Robotic mowers
What is a robotic mower?
Robotic mowers are autonomous machines designed to mow grass. These robots are equipped with sonar, sensors, and work on the basis of either a buried perimeter wire or GPS technology, to ensure accurate, safe and consistent mowing, replicating the maintenance of traditional mowing equipment and a human operator.
For the purposes of this card, we will be explaining how GPS autonomous robotic mowers work.
🗝️ Key Features
Autonomy: They can mow pitches without a human operator once programmed and set up.
Precision: Using advanced sensors and GPS, they can mow in a striped pattern to high accuracy within +/-2cm
Efficiency: They work based on constant operation and will autonomously dock with the charging station when required. On this basis some robots on the market can manage to mow up to 75’000m2 twice per week.
Versatility: The number, type and size of robot/s you need and therefore the cost, is determined by how big an area you have to mow, how frequently you want it mowed and how many hours per day the robot can be out mowing. They can be programmed to maintain different areas at different mowing heights and scheduled to charge during matches or training.
👉 How do they work?
Robotic mowers rely on GNSS (Global Navigation Satellite System) which is an enhanced version of GPS (Global Positioning System) used by many devices that we take for granted such as smart watches and mobile phones.
➡️ However GNSS signal from satellites can sometimes have interference. A simple change of weather can cause clouds to disturb the signal sent to the line marker, so modern robotic mowers use something called RTK (real-time kinematics). RTK receivers take in the normal signals from GNSS but with a correction stream which allows accuracy to within 1-2cm.
➡️ RTK either works from an onsite antenna base station (also known as reference station) installed as a permanent fixture onsite or a CORS (Continually Operating Reference Station) network.
➡️ As a rule a locally installed antenna base station will be receiving its correction stream based on data from your site giving optimal accuracy and reducing the risk of interference whereas reliance on a CORS network may be absolutely fine but does depend on the distance from your nearest CORS and how strong that networks signal is which potentially has more margin for error. The benefit of relying on the CORS network is that you do not have to have an onsite antenna which will normally be mounted as high as possible on a building or similar and ideally needs a direct line of site to as much of the sky as possible meaning installation above the tree line is desirable.
🔧 How are they operated?
👉 Operation and monitoring of robotic mowers is typically via a smartphone app and online portal that allows operators to create a mowing map, set boundaries, set mowing schedules, height of cut and even areas to avoid such as goal mouths under repair, waterlogged areas etc.
👉 Remote monitoring gives you all sorts of data on the robot’s operation and any faults or alarms that might occur which helps to avoid nasty surprises such as turning up and finding a pitch hasn’t been mown.
What are the benefits?
✅ Fully autonomous mowing, comparable costs to traditional maintenance equipment.
✅ GPS-RTK allows pattern mowing in traditional stripes. Up and down, across or diagonally.
✅ Robotic mowers work on the basis of mowing the given area 2-3 times per week (at least), so your package would be priced and installed accordingly to achieve this.
✅ More regular mowing = a better pitch. More uniform grass coverage and consistent playing height.
✅ No more clumps of grass from infrequent mowing.
✅ Robotic mowers are one option that can help with workforce challenges or a lack of volunteers.
✅ Environmentally friendly, quiet, and cheaper to run than traditional mowing equipment.
✅ The blades attached to the mowing heads are for want of a better term like razor blades meaning cutting quality is very high and the regularity of mowing means clippings are mulched and don’t need to be collected.
✅ Robotic mowers are equipped with anti-theft systems, track and trace GPS and will immediately stop working if tampered with or overturned. Sensors and sonar help them to stop if they encounter obstacles.
Points to consider…
📌 Although rare, robotic mowers are more susceptible to theft or vandalism, given they are fully autonomous a person will not necessarily be onsite when they are operational, meaning, they are probably best suited to secure sites or where vehicular access is limited.
📌 Some of the lease models do include insurance but ensure you can secure appropriate insurance.
📌 Robotic mowers can operate in the rain without damage but generally must be cleaned using dry methods such as brushes or leaf blowers. They won’t operate if cold enough for frost.
📌 Robotic mowers are not monitoring free! Users will still need to clean the mower regularly and interact with the monitoring app and deal with any malfunctions should they occur.
📌 From user experience a period of between 2-4 weeks is often necessary to calibrate the robotic mower to its optimum efficacy and contingencies using traditional equipment should be available for this period.
📌 The mowing blades do need replacing regularly every 4-6 weeks and this cost should be factored in.
📌 If you have pitches that are split across multiple areas, robotic mowers can be programmed to have travel paths between pitches however they cannot go across public roads, down steps etc but will cope with gentle slopes.
📌You will need a power supply for the charging station although solar charging stations are becoming more common.
Tips before purchasing…
💡 If you have site specific complexities like a tree lined site or mowing areas under tree canopy ensure this is thoroughly tested during demonstrations.
💡 Consider which RTK technology is appropriate for your site and location, is access to the CORS network adequate or will an onsite base station/s be necessary.
💡 If you are using an antenna base station check what the operating range is from the robotic mower.
💡 The signal transferred from an antenna base station to a robot usually works using a 900MHz radio signal that should be able to penetrate through walls and trees meaning the base antenna shouldn’t need to have direct line of site with the actual robot. On very large sites you may need additional antenna if using a model that relies on base stations.