Lower body exoskeleton ExoChair (version 2019)
Overall project description
The problem statement is similar to the 2018 exoskeleton version (the ExoChair exoskeleton works as a portable chair in which the operator’s landing height is fixed by power pneumatic cylinders).
In this version, the exoskeleton is made of aluminum (which makes its weight ligher by 30% compared to the previous version).
We perfomed in the project:
- Stress analysis
- Design optimization (weight, geometry, materials)
Exoskeleton balancing
We have created a mathematical program that defines loads in the main components of the structure. This allows, separately from finite element modeling (see below), to analytically evaluate the loads on rivets, bolts and axes.
Finite element modelling
The verification calculation was carried out using the created finite element model.
The model takes into account:
- Complex contact in knee joint
- Features of riveted joints
- Transmission of stresses through a power pneumatic cylinder
- Mobility of all structural units
Weight optimization
To increase strength and reduce weight of the structure, we gave recommendations on reassigning materials, changing the geometry of individual parts, etc.
When fulfilling all of the recommendations, it is possible to reduce the mass of the structure by 10..15%.
