Cutting sports fields is one of the most time consuming, uninspiring and repetitive activities one will have at a sports club. Autonomous mowing robots are less demanding and can do it cheaper. They don’t have any expectations, free up manpower that can be used elsewhere and are more affordable. The two best known autonomous mowing robots each have their own personality.

The development of autonomous mowing robots really took off in 2012. The best-known autonomous mowing robot is the Bigmow from Yamabiko (formerly known as Belrobotics). From this year, Husqvarna is also vying for a slice of the market. The Ceora Epos is currently an autonomous mowing robot but should, in fact, be seen as a tool carrier, as Husqvarna intends to expand the functionalities of the Ceora Epos in the future.

Better grass quality

Grass grows on average about 40 mm per week, although that length can go up to 80 mm in places where healthy grass growth is being pursued more rigorously and by specialists. Nevertheless, the various football associations demand a length of 25 to 30 mm maximum.

The biggest advantage of autonomous mowers is that they trim the grass blades continuously, which results in a healthier grass plant. The Bigmow has a cutting width of 105 cm and 11 different cutting height settings: from 20 to 100mm. The Ceora Epos cuts 72 cm wide but cuts at a higher speed. It can cut lengths from 20 to 70mm.

The robots can operate day and night, depending on the weather or usage intensity of the field.

The Ceora Epos weighs 38 kg while the Bigmow weighs 51 kg, making both robots light enough to not leave tracks on the (wet) field.

As the razor trims only the section of the grass blades that is most receptive to developing fungal diseases, the likelihood of getting a disease is reduced to almost zero. The short clippings also act as a natural fertilizer and won’t deny the grass light or oxygen when heaps of grass clippings accumulate on the surface, as is the case with traditional grass cutting machines.

Charging station

Autonomous mowers need a charging station onsite. This station should be placed strategically to enable the device to easily access it but where it is also sheltered from the elements. Protection from the sun will positively influence the lifespan of the battery. It takes one hour to charge the Bigmow battery, after which it will work for one hour. Charging the Husqvarna Ceora Epos battery will take two hours but this will allow the device to operate for five hours minimum.

The robots continuously calculate their battery capacity and will make sure they’ll have just enough juice to return to their charging station. For their return, they’ll follow the most direct route. Before they return, they’ll map their final position to ensure that, once the battery is fully recharged, they’ll continue where they left off.

To make maximum use of the robots, it is important to remove obstacles like branches or the goals from the field, as well as to lift the nets to allow the robots an uninterrupted run. Otherwise, the mower will get entangled in the ropes, which will require somebody to free the device (and likely to replace the netting that has been cut through), or the cutting blades will get damaged once the robot encounters sticks or branches on the field.

Crisscross pattern

The Belrobotics Bigmow used to only be able to mow a field in a spontaneous crisscross pattern that made little to no sense other than that the grass blade would always be cut from a different angle. This could result in some sections of the field experiencing a higher mowing frequency than elsewhere. Since 2021, the Bigmow RTK is also capable of mowing in straight lines. The Husqvarna Ceora Epos can only cut in lanes but can do so horizontally, vertically or diagonally. For economic reasons, both mowers usually run the length of the field.

Cutting grass in straight lines is more economical. When mowing a field in straight lines, one autonomous mower can maintain 50,000 m2 of grass. That’s about six football fields. However, factors like the usage of the field, the positioning of the charging station, grass height and weather conditions all have an impact on this capacity.

Smart and safe technology

Both robotic mowers have floating mowing heads fitted to allow the device to adjust to possible uneven sections in the field. The BigMow has five cutting heads with three blades on each head. For the Husqvarna Ceora Epos, this is the other way around: it has three floating mowing heads with five blades on each. The blades work like a box cutter and will automatically fold in when the robot is lifted.

Both robots have collision sensors fitted that will stop the robot as soon as it detects obstacles at ground level in its vicinity. If the mower cannot continue independently, a message is sent to the mobile phone of an administrator. This also applies if the BigMow or Ceora Epos is lifted by unauthorized persons. Thanks to an anti-theft app, the robots can always be traced, even when they are taken away in a vehicle.

Identifying the perimeter

Until recently, the BigMow required a special control cable to be buried just outside the playing field to mark the area in which it was expected to operate. Since 2021, it uses GPS positioning. As of this year, the Bigmow uses the GPS-RTK technique, for which it requires a 4G network. Thanks to this upgrade, trees no longer have a disruptive effect on the positioning of the mowing robot in relation to the satellite. The Bigmow continuously communicates with four different satellites as well as with a base station on site. The Husqvarna Ceora Epos uses only one RTK GNSS connection by default.

Both robotic lawnmowers are accurate within two to three centimetres.

The right partner

Apart from selecting the robot that is suitable, it is also important to select the best partner. That partnership should go beyond just placing and installing the technology. One of the crucial issues that should be determined upfront is the service and follow-up speed when a malfunction is recorded. Regardless of who is to blame for that malfunction, it is important that the unit is (temporarily) replaced as soon as possible to avoid it falling behind in maintaining the grass at an acceptable length.

It is also important to properly plan the annual servicing of the unit. Suppliers prefer to collect the unit at the beginning of winter and return it just before the start of the second half of the season. Be clear about what happens when the winter is mild and grass growth continues, meaning that you need to extend your cutting period. This is to prevent the grass from being that long by spring that the mower cannot cut it, which could result in a traditional unit having to be brought in.

Whether or not included

It is also important to be clear about what exactly is and what isn’t included in the agreement. In addition to installing the robotic mower and charging station, the supplier should ensure that the mower is correctly set and provide the operator with thorough training. Furthermore, all warranty details must be agreed upon, and it should be clear what exactly is and what isn’t guaranteed. Will it be just the mower and the base station or does it also include the GPS system? It must also be clear how and for how long the software is updated and how that period can be extended.

Suppliers often expect administrators to carry out minor maintenance activities themselves. This includes the weekly cleaning of the underside and wheels (either by using a scraper or compressed air) and replacing the cutting blades. In addition, the supplier might expect you to regularly clean the contact points on both the robot and the charging station to ensure the charging process will run optimally.

How much does an autonomous mowing robot cost?

The price tag will differ per supplier, but to give you an indication of costs involved, we have put some figures here. These have been made available by Vitaro Robotic mowers, which offers both the Belrobotics Bigmow and the Husqvarna Ceora Epos.