ETS-7 space robot teleoperation through virtual force reflection

The National Aerospace Laboratory (NAL) is participating in the ETS-7 robot experiments in order to establish the basic technologies for on-orbit truss assembly by ground teleoperation. Several different approaches have been tested so far. This paper describes one of them: the application of force reflecting (FR) hand controllers to improve continuous teleoperation with long communication delays. After a comprehensive analysis of the current state-of-the-art, four distinct fundamental ideas have been implemented: a) the use of FR to limit speed of command; b) the use of potential force fields for guidance during grasping and inspection; c) the use of the FR hand controller to generate physical constraints and d) the use of the FR device to intuitively correct modeling errors after probing the environment. All of them have been successfully tested on the ETS-7 robot system using NAL's Ground Teleoperation Facility (GTF) and two 2-DOF Force Reflecting Joysticks. This paper reports the conduction and results c;lf these experiments.