This is a question just because I am curious. I am following this SE site for a long time and I got the impression that is was in beta stage for a long time so I checked the Area 51. What I saw was that it is in beta for more that 5 years! How is that possible? Is there a timetable for the "graduation" of this community?
Graduation is no longer either required, or expected of small Stack Exchange sites, and as long as we are still an active community we are at no risk of being closed down.
It's been a few years since Stack Exchange woke up to the idea of perpetual beta sites - small, niche sites, such as Robotics, which may never reach graduation criteria, but equally will never disappear.
In addition to Graduation, site closure, and a clearer outlook on the health of SE sites , see Should we rename or remove the "beta" label? for more information.
In the long term, I hope that perpetual beta sites will start to get some of the benefits of graduated sites, even if it isn't worth Stack Exchange spending time and development resources on a custom site design.
Also, consider this, we don't have a single 10k user right now. If we were to graduate today, the only people who would have access to moderator tools would be ♦ moderators. The problems are even worse further down the reputation scale, we only have 6 users with 3k or more reputation, who aren't already ♦ moderators, so only these 6 people would be able to cast ordinary close votes.
This is just the tip of the iceberg when it comes to graduating too soon.
For the moment, Robotics simply isn't a big enough site to qualify for graduation right now. If you want it to be, we need more questions, more answers, more votes, and these come from more active participants in the site. Growing our community is the only way gain the critical mass required to get to graduation.