Robots Big and Small

Close your eyes and picture a robot. How big is it? Maybe you imagined something about your size. But robots can be gigantic — as big as a house! And robots can be so tiny they fit on the tip of your finger. In fact, scientists are working on robots so small you would need a microscope to see them. Today we are going to explore the wonderful range of robot sizes and find out why size matters so much for what a robot can do.

Why Size Matters

Size is one of the most important choices engineers make when designing a robot. A robot's size must match what it needs to do. A robot that needs to move through a crack in a wall has to be tiny. A robot that needs to lift a car has to be enormous and powerful. A robot that needs to work safely next to children in a classroom should probably be about the size of a backpack — not so big it could hurt anyone, not so small it gets lost. Just like you pick the right tool from a toolbox — a big hammer for big nails, a small screwdriver for tiny screws — engineers pick the right size for each robot job.

Let us look at some examples from both ends of the size scale. Giant robots are used in shipyards to lift huge metal plates that weigh thousands of pounds. They are also used to build airplanes, where giant robotic arms weld and bolt together enormous pieces of metal. These robots are bigger than most living rooms. You would not want one of these in your kitchen! Medium-sized robots include the robot arms in car factories that are roughly the size of a tall adult. They paint car bodies, tighten bolts, and check for defects. They are big enough to handle car parts but not so big they take up the whole factory. Small robots include the round vacuum robots that clean your floor — about the size of a dinner plate. Some delivery robots are the size of a large cooler and roll along sidewalks bringing food to your door. Tiny robots are being developed to do things like travel inside a human body to deliver medicine to exactly the right spot. Some are smaller than a grain of rice!

Here is something fun to think about. The biggest robot in the world and the smallest robot in the world both still do the same three things: sense, think, and act. The giant shipyard robot senses where the metal plate is, thinks about how to grip it, and acts by clamping on and lifting. The tiny medical robot senses where it is in the body, thinks about which direction to move, and acts by swimming toward the target. Big or small, the robot loop is always the same. Only the size changes!