Hey there. I see you’re from AAU? I might go to that school
in the future if funds permit…
Anyway A few friendly suggestions…
Seems like you need some REALLY good inspirational items to look into
researching before even putting that pen & maker to paper…
Since its a walker and has “legs” I highly suggest thinking out of the box
for this project and look into robot legs.
Here’s a quick google search I did for you:
https://www.google.com/search?site=imghp&tbm=isch&source=hp&biw=1280&bih=610&q=robot+legs+sketches&oq=robot+legs+sketches&gs_l=img.3...64956.69081.0.69233.19.12.0.7.7.0.160.893.10j2.12.0....0...1ac.1.32.img..2.17.903.h0GOUbixHGM#q=robot+concept+sketches&tbm=isch
Robots are great inspirational sources to draw from!
Even some vehicle design can be traced from japanese
gundam and robotech robots.
Another good source of inspiration are those caterpillar and komatsu
construction equipment… Like for instance the forklifts can signify
(from an emotional design perspective) STRENGTH AND SUPPORT.
This is a good concept to draw on your project since you want your walker
to have STRENGTH AND SUPPORT for the kid using it… 
Here’s a good source:
https://www.google.com/search?site=imghp&tbm=isch&source=hp&biw=1280&bih=610&q=robot+legs+sketches&oq=robot+legs+sketches&gs_l=img.3...64956.69081.0.69233.19.12.0.7.7.0.160.893.10j2.12.0....0...1ac.1.32.img..2.17.903.h0GOUbixHGM#q=caterpillar+equipment&tbm=isch
There are MANY other sources of inspiration you can draw from as well.
You just have to look for them…
Lastly, you can try listening to “Save tonight” by Eagle Eye Cherry
and a cup of coffee and start cranking those sketches and see what you find… Good luck! 