Hierarchical Design for Position-Based Formation Control of Rotorcraft-Like Aerial Vehicles

A hierarchical control strategy is designed for the position-based formation tracking control of rotorcraft-like aerial vehicles without linear velocity measurements. In the outer loop, the cooperative algorithm is designed based on auxiliary systems, to let all agents go toward desired positions. Based on an extraction algorithm, the desired quaternion-based attitude is extracted. In the inner loop, the inherent passivity property is applied to compensate for the desired but unextracted angular velocity, which makes the hierarchical control procedure more separate. Combined with the inherent passivity property, the quaternion-based attitude and the proposed bump-like functions, a hybrid formalism is established for the attitude loop containing a hybrid control strategy. In this case, the global attitude control can be realized via determining the torque orientation and overcoming the topological constraint on SO(3). The effectiveness of the hierarchical control strategy is verified by the position-based formation of six miniature quadrotors.