What is an actuator used for in mechanical systems?

An actuator plays a crucial role in mechanical systems by converting energy into mechanical motion. This process is essential for driving various types of machinery, equipment, and mechanisms. Actuators work by taking an energy source—such as electrical, hydraulic, or pneumatic energy—and transforming it into movement, which can then perform tasks such as opening a valve, moving a robotic arm, or driving a motor. This characteristic makes actuators integral components in automated systems, robotics, and industrial applications where precise and controlled movement is required.

The other options address different functions related to mechanical systems but do not define the primary role of an actuator accurately. For instance, while reducing friction, amplifying force, or storing energy are critical mechanical concepts, they pertain to other components or systems rather than the specific function of actuators, which is focused on motion generation.