A device which forms part of a control system – often taking the error between the desired state and the actual state and generating data used to affect an actuator.

An information processing device whose inputs are both the desired and measured position, velocity or other pertinent variables in a process and whose outputs are drive signals to a controlling motor or actuator. (R15.02).

Part of a computer, typically a separate circuit board, which allows the computer to use certain kinds of peripheral devices. A disk controller is used to connect hard disks and floppy disks, a network controller is used for Ethernet. Other controllers are: keyboard controller, interrupt controller and graphics controller.

Every robot is connected to a computer, which keeps the pieces of the arm working together. This computer is known as the controller. The controller functions as the “brain” of the robot. Robots today have controllers that are run by programs – sets of instructions written in code.

Almost all robots of today are entirely pre-programmed by people; they can do only what they are programmed to do at the time, and nothing else. In the future, controllers with artificial intelligence, or AI could allow robots to think on their own, even program themselves. This could make robots more self-reliant and independent.