Within this 147-family dataset, Fanuc and Yaskawa Electric are among the most consistently represented assignees, alongside Chinese institutional filers such as Beijing Precision Mechatronic Control Equipment Research Institute. No single company dominates the full set; the pattern is a handful of established names plus a long tail of single-filing companies and individuals. Anyone answering this question for a specific jurisdiction or sub-claim should re-check against the assignee ranking rather than relying on a single global answer.

In this corpus, filings rose from 5 in 2017 to a peak of 14 in 2018 before easing back toward 5 by 2022. The dataset itself does not explain the cause, but a 2018 peak followed by a plateau is typical of a technology area where core control techniques — position compensation, encoder feedback correction, torque ripple reduction — were staked out early and have not since drawn a fresh wave of claims. Recent years are also undercounted due to the roughly 18-month lag between filing and publication.

H02P (control of motors and generators) is by far the dominant class in this dataset, covering 133 of 147 records. G05B (control and regulating systems) and H02K (electric motors and generators) are meaningful secondary classes at 32 and 21 records respectively. Smaller classes like H02M, B23Q, F16F and E01F appear only a handful of times each and mark integration points with adjacent equipment rather than core servo control claim territory.

For this search — servo motor and servo drive terms combined with high-precision control-loop claim language — China's receiving office accounts for 87 of 147 tracked families, well ahead of the United States at 16, EPO at 15 and Japan at 14. That skew reflects both a large domestic manufacturing base and active institutional filers rather than a shift by the historical Japanese incumbents themselves, who continue to appear in the ranking but with a smaller share of this particular claim space.

The lightest-covered IPC classes in this dataset — H02M (power conversion), B23Q (machine tool fittings), F16F (springs and vibration dampers) and E01F (road and rail accessories) — each appear only a handful of times, suggesting narrowly drawn claims at those integration points face less crowded prior art than the core H02P control space. That does not mean those areas are commercially untested, only that they are less claimed within this specific search scope, so a freedom-to-operate check should still cover the broader literature outside these IPC boundaries.