Types of robots can be separated by the tasks that they are meant to perform, their role within society, their level of advancement and other criteria. In contemporary terms, types of robots are often separated into classes by the jobs that they perform, such as industrial, scientific, and consumer robots. Within the industrial sector, robots are also categorized further as to the types of capabilities and functions of which they are capable. Cartesian or gantry robots have an articulated arm that does various welding, assembly, and part-movement functions. Robots with other ranges of motion are labeled as cylindrical, spherical, and parallel depending on where they can reach and the level of dexterity and control that their arms possess for detailed work.
Aside from how a robot is physically designed, its degree of mobility and size is also an important factor in categorization. Especially within fields such as the military, combat robots can be autonomous flying drone aircraft, micro robots the size of insects build for surveillance, or large robotic systems built into land vehicles designed as logistical support or autonomous fighting machines. Some military machines are also semi-autonomous robots that can perform basic maneuvering functions on their own, but require special human control for complex actions.
Scientific robots are used in a laboratory setting to automate certain tasks, or in exploratory areas to which humans are unable or unwilling to go. This can include types of robots such as those carried by space probes to the surface of Mars or an asteroid, robots built to inspect the interior of nuclear reactor vessels, and robots that inspect suspicious vehicles or packages for the police in case they contain explosives. Laboratory or medical robots also can aid in the automation of mixing drugs or biological samples, as well as performing microsurgery under the guidance of a physician.
Humanoid robots are among the types of robots most often pictured in fiction or movies. They can serve educational or entertainment functions, and are often seen as a form of servant to people with a level of intelligence of their own that puts them on a par with the simple thinking of young children or pets. Where they get out of control, they are often a subject of debate about whether they should have been created in the first place. Types of robots built on the human model are the most challenging to create due to the fact that simulating how human beings walk is a very difficult task to do for a machine, as well as how human beings see the world or understand language so that they can effectively interact with each other.
As technology advances, robots become more and more a part of day-to-day life. Much of what they do remains hidden from society in general as they work in factories and remote regions, taking dangerous jobs once required of people. As industrial, scientific, and military robots become more advanced, however, these developments are being used to improve upon humanoid models that may one day exist and work alongside people on a routine basis.