Shadow Dexterous Hand

Twenty motor modules in the forearm base pull tendons to move 24 joints: the Shadow Dexterous Hand remains the reference design for tendon-driven humanoid hands. Four fingers and a thumb provide twenty actuated degrees of freedom plus four coupled joints; the thumb has five, each finger three across four joints, and the wrist two.

Including the forearm the hand weighs 4.3 kg and carries 4 kg in a power grasp, with a full joint stroke at 1 Hz. More than one hundred sensors are sampled at 1 kHz, among them forty tendon-force sensors, joint positions, an IMU, temperature and current; two Shadow Tactile Fingertips are standard and up to five can be fitted.

Communication is EtherCAT at 100 Mbit/s with ROS; position control runs on the host at 1 kHz, the torque loop in the motor at 5 kHz, and the software is released under GPL and BSD licences. Materials are aluminium, brass, acetal, polycarbonate and polyurethane. Shadow lists Universal Robots integration as an option and compatibility with the PR2.

Lighter derivatives are the Lite (13 DOF, 2.4 kg, see Shadow Dexterous Hand Lite), Extra Lite (10 DOF, 2.1 kg) and Super Lite (7 DOF, 1.8 kg). Price on request. The catalogue photo dates from 2007 and shows an earlier generation; the maker's three-finger DEX-EE serves a different purpose.