Robot hands are normally first in contact with the environment and should withstand hard contacts. Variable compliance systems as realized in David can handle impacts and store energy for periods of time.
In contrast to our other robot hands, David's hand has no sensors and actors in the hand. The actors and sensors are located in the forearm of the handarmsystem. This allows building a hand with the size and dexterity of a human. Every joints is actuated human like by two motors. The hand can control its position and its passive joint stiffness simulatneously with an nonlinear spring mechanism coupled to the tendons. The decoupling from the gear and output makes it very robust against hits and allows the system to run stable with low controller frequencies. The system is used to compare different tendon couplings and degree of freedoms. Furthermore dynamic grasping combined variable stiffness is explored.