actually the obstacle detect is the easy bit... just need to monitor the current draw by the motor over a few open/close cycles to learn the profile... any deviation from that is a 'stop & back off, wait, try again' cycle (exactly how my lift doors do it).
The harder bit is working out the actual mechanism. Standard units don't use ballscrews, just a motor and gearbox turning a shaft and an articulating (low torque/more complex engineering) or sliding (simpler, but higher torque and higher maintenance/wear) arm.
Sorry Irving, I had no idea that you had an accident, very sorry to hear of it.
It may be worth a look in the Hafle direction, they have a good range of gear and some good drawings. Best of luck with the project and the workshop once you get to that.
All the best
How about this for a Heath Robinson solution...
Door is closed by a standard door closer.
Door is opened by string wound around a bobbin on an electric motor.
I haven't had time to look at interference between opener and closer but it should be possible to work around it.
Apologies for the dreadful drawings...
lol, don't think my wife would accept a heath-robinson approach! having said that, I did look at a cable pull design, but the door closers don't give a positive closure against the draft proofing for the multipoint locking to engage, so needs to be an active pull closure as well. also needs a clutch/freewheel to allow manual opening of the door.
Designing a linear motor, in an arc shape, to embed in the floor would be a fun way to do it ...
The attractive forces between the armature and stator could be problematic (i.e. very rigid hinges required), but perhaps it could be a core-less motor to mitigate that. Line of magnets in the floor and a couple of coils on the door perhaps...
If it's possible to access directly beneath or above the rotating centre of the door hinge, either from the top or under the floorboards you could install an extension shaft to the top/bottom of the door that is in alignment with the hinge axis with a geared wheel, and drive this with a worm(and suitable motor) the motor housing could be actuated to swing the worm out of engagement for manual operation.
Not had a windscreen wiper motor to bits in a lot years but if memory recalls they might have some usefull bits, if it would produce the required torque.
Last edited by mekanik; 23-01-2015 at 12:45 PM.
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