Application Note

What Is The Difference Between Parallel Positioners And Stacked Serial Kinematics?

When faced with a multi-axis motion application, many users stack motion stages, and in fact that is a fine approach for assemblies of just a few axes. But as applications become more complex, so do the equivalent stacks-of-stages, and very real and practical considerations begin to come into play.

  • Stiffness.  Some stage manufacturers publish stiffness specifications in terms of axial deviation per unit force, but this is of little utility in estimating the dynamic performance of a stage …or a stack.  A more pertinent metric is the resonant frequency, as it integrates both the effective coefficient of stiffness of a mechanism and the summed mass of its construction.  (Accordingly, knowing Fres means you can easily estimate the possible step/settle time for a well-tuned closed-loop stage: approximately [3 Fres]-1).  In our experience, most high-quality conventional linear stages will exhibit resonant frequencies on the order of 75-120Hz, unloaded.  Stack them, and the resulting structure can have significantly limited responsiveness and long settling times.
VIEW THE APPLICATION NOTE!
Signing up provides unlimited access to:
Signing up provides unlimited access to:
  • Trend and Leadership Articles
  • Case Studies
  • Extensive Product Database
  • Premium Content
HELLO. PLEASE LOG IN. X

Not yet a member of Photonics Online? Register today.

ACCOUNT SIGN UP X
Please fill in your account details
Login Information
ACCOUNT SIGN UP

Subscriptions

Sign up for the newsletter that brings you the industry's latest news, technologies, trends and products.

You might also want to: