Historical details

Data sheet of DLR Hand II

Sensors of a single finger

• 3 joint position sensors: specially designed conductive plastic potentiometers
• 3 joint torque sensors: strain gauge sensors
• 3 motor position/speed sensors: analog Hall sensors with interpolation
• 1 six-dimensional finger tip force torque sensor: strain gauge sensors
• 3 motor temperature sensors: NTCs
• 3 sensors for temperature compensation: integrated sensors

Actuators

Brushless DC motor with Harmonic-Drive and tooth belt gear

Motors:	11(24) mNm, 17,000 rpm for medial joint 24(35) mNm, 6,000 rpm for proximal joint
Gears:	Harmonic Drive gears, 1.8 Nm, 6,000 rpm, 100:1 identical for all joints
Tooth belt gear:	1.2:1 in proximal joint 2:1 in medial joint

 

Degrees of Freedom

• Four identical fingers with four joints and three degrees of freedom the medial and distal joints are directly coupled 1:1. One additional degree of freedom in the palm. In total the hand has 13 degrees of freedom.

Mechanics

• Four identical fingers with four joints and three degrees of freedom each and an aluminum open skeleton structure with injection molded plastic shells
• bevel gear in the base joint

Motion ranges

extension / flexion	proximal joint	- 55° / 75°
abduction / adduction	proximal joint	± 37°
extension / flexion	medial and distal joint	- 20° / 105°

 

Link lengths

proximal link	75 mm
medial link	40 mm
distal link	40 mm

 

Forces/Torques

active force perpendicular to the stretched fingertip: 30 N

Speed

approximately 360°/s for each joint

Weight

a single finger: 375 g
the complete hand: 1800 g

Electronics

• Sensor electronics located directly beside the sensors
• A/D-conversion in each finger link. Serial communication system connecting within the finger to connect the finger links with a minimum number of cables. Serial communication system connecting the fingers to the hand and the hand to any external control computer.
• Number of cables to the hand:
  • 4-wire power supply (24 V motor power supply and 50 V, 20 kHz power supply for electronics)
  • 8-wire serial communication interface
• Hot pluggable tool change within a few seconds with a customized tool retainer

Control computer

Two-CPU PowerPC VME bus system