On the Use of Tethered Configurations for Augmenting Hovering Stability in Small-size Autonomous Helicopters

Helicopters are well-known by their hovering capabilities. However, the performance of this valuable feature can be seriously affected by external disturbances such as wind effects. The latter could be even more significant when dealing with small-size helicopters, which are commonly adopted as base platforms for developing unmanned aerial vehicles. Motivated by this context, this work proposes an augmented configuration for performing more stable hovering maneuvers that consists of the unmanned helicopter itself, a tether connecting the helicopter to the ground, and a device on ground adjusting the tether tension. A modeling analysis on the inherent benefits to the proposed configuration as well as the control guidelines to exploit such potentialities are presented in this paper. As a proof a concept, a first basic implementation of the control structure for the entire system is also included. Finally, several demonstrating simulations under artificially generated wind influences are presented to endorse the validity of the proposed approach. Keywords—Unmanned aerial vehicles, helicopter, modeling, tethered systems, stability augmentation, control.