I find this topic of great interest, as I think it's one of the most important technologies on the horizon, with applications both on Earth and on Mars.

A great place to start on this topic is with Robert Freitas' 'Kinematic Self-Replicating Machines', which covers pretty much every advancement in the field up until the date of its publication. Adrian Bowyer (inventor of the RepRap) also has a chapter in 'Biomimetics: Nature-Inspired Innovation' that is worth a read.

There has been some work done on the topic by Gregory Chirikjian's lab at Johns Hopkins: doi:10.1109/CIRA.2003.1222279

A lot has also been published on this topic by Alex Ellery at Charleton University, including an exploration of 3D printed electric motors and analog neural network control systems: doi:10.7551/ecal_a_026

You can also check out this wikibook I found on seed factories - a topic which I think will be relevant going forward: https://en.wikibooks.org/wiki/Seed_Factories

Following the citations in the above papers will lead you to more labs working on the topic. I haven't looked into the topic since *2019, so I would love to hear about new developments. I would love to hear from you if you find something of interest: anlum [at] protonmail [dot] com