DIY Robotic Lawn Mower 

ObjectiveS

To build a robotic lawn mower 

• using an existing gas powered push mower for the actual grass clipping functions. 

• using a custom-built chassis and propulsion system for mowing around the lawn.

• develop remote control and more advanced algorithmic experiments. 

Design Assumptions

The design was done using a CAD tool using certain assumptions.

• Try to avoid metal fabrication if possible - Avoid welding.

• Due to ease of assembly, use https://8020.net aluminum extrusion products to the extent possible -. 

CAD DESIGN

THE Assembly

The assembly took several days to go from the start to finish.

• Assemble the basic frame

• Mount the wheels

• Remove the wheels etc from the push mower

• Mount the mower body onto the robotic chassis.

• Build the electronics and motor control

• Build the remote control circuitary.

• Software 

Testing

This video was captured after several smaller tests were completed.

 

Analysis

The prototype works but there is room for significant improvement.  The extruded aluminum was a good idea for ease of fabrication. However the weight of the steel mower and the height of the gasoline engine above the ground ( high CG)   makes it very hard to steer on slopes. The mower starts to slide sideways sometimes on slopes. 

Next Steps

A version 2 of this robotic lawn mower should be built sometime in the future but instead of going with an existing gasoline lawn mower this time I would try 

• fully electric propulsion and cutting

• all four wheels to have motorized control

• height control 

• cameras with OpenCV to determine where the robot was at any given point of time

• Fine grain GPS control.

• Other Machine Learning enhancements.