Center-Pivot System Modified to Mow Lawn

When flying over the United States, Australia, and a few other vast and relatively empty parts of the world, strange circular formations can be spotted. These are typically center-pivot irrigation …. Center-Pivot System Modified to Mow Lawn.

These are typically center-pivot irrigation systems, an effective way to irrigate crops if efficient use of space is not too big of a priority. Keeping these massive machines in a straight line is an problem, though, and [rctestflight] built a miniature version of his that works on the same principle but mows his lawn instead. These systems work as semi-independent sections that are flexibly coupled at either end.

The control scheme initially used here was to drive the outermost set of wheels at a constant speed, and then use limit switches at each coupling inside of that to drive inner sets of wheels once the outer set passes a setpoint. Eventually a potentiometer-based proportional controller was installed in place of the limit switches. With some other drivetrain issues sorted out it was on to building the mower attachment.

This uses a pair of pivoting precision knives mounted to motors that ride along a carriage attached to any one of the linkages of the center-pivot system.