Design resolution
= Design resolution
<Design resolution> is the theoretical smallest commanded movement implied by a positioning mechanism's drive components. For a screw drive, it can be calculated from screw pitch, reduction gearing and motor or encoder increments. It is not automatically the <minimum incremental motion> that the final load executes repeatedly.<Precision Motion and Positioning: Difference between Micropositioning and Nanopositioning by Physik Instrumente>[Glossary, Design Resolution and Minimum Incremental Motion]{ref}
For an original ideal drive, let a <lead screw> advance $p=0.50\,\mathrm{mm}$ per revolution, with 50 motor revolutions per screw revolution and 2000 resolved counts per motor revolution. One count corresponds to
$$
q=\frac{0.50\,\mathrm{mm}}{50\cdot2000}=5\,\mathrm{nm}.
$$
Doubling the count resolution to 4000 per motor revolution gives theoretical $q=2.5\,\mathrm{nm}$ without changing the screw. That calculation does not halve <friction> or remove <backlash>. A controller may display both increments even if the load moves only after several such commands have accumulated.
Keep the location and counting convention of the feedback sensor explicit. Counts at a motor shaft, counts at a screw and directly measured load position are different observations. A gearbox can introduce compliance between them. Pair the design calculation with an independent motion test to establish operational performance. A smaller theoretical increment also does not by itself establish absolute positioning accuracy or a smaller <measurement uncertainty>.