A new approach for the design of robot joint transmission

Until recently the only alternative to traditional transmission techniques for robot manipulators was direct-drive (DD), and associated transmission m echanisms. These methodologies were developed to overcome the inherent prob lems of friction, backlash and compliance of gearboxes. The DD concept is h owever not ideal as the absence of a reduction ratio, means that dynamic co upling and joint interaction become important at the motor shaft. An altern ative approach that keeps the directness of DD, while providing dynamic cou pling and joint interaction attenuation, is the non-linear direct transmiss ion. The new concept is applied to the prototype SPRINTA robot and its perf ormance demonstrates the potential of the non-linear direct transmission ph ilosophy. (C) 2001 Elsevier Science Ltd. All rights reserved.