Robotic lawn mowers

Robotic lawn mowers represented the second largest category of household autonomous robots used by the end of 2005. A typical robotic lawn mower requires the user to set up a border wire around the lawn that defines the area to be mowed. The robot uses this wire to locate the boundary of the area to be trimmed and in some cases to locate a recharging dock. Robotic mowers are capable of maintaining up to 5 acres (20,000 m2) of grass.

Robotic lawn mowers are increasingly sophisticated, are self-docking and some contain rain sensors if necessary, nearly eliminating human interaction.

Robomow is capable of maintaining up to 1/2 acre of grass while the larger professional LawnBott is capable of maintaining up to 3 acres (12,000 m2). The Husqvarna Automower targets primarily homeowners and can mow up to 3/4 acres.

The Husqvarna Automower was the first robotic mower made available through mainstream channels. Between 1995 and 1999 Husqvarna introduced their first fully solar robotic mower and their first Generation 1 automatic robotic mower. From 1995 through 2003 Husqvarna's Automower was successful. However, Husqvarna's boom in robotic mower sales really began in 2004 with the introduction of the Generation 2 Automower.

Originally branded the Electrolux Automower after Husqvarna's parent company at the time, the Gen 2 machine featured many advancements not previously seen. The primary advancements were the ability for the mower to find its charging station via radio frequency, by following the boundary wire, or by following an optional guide wire. This improvement eliminated wear patterns in the lawn caused by the mower only being able to follow one wire back to the station. The Gen 2 Automower also has the ability to be easily programmed to follow the guide wire or the boundary wire out of the station to remote areas. This assures that the mower will always get to all areas of the lawn even if they are accessible only through narrow passages. Improved wheel motors and more aggressive wheels provide even more stability on hillsides and the blade height adjustment is easily accessible from the top of the machine versus from below on the Gen 1. A LCD screen with menu options also made the Gen 2 much more user friendly.

As of this writing, Husqvarna has taken the top position as global leader in robotic mowing technology and sales with over 70,000 mowers operating in Europe alone. The brand is no longer tied to Electrolux and is branded Husqvarna all over the world. In Europe, Husqvarna offers 5 models listed below. The US offers the 210C, 220AC, 230ACX, and Solar Hybrid in 2009 with plans of launching the 260ACX in the US in 2010.

1. 210C (Chargeable) The 210C is designed for smaller lawns. The mower operates along the same principle as other robotic mowers described here with exception of the unit being able to recharge itself. The mower is designed to be put out by the owner one or two times a week and the mower mows up to five hours at a time. The mower is then stored until the next mowing.
2. 220AC (Automatic Charging) Contrary to the model number, this unit does not require a 220v system. It is powered off a standard 110v power supply. This mower is fully automatic, will find its way back to the station on its own, and is fully programmable. The 220AC is designed for lawns up to 1/2 acre.
3. 230ACX (Automatic Charging Xtra) The 230ACX is very similar to the 220AC with exception of a few factors. With twice the battery strength and more powerful wheel motors, the 230ACX is able to stay out longer on a charge as well as move faster while cutting. This allows the 230ACX to handle lawns up to 3/4 of an acre. The 230ACX also comes with the ability to run two guide wires, program up to five remote areas, and the backlit display and keyboard improve the owners interaction experience.
4. The Automower Solar Hybrid - The solar hybrid is the return of solar mowing technology. The solar hybrid is designed to draw as much of its power supply as possible from the sun, further reducing the electricity from the home used to support the mower. The solar hybrid's functionality is very similar to the 230ACX with exception to the solar technology.
5. 260ACX (Automatic Charging Xtra) The 260ACX handles up to 1.5 acres (6000 m2) of lawn, has built in anti collision sensors and is able to send mobile text messages.


Robomower

The Robomower is a robotic mulching lawnmower made by Friendly Robotics.

Invented in Israel, the product charges from household current, so it does not directly emit any greenhouse gases. It was identified by the Guinness Book of World Records as the best-selling robotic lawn mower in the world. It comes with a rechargeable lead-acid battery pack. It can be programmed to mow around the perimeter of the lawn and inside the lawn. It has sensors on the front and on the back.

The Friendly Robotics mower uses sophisticated patented tiling algorithms to calculate the most effective pattern for cutting the entire lawn.


LawnBott / Mowbot

The LawnBott is a robotic (autonomous) lawn mower marketed in the U.S. and Canada by Kyodo America Home Robotics. The mowers are manufactured by the Italian engineering company Zucchetti Centro Sistemi, and are distributed in some European countries under the brand names Mowbot, Ambrogio, Oscar, and Wiper. They are programmed to emerge from a recharging station on command or at a scheduled time. The mower will criss-cross a lawn (from edge to edge) at random angles and will spiral randomly usually in the middle of the lawn. The more advanced models can control blade speed based on grass height and spiral when longer grass is found (bit like an irobot roomba when it finds dirts). When the battery is exhausted or the schedule has ended the mower will return automatically to its base to recharge by following the perimeter guide wire. There are around 15 active dealers in the U.S. LawnBott currently has 4 models:

1. LB2100 / LB2150 (Professional)- comes standard with 2 lead acid batteries. The stated coverage is 1/2 acre with slopes of up to 12 degrees. Currently it retails at $1,999. Added in 2009, the LB2150 is the same model but with a single lithium battery for $2,150 and can cover slopes up to 27 degrees.

1. LB3200/LB3210/LB3250 (Evolution)- is the same size as the LawnBott Professional however it has a very high-tech lithium-ion battery. It can cover 3/4 acre and 27 degree slopes. Optional spiked wheels increase slope performance to 30 degrees. A 2nd internal lithium-ion battery can be added to increase coverage to approximately 1 1/4 acre.

1. LB3500 / LB3550 - comes standard with a single lithium-ion battery having the equivalent performance of two Li batteries with room for two more. It can cover 1 acre (43,000 sq ft) of grass out of the box and lots (including house, driveway, etc.) up to 2 acres (8,100 m2) with two more extra batteries (grass area approx. 1.5 acres (6,100 m2)) with slopes up to 30 degrees with optional spiked wheels.

1. LB1200 / Spyder - the first household robotic lawn mower that requires no perimeter wire. It comes with 1 lithium battery. The stated coverage is 5,500 sq ft with slopes of up to 27 degrees. Currently it retails at $1,399.

The lithium-ion batteries contain smart chips to improve life expectancy. One of the biggest factors in battery life is the number of recharge cycles. Adaptive technology on the LB3200/3210/3500 keeps the Lawnbott in the charging station when the grass is dormant or growing slowly. Lawnbott only mows when necessary, improving battery life, reducing wear and tear and improving its overall life expectancy.

Lawnbott is small and maneuverable. The LB3200/3210/2100 measures roughly 22 x 16 x 10 inches and weigh 22 pounds. LB3500 is 25% larger and somewhat less maneuverable. LB3200/3210/2000 performs better on yards with many obstacles vs. LB3500. LB3500/3200/3210 work well on steep slopes. The LawnBott LB1200 weighs only 18 pounds.

The newest model is designed for yards of up to 1.5-acre (6,100 m2) with installation of extra batteries. A perimeter wire is included, for marking off the area to be mowed. They are designed to cut the tops of the grass stalks, that is, less than will usually be cut by a push-mower, and to compensate by cutting more often.