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--- comparison_of_asi_closed_loop_stage_and_control_electronics_with_competing_products [2019/04/18 19:34] – external edit 127.0.0.1
+++ comparison_of_asi_closed_loop_stage_and_control_electronics_with_competing_products [2021/09/23 17:15] (current) – external edit 127.0.0.1
@@ Line 13: / Line 13: @@
 ===== Low-end, low cost stages =====
-Low-end low cost stages are designed with the price-conscious consumer in mind.  These stages are usually priced at around US$4-5K, and are used primarily in applications where only automated movement is required, and resolution and repeatability issues are not important factors.  ASI's MS-4 series, Ludl's Biopoint series, and Marzhauser's Econo line are examples of this type of stage.  In order to keep the cost down, these stages are always manufactured with low-cost stepper motors operating in an open-loop configuration.  Geared rack and pinion positioning elements are also used instead of more expensive lead and ball screws, and low cost bearing assemblies and guides are utilized instead of more expensive cross roller bearings and precision machined guides.
+Low-end low cost stages are designed with the price-conscious consumer in mind.  These stages are usually priced at around US$4-5K, and are used primarily in applications where only automated movement is required, and resolution and repeatability issues are not important factors.  Ludl's Biopoint series and Marzhauser's Econo line are examples of this type of stage.  In order to keep the cost down, these stages are manufactured with low-cost stepper motors operating in an open-loop configuration.  Geared rack and pinion positioning elements are also used instead of more expensive lead and ball screws, and low cost bearing assemblies and guides are utilized instead of more expensive cross roller bearings and precision machined guides.
 ===== Medium-level, moderately priced stages =====
@@ Line 26: / Line 26: @@
-Upper-end premium priced stages in the US$14-20K range utilize the same high quality components that the medium-level stages utilize, and in addition, a direct-motion feedback element is also added.  ASI's premium stage systems utilize linear encoders to provide a resolution of 20 nm.  However, due to the mechanical limits of cross-roller bearings and lead screws used, realistic resolutions at the optical axis are in the order of 50 nm or so.  To do better than this, air bearings or more sophisticated designs offering much less friction need to be used. With standard designs utilizing cross-roller bearings and lead screws, and with well-designed controller electronics and motion-control algorithms, stages with linear encoders can achieve bi directional repeatability accuracies on the order of less than 200 nm RMS for small moves of a few hundred microns or so, and about twice this on larger moves.  When working at these levels, the thermal expansion of the metal from which the stage is built must also be considered, and the resolution of the motor becomes a factor.  Since ASI stages utilize DC servomotors rather than the lower cost stepper motors that the other manufacturers use in their basic stages, ASI stages out-perform the competition.
+Upper-end premium priced stages in the US$14-20K range utilize the same high quality components that the medium-level stages utilize, and in addition, a direct-motion feedback element is also added.  ASI's premium stage systems utilize linear encoders to provide a resolution of 20 nm.  However, due to the mechanical limits of cross-roller bearings and lead screws used, realistic resolutions at the optical axis are in the order of 50 nm or so.  To do better than this, air bearings or more sophisticated designs offering much less friction need to be used. With standard designs utilizing cross-roller bearings and lead screws, and with well-designed controller electronics and motion-control algorithms, stages with linear encoders can achieve bi directional repeatability accuracies on the order of less than 200 nm RMS for small moves of a few hundred microns or so, and about twice this on larger moves.  When working at these levels, the thermal expansion of the metal from which the stage is built must also be considered, and the resolution of the motor becomes a factor.  Since ASI stages utilize DC servomotors rather than stepper motors, they out-perform the competition.
 ===== Links and supporting documentation =====

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