Hybrid actuation concepts for a rope robot as a haptic interface

The demands on the dynamics of haptic interfaces can vary strongly for different rendering and control tasks. Especially, in the field of realistic sports simulation, the requirements on the haptic display concerning producible power and forces are high. Furthermore, the maximal forces can be highly direction-dependent which has to be taken into account for the design of the haptic interface. This paper describes two design and control approaches of hybrid active/passive actuation concepts for a rope robot. These approaches meet the requirements of generating direction-dependent maximal forces. Additionally, one concept allows the application of large counter-forces on the user and the absorption of elevated power in a save and controllable way. For these concepts, an active motor unit is replaced by passive elements consisting of a controllable brake and/or a spring mechanism. We first introduce the actuation concepts and the chosen passive components. Then, a basic control approach for the hybrid interface is explained. Finally, the control concepts are evaluated. The results of the evaluation confirm the applicability of these concepts and the choice of components.