Force reflection for time-delayed teleoperation of Space robots

Continuous on-orbit teleoperation of robots by operators on Earth is seriously impeded by signal transmission delays imposed by limits on computer processing at transmission stations and satellite relay stations. For Earth-orbit applications the time delay is normally between 5-7 seconds. On the other hand, it is well known that task execution performance can be dramatically improved with the addition of some kind of force reflection (FR) to the operator, although time delay makes its application extremely difficult. This paper reports on several proposals to improve continuous teleoperation through long communication delays using force reflecting hand controllers. It also addresses the implementation of these ideas for the ground teleoperation of the ETS-7 satellite robot arm. Results of the first extensive application of FR for ground teleoperation of a real space robot are explained in detail.