The concept of robots is one which has been with superheroes in comics almost from the earliest adventures of heroes in the golden age. The concept or robots figured common only into stories involving Superman and Wonder Woman and for various reasons. Common among these were a robot impersonator of the heroes meant to steal their identity, a robot villain that could match the heroes in strength or a robot. The appearance of these early robots usually hinged on the concept that they were highly advanced enough to be mistaken for humans. This required an extremely well developed artificial intelligence and whose appearance was human like.
As the comics industry gradually moved towards the silver age of comics, the concept of robots took on a different form. The portrayal of robots shifted away to beings who were still humanoid but who wrestled with the ability to act and feel human (though some of the earlier versions of robots still manifested themselves.) Characters such as the Red Tornado or the Vision went through their adventures, even finding reciprocated love in human women, but still often questioning what it meant to be human.
Robot figure heavily into science fiction stories as well. In often cases in anthology or cult classics a twist at the end of a science fiction story is that some characters were in fact robots.
As comics encompass a huge range of science fiction based stories, the various kinds of robots are equally diverse.
These are robots that are considered a mechanical lifeforms. They are created thru various means to include asexual reproduction or being built and infused with the spark of life. They are not controlled by others and can think and act for themselves. They understand the concept of death & morals and can show emotion. The best known are the Transformers.
These are among the most common of robots. They generally have a relatively humanoid form and possess a form of artificial intelligence. Jocasta is an example of this kind of a robot. Other androids had a limited form of intelligence and then developed a form of sentience on their own, such as Stel from the Green Lantern Corps, or the Manhunters.
These robots are a version of an android, but instead of having an artificial intelligence they have a transferred intelligence (though this may be supplemented by artificial intelligence as well). Red Tornado and the Vision are examples of this kind of robot.
Similar to an android, these robots still have a highly developed sense of artificial intelligence, but they are not designed to appear human. R2-D2 would be an example of this kind of an android.
A synthesis between a living being and a robotic machinery. Although robotic components depend on the brain of the living being to direct its function, there are still functions such as joint movement which are performed by the robotic element. This form of robot takes on many forms. Some early cyborgs (named for cybernetic organisms) were simply a human brain transplanted into a robotic body (as with either of the characters named Robotman), others were a very visible combination of living being with machine (as in the case of Cyborg) while others appeared completely human (as in the case of the Six Million Dollar Man and the Bionic Woman).
This is similar to the concept of bionics, but in this case there is not direct link between human and machine, rather the robot requires sensory or verbal input as to what actions to accomplish. Early versions of the Iron Man armor would be included in this category (though later versions, where the suit has been internalized would be more like bionics.)
Somewhat different from other versions of robots, these are machines designed to fill a specific function and which may be designed to interface with humans, but which retain a shape conducive to completing their task without appearing as humans. The Batmobile (with its ability to pilot itself) would be considered such a type of robot.