Mo - Robotic Lawn Mowing

My first proof-of-concept lawnmower, 'lawna' proved very successful and I learned a great deal during the research and implementation. The main lessons I learned were:

• You need lots of power both to propel a mower, and to cut grass effectively in all but golfing-green conditions.
• There is a great deal of tradeoff between power and runtime.
• Generally, keeping things simple is a good plan (at least initially).
• With large motors and gearing, there is a lot of RF and grounding interference, making it challenging for the electronic microcontroller components.
• Making the robot cater for the all the obstacles and grass types that arise in a garden is difficult. Bushes, paths, holes all are challenging obstacles.

Lawna was small which made the task of squeezing everything onto the small chassis difficult. It also had a small cutting width of about 10cm which meant it would take a very long time to cut the lawn, with several recharges being necessary.

With all these lessons learned, I decided to embark on building a larger model that would serve as a real labour saving device, and being capable of carrying large lead-acid batteries if I choose to go down that path. With the idea of this being a functional machine, I need to scale back some of my software plans for localization, beacon tracking etc and go for something simple. Once I have a robot that can efficiently cut the grass, thereby freeing some of my time, then I can indulge these more challenging persuits.

Goal

Build a simple full-scale functional autonomous robotic lawnmower

As with Lawna, this will be a mulching mower that cuts the tips of the grass regularly, keeping it short and removing the need to collect grass clippings.

June 2014