Robotics
End effector
Definition
An end effector is the part of a robot positioned to perform a task at the end of a manipulator, such as a gripper, hand, suction tool, or welding tool. Its pose and interaction forces are often the quantities a task controller regulates.
Also known as: End-effector, Robot end effector
Updated
The tool that meets the task
A humanoid hand is one example, but an end effector need not resemble a hand. A suction cup, screwdriver, or probe can serve the same role for a different task. Its geometry determines where useful contact occurs, while the arm positions it.
Modern Robotics distinguishes the task space used to express the job from the workspace of end-effector configurations the robot can reach. A marker tracing a board can have a planar task even when the supporting arm has many joints.
Choosing a reference frame
The end-effector frame is a coordinate frame attached to the relevant part of the tool. Its origin may be at a tool tip rather than at the wrist flange. MIT's manipulation notes emphasize choosing a frame near the expected contact when defining task-space interaction behavior.
Changing tools therefore changes more than appearance: the tool offset changes the relation between joint angles and contact position, and the tool's mass affects dynamics and force compensation.
Tool capability and robot capability differ
A gripper can hold a particular object only if its geometry and forces suit that object. Reaching a pose does not establish a stable grasp, adequate payload, or collision-free access. Those require separate kinematic, contact, and dynamic checks.
Sources
Related terms
Robotic manipulation
Robotic manipulation is the use of a robot to change an object's position, orientation, or state through physical interaction. It includes grasping and moving objects as well as actions such as pushing or carrying them without a grasp.
Forward kinematics
Forward kinematics calculates the position and orientation of a robot link or end-effector from the robot geometry and joint positions. It maps a robot configuration to a pose.
Workspace
A robot workspace is the set of positions or poses its end-effector can reach under specified geometric and joint constraints. Its meaning depends on whether orientation is included and which base and tool configuration are assumed.
Operational-space control
Operational-space control formulates a robot’s motion and force behavior in task coordinates, such as the position and orientation of its hand, while accounting for the robot’s dynamics. Secondary joint objectives can be coordinated with the primary task.