Introduction
This project directly continues Prathamesh Darwade’s “LABOUR SUPPORT USING EXOSKELETON” project. He developed at Vigyan ashram a prototype for an exoskeleton to support shoulder and arm weight when one needs to keep the same tiring posture for long periods of time. This project was promising, and the main technological development has been achieved during this project. However, some of the parts of this project are still to complete, and the main problem and that you need someone’s assistance to wear the device and set up the springs to provide adequate torque. The goal of this project is to overcome this issue and create a more simple way to wear the exoskeleton by yourself only
Attachment system
This part o the project has been made in collaboration with Abhishek Ahivale, this blog is a sum up of both our work.
The first problem we tried to solve was the attachment system of the apparel. As explained above, the system can’t be managed alone as someone has to attach all the webbing while the other holds the device in the correct posture. To overcome this issue, we wanted to create an attachment system similar to the one found in a walking backpack, with adjustable size, having a close and tight fit to the body.
We then bought all the necessary components and assemble it all the exoskeleton, here is a video of the result :
Spring loading
The second part of this project is to be able to load the spring by yourself, without the help of someone else.
At this point, I had two possibilities, the first one was to load the spring while wearing the exoskeleton, which could allow a more precise tuning and hence better support, but as the motion is a little bit restricted by the exoskeleton, it could be hard to provide enough torque to load them the correct amount. The second option is to load the spring before wearing it, then lock them and wear the exoskeleton normally afterward. This second option has been chosen because it allows loading the spring once for every day of use, without ever unloading them, which is quite nice if you use it very often.
Several ideas have been developed to solve this issue, but the easier and best one has been found to be as simple as the following.
I then built it assemble it on the actual exoskeleton and I obtained the following result
Testing
We tested this exoskeleton with a real application, cow milking. Indeed, milking multiple cows successively can be very tiring. Here is a picture of the testing
It results that most of the stress caused by this process being in the forearm and not that much in the shoulders. Even if the support could be felt and was appreciable, the comfort and motion restriction make the device not that useful. Moreover, this exoskeleton has a lot of sharp edges that could potentially hurt cows when they move, which is a big issue in usability.
Another test has been performed using a grass-cutting device, known to be very tiring and constraining. However, the device is already bulky, and adding an exoskeleton on top of this was clearly too much. Moreover, the person testing it had shoulders larger than mine which result in the amplitude of motion being highly decreased. It was clearly not useable for him, very bulky, and almost painful to wear.
