Collision-free UAV formation flight control based on nonlinear MPC

A collision-free formation flight controller for unmanned aerial vehicle (UAV) is designed in the framework of nonlinear model predictive control (MPC). It can consider control input saturation and state constraints explicitly. Formation configuration is determined based on virtual reference point method, which has no error propagation in the formation. The formation flight controller is designed in a distributed way. Based on the tracking error, the objective function for each UAV is designed in the nonlinear MPC framework. A new type of cost function, based on the UAV´s velocity orientation and relative distance between UAV and obstacle, is added to the objective function to guarantee obstacle avoidance. Inter-vehicle collision avoidance is also ensured by cost function combined with a priority strategy. The nonlinear optimization problem is solved by the filter-SQP method, which has the better convergence and numeric. Simulation results are provided to evaluate the performance of the designed collision-free formation flight controller.