A battery powered robotic lawn mower was developed, as an IoT device, with a number of criteria that exceed those seen on the market today :
- Determine the lawn boundary position without the use of a boundary cable
- Control the mowing motion based on user defined criteria
These two simple criteria differ significantly from most robotic mowers on the market today, which use a boundary cable to determine where they can move and mow in random patterns, with bump detection to avoid obstacles.
The first step was to establish a boundary detection technology. This was done using two separate technologies, the first was vision (which is also used for obstacle avoidance) and the second GPS./RTK which provides centimetre level positioning accuracy. The most important assumption of the project was to require internet access through wifi at all times. However, an offline version of the mower was also developed, which was significantly more complex.
The developed robotic mower, was based on ESP32 for communication and contained a GPIO board for interfacing to the various sensors and motors on the device. Other than that all processing, is done on the cloud, using StreamBlocks.
The robotic mower, is able to “remember” the paths it has taken, avoid collision through vision with objects it does not recognise, and can mow in user defined patterns. The mower can also track paths to secondary lawns and start mowing there as well. When the battery is low, the mower will go back to base and will locate the docking station (using the Hall Effect) until it is fully charged again.
By having no processing capability in the mower, and moving all functions to the StreamBlocks server or cloud, the cost of manufacturing is significantly reduced and the ability to add functionality, significantly enhanced.
