Some relevant projects I found:
[1]: GitHub - AutoRoboCulture/Nindamani-the-weed-removal-robot: Nindamani ...
[2]: GitHub - BrandonAllan/Weeding_robot: The Weeding Robot Project is a ...
[3]: A Development Platform for Autonomous Weeding. - GitHub
[4]: anida16/Autonomous-InterRow-Weed-Removing-Robot - GitHub
[5]: GitHub - rahularepaka/Project-Cyclops: Weed Detection and Laser ...
[6]: Agroecology-Lab/Open-Weeding-Delta: Open Weeding Delta - GitHub
[7]: GitHub - brycejohnston/awesome-agriculture: Open source technology for ...
I think one of the keys is that they have to be able to be constructed relatively cheaply and with off-the-shelf components. If it costs $5000 and you need an engineering degree to build the final product it isn't really a leveler, more of a toy for wealthy land owners.