Skip to main content

Sewn prototype

The most important part of any device is that which interact with human the most. In computing it’s interface, in case of exoskeletons and orthopedics it’s padding attached to the body. The padding determines users comfort and experience with the product and if badly designed, poorly manufactured often leads to users aversion. It’s basic rule of all of us, especially the most gentle: children.

I experimented with different types of padding and came to the conclusion that less is more. I mean by that it should be unnoticeable like everyday cloth, be soft and drain the moisture out.


I feel more confident in hard surface modeling and got help with sewing from my grandma. I cut the template from cardboard and then from mesh fabric. Grandma added trimming and ribbons. Ladder locks were downloaded from GrabCAD rapid manufactured.




Comments

Popular posts from this blog

Design choices

  Recently I had opportunity to talk with two SMA child families and discuss issues in existing exoskeleton solutions. Before that, they mentioned rubber bands of Angel Arms and Magic Arms are difficult to setup, and change its characteristics over time. I came out with a new idea and wanted to verify it with them.   I prepared some generic images of concepts and ask the parents to choose the most comfortable in their opinion. I tried not to bias their decisions, and restrict myself to raw description. A-B test used with parents   They agreed elimination of rubber bands and separation active and passive modules were good starting point.   I did several design choices to follow: the device should be fully mechanical the device should be counterweight driven the active (counterweight) module should be separated from passive (exoskeleton) module passive device (exoskeleton) could be mounted to corset forearm axi...

Rocky road to refinement

 Days passed… Stuck hard to my design guidelines I was still away from even a tiny sketch of the device. I was sure the direction but the horizon was covered by haze. I could recognize the overall shape but unable to see in details. And the devil is in the details. Working with form is like sculpting in clay; early stages of process give more freedom in reshaping but often it’s double-edge sword: you end up a day devastated by endless versions of nothing. And there’s no place for shortcuts. You can go on with refinement and detailing ONLY after previous stage is done. Every missed step will be only magnified by the next ones. I experimented a little with double bar design similar to Magic Arms, but being still unsatisfied I came up with the idea of hiding whole positioning “drive train”. This is what I like! The devices that are hard to figure out how they actually work! I did one more design choice: to achieve 180 degrees of motion. Its unnecessary in orthopedic a...

Assembling

Having all those pieces everything I had to do was put them together. The prototype contains 3D printed parts in three different technologies: SLA , SLS and FDM on a pair with standardized parts and even sewed padding. Assembling was a bit like jigsaw but done same way as simulated in Fusion 360 design software and took about 20 minutes. Passive module (mounted on hand) weights 350g and is way too heavy to be mounted directly on corset. Moreover, most users will be in half sitting position with head support right behind them. Following advice of physiotherapy experts, orthopedists and parents I added simple tripod mount to be used with Manfrotto Mini Arm and mounted at the back of any chair. After first try-on (without counterweights) the feedback was very positive. The device follows natural arm movement and doesn’t lock in any position. Looks as if it’s indeed more resistant to misalignment than Magic and Angel Arms. The prototype padding could be better, ladder locks and...