End-effector pose accuracy vs repeatability: which statement is correct?

• A. Accuracy is how close the actual pose is to the commanded pose; repeatability is the consistency of achieving the same pose over multiple trials
• B. Accuracy means speed; repeatability means energy consumption
• C. Accuracy equals repeatability
• D. Accuracy is only about translation; repeatability only about rotation

Answer: (A)

The key idea is distinguishing how close you get to the exact commanded pose versus how consistently you can hit the same pose across repeated tries. Accuracy means the actual pose you achieve is as close as possible to the pose you commanded. It reflects bias or systematic errors from calibration, the kinematic model, and sensor/actuator offsets. Repeatability means how tightly the results cluster when you repeat the same move under the same conditions—how consistent you are from trial to trial.

So the statement is correct because it pairs accuracy with closeness to the commanded pose and repeatability with consistency across multiple attempts. A robot can be very repeatable (always lands near the same place) but not accurate if that place is off from the commanded pose, or accurate on average but not repeatable if the results vary widely around the target.

The other ideas mix up concepts: accuracy isn’t about speed and repeatability isn’t about energy; accuracy and repeatability are distinct properties, not the same; and end-effector pose involves both translation and rotation, so both accuracy and repeatability relate to the full pose, not one to translation and the other to rotation.