While many robots are controlled remotely, others, called autonomous robots, can move about on their own. In order to move without humans actively controlling them, autonomous robots must be programmed to respond a particular way to outside stimuli. Whether they have bumpers to detect obstacles or more advanced sensor systems, autonomous robots wouldn't work without expert programming. Advanced autonomous robots have all sorts of ways to navigate, including infrared or ultrasound sensors, stereo vision or simply randomness.

Robots equipped with infrared or ultrasound sensors can sense objects in their way much like a bat uses animal echolocation. The robot sends out a light beam or sound signal, and the amount of time it takes to reflect back will indicate how close the robot is to that obstacle [source: ScienceDaily]. Stereo vision is a more advanced way for robots to maneuver. It involves cameras, for depth perception, and image recognition software, which can locate and classify objects. A robot that operates using randomness has a simpler way of getting around -- when it hits an obstacle, it will move every which way until something works to get it unstuck. Depending on how advanced a robot is, it may be able to maneuver only in a defined environment, or it may be able to adapt to an unfamiliar situation.

Of course, if a robot is designed with legs, a whole new set of considerations come into play. Understanding natural locomotion is an important factor in developing robotic legs. Depending on the type of terrain the robot needs to cover, designers may choose wheels, tracks, legs or other means of locomotion. If the terrain is rough, however, designers often prefer to use legs, which are more adaptable to variable topography. Hydraulic or pneumatic pistons attach to different leg segments to move them back and forth. Similar to muscles in a human body, the pistons need to enact precise combinations of contractions to be able to walk properly. In addition, many robots have a balance system, which enables the robot to adjust its movements as it goes. To create an even more stable and balanced robot, designers often use multi-legged robots [source: Gottlieb].