Hand Arm System


Anthropomorphic light weight robot:

  • Variable passive compliance in each joint
  • Human like strength
  • Human like range of motion
  • Robust to impacts
  • Potential energy storage in joints
  • 3 different variable stiffness actuator (VIA) concepts
  • No torque sensors
  • Fully integrated electronics
  • Modular design


Degrees of freedom     
Position sensors          
Control frequency      

13.5 kg
3 kHz 

Variable Stiffness Actuators (VSA)

The Hand Arm System is equipped with 3 types of Variable Stiffness Actuators:

  • Antagonism (19 DoF Hand):
    • 2 equivalent motors adjusting joint stiffness and position
    • in-tendon progressive spring mechanism
  • BAVS - Bidirectional Antagonism with Variable Stiffness Actuation (2 DoF wrist,1 DoF forearm-rotation):
    • 2 equivalent motors adjusting joint stiffness and position
    • Asymmetric cam disc shape
    • Redundant joint actuation
  • FSJ - Floating Spring Joint (4 DoF upper arm joints):
    • one big motor for joint positioning
    • one small motor to change the stiffness
    • one single spring


Very high integration and power density

Units integrated in the forearm:

  • 44 intelligent motor modules with integrated power inverters and 180 W peak power each
  • 2 FPGA based control units
  • 12 V & 5 V power supplies and distribution
  • Spring deflection sensors

Units integrated in the upper arm / shoulder:

  • 8 motors with up to 1 kW peak power
  • Modular power inverters
  • Spring deflection sensors
  • Control units

Customized power supply (IGOR):

  • 5 Independent 24 V & 48 V outputs with soft start and fast electronic fuse to power the complete Hand Arm System
  • 4 kW peak source and sink capability
  • Energy storage using supercapacitors allows operation from standard wall outlet
  • Control via touch screen display or USB/RS232


Driving a Nail:

Robustness of the fingers:

The arm being hit by a baseball bat:

Sebastian Wolf
German Aerospace Center

Institute of Robotics and Mechatronics
, Mechatronic Components and Systems
Tel: +49 8153 28-1060

Fax: +49 8153 28-1134

E-Mail: sebastian.wolf@dlr.de
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