The future of free-wheeling automated yard work took a step closer to American consumers on Wednesday after U.S. regulators gave robot maker iRobot Corp Inc technical clearance to make and sell a robotic lawn mower.

The company, known for its robot vacuum cleaner Roomba, has designed a robot lawn mower that would wirelessly connect with stakes in the ground operating as signal beacons, rising above the ground by as much as 61 centimetres.

Automated grass-mowers have spread across Europe in recent years. In the U.S., iRobot told the FCC its competitors only offer hands-free mowers that require underground fences or other elaborate setups.

IRobot's stake design, however, required a waiver from the Federal Communications Commission to make sure that transmissions between its machines and the antennas wouldn't interfere with other devices using the same frequencies.

The FCC usually prohibits the operation of "fixed outdoor infrastructure" transmitting low-power radio signal without a licence, and iRobot's lawn mower beacons fell in that category.

The National Radio Astronomy Observatory had fought iRobot's waiver request, saying the lawn mowers would interfere with its telescopes. But the regulators waived the rules for iRobot, saying its beacon design should be safe with the promised limitations on height, signal strength and use in residential areas.

"The FCC's assessment agrees with our analysis that the technology will not have a negative impact on radio astronomy," iRobot's spokesman said in a statement welcoming the FCC's move.

"The FCC's decision will allow iRobot to continue exploring the viability of wideband, alongside other technologies, as part of a long-term product exploration effort in the lawn mowing category."