So to know what obstacles occur in the garden I will use a Scanse Sweep lidar with 360 degree sensing capabilities. Mounted on the top of the robot and taking advantage of its 360 degrees view. It will be mounted at a height of approximately 270mm from the lawn to the center of the eyes on the lidar. cIn parallel to this I will also use a Intel RealSense ZR300 Camera, mounted at the nose of the robot. It will be mounted at approximately 100-150mm from the lawn to the center of the eyes. More about this later.
The Scanse Sweep has a range of approximately 40Meters and a 1000 Samples per Second. The rotation frequency is 1-10 Hertz. The Scanse Sweep allow you to adjust the rotation speed on the fly so you can slow it down for more details or turn it up for faster reactions times.
The Scanse Sweep cost around 349USD. A bit pricy, but hey its a working solution.
So the two system will work in parallel to find obstacles and also to map the garden in 3D. The idea is to first drive a few laps around the plot to build a map. From the 3D map and 2D maps adjust the zones for the mower. This two system will also work together with the Reach RTK for Centimeter precision. If one of the systems starts failing it will fallback to one of the others and still be able to move around until all systems are active again (For example if the robot enters a GPS darkspot and don’t know where it is)
We will talk more about this further down the line.