Most of the time, mobile robots do useful things thanks to remote sensing systems. That is, they have cameras, radar, ultrasound, LIDAR, or other ways of finding stuff about the world around them. That’s great, but there are all kinds of applications that require more direct forms of sensing: namely, sensors that are in direct contact with the thing that you want to sense. Mobile robots can carry around probes and whatnot to make measurements like this, but that’s difficult and time consuming.
For example, let’s imagine a completely hypothetical scenario: we live in California, and we’re trying to grow some food in a field, but we barely have any water. In order to grow plants most efficiently, we’d want to be able to measure moisture levels in the soil to make sure that we’re not over or under watering. Assuming that we’re looking for a better solution than a human to walk around probing the soil all the time, we could try to have a mobile robot do the same thing, but that can be tricky and probably expensive. Another option might be to put sensors in the ground all around the field, but then you’ve got to buy the sensors, power them, and do some sort of fancy wireless thing to get them all reporting back.
In a paper recently posted on arXiv, a team of researchers has proposed a hybrid approach using long-range UHF RFID sensors that are dirt cheap and require no power source, combined with a mobile robot that can talk to them. Is it the best of both worlds? Yes. And does it work? Yes. It does. Maybe.