Walk This Way
	See the Honda Humanoid Robot in action in Honda's promotional video. (1.5MB) Learn more about Asimo. [Need help?] Photo courtesy of American Honda Motor Co., Inc. Walking may seem simple, but making a robot that can walk like a person is no easy feat. Even when you seem to be standing still, you’re really making constant adjustments to keep from falling over. Engineers at Honda have designed two humanoid robots, P2 and the newer P3, that do what no two-legged robot has done before: walk, climb stairs, and regain their balance. The Honda Humanoid Project is a first step towards universal robots–robots with the flexibility, intelligence, and mobility of human beings.

Robots are defined in part by their ability to move; it’s what sets them apart from computers. The fancy word for a mechanical device that produces motion is an actuator. A single robot can contain dozens of different types of actuators, each chosen to do a specific task.

Learn more about Skyworker. (15.5MB) [Need help?] Skyworker is a prototype robot for building, assembling, and maintaining future space stations. Designed to walk and work on the very structure it is building, skyworker carries loads much like a waiter carries a heavy tray: the load is held steady, separate from the motion of the "feet" below.

Electric motors are actuators that produce motion from electricity by the electromagnetic effect: when electricity moves in a coil of wire that is near a magnet, a force pushes on the coil. Electric motors typically operate at a high speed and have small turning power. But most robots need low speed but large power. A collection of gears, called a gearbox, is used to adjust the speed and force of the turning power.

Not all electric motors produce rotational motion. Solenoids are electric motors that produce linear, or in-and-out motion. Solenoids are frequently used in switches that turn things off and on.

RoboTuna, developed at MIT, was designed to swim like a real tuna. What good is a robotic fish? A speedy, energy-efficient underwater robot could be used for underwater exploration or covert surveillance. [Click for larger images.] Photos courtesy of Josh Tolford Davis, MIT Towing Tank, Massachusetts Institute of Technology.

Careful adjustments in position are often important in robotics. Special motors called stepper motors turn in precise, incremental "steps," making them ideal for small, repeated adjustments in position. Another electric motor used for positioning is the servo motor. This kind of motor can only turn 90° to the right or left. If you’ve ever driven a remote-control car, boat, or plane, it was probably a servo motor that controlled the steering.