Dyson seems pretty good in vacuum cleaners and may well have tried this and found it doesn’t work, but then again, sometimes people in an industry can’t see the woods for the trees so who knows, there may be something in this:
Jess the cat
At a smaller scale, velcro uses tiny little hooks to stick together, copying burs from nature.
Suppose you make a tiny little ball that has even tinier little retractable spines or even better, hooks. And suppose you make them by the trillion and make a powder that your vacuum cleaner attachment first sprinkles onto a carpet, then agitates furiously and quickly, and thus gets the hooks to stick to dirt, pull it off the surface and retract (so that the balls don’t stick to the carpet) and then you suck the whole lot into the machine. Since the balls have a certain defined specification, they are easy to separate from the dirt and dust and reuse again straight away. So you get superior cleaning. Some of the balls would be lost each time, and some would get sucked up next time, but overall you’d need to periodically top up the reservoir.
The current approach is to beat the hell out of the carpet fibers with a spinning brush and that works fine, but I think adding the active powder might be better because it gets right in among the dirt and drags it kicking and screaming off the fibers.
So, ball design. Firstly, it doesn’t need to be ball shaped at all, and secondly it doesn’t need spines really, just to be able to rapidly change its shape so it gets some sort of temporary traction on a dirt particle to knock it off. What we need here is any structure that expands and contracts or dramatically changes shape when a force is applied, ideally resonantly. Two or three particles connected by a tether would move back and forwards under an oscillating electrostatic, electrical or magnetic field or even an acoustic wave. There are billions of ways of doing that and some would be cheaper than others to manufacture in large quantity. Chemists are brilliant at designing custom molecules with particular shapes, and biology has done that with zillions of enzymes too. Our balls would be pretty small but more micro-tech than nano-tech or molecular tech.
The vacuum cleaner attachment would thus spray this stuff onto the carpet and start resonating it with an EM field or sound waves. The little particles would wildly thrash around doing their micro-cleaning, yanking dirt free, and then they would be sucked back into the cleaner to be used again. The cleaner head doesn’t even need to have a spinning brush, the only moving parts would be the powder, though having an agitating brush might help get them deeper into the fabric I guess.