Unusual 2DOF design help

I have an unusual design help request please from a Limey

I want to make a 2DOF office chair. Its not SIM, its a prototype for a very specific purpose disabled person aid.

BOD is similar to 2DOF sim, except motion requirement is quite opposite - very slow - like mm/sec, much more limited range of movement - say 15deg each direction, motion needs to be very accurate -and super smooth.

For now it will pivot on standard UJ. My thoughts are to have 2 motors, 1 per DOF instead of 2 coordinated motors as seems to be the case for most basic 2DOF builds. This would seem to be better for my control requirements (see below pls). Is the coordinated approach because that works for how sim motion input data is presented? My motion data will be in the form of a fixed map tailored to the user requirements (think EFI map) Any help of pros/cons I don't know about appreciated.

Its built into an office chair so need to be compact, light and quiet. Cost is a consideration.

Any suggestions for suitable motors? 12v preferably. I assumed just need a highly geared dc servo, but you all seem to use more available motors with separate encoders.

Sorry if this is a lame description, I'm just getting started albeit I have been thinking about it for 15yrs! Any input appreciated.

Hi noorbeast. UJ idea is new so being a dumbass. Before I was thinking of controlling each DOF separately using custom gimbal. Its obvious now why motors have to be connected that way.

So I just need some ideas on motors, if you have any.