Electronic – High accuracy servo


I'm looking for a two servos to power a pointing and tracking gimbal I'm building for some optics. I'm trying to find the highest accuracy servos I can buy in the standard servo package (or close to it). Does anyone have any recommendations? Most hobby servos don't list the positional accuracy.

Update I'd like <1 degree accuracy (less is better). I've considered using a stepper motor, but then I'd have to incorporate my own feedback. I'd like a COTS (commercial, off-the-shelf) solution.

Best Answer

You may want to check out the Dynamixel AX-12 Digital Hobby Servo, It has a built in 10-bit (1024 position) absolute encoder.

It is also a highly-customizable servo, and is easily interfaced to via serial. There are already Arduino and C++ libraries available if you would like to interface through either a microcontroller or computer serial port.

I believe that 300 degrees corresponds to 1023, 150 degrees corresponds to 511, and 0 degrees corresponds to 0. This would indicate about 1/3 of degree resolution.

Depending on your torque, speed, and angle requirements, you could also consider gearing this down further to get more accurate resolution.

If you need something more heavy-duty, there are many other servos in the Dynamixel Series. The EX-106+ has pointing accuracy of 0.07 degrees, but costs about 500 dollars, as well.

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