String of Drones for Load Carrying

Carrying a load by a group of drones can be done in different configurations, which may also be changed during flight. There are many considerations when planning the applied configuration; most importantly, the number of drones should fit the weight of the load. Energy is a critical factor, because of its influence on the flight range. Previous configurations presented in literature include counteracting carrying forces, which deteriorate energy efficiency. To prevent this, we propose an innovative carrying configuration that is based on a string of drones. Each drone is connected to the drone below, by a cable, and the lowest drone is connected with the load. The paper deals with a point-load carried by a string of n drones. It shows the development of the group's equations of motion, and the design of a control law that allows the load to track a desired trajectory.