Nothing to see here, folks. Move along. It’s just a bunch of dummies on Segway RMP 200/ATV platforms being developed by Marathon Robotics for live-fire training. The RMP 200/ATV is one of several two- and four-wheel Segway Robotic Mobility Platforms designed for use in a variety of applications including exploration, mapping, surveillance, mobile manipulation, and more. They even have models with Mecanum wheels (and neat animation on the website showing the sideways and rotating movements possible with these wheels).
For the live-fire training with these moving targets, Marathon Robotics armor-plated the platforms and added mannequins that stop and drop when shot. At the same time they send out a message to the other platforms so they can run for cover.
RMP 200/ATV [Manufacturer's Site]
Rover System [Marathon Robotics]