Accuracy in robotics measures how close a robot's movement gets to the commanded position. Tell a robot arm to move to a point, and accuracy tells you how near it lands. Repeatability tells you how consistently it lands near the same spot. Both matter, but they are not the same thing.

A robot can be repeatable without being accurate. It might consistently miss the target by the same offset. That is useful for some tasks but not for others. A robot that is accurate and repeatable hits the target every time. Calibration improves accuracy. Mechanical wear, temperature changes, and backlash degrade it.

Accuracy versus repeatability

• Accuracy: closeness to the commanded target.
• Repeatability: closeness of repeated movements to each other.
• Precision: often used interchangeably with repeatability.
• Calibration corrects systematic errors.
• Backlash and flex reduce both.

In manufacturing, accuracy determines whether a robot can drill a hole in the right place. In surgery, it determines whether a tool reaches the correct tissue. In agriculture, it determines whether a seedling is planted in the right spot. Engineers measure accuracy with laser trackers, coordinate measuring machines, and vision systems. They then compensate with software corrections. No robot is perfectly accurate. The goal is to be accurate enough for the task at hand.