Vector Field Guidance for Fixed-Wing UAVs

This work was presented at Indian Control Conference 2021: Minimum-time Path Convergence for UAVs in Wind Using Vector Field Guidance.

This work introduces a novel guidance algorithm for unmanned aircraft to converge to a smooth path optimizing time in the presence of wind. A Lyapunov vector field based method is used to achieve convergence and tracking. The proposed framework performs better in comparison with the similar work existing in literature. The presented approach modifies the vector field according to the velocity of the wind, facilitating faster convergence. A customised optimisation algorithm is then used to find a suitable design parameter for vector fields. To demonstrate the efficacy of the proposed approach, numerical simulations are shown and the results are compared with the optimal time paths obtained using optimal control theory.

Combined Vector Field: Two vector fields, conservative and solenoidal are combined with appropriate weight functions such that the converging field dominates at larger distances and the tracking field dominates when the UAV is closer to the curve. The weighting parameter is then optimized to ensure fast convergence to desired path.

Time-optimal Convergence in Wind: Additional modifications are introduced that factor in the windspeed and directions to change the vector field for near-optimal performance compared to discontinuous min-max controller.