Cooperative formation control of quadrotors with obstacle avoidance and self collisions based on a hierarchical MPC approach

This paper presents a hierarchical model predictive control (MPC) approach for cooperative formation flight control and stabilization of a team of quadrotors under constraints. The proposed control structure is a hierarchical scheme with two layers. At the top layer, a linear MPC controller is developed to generate the optimized reference trajectory to be used in the lower-layer with an MPC attitude and altitude controllers. The MPC controller units in the lower-layer are considered separately for each quadrotor. At the top-layer, data transfer between the quadrotors is implemented cooperatively. Three cost functions are considered for keeping the quadrotors in a desired formation while avoiding obstacles and inner-vehicle collisions. The simulation results show that the overall hierarchical MPC approach effectively tracks the quadrotor reference trajectory while avoiding self and obstacle collisions.