Autonomous Robotic Lawn Mowers - How They Work

Autonomous robotic lawn mowers are not identical but modern machines typically work off some combination of the following systems:

RTK Positioning:  RTK stands for real time kinetics.  Traditionally it has involved placement of a dedicated reference or base station at a fixed location that supports the mower it is intended for.  This station would communicate to satellites and remain fixed at a location, it would then broadcast a signal, typically within 1-2 kilometers that the robotic mower could use with a high degree of accuracy within that range of the base station..  We are seeing a shift into virtual systems that communicate directly to machines needing this technology.  Mammotion is leading the industry in this adoption with their iNavi platform.  By communicating with multiple GPS satellites and ground based stations a higher level of accuracy can be maintained versus something like a traditional handheld GPS receiver.  Often these systems boast accuracy tolerances between 1-2 centimeters and they can continue this accuracy whether the machine is moving or stationary..

This technology does several things compared to older systems that often used boundary wires, this includes:

1. Allowing for easy mapping and geofencing/referencing.

2. Ability to replicate identical patterns with great accuracy.

3. Optimized energy usage by creating near perfect lines and pattern optimization versus a random cutting pattern.

4. Ability to work both day and night and in low visibility or foggy conditions.

5. Adaptability to varying terrain while maintaining straight lines.

6. Ability to operate with no or minimal human oversight.

Advanced Cameras including some with AI recognition:  Many mowers use a high level system that contains multiple cameras along with AI recognition.  This allows a mower to have superior obstacle avoidance when it comes to avoiding kids, dogs, furniture, toys, etc left in a mowing area.  This system also helps a mower determine the boundary of a mowing area compared to a flower bed or woods edge as well determining what is grass compared to gravel or standing water in a ditch.  The AI systems let the mower recognize what many items are as soon as it sees them.  There are limitations on these systems as they do depend on lighting so darkness, shadows, or low visibility can hinder their ability.  Typically these systems are combined with an RTK system and they compliment each other very well.

LiDar:  LiDar allows a mower to obtain a 3D map in real time.  These systems can send up to 200,000 individual data points per second back to a machine in real time.   LiDar uses lasers and their reflection time to determine obstacles and build a map.  This same technology is used in self driving cars and is some of the newest and most technologically available in robotic mowers.  This system can be used in combination with others. 

Physical buttons or sensors on the machines:  These can be a stop type button that can be pressed to halt all operations or bumper or an inertial sensor that provides physical feedback if a machine runs into something or gets a wheel off the ground.  These are often for safety and last resort issues that provide redundancy in case one of the more technologically advanced systems fails.   

Mammotion products use all of the above technology in their newest models and are one of the few manufacturers that does.  These systems work well together and also allow for continued operation without interruption or performance degradation in the event one of the systems isn’t available, such as loss of RTK signal temporarily.  Our commercial mowers typically are using all of these systems as well.