Robotic DLR hand: A furious metallic claw compatible with the humanoid robots

Survival remains the driving force behind every evolution, to an extent this can be applicable to humanoid robots too. The very latest conception of such robotic evolution is an anthropomorphic robot that can resist powerful collisions and even strikes – designed by the Institute of Robotics and Mechatronics, part of the German Aerospace Center (DLR). Intelligent mechanism is the motto of DLR which has concluded the toughest robotic hand ever. Almost 13 researchers are coordinating experiments under DLR project, which costs between 70,000 and 100,000 euros.

dlr robotic hand

The DLR hand has been given the shape of a metallic human hand, with five articulated fingers powered by 38 tendons (made of synthetic fiber called Dyneema) integrated with an individual motor on the forearm. The spectacular ability to regulate the stiffness differentiates DLR hand from other robotic hands. Its motors can control the tendons for allowing the hand to absorb violent shocks. While conducting tests, the researchers gave a baseball-bat blow to the DLR hand, creating a 66 G impact – which was successfully overcome by it.

humanoid justin

DLR's ultimate goal is to develop a humanoid robotic hand which excels dexterity and resilience. The hand has a total of 19 degrees of freedom and it can easily move its fingers for grasping varied objects. Astonishingly, the robot hand generates force of 30 newtons at the fingertips. Spring mechanism has been used for more elasticity, allowing the fingers to absorb and release energy, like a human hand does. This mechanism delivers precision in achieving elements like: robustness, mimicking kinematic, dynamic and force properties of human hand.

During normal operations the finger joints turned at 500 degrees per second. But the DLR technology assures that the joint speed can reach up to 2000 degrees per second – with the tensioning of springs. Markus Grebenstein, Lead Designer, says that “If every time a robot bumps its hand, the hand gets damaged, we’ll have a big problem deploying service robots in the real world.” So the need of the hour was a extra strong robotic arm.

With the superior antagonistic actuation, the DLR hand can regulate its stiffness – where joints of each finger are driven by two tendons, attached to one motor. When the motors turn in the same direction, the joint moves; and the joint stiffens when motors move in opposite directions.

justin humanoid

Previous designs of the Shadow hand (designed in the U.K) and humanoid Justin (previous design of Grebenstein) were good enough but had their own limitations. The latest design of Grebenstein's is smart and spontaneous enough to catch a ball thrown from several meters away. Special sensor gloves for send grasping commands are being used for operating the DLR hand. The control system depends upon on monitoring the joint angles. The hand analyzes the elongation of spring mechanisms to conclude how much force shall be exerted while gripping. The researchers want to execute project DLR Hand Arm System - two-arm torso. The vision is to develop innovative grasping, manipulation strategies and bimanual manipulations for the future humanoid robots.

Via: Spectrum.ieee