Took a while to remember who Helen Greiner is/was. She was a founder of irobot. She bounced around the quad copter startups when that was big, but now has landed at a weed whacker startup. It has a simple string trimmer on the bottom which chops a weed, but it doesn't suck them into a vacuum bag. Theoretically, chopping off the weed is enough to deal with the problem.
The problems is has to solve are getting around uneven dirt without falling over or getting stuck, differentiating plants from weeds. It uses capacitive sensors to navigate around taller plants. Plants which impinge on the capacitive sensors cause it to turn.
The string trimmer runs slowly to detect shorter plants. Plants which are short enough to pass under the robot & impinge on the string trimmer are treated as weeds & cause the string trimmer to spin up. There are ways to make it avoid short plants by erecting metal barriers. It has to be waterproof. There's no lidar. It manages to generate all its power from a solar panel.
Basically not much more than what a $50 toy used to do, but in the QE world now valued at $400. It's the epitomy of a minimally viable product which they hope to bootstrap off of & improve upon. For those of us without the $25 million for a back yard near a job market, the most useful part may be the traction system for navigating around dirt. It's surprising those goofy diagonal wheels would make any difference.