Solenoid Actuator?

[mtowns]

I am trying to actuate a metal rod to move with certain different
velocities. I am hoping to use a solenoid and a velocity-sensing
feedback system. The output should be appropriate for pusing a
weighted piano key. Is this feasable? Are soleniod actuators avaliable
pre-assembled, or would I have to make one myself? Thanks.

 

[Bob Eld]

I am trying to actuate a metal rod to move with certain different
velocities. I am hoping to use a solenoid and a velocity-sensing
feedback system. The output should be appropriate for pusing a
weighted piano key. Is this feasable? Are soleniod actuators avaliable
pre-assembled, or would I have to make one myself? Thanks.

Yes it feasable. It requires pricise control of the the solenoid current and
timing. Diskclavier works this way. Check them out you may get some hints.
Also QRS piano roll company has a piano playing mechanism that works this
way, not cheap.You will probably have little luck finding a ready made
actuator at any price you can afford, so if you are serious will have to
design and build your own. Good luck.
Bob

 

[Don Lancaster]

I am trying to actuate a metal rod to move with certain different
velocities. I am hoping to use a solenoid and a velocity-sensing
feedback system. The output should be appropriate for pusing a
weighted piano key. Is this feasable? Are soleniod actuators avaliable
pre-assembled, or would I have to make one myself? Thanks.

Don't the player piano restoration supply houses have these as a stock item?

How about Allen Organ?



--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[[email protected]]

I am trying to actuate a metal rod to move with certain different
velocities. I am hoping to use a solenoid and a velocity-sensing
feedback system. The output should be appropriate for pusing a
weighted piano key. Is this feasable? Are soleniod actuators avaliable
pre-assembled, or would I have to make one myself? Thanks.

It is used in professional systems, but itsn't all that practical - in
particular, with the space available you can't match the accelerations
and velocities you get when you strike a piano key, rather than pushing
it down.

E-mail me - I've got a handful of references on the subject.

Compumotor has an ironless linear electric motor which is powerful
enough and almost compact enough for the job,

http://www.parker.com/compumotor/cat/english/Trilogy/110.pdf

but it isn't cheap.

see also

http://www-personal.engin.umich.edu/~brentg/Publications/Conference/icmc92b.pdf

http://www-personal.engin.umich.edu/~brentg/Publications/Conference/icmc92.pdf

 

[Rich Grise]

I am trying to actuate a metal rod to move with certain different
velocities. I am hoping to use a solenoid and a velocity-sensing
feedback system. The output should be appropriate for pusing a
weighted piano key. Is this feasable? Are soleniod actuators avaliable
pre-assembled, or would I have to make one myself? Thanks.

Find an amusement machine vendor in your area who still does pinball
machines, and get some drop target reset solenoids. I used to work
repairing pinball machines (and juke boxes, Pac-Man, and so on - kewl
job!), and was tempted to use them in a piano project of my own, which
never materialized. (sigh)

If you've ever played pinball, you've seen drop targets reset - the
stroke is maybe 1-1/2", and they don't have a lot of force (they raise
those little plastic targets, which latch in place), but by eyeball
and gut feeling, they looked like they'd be ideal. You'd have to
carefully control the current, to give the attack and sustain that
you want, of course.

Good Luck!
Rich

 

[[email protected]]

Find an amusement machine vendor in your area who still does pinball
machines, and get some drop target reset solenoids. I used to work
repairing pinball machines (and juke boxes, Pac-Man, and so on - kewl
job!), and was tempted to use them in a piano project of my own, which
never materialized. (sigh)

If you've ever played pinball, you've seen drop targets reset - the
stroke is maybe 1-1/2", and they don't have a lot of force (they raise
those little plastic targets, which latch in place), but by eyeball
and gut feeling, they looked like they'd be ideal. You'd have to
carefully control the current, to give the attack and sustain that
you want, of course.

The throw on a piano key is about 9mm - 3/8 of an inch.

To simulate the force that is required to accelerate the hammers at a
5:1 mechanical advantage, you need to develop forces of the order of 20
Newton (about five pounds weight).

Modeling the 14-19 moving parts between the key and the hammer seems to
be a fairly important part of the job - carefully controlling the
current to do that is quite tricky.

Brent Gillespie's Touchback Keyboard project is described in the
literature - I posted a couple of URL's earlier in the thread - and
level of simulation required seems to eat up quite a lot of computing
power.