Earlier this year, I replaced my battery-powered push mower with an iPhone-controlled robot lawn mower. That machine creates a virtual map by letting you manually steer it around the perimeter of your yard. Once everything is configured, it takes over mowing duties on a schedule.More recently, I’ve been testing another system called the TerraMow V1000. It takes a substantially different approach to navigation, and after several weeks of testing, I think it may be the more user-friendly option for a lot people.