Design and implementation of a control algorithm for an autonomous lawnmower

This paper presents the design and implementation of a GPS-aided autonomous lawn mower. The lawn mower is an integrated system of sensors, motors, processors, and control software. A key position sensor is a unique custom designed and implemented differential GPS (DGPS) system that utilizes low-cost off-the-shelf stand alone GPS receivers. The DGPS system provides the platform position and orientation information with an update rate of 10 Hz. A set of Hall sensor-based odometer provide additional position and vehicle orientation inputs to the system in between the GPS data updates. The lawn mower chassis was custom designed and implemented by a team of undergraduate students at Miami University. The control software was written in Java and executed on a Systronix Saje microcontroller. Multilayered ND controls were implemented in the control software to keep the lawn mower moving in a pre-planned path with optimum path overlaps. In addition to these components that are necessary for the autonomous operations of the lawn mower, an extended remote monitoring/control program has also been implemented. The remote station communicates with the lawn mower through an 802.11b wireless router. Lawn mower status and process logs were continuously monitored at the base station. Detailed design and implementations of the overall integrated systems were discussed in the paper