What characteristic defines stepper motors in robotics?

Stepper motors are defined primarily by their ability to follow steps one at a time. This characteristic allows them to move in discrete increments or 'steps', which makes them highly precise in their positioning. Each step corresponds to a specific angular movement, enabling exact control over the rotation and position of the motor shaft. This feature is particularly valuable in robotics applications where precise movements are critical, such as in 3D printers, CNC machines, and robotic arms.

The ability to perform discrete movements leads to high repeatability and accuracy, which are essential for tasks that require fine control. Additionally, this stepping mechanism allows for open-loop control, meaning that the motor does not require feedback systems to achieve accurate positioning, simplifying control systems in many applications.