A whistle sounds in the stadium. The players run on. Bright flood­lights illu­mi­nate every angle of the space. And the audi­ence can see a perfectly mowed lawn. Admit­tedly, most visi­tors are prob­ably more excited about watching a great soccer match – the lawn has become part of the back­ground. It lays the foun­da­tion for an exciting sporting event. And there is a lot of intense work involved in making the greenery look so good. On a soccer field of up to 8,250 square meters, there is a lot of grass to main­tain. There is even more to do on golf courses.

The CEORA robotic mower robot travels at one meter per second. EC external rotor motors from ebm-papst ensure the neces­sary propul­sion. (Photo | Husq­varna)

So it is good to have a strong helper like the CEORA robotic mower from Swedish manu­fac­turer Husq­varna. Depending on the cutting quality, the profes­sional turf care device can mow up to 50,000 square meters in a period of two days. And it does all of this on its own, quietly and without emis­sions. This not only alle­vi­ates the soccer stadium’s groundskeeper but also makes for easier work on golf courses. And it is a reli­able partner for taking care of public green spaces. How does it do it? Using compo­nents that devel­opers have specially designed for these Herculean tasks.

The one for big spaces

The cutting deck can be folded upwards quickly, making it easy and ergonomic to clean. (Photo | Husq­varna)

Bilader Younadam is an electro-mechan­ical motor design engi­neer at Husq­varna and is respon­sible for the CEORA project. He explains, “The robotic mower has a modular design. It consists of a drive unit and a front unit with a cutting deck. Here, a total of 15 high-speed steel blades are mounted across three blade discs. They ensure effi­cient and precise cuts.” If main­te­nance or cleaning is required, the cutting deck can simply be tilted into an ergonomic posi­tion and worked on comfort­ably. The drive unit is avail­able in two versions with varying cutting powers. Younadam says: “Profes­sional users require high perfor­mance from our devices. At CEORA, we have increased the capacity by ten times compared to our other robotic mowers.”

Reli­able drive

The powerful helper moves over green spaces at one meter per second. Two impellers propel it on its long jour­neys. To keep doing this reli­ably, Husq­varna relies on motors from ebm-papst. “When selecting the compo­nents, we look for high quality levels, good perfor­mance and the right price-perfor­mance ratio,” says Younadam. EC external rotor motors from ebm-papst were chosen for the wheel motors. “Of course the energy effi­ciency of the drives also plays a major role for us,” he says. “After all, the mower should work for as long as possible without charging.”

Armin Pokorny is Indus­trial Drive Tech­nology Market Manager at ebm-papst and is Younadam’s contact person for the project. He recalls: “In order to meet the speed require­ments of the CEORA devel­opers, we have adapted the stan­dard motors’ wind­ings. So Husq­varna can retrieve the maximum power at 36 volts. A trans­mis­sion with the special Performax Plus 63.2 gear reduc­tion is also used.”

The energy effi­ciency of the drives plays a major role for us. The mower should work for as long as possible without charging.Bilader Younadam, Electro-Mechan­ical Motor Design Engi­neer

Hard work gener­ates a lot of heat. To ensure that the drive does not get too hot, the engi­neers at ebm-papst put holes in the motor’s stan­dard hood: “We affec­tion­ately call it the Swiss cheese hood,” says Pokorny, laughing. “The cutouts in the aluminum cap now ensure that the heat is reli­ably dissi­pated and thus achieves the maximum motor power.”

When things get tough

There are strin­gent require­ments for the robust­ness of the compo­nents too. For example, the CEORA mower and the trans­mis­sion also have to with­stand falling from certain heights. “We rein­forced the bear­ings accord­ingly and manu­fac­tured the output shaft of the trans­mis­sion from a more stable, rust-free mate­rial. This enabled us to meet the require­ments,” says Pokorny. In a profes­sional mower, the noise also plays a role, as Younadam empha­sizes: “For our customers, it is very impor­tant that the mower oper­ates as quietly as possible. Here, too, ebm-papst has found the right solu­tion and designed the motors accord­ingly.”

Active wheel brushes clean grass residues from the impellers. The ECI-42 wheel brushed motors with Performax Plus trans­mis­sion is supplied by ebm-papst. (Photo | Husq­varna)

Active wheel brushes are used so that the cut grass does not adhere to the wheels. They rotate while the mower is moving, removing the grass residues – with a double benefit: The CEORA can continue mowing without being disrupted and no lumps of grass remain on the lawn. The small brushes are driven by the ECI-42 wheel brush motors with the Performax Plus trans­mis­sion from ebm-papst. They also excelled in terms of energy effi­ciency and dura­bility.

Precise without a wire limit

Using satel­lite tech­nology, the profes­sional mower always knows where it has to be. There is no need to route wires to limit the work space. (Photo | Husq­varna)

It is worth noting that the CEORA does not use a boundary wire laid on the ground like usual robotic mowers. Instead, it uses the most up-to-date satel­lite tech­nology. Younadam explains, “We use the Husq­varna Exact Posi­tioning Oper­ating System (EPOS) here. The users define the working areas virtu­ally. The mower is then given a highly precise posi­tion using the satel­lite system. It oper­ates at exactly the set limits up to two centime­ters.” On defined trans­port routes, the CEORA will switch between different work areas and finds its own way to the charging station if the battery needs more power.

Users do not only specify where it needs to work, but also when and at what cutting height. “The frequent, system­atic and highly precise mowing ensures perfect results, as only a small quan­tity is cut each time. It ensures that the turf is always opti­mally venti­lated and grows in a lush green color,” explains Bilader Younadam. And at all times, the CEORA robotic mower very quietly goes about its work and leaves a perfect green space strip after strip, which awaits the next big event.