How does the Irobot Roomba Work?

First I am not by a long shot an expert in robotic engineering so here is my layman’s version.

The video below gives you an idea of how well the Irobot Roomba covers the floor, the Picture at the top is the latest Roomba, the ne bottom right is an older model and the bottom left is a manual hoover. After seeing this video I know my preference.

There are 3 sections to the Irobot Roomba, the Drive system, the Hoover section and the Brains or sensor system. All three of these combined allow for the robot to go around your floor on its own and do the vacuuming.

As part of this post I will try to explain the above three components.

THE Drive system.

I was impressed with the drive system on the Irobot roomba, it comprises of a 3 wheel chassis. Two main wheels to drive and a third directional wheel at the front. All the three wheels are rubberised and generate good traction. The wheels are on a movable chassis, which allows for them to compensate for change in floor heights for various obstacles. This makes the unit very versatile for going over door jams and small height differences in the floor. The drive motors push the irobot roomba at a good speed similar to that of someone vacuuming.

With the unit being driven by 2 wheels it allows the unit to turn on the spot. This allows the unit to both get into and out of small spaces without to many issues. Due to the small light nature of the irobot roomba, the motors don’t have to be that big allowing for a relatively quiet operation.

The Hoover system.

A slightly different vacuum system to normal vacuums.
The first element is a rubberised paddle that collects the heavy material on the surface. Stones, and surface dirt is scrapped up and into the collection bin.
The second element is a deep brush that brushes deep into the fiber of your carpet collecting dust and hairs and ground in dirt.
The third element is a rotating brush, this brush pushes any dirt at the edge of the wall or around/under chair legs and other furniture. This is an extra benefit as it does something most traditional cleaners don’t which is really clean the edges of the home.
All of this debris is deposited into a collection bin at the back of the unit, either through a filter system to remove dust or in the pet models a straight bin.
One final word on the vacuum system is the cleaning of the unit. Due to the size of the unit the vacuum holds about 3 vacuums before it needs emptying. I will do a later post on the simplicity of cleaning the vacuum compared to other upright units.

The “Brains” of the irobot roomba.

The design team could have gone with two methods of brains, one that efficiently remembers the room and then cleans it with one pass. This provides the issue that when you move the sofa to the ottoman it gets confused. The irobot team went with a more simple system. The irobot roomba finds the edges of the room and crosses at angles. It also does a circular clean if it detects dirt. This thought process is based on the various sensors it has.

This thing is loaded with sensors from, distance sensors it will slow down when it gets near the wall, allowing for fast speed over the open carpet. Bump sensors for the edge allowing the unit to get up close to the edge of the wall. Dirt sensors I imagine these are based on colour difference. Height sensors, in my house with many edges I do like this feature that it can detect the top of the stairs. Vacuum along it before turning and cleaning the rest of the room. It also has a homing beacon that allows it to detect the home base for charging but also Irobot Roomba barrier towers or room divides.