RC Lawn Mower

on July 11, 2015

When my brothers and I finished planting all the trees for our Forestry project, we realised that we had underestimated how difficult it would be to mow the area. Small trees can be quickly overtaken by fast growing grass and grass grows fast when it is irrigated alongside young trees.

Using sloped land for a tree farm, seemed like a great idea because we couldn’t really use it for much else but it had a downside. Using a ride on mower on steep land requires very careful driving or you can get yourself into trouble, which my brother Damian managed to do regularly.

Because of my experience with Robotics, Drones, Remote Controlled Vehicles, Engineering and Electronics, I decided to build a remote controlled lawn mower. To test my ideas, I bought an old lawn mower which threw grass out the side. This was an important choice for the safety of the person remotely controlling the mower. I stripped it down to the deck and motor and bolted some wheel chair motors where the back wheels were, welded some trolley wheels on the front and wired up a motor controller, batteries and remote control.

Below you can see the first version of the remote controlled lawn mower.

The first version worked really well for approximately 12 months but being used so regularly for very rough work, resulted in the motor cracking it’s mount to the frame.

I set out to build a new version from scratch, including the mower deck, that was much more robust but also engineered to solve a few other issues. My brother had noted the mowers direction had to be regularly corrected because it had a tendency to hit a rock or divot then move left or right and no longer be facing straight down the line of trees. To solve this, I used a gyroscope which corrected the small bumps the mower regularly encountered. My brothers other piece of feedback was having to charge the batteries. The first version could only drive as long as the batteries lasted. I decided to use an alternator, driven from the lawn mower engine, that could provide 24v and use it to charge a smaller 24v Lithium Phosphate battery to run the motors. This mean’t the mowers range was only limited by the amount of fuel provided to the petrol engine. Both of these additions worked very well.

Below you can see the second version of the remote controlled lawn mower.

I built a much larger (1.2m x 1.2m) tracked robot to support our tree plantation further. It was designed to be the drive and power platform for a flail mower, a hole digging machine and to pull a small trailer over uneven ground. At this time, I am unable to locate any photos of this robot.