A 21-DOF Humanoid Dexterous Hand with Hybrid SMA-Motor Actuation: CYJ Hand-0

CYJ Hand-0 is a 21-DOF humanoid dexterous hand featuring a hybrid tendon-driven actuation system that combines shape memory alloys (SMAs) and DC motors. The hand employs high-strength fishing line as artificial tendons and uses a fully 3D-printed AlSi10Mg metal frame designed to replicate the skeletal and tendon-muscle structure of the human hand. A linear motor-driven module controls finger flexion, while an SMA-based module enables finger extension and lateral abduction. These modules are integrated into a compact hybrid actuation unit mounted on a custom rear support structure. Mechanical and kinematic experiments, conducted under an Arduino Mega 2560-based control system, validate the effectiveness of the design and demonstrate its biomimetic dexterity.