Hierarchical Intelligent Redundancy Resolution for Improving Haptic Device Stability

The increasing complexity of the tasks that haptic systems (HD) are expected to do, can be expedited by the multi-degree-of-freedom (DOF) haptic interface. Interfaces play a crucial role in enhancing user interaction with virtual environments. However, stability during haptic interactions, especially with complex virtual environments, remains challenging. This study proposes a novel intelligent hierarchical approach to address this issue. By employing robot redundancy, we aim to expand the stability domain of haptic devices for a different and wide range of visco-elastic obstacles in a desired stylus position. This issue has not been employed before for HDs. Stability analysis is carried out in the least conservative case by considering viscosity, Coulomb friction, and sensor quantization in robot joints during stability analysis. Our method incorporates non-strict priority allocation, facilitating efficient utilization of redundant degrees of freedom. Through this hierarchical approach, we extend the stability domain significantly, improving the overall performance of redundant haptic device interfaces.