Hi,
"keyboard" has many meanings. Please clarify which one you mean.
And describe the expected function.
Example: computer keyboard.
Do you want to press a single key and never any other (to test how many strokes the key can survive)
Or you need a single sroker to be moved over the whole keybord to be able to press every of the more than 100 keys
Or ten stroker that emulate two hands
Or one stroker for every key
Adjustable stroke speed or adjustable force
How to be controlled? Electrically, pneumatic,
What lifetime to you expect?
Now I wrote a lot more words than you did....
Klaus