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.

Outage-free maintenance of electrical power lines has been conducted throughout the years in order to fulfil the increasing demand of uninterrupted power supply. In these techniques care regarding electric shock and falls must be exercised while the work is performed on or near energized elements. In order to increase the safety and comfort of the workers as well as the overall efficiency, a teleoperated system for live-line maintenance, called ROBTET, has been developed for the electrical utility IBERDROLA. ROBTET is described in detail in the paper. It has two hydraulic-driven master-slave teleoperated manipulators on top of an insulated boom over a truck. The operator commands the manipulators from a cabin on the truck via a pair of master arms, while he receives visual feedback through a vision system. Multimedia display, voice commands, stereo vision and force-feedback are some of the new features implemented in order to achieve the required telepresence of the operator and hence increase the performance of the system.

In master-slave teleoperation systems the control loop is closed through the human operator. He acts as a controller generating actuating signals based in visual and kinesthetic cues. It is then indispensable to have a model of his behavior in order to design and study this type of systems coherently. Up to now only simplified arm dynamic models have been included in the study of bilateral control schemes. This paper makes use of already existing human-in-the loop models, developed for aircraft piloting, in order to construct a complete and simple model of human behavior for master-slave teleoperation systems with visual and kinesthetic feedback. The model was validated through several experiments with two different master arms and under various circumstances of operation. It includes complete human dynamic behavior: both the generation of control actions and limb dynamics.