I haved an application that requires the synchronization of 2 axes. There is very little load variation and zero speed variation once the system is running... each axis is a mechanically identical device that should be turning at 1500 rpm, in a 1:1 relationship. The identical rotary position is very important as each axes is a camera, capturing a high resolution image that must be identical to the other.
How much positional error can I expect from an optima controller driving a properly tuned servo and a high resolution optical encoder? Are there better/worse types of servo motors for this? Brushless vs. brush - or specific sub-types with better response time? Are there any other design issues for the electronics that I should pay atention to that can contribute to achieving this goal?
Thank much,
Aaron Keit
Buz on 09/18/2006 - 19:23
From my experience, you may be better off using the resolver on the servo motor for feedback on something you want tightly coupled. No matter how tight the coupling between the motor and the load, the slop will limit the ability to tune tightly, and thus magnify the slop in performance. Using the resolver limits your error between the axes to the amount of play in the couplings. Just my 2 cents.
Galil_RobinR on 09/19/2006 - 09:32
The electronic gearing is very accurate, especially with an 'even' ratio of 1:1. I would be much more concerned about the mechanics. Even if they are designed as identical, over time, some play will develop which could affect your image. Can we look at direct-drive motors? The motor technology (brush vs brushless) matters less, but I'm sure you'll have an easier time finding brushless. If there is no mechanical slop between encoder and shaft output (in the case of direct drive) the gearing will stay tight forever (unless your shaft can twist!)
If you mechanics need to be more complex (right-angle, gear-reduction, belt-drive etc) I suggest you either call in/email Galil support to discuss, or contact your local rep to talk about it:
http://66.60.181.132/xnet/findgalilrep.aspx