Autonomous Load Control and Transportation Using Multiple Quadrotors

This paper discusses the development of a generalized framework for collaborative control and transportation of a suspended load using multiple quadrotors. For this, first, a flight dynamics model of quadrotors with suspended load system is derived using Newton's approach. Next, a cooperative control law is developed to control the motion of the quadrotor(s) and the suspended load. The vehicle formation ensures that the load distribution among vehicles remains equal throughout the transportation task. The proposed control approach uses the combination of a proportional–integral derivative (PID) and a proportional derivative (PD) controller for position control and transportation. The PID controller controls the motion of quadrotor, whereas the PD controller controls the swing, maintains the formation of quadrotors, and simultaneously damps the oscillation of the load. The combination facilitates the waypoint transition and trajectory tracking of the load. A minimum snap trajectory generation approach for the suspended load is also presented. The performance is demonstrated in a simulation as well as experimentally on a single and multiple quadrotors in three-dimensional environment using the motion capture system. The experimental result for a single-lift system is also presented for the outdoor environment.