Hardware & control
Gripper
A gripper is a robot end effector designed to seize and hold an object. It may use fingers, jaws, suction, magnetism, adhesion, or another grasping mechanism. A gripper can open and close with one command or expose several independently controlled joints, but it is not synonymous with every end effector or with a complete robot hand.
Also known as: robot gripper, robotic gripper, grippers
Updated
A gripper is one kind of end effector
ISO 8373:2021 defines a gripper as an end effector designed for seizing and holding. The distinction matters because an end effector may instead be a welding gun, spray tool, camera or another task-specific device.
Parallel jaws and multi-finger mechanisms are grasp-type grippers. Other designs hold objects with vacuum, magnetic force or adhesion. A humanoid hand can act as a gripper, but “robot hand” usually implies a more hand-like articulated mechanism and does not guarantee that the device can grasp reliably.
Mechanism and control shape the data
Two grippers can produce incompatible action records. One policy may output a binary open-close command, another a jaw width or force target, and a dexterous hand may command several joints. The same value can also mean a position, velocity, motor current or normalised actuator request.
Mechanical details affect the observed interaction. Finger geometry, stroke, payload, compliance, backdrivability, closing speed and contact material change which objects can be held and how failures appear. Tactile arrays or motor-current sensing can add evidence that a command actually produced contact.
Dataset metadata must identify the gripper
Large robot datasets often standardise the gripper to make demonstrations easier to compare. DROID used a shared Franka-based collection platform, including a common manipulation setup, across many sites.
A training record should name the gripper model and fingers, action encoding, limits, calibration, control mode and sensor channels. It should keep commanded state separate from measured opening and contact where possible. Without those fields, an apparently simple “close gripper” label may not transfer to the target hardware.
Sources
Related terms
Hardware & control
End effector
An end effector is a task-specific device attached to a robot manipulator’s mechanical interface so the robot can act on its environment, such as a gripper, hand or welding tool. It is distinct from the wrist or mounting flange, and from the tool centre point, which is only a coordinate frame used to plan the device’s motion.
Hardware & control
Actuator
An actuator is a robot’s power mechanism that converts electrical, hydraulic, pneumatic or other supplied energy into controlled mechanical force, torque or motion. In a humanoid, actuators drive joints, often through transmissions; they are distinct from the joints and sensors, and their arrangement need not correspond one-to-one with the robot’s degrees of freedom.
Hardware & control
Robot manipulation
Robot manipulation is a robot's controlled physical interaction with objects or its environment to change or maintain their state. It includes grasping, carrying, pushing, pulling, inserting, wiping, folding, tool use, and other tasks performed through selective contact. Manipulation can use a gripper, hand, tool, arm, or another part of the robot.
Hardware & control
Tactile sensing
Tactile sensing is the detection and measurement of physical contact properties at a robot's surface or contact interface. Depending on the sensor, it can report pressure or force distribution, contact location, shear, vibration, slip, texture, temperature, or deformation. Tactile data complements vision by measuring interactions that may be hidden at the point of contact.
Data & collection
Demonstration
A demonstration is a recorded example of how an intended task or behaviour is performed, usually represented as a time-aligned sequence of observations, states and actions. For humanoid robot learning, demonstrations may come from teleoperation, kinaesthetic guidance, motion capture or autonomous experts and provide targets for imitation.