The lazy days of summer are often consumed by the seemingly endless chore of keeping the grass trimmed. But what if you could switch on the lawn mower, sit back with a glass of iced tea and watch the grass get cut?
That's precisely the picture the inventors of a robot lawn mower hope to see one day. Thomas H. Noonan and two partners, John Fisher and Barry Bryant, have won a patent for an automatic, self-propelled mower that stores a map of terrain and a cutting route in its microprocessor.
"Basically, it can memorize a lawn and then re-route itself," Noonan, a salesman for 3M in Havertown, Pa., said of the mowing robot he and his partners call Mobot.
The gas-powered mower relies on three navigation systems. First, the computer map tells it where to cut and when to turn or slow down for a hill. Because mechanical problems, like wheel slippage, can still knock it off its route. it adjusts its position by using sensors to detect metal markers buried in the lawn.
If the mower cannot find its way, it shuts itself off. Ultrasonic sensors also tell the mower to shut down if there is an obstacle in its path. An alarm would alert the owner to check out the problem.