Robotic mowers - background

Believe it or not, robotic mowers have been around since roughly the mid nineties. The ides of the perfectly mowed lawn every day with minimal effort is every gardeners dream. Now, thanks to advances in robotics this is finally achievable. Enter the ....

Stihl iMow

Stihl has brought three of their robotic mowers, called the iMow, to the Australian market. The models are the RMI 422 P, the RMI 522 C and the top of the line RMI 632 P. For a quick rundown of the specifications and difference between the models, please see the table below :

How exactly do they work?

Robotic mowers do require installation. As it currently stands most robotic mowers require a boundary wire to be placed around the mowing area. For the Stihl iMow this boundary / guide wire performs the tasks of defining the area/s to be mowed, directing the mower around fixed obstacles and as a guide to assist the mower back to it's docking station for recharging. There are numerous ways for this boundary wire to be installed. Most common is for the wire to be pegged into the ground. Normal growth conditions will see this wire disappear into the grass in approximately two to four weeks. By pegging the boundary wire you have the advantage that small changes to the mowing area are easily undertaken immediately after the install however the wire can be damaged quite easily by the mower if it not pegged entirely flat. Depending on the terrain and the grass coverage the wire may also not uniformly bury into the grass pile. Our preferred method of installation is with a specially designed and purpose built cable layer. This buries the wire approximately 25mm below the surface leaving a faint trench line that disappears within two to five days leaving no trace. This method protects the wire from accidental damage. Proper planning as to the location of the boundary wires, the determination of the mowing areas and the way with which the mower will interact with the mowing environment is crucial to a successful robotic mower install. 

Another important consideration is the location of the charging station. The Stihl iMow docking stations can be either located in the mowing area itself on the perimeter, or, placed outside the mowing area. If placed outside the mowing area the mower accesses it through the use of a specially created corridor and boundary wire shape creating a virtual 'gate'. It is important to ensure adequate space around the docking station (this varies in size depending on the model purchased). The docking station must also be placed on a flat surface, level with the mowing area. Other considerations for placement should be how long the station is in direct sunlight in hot climates and the consideration of adding the protection sun canopy for harsh climates.

The area to be mowed should be examined for protrusions above the grass level such as sprinkler heads or tree roots. These need to either be islanded in the install as obstacles to be avoided or removed from the mowing area entirely. Other considerations should be items such as grey water discharge hoses and how they are going to be dealt with in the mower plans.

If I get a robotic mower does that mean I never have to do lawn maintenance again?

Whilst properly installed robotic mowers definitely take a large chunk of the lawn maintenance off the to do list, there are some tasks that still need to be undertaken. 

1. Lawn edging - This still needs to be done. The iMow can and will do an edge mow, however this is not a replacement for a lawn edger or whipper snipper. This task will need to be undertaken to ensure properly defined edges.
2. Stick collection - Depending on the trees found in the garden, sticks can become an issue. Fallen sticks will become obstacles for your robotic mower as it goes about mowing the lawn. These sticks, depending upon their size, can damage the cutting blades of the mower. If you have the mower to operate at night they will also create undue noise as the mower passes over them. The mower may also get stuck on the stick of drag the stick around resulting in inefficient operation. 
3. Servicing - Robotic mowers need maintenance just as the petrol cousins do to ensure proper operation. 

How many times should my robotic mower mow my lawn?

Most robotic mowers are designed to mow every day ensuring your lawn is presented as always freshly cut. This does depend on the size of the area to be mowed with larger areas mowed more often for longer periods. The Stihl iMow takes the guess work out of this by suggesting a mowing plan to suit the area once it has checked the install. This of course can be  tweaked according to your needs and seasonal growth changes.

In summary

In the correct location with the correct installation a robotic lawn mower can be an asset to any location requiring lawn maintenance. Whilst a robotic lawn mower has the ability to automate the task of mowing there are still other tasks such as edging and stick pickup that need to be done to ensure an optimally functioning mower and presented lawn area. The Stihl iMow range provides tailored solutions for your automated lawn mowing requirements. Keep an eye out for further articles on this topic as we delve into the nitty gritty of the Stihl iMow range.