degrab

Degrab is a term used in robotics to describe the act of releasing or disengaging a robotic gripper from a previously grasped object. It denotes the end of a grasping step and prepares the end effector for subsequent motion, such as regrasp, transport, or placement. In practice, degrab is executed by reducing grip force or opening the grasp mechanism.

Etymology and usage: the word is a portmanteau of de- indicating reversal and grab, and it appears in robotics manuals, control software, and industry discussions to differentiate the release phase from approach and alignment phases. Degrabbing is often coordinated with motion planning to maintain stability of the object and avoid unintended contact.

Mechanisms: active degrab can involve opening jaws via electric, pneumatic, or hydraulic actuation; reducing grasp force to a safe level; or using soft/gripper compliant release to minimize impact. Sensor feedback such as force, torque, or tactile sensing is commonly used to verify a successful release.

Applications and challenges: degrab is essential in pick-and-place, assembly lines, packaging, and laboratory automation. Challenges include ensuring stable release, avoiding object drop or slip, handling delicate items, and synchronizing degrab with downstream motions for high throughput.

Variants and related terms: rapid degrab, soft-grip degrab, release, grasping, end effector.