Grippers and robot hands: how robots hold things

A robot arm on its own only moves a flange around in space. The end effector, the tool mounted on that flange, is what actually picks, welds, screws or paints. Choosing it is often harder than choosing the arm.

Parallel grippers

Two (or three) fingers close in parallel on the object. Electric parallel grippers are the most common tool on cobots: they are easy to program, can measure the gripping width and force, and fingers can be custom-made for each part. Pneumatic grippers are faster and stronger for their size but need compressed air.

Vacuum suction

Suction cups hold flat, smooth objects such as boxes, sheets and glass. Vacuum is generated by an electric pump or a compressed-air ejector. Porous or uneven surfaces need foam pads or more airflow.

Soft and adaptive grippers

Soft fingers made of flexible material wrap around delicate or irregular objects such as fruit, bakery products or bags. Underactuated "adaptive" grippers use linkages so that the fingers conform to the object's shape.

Dexterous hands

Humanoids and research robots use multi-fingered hands with many joints and often tactile sensors. They can handle tools made for people but are complex, expensive and harder to program than a simple gripper.

Tool changers

An automatic tool changer lets a robot swap grippers or tools by itself, passing through air, power and signals. It makes one robot useful for several jobs.

Tips

• Check the payload: it includes the weight of the gripper, not just the object.
• Look for plug-and-play kits certified for your arm brand; they save integration time.

Browse grippers, robot hands and tool changers with compatibility per robot, and their makers.