1. What is a robot?

There are many definitions, but most share a few things in common and fit the MAR profile. What's MAR? A Mobile, Autonomous Robot.

1. Mobile: it can get around on its own, usually on wheels-- though there are a few four legged robots and even fewer two legged robots.
2. Autonomous: it reacts to its environment and makes decisions of its own. It doesn't require human guidance to do this. That's why you can leave a robot vac at home to clean your house: it doesn't need you to tell it what to do next.
3. Robot-- well there ya, go, it's a robot.

Webster defines robot as: ""An automatic device that performs functions normally ascribed to humans or a machine in the form of a human."

2. Where does the word robot come from?

A Czech playwright by the name Karel Capek coined the term in his 1921 play, R.U.R. (Rossum's Universal Robots).

Isaac Asimov, the famous science fiction writer came up with the word "robotics" in Runaround, a 1942 short story. His collection of short stories about robots, "I, Robot, are the basis of the 2044 movie "I,Robot" starring Will Smith. The movie and its robots have no relation to the company iRobot who makes the popular Roomba vacuum!

3. What were the earliest robots?

In the mid-1950s the first robots made their appearance. The Unimate, made by Unimation, is generally considered the first robot. Unimates worked in automotive plants doing assembly work and today robots are commonly used in automotive manufacturing across the world. These robots can handle hot metals, paint cars and assemble parts. Unlike the robots we cover here, they aren't mobile and spent their lives in one location doing their work.

4. Why do most robots have wheels instead of legs?

We take balance for granted but it's actually a very complex thing. Our brains do a huge number of calculations to determine our state of balance and what muscles must be moved to keep us upright. We also consider and react to bumps, hills and obstacles without falling. We have sight and touch to help us keep our bearings and many very flexible joins to keep us upright.

So a two legged robot is still an expensive thing. It must have a powerful computer to calculate and manage all the factors that affect balance, it must have many articulated (moveable) joints, and several sensors to determine if it's upright, tilting left, leaning back and so on. The Honda Aismo is one expample of a two legged robot, and he appears at trade shows several times a year.

Four legged robots like Sony's Aibo, the robotic pet/entertainment critter are easier because it requires less balance to walk on four legs. After all, we all start out life on "all fours" and it takes us a few years to get going on just two. Walking on four legs still requires a decent amount of work and the robot must have articulated joints in all four legs to maintain balance. That's why Aibo ain't cheap.

Wheels are very efficient: no balance required, and no articulating joints. With aggressive tread, they can make it up decent inclines too. That's why most robots have wheels.

5. How do robots get information about their environment so they can react and interact?

We have eyes and ears, among other senses. Robots use sensors. Some sensors are very inexpensive these days (bump and IR sensors can be as cheap as $1 each), while others are $20 apiece or more. Here are some sensors and their functions:

1. IR: just like the IR used by your TV remote. These are used for remote control of the robot via a remote, to send out a docking beam for a charging station and to estabish perimeters that the robot shouldn't cross (IR beams can travel many feet).
2. Touch sensors: also known as bump sensors. Robots use these to determine when they've come in contact with something. For example, home robotic vacs use these to know when they've encountered a wall, a piece of furniture or you!
3. Sound (accoustic) sensors: Robots like Aibo and those you can build from the Evolution ER1 kit can recognize voice commands using these.
4. Sonar sensors are another flavor and aren't used for human-robot interaction but rather for navigation. They are more a more sophisticated version of the bump sensor, allowing the robot to sense an object is approaching without having to bump into it. Sonar sensors and ultrasound sensors send out very high pitched sound waves (way beyond the range of human hearing) and measure how long it takes for that sound to bounce back to them. The shorter time it takes for the sound to bounce off a surface and return back, the closer the object is. Bats use sonar to fly in the dark and sonar is used in submarines to detect the presence and distance of ships and other subs.
5. Visual sensors: like web cams (some in fact are web cams!), these can "see" items that the robot needs to interact with such as furniture (avoid) or a can of Pepsi (fetch). The Sony Aibo uses visual sensors to recognize its owners, react to certain colors (it likes to chase a pink ball) and more.

6. Why do some robotic vacuums cost $300 or less while another groups costs around $2,000?

Technology differences: The under $300 robots use less expensive sensor technology. They rely soley on bump sensors to discover obstacles in their evironments and will bump into your walls and furniture (albeit gently) as they make their way around a room. More expensive vacs like the Electrolux Trilobite have bump sensors but primarily rely on more expensive sonar sensor techology. This means the Trilobite rarely bumps into anything, but rather stops about an inch or two before walls and furniture, then navigates around them.

Room mapping: the expensive vacs use room mapping. They collect large amounts of data about a room and save it to memory. Just as we build mental maps of a room or environment, so do these ~$2,000 vacs. This means they know where they've been and where they no longer need to vacuum. The $300 and under vacs have no idea where they've been, so they run longer and cover each section of a room at least two times just in case they missed a section. The under $300 models take about 30 minutes to clean a 10 x 15 foot room when following their pre-programmed cleaning routine. Depending on vacuum strength, the expensive ones can do it in less time.

Some manufacturers are working on adding visual sensors (aka web cams) so the vacuum can create a visual map of a room and its contents and even know when you've redecorated. If you do redecorate, it will update its mental map of the room! These web cams can also do double duty as home surveillance tools.

The new Roomba Discovery uses an accoustic sensor to "hear" dirt, and this is the basis for the new Dirt Detector feature. Roomba Discovery uses a transducer (also used on guitar pickups) to hear dirt. When it does, it spends extra time cleaning an area. This is much better than having a vac happily pass over a very dirty area without deep-cleaning it.

Mechanical or standard vacuum differences: More expensive vacuums have more powerful motors to pick more dirt per pass.