#Robot #Wrist #Tendon #Pulley

Assembly of one of the four simple pulleys that turn the wrist tendons through ninety degrees. Boeing has done the most extensive study, that I know of, in the lifetime fatigue of tendon driven systems as many planes originally had a direct cable connection between the pilot and the plane. Even the mighty 747 which was a surprise to me. From memory, steel requires a 16:1 ratio between cable and pulley and most polymer fibres a mere 4:1. Here a nominal braided dyneema tendon passes round a 15mm pulley so in principle the fatigue life should be indefinite.