want to couple 2 servos in parallel

Hi. I want to couple 2 servos in parallel, so to speak, for double the lifting power for a small robotic arm. I want both servos to rotate the same
amount with a single signal sent to both.
Can I just use a Y-splitter cable type arrangement, or do I need to drive each servo from a separate servo connection (such as SSC, Phidgets, etc. ) My concern with separate connections is that there might be some signal lag between the two, and this could damage one or the other servo since they will be linked mechanically.
Thanks !
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You can feed the same signal to two servos, they will move in parallel.
The problem with linking 2 servos directly mechanically is that there is no guarantee that both servos will have the exact same speed, response, movement envelope, be trimmed the same, etc. they are going to fight each other and you will waste power and energy. (and strain the servos needlessly)
I think if you couple them through a differential, that would solve the problem, effectively taking the average of both servos movement, mechanically. But you will have to invert the signal going to one of the servos (there are cables you can buy that do that). With this arrangement, you will get a free bonus: rotation of the arm. So you will have double the power for flexing, and be able to rotate the arm.
bruno
pogo wrote:

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A mechanical differential will work. Tearing apart the servos and running both motors from the same controller will work, maybe. Using real servomotors with encoders and forcing synchonization in software will work.
All those solutions will cost more than getting a bigger R/C servo.
                John Nagle
bschwand wrote:

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