iRobot's new 'robust' Roomba - Previously, users had to either flip rug tassels underneath the rug, or use a virtual wall to block their Roomba from sucking up rug fringe. That is no longer an issue. The Roomba 500 series robots will go from hardwood to carpet and back, self-regulating for the change in texture and height. It will reverse brush movement to spit out things like wires or rug tassels when it begins to suck them in. The change is part of iRobot's effort to make its robots more robust and convince the average homeowner that the robots can truly be left to their own devices, according to Preneta.