The main difference between the arm of the robot and that of a human is found at the arm's extremity. Rather than having a flexible, multi-fingered hand, typical robot arms end in special-purpose devices called end-effectors, which are installed directly into the wrist. To reduce the number of calculations, needed to determine the robot's exact position, the base is generally kept stationary. In a few applications, however, like the robots in spot welding, robots are programmed to follow an assembly line. The motions of the robots can be programmed by means of direct teaching where the arm is manually guided through its desired motion and the robot's computer remembers these specific motions, sort of like a watch and learn method. Robots can also be taught by means of programming by a computer specialist. Finally there is always the option of creating a learning computer that will gather data as it makes mistakes and on the following attempt, it won't make the same mistake again. However, this method isn't suited for all instances. For example, having a surgical robot that is about to operate on you and is still in the process of learning where to make the incision won't give you the feeling of security. Nevertheless, this still can be used for robots in the real world, life is completely unpredicatable.

On assembly lines, this is accomplished by fixing some robots to overhead tracks called gantries and hang downward from their bases to perform such tasks as assembling automobile engines. An industrial robot arm's actuators, the muscle power that produces motion, must be carefully regulated to ensure that the arm performs the task with the required amount of strength and precision.

General industrial arms use either hydraulics or electrical actuators, depending on the nature of the robot's jobs. Hydraulic actuators, which typically use pressurized mineral oil to slide and rotate segments of a robotic, are employed in about half of all industrial robots.

Hydraulics are several times more powerful that electrical motors of the same weight, making them well suited for work in foundries, for example, where they easily manipulate loads of more that 100 pounds. Also because they are not subject to electrical arcing, hydraulics are useful in environments where fire is a hazard, such as a paint booth or chemical facilities. However, hydraulics are prone to drip oil and therefore, require frequent maintenance.

Electrical actuators are often used in tasks that hydraulic actuators would be too non imprecise, such as inserting components into a printed circuit board or in surgery. However the main drawback of electrical motors is their lack of strength, therefore confining them to jobs where they only have to manipulate light objects. Some extra strength can be gained through the use of brushless motors. In reversing the standard motor design, in which exterior brushes convey current to a rotating interior electromagnet, the brushless motor reduces the friction and achieves a higher power-to-weight ratio. Also because such motors require more electronic rather than mechanical control systems, they are generally more expensive. The last type of actuators is the pneumatic drives, is the simplest but least precise power source. The fluid that makes the robot move is compressed air, which is so compressible that unless mechanical stops are used to regulate motion, fine control is difficult.