Robotic lawn mower

A Robot Mower (short grass called robot ) is a service robot that can automatically mow lawns. The mower is not remotely in the rule, but is free to decide where everything needs to be mowed and where not: it operates autonomously. Various processes are used. In commercially available mower since the mid- 1990s.

History

After the first devices from 1995 in particular applies the available from 1998 Automower G1 by Electrolux or Husqvarna was the first real mower. This robot mowed not only the area to be treated independently, but could for the first time automatically go back into a charging station to recharge its batteries. He was so apart from maintenance operations in a position to take over without human control, the lawn care of any length alone. The best selling mower are the Automower family of Husqvarna, which were partially sold until 2006 under the name Electrolux.

The main competitor is considered the Israeli company Friendly Robotics, which produces a RoboMow.

However, there are now a large number of manufacturers who offer some of in-house developments and partly Lizenznachbauten. Especially Husqvarna Automower and Friendly Robotics robotic mower be with some marketed modified housing forms or deviating coloring under the names of famous garden tool manufacturer.

As in many other technical fields, there are open source projects that allow for cheap replica in Mähroboterbereich.

Design and operation

Mower are almost exclusively battery powered and cut the lawn with sharp knives. You are mulching mowers because they cut the grass so fine that no residues must be collected and nutrients are returned to the soil.

The Mowers Mower are the significantly less powerful than that of hand-held lawn mowers. The performance of the straw with knives (instead of Abschlagens as in conventional lawnmowers ) is not suitable for high grass.

For these reasons, the mower the grass moves in a typical application scenario from the time, only interrupted by loading pauses. So the grass is always short enough to still remain editable by the relatively weak Mowers, and all areas are due to the high period of use, despite the generally little systematic shut-down of the grass finally mowed.

Most devices are so quiet that they can be used without harassment in continuous operation just by the low performance of the mowers.

The drive usually takes place over two separate motorized and controllable wheels, which are responsible for driving and steering. The wheels are not actually steered; is guided only over various rotational speeds of the driving wheels. In extreme cases ( one wheel forward and the other rotates backward) can Lawnmower turn on the spot. Another pair of wheels, less stressed and with a smaller gauge, and (passive ) Casters - some models also merely a centrally mounted ball wheel - supports the robot forwards.

Orientation by boundary wire

The terrain is mostly to be mowed with a wire loop, called the perimeter wire, surrounded. On this loop is a signal to record the sensors in the mower and recognize it when they approach the wire. This can turn the robot before it travels over the wire and remains so in a clearly defined area.

In this area, the robot moves more or less randomly back and forth. These various strategies are pursued depending on the manufacturer, such as spiral journey, changes in direction after a certain time or just straight ahead until the perimeter wire is reached again, and then reverses to a random angle. In most cases, the robot does not move from the lawn at regular orbits, as people would use manually guided equipment. So most robot models, for example, do not try to ensure that a straight-ahead is really just about by causes small directional deviations, thereby actively correct irregularities.

Therefore always arises in a partially chaotic appearing mower mowing pattern. Difficult to reach corners of an irregularly shaped turf are sometimes achieved only after prolonged use. Therefore, a mower should deal with the lawn more or less daily, so as to finally achieve a uniform lawn height.

Obstacles are detected independently by shock sensors or ultrasound, but can be left out ( beds, ponds, trees, etc. ) with the help of the boundary wire.

Problematic, however, are obstacles that lie flat enough to be run over by a robot, eg smaller stones or left behind clothes.

Just about all currently on the market models are in demand independently to the charging station to recharge itself. In cheaper models they are looking to the perimeter wire and drive this so long, until they come to the base station, which also feeds the wire to the signal mentioned in the rule. Here, the robots move towards charging contacts and then switch for the duration of the charge from.

Better -equipped models offer additional " search wires " pointing towards the base station. In addition, the base station emits a signal itself, which receives the robot, if it is the station near. Search wires can also be used on some models to guide the robot lawn specifically in remote areas of a lawn. In extreme cases, such discontinuous surfaces can also be cut by the robot is programmed to a second surface, for example in 50 percent of all bets visits by following a search wire. Since limiting and also search wire usually up to 10 centimeters depth can be buried, the mower even further distances can thereby cover over paved roads and normal traffic areas such as terraces or streets to get to the second lawn when the search wire under the pavement was moved.

Mower are provided depending on the manufacturer with numerous additional sensors that determine if the mower was tilted monitor the battery temperature, pause in the rain mowing, stop the knife with him closer, domestic animals, try the lawn height to determine and then adjust the speed and the like.

More expensive models are for orientation on a GPS that is not usually used for the control on the lawn, but the localization of the robot on large parcels or in case of theft. These GSM modules are installed, the call automatically to report the abandonment of a particular area or can be called to command the robot, for example, cut back to the base station or transmit its position.

Orientation by lawn sensors

Alternative to the use of a perimeter wire there in recent years, models that try to detect with sensors, whether they are on a lawn or not.

However, this requires a clear separation between lawns and other vegetation zones as eg Flowerbeds.

Area performance

Mower is available for areas from 500 m2 up to 20,000 m2. For larger areas more mower used. Especially in the areas of 800-5000 m2, the robots often differ only by the installed battery performance and the performance of the charging electronics to allow the longest possible uninterrupted mowing.

There are also models with solar panels on the enclosure, which further increase so that by recharging the batteries when light falls on the period of use.

Typically, slopes are handled up to 30%, but mostly a contact is not possible in such a slope, ie the boundary wire must not be in such a slope.

Disadvantages

See: Possible problems with mulch mowing