment is suitable for master students from Design Engineering,  Biomedical Engineering, Biomedical Engineering, Mechanical Engineering or Electrical Engineering.

This assignment is a collaboration between the Robotics and Mechatronics group and the Design Engineering group, and also has the companies Yumen and TMSi involved. Your daily supervisor will be Martijn Schouten from the Robotics and Mechatronics group and your other supervisors will be Gijs Krijnen and Kostas Nizamis.

[1] G. Wolterink, R. Sanders, F. Muijzer, B. van Beijnum and G. Krijnen, "3D-printing soft sEMG sensing structures," 2017 IEEE SENSORS, 2017, pp. 1-3, doi: 10.1109/ICSENS.2017.8233935.

 

We look for:

  1. A motivated student
  2. Excellent communication in English both speaking and writing
  3. Mechanical, Electrical, Industrial, or Biomedical Engineering
  4. Knowledge of 3d printing, electronics, and design is needed
  5. (Bonus) Having a 3d printer at home will help a lot!

 

We are offering:

  1. A very interesting and novel topic
  2. An excellent multidisciplinary supervision team
  3. Collaboration with companies
  4. The facilities of RAM (3d printers,etc.)