What is repeatability in robotics?
Repeatability is how closely a robot returns to the same commanded position over many cycles. It is quoted as ± millimetres and is different from accuracy.
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Definition
Repeatability measures how consistently a robot reaches the same commanded pose again and again under the same conditions. A spec of ±0.03 mm means repeated visits land within about 0.03 mm of their average position. It says nothing about whether that average is exactly where you asked the robot to go; that is accuracy.
How it is measured
The standard method, ISO 9283, sends the robot to the same pose many times (typically 30) and measures where the tool ends up, often with a laser tracker. Pose repeatability is the mean distance from the centre of those points plus three standard deviations. Path repeatability applies the same idea to following a path rather than stopping at a point.
Why it matters
Repeatability decides which jobs an arm can do without extra sensing: precision assembly, dispensing, machine tending and electronics work need tight figures, palletising much less. Industrial arms typically quote a few hundredths of a millimetre up to about a tenth. Gear backlash and stiffness in the actuators, payload and temperature all affect the real number, and the end effector adds its own error.
Frequently asked questions
What is the difference between repeatability and accuracy?
Repeatability is how tightly repeated moves cluster around one spot. Accuracy is how close that spot is to the position you asked for in absolute coordinates. Robots are usually far more repeatable than accurate, which is why taught positions work better than uncalibrated coordinates from a CAD model.
Does a smaller repeatability figure always mean a better robot?
Not by itself. Figures are measured at a stated payload, speed and temperature, so check the conditions. For vision-guided or offline-programmed work, accuracy and calibration matter as much.
Why do robot hands and humanoids quote repeatability too?
It is the same metric applied to a fingertip or end effector. Values are usually much looser than for industrial arms because hands and humanoids use lighter, more compliant structures.
Coverage
ABB launches the IRB 1700 family: 6–12 kg arms with 0.03 mm path repeatability
ABB debuted five IRB 1700 variants at CIIF Shanghai, including an IRB 1700ID with internal cabling, aimed at welding, machine tending, deburring and even AI server rack assembly.
BYD's humanoid design patent surfaces while a formal debut waits
China's IP office published BYD's embodied-intelligent-robot design patent on Oct 9, 2026 — a bipedal look aimed at service, education and industry — but the company has still not formally unveiled the product.
DH-Robotics debuts a 13-DoF direct-drive five-finger hand with swappable sensors
The 735 g ADH-5-13 has 13 active degrees of freedom, fingertip tactile sensing, ±0.2 mm repeatability and modules that can be replaced without taking the hand apart.
Sharpa's IROS trio: a skin-covered robot, a 21-DoF tactile hand and a haptic data glove
Sharpa launched D01, a dexterous robot with body-wide electronic skin, W02, a hand about 30% smaller than its predecessor with 21 active degrees of freedom, and AE01, a 22-encoder haptic glove for teleoperation data.
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