Geometric and constrained control for a string of tethered drones

• Published in: Robotics and autonomous systems 2020-11, Vol.133, p.103609, Article 103609
• Main Authors: Kosarnovsky, Benny, Arogeti, Shai
• Format: Article
• Language: English
• ISSN: 0921-8890; 1872-793X
• DOI: 10.1016/j.robot.2020.103609

In this study, we present a novel concept of a multi tethered drone system. The system includes an arbitrary number of drones connected serially to an active ground station. The considered drones are of quadrotor type. Utilizing a unique pulley–gimbal mechanism, each drone can freely move along the tether, and its state is measured with respect to the ground station without the use of standard onboard inertial sensors or GPS. The proposed system can be thought of as a robotic arm where each tether section acts as a variable-length link and each drone is a joint actuator. We model the coupled behavior of the ground station and the string, taking into account an arbitrary number of drones. Then, a controller that combines tools from geometric-control and Model Predictive Control is suggested. The developed model and control approach are also applicable for other swarm applications where the position of agents is to be controlled to a string-like form. Finally, the concept is demonstrated using numerical simulations and an initial experiment, which illustrate its potential effectiveness. •An arbitrary number of drones are connected serially to an active ground station.•The tether is utilized for position and attitude measurements.•It resembles a robotic arm that can be controlled to a desired configuration.•A model is developed using computational tools from geometric mechanics.•The control system combines geometric-control principles and MPC.