A wall-mounted, motorized, no-legs cantilevered desk that accommodates standing and sitting heights.
Functional Requirements (in order of importance)
- Goes up and down, to accommodate sitting and standing-desk heights
- No legs! Full cantilever / wall mounted
- "Real Desk": holds ~300lbs when locked (I could stand on it), ~50lbs when moving.
- "Precision", repeatable position control and unnoticable (visual or tactile) deflection under load
- Quiet under operation (nom. load 50 lbs) and reasonable power requirements (wall plug w/ min. risk of fire)
- Avoid buying stuff: use ballscrews, motors, and linear rails I already have in my room
- Flat-pack Disassembly
Design Parameters
- Hollow desk top with internal structural truss (help with cantilever/ "floating desk" look)
- French cleat attachment mechanism (help with cantilever)
- Robust linear rails that can take large moments
- Re-use Ballscrew & stepper with optical encoder position feedback
- No legs! Gotta address moments and stresses all applied at the cantilever contact point and in the linear carriage.
- Biggest issue I'm expecting will be moments/rattle on the bearings in the rails that would cause them to bind
- No legs! How deep of a desk can I get away with before cantilever attachment becomes a problem?
- "Precision" over time. I probably need to add an encoder & closed-loop position control to avoid motor-skipping errors
- The ballscrew I have + available stepper combos might end up being loud...
- Can the stepper handle load without a lock? Or do I need to make a mechanical lock that doesn't mar bearing surfaces?
Analysis Needed
- First-order analysis of linear rails - week 2 project fun
- would be good to make a scale model using steel-honeycomb for the desk top and 2 rails
- truss/cantilever math for desktop moment/stresses imposed on the rails
- energy accounting for motor & transmission, and finding out resonance of the motor
good, looking forward to the details!
ReplyDelete