servo motor selection

[idhar]

am a newbee to this forum.
My requirement is to control a hydraulic valve linear movement. Its travel is 20 mm. I need to control its position anywhere within 20 mm travel with resolution of 0.1 mm, I mean say 1.1 mm or 15.6 mm etc., The linear movement positioning is by lead screw. Calculation shows that with maximum hydraulic loads acting on the valve, 1 Nm is the maximum torque required to move the valve. Intention is to have a closed loop control with DC servo motor (24 V, current max 10A) and valve movement by LVDT feedback. I need help on:
a. What is the DC motor rating? (torque)
b. Brush or BLDC for effective control?
c.Mathematical models on position control with load (web site)
d. anyother details to be considered
thanks in advance

[Al_The_Man]

Sizing software
http://www.electromate.com/technical...morgansoftware
In 1:1 applications with no gearing, BLDC may show some slight cogging at very low rpm due to coarse commutation, otherwise they may be preferred due to no brushes.
Al.

[gridley51]

An easier and more accurate way is to use a servo valve and controller card.Standard technology,available off the shelf.