Three-dimensional Path-tracking Method Based on Mixed Convergent Guiding Vector Field
In response to the trajectory oscillation problems that arise from the traditional guiding vector field in the three-dimensional path following of fixed-wing unmanned aerial vehicles(UAVs),a construction method of the guiding vector field that employs a mixed convergence strategy and adaptive gain is proposed.This approach is intended to achieve stable tracking of the three-dimensional path for UAVs.Initially,by utilizing the Hessian matrix of the error function of the desired path,a correction matrix for the convergence direction of the guiding vector field is established.Subsequently,a mixed convergence guiding vector field that combines the Newton direction and the gradient direction is introduced.This method enhances the smoothness of the flight trajectory.Then,an adaptive gain strategy for the guiding vector field is devised.This strategy enables the adaptive adjustment of the gain of the convergence term based on the trends of error variations and the degree of local vector field changes.Simulation experiments show that the proposed method effectively resolves the trajectory oscillation problems encountered by the traditional guiding vector fields when converging the flight trajectory near the desired path.The approach demonstrates superiority in terms of tracking accuracy and convergence speed.