Linkerbot’s Linker Hand L30 Can Tighten Screws in Seconds

A Beijing-based Linkerbot robot hand swoops in and grabs a loose screw, aligns it, and tightens it in less than 2 seconds. When it comes to assembly tasks like this, the L30 model is a speed demon that outperforms most humans.

Linkerbot built the L30 to be utilized on robot arms and humanoid platforms that require more than just a gripper. The hand is roughly the size of an adult human hand, but inside it is made up of wires and tubes rather than hard gears. The cables they’re using are actually fairly strong synthetic rope wound into smooth plastic sleeves, and they strain on the finger joints of motors set far back. This keeps the fingers light and fast while allowing them to flex naturally when in touch with something.

The hand has 17 joints that can actually move, and additional 4 that bend and flex when pressure is applied to help with grip stability. Each finger can curl, stretch, and twist much like the real thing, and the entire unit weighs only about 1.4 kilograms, making it ideal for robot arms. At the same time, it has the strength to lift five kilograms and utilize enough force at the fingertips to handle tools and parts without them falling out of its hold.

Control occurs via a CAN FD connection capable of handling 500 kilobits per second, and a simple USB adapter connects it all to a computer running Linkerbot’s software. That is where you may specify positions, speeds, and force levels, and the hand will execute them. It can open and close entirely in 0.2 seconds and return to the same position within 0.2 millimeters every time. The thumb tip can generate 8 newtons of force, while the other fingers can generate 7 apiece, resulting in a full five-finger hold with a force of 12 newtons.

Engineers also adjusted the cable drive so that the hand adapts when it encounters resistance. There are also sensors at the fingertips that sense how much pressure is being exerted, and the fingers will relax or stiffen as needed for delicate tasks. All of these actions rely on route control and force feedback to ensure that they do not just break something delicate.

Power is supplied by a conventional 24-volt supply; at rest, the hand draws .45 amps, and even when moving quickly, the average current remains under one amp unless it encounters significant resistance. Linkerbot contains the mounting hardware, connections, and some basic software, allowing developers to simply drop this hand into their existing robot configuration. They ship these devices to industries and research institutes, including Samsung, for roughly twenty grand.
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