Koch v1.1 Arm

An open-source, low-cost leader-follower robot arm built from Dynamixel servos and 3D-printed parts.

The Koch arm was originally designed by Alexander Koch of Tau Robotics, and Hugging Face engineers later reworked it into the easier-to-build v1.1 version. It has 6 degrees of freedom (5 joints plus a gripper), 3D-printed structural parts, ROBOTIS Dynamixel XL430 and XL330 servos at the joints, and communicates over a USB serial connection. A set consists of a leader arm and a follower arm: a person moves the leader by hand, the follower mirrors it in real time, and the resulting motion is recorded as demonstration data, which is then used to train an imitation-learning policy with an algorithm such as ACT. According to distributors, a single arm can be built for around $400. It was the hardware featured in LeRobot's early tutorials, though the cheaper SO-100/SO-101 arms later became the more common choice.

ExampleFollowing the LeRobot tutorial, someone builds a pair of Koch arms, records 50 demonstrations of “put the block in the box,” and trains an ACT policy on the data.

Also called

Koch Arm, Koch v1.1

Related

LeRobot · SO-100 / SO-101 Arm · Leader-Follower Teleoperation · ROBOTIS Dynamixel Servo · Action Chunking with Transformers · Desktop Robot Arm

Sources

Koch v1.1 - LeRobot Documentation (Hugging Face)
Koch v1.1 Low-Cost Robot Arm: Follower - ROBOTIS

As of

2025