I built a robot which is controlled by bluetooth (computer or phone). The uses for the project is for disable people for example instead of having a nurse moving the wheelchair it could be done automatically in front of a computer.
-Using sensor so it does not hit the wall or make it automatic is a good idea?
-Any ideas to make the system better?
I’m thinking line follower
I’m thinking line follower with some built-in failsafe. Perhaps different “tracks” for going to different areas like dining room, visiting area or activity area. Several chairs could use the same tracks with some type of proximity sensor to prevent crashes \o/
Maybe not as autonomous as you would like but many automated warehouse systems use a similar scheme. You would also have to have some type of GUI for “command central” with a map of the facility.
Point-click-send Mr. Jones to TV room 
"Heyyyy maaaaaan! Whatcha doooooiiiiiin!"
Probably best to visit a healthcare facility and ask the staff what they would want and get a feel for things.
GOOD ON YOU FOR WANTING TO HELP PEOPLE!!
This is just my 2 cents, but
This is just my 2 cents, but why would you use bluetooth for this, unless it is purely a proof of concept. The range is not great, and it is easily hacked. I would want to be sitting in it.
Other than that though i agree proximity sensors and line following to designated areas sounds cool, kind of like an automated porter, but you would need an emergency stop, and a call for help button that could be easily used by the person in the chair, also perhaps some sensors on the foot plates, so that if the occupant tried to stand up, or lifts there foot off the rest the system shuts down and notifies the staff. I would however just have a control panel on the chair, it would scare the s*it outta me if i was in a wheelchair and suddenly it tried to cart me off with no-one in sight. Also a manual start means a staff member can ensure the user is properly seated. Im guessing that the last thing someone who needs a wheelchair needs is a wheelchair disappearing from under them just as they sit down.
I do however think the idea has merit (was going to write something else here but the pun was too bad) and with some careful though and input from wheelchair users and staff you could have a viable product.
Good luck with it 
what wireless module do you
what wireless module do you advice me instead do the bluetooth?
