Peg-in-Hole Insertion

Inserting a pin, shaft, or plug into a matching hole, a task that tests precision and force control.

Peg-in-hole insertion is the task of fitting one part, such as a shaft, pin, or plug, into a matching hole in another part. It is one of the most studied operations in industrial assembly and a standard testbed for contact-rich manipulation, meaning manipulation involving sustained, complex contact forces. The difficulty is that the clearance between parts is often tiny, so position control alone tends to jam or wedge the parts; the robot must continually adjust based on the contact forces it feels. A 2025 survey in the Chinese Journal of Mechanical Engineering (English edition) splits the process into three stages, search, alignment, and insertion, and groups methods into passive compliance (such as remote center compliance devices), active compliance (force control, impedance control), and learning-based intelligent compliant assembly. Imitation learning, reinforcement learning, and sim-to-real transfer research also commonly use it as a benchmark task.

ExampleThe Insertion task in the ALOHA simulation: two robot arms each pick up a socket and a plug, then insert the plug into the socket in midair.

Also called

Peg-in-Hole Assembly

Related

Contact-rich Manipulation · Robotic Assembly · Force Control · Impedance Control · Remote Center Compliance (RCC) Device · Factory / IndustReal

Sources

Advances in Robotic Peg-in-Hole Assembly: A Comprehensive Review (Chinese Journal of Mechanical Engineering, 2025)