Which of the following statements about encoders is true?

Encoders are devices that measure the rotation of a shaft or axle, making them essential in robotics for tracking rotational movement. When an encoder is attached to a motor or wheel, it generates signals that indicate the angle or rotation of the component, allowing the system to determine how far and how fast the component has turned. This capability is vital for precise control in applications such as robotics, where knowing the position or rotation of a part is crucial for accomplishing tasks accurately.

The other statements do not fully encompass the functionality of encoders. While encoders can contribute to distance calculations by translating rotary movement into linear travel, they are not limited to just distance measurement. They inherently provide information about the speed at which a motor or wheel is turning as they generate pulses over time, but this is secondary to their primary role of indicating position and rotation. Encoders do not require calibration after every run; they are typically calibrated once, and as long as they function properly, they can be reused without additional adjustments. Thus, what makes the statement about encoders tracking rotational movement accurate is their core design and utility in providing feedback about rotational position, speed, and direction.