Navigation problems of unmanned air vehicles (UAVs) flying in a formation in a free and an obstacle-laden environment are investigated in this brief. when static obstacles popup during the flight, the UAVs are required to steer around them and also avoid collisions between each other. In order to achieve these goals, a new dual-mode control strategy is proposed: a “safe mode” is defined as an operation in an obstacle-free environment and a “danger mode” is activated when there is a chance of collision or when there are obstacles in the path. Safe mode achieves global optimization because the dynamics of all the UAVs participating in the formation are taken into account in the controller formulation. In the danger mode, a novel algorithm using a modified Grossberg neural network (GNN) is proposed for obstacle/collision avoidance. This decentralized algorithm in 2-D uses the geometry of the flight space to generate optimal/suboptimal trajectories. Extension of the proposed scheme for obstacle avoidance in a 3-D environment is shown. In order to handle practical vehicle constraints, a model predictive control-based tracking controller is used to track the references generated. Numerical results are provided to motivate this approach and to demonstrate its potential.
X. Wang et al., "Cooperative UAV Formation Flying with Obstacle/Collision Avoidance," IEEE Transactions on Control Systems Technology, Institute of Electrical and Electronics Engineers (IEEE), Jul 2007.
The definitive version is available at http://dx.doi.org/10.1109/TCST.2007.899191
Mechanical and Aerospace Engineering
Keywords and Phrases
Grossberg neural network (GNN); collision avoidance; cooperative control; model predictive control (MPC); obstacle avoidance; unmanned aerial vehicle (UAV); visibility graph
Article - Journal
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