Elliptical encirclement control capable of reinforcing performances for UAVs around a dynamic target

Abstract

Most researches associated with target encircling control are focused on moving along a circular orbit under an ideal environment free from external disturbances. However, elliptical encirclement with a time-varying observation radius, may permit a more flexible and high-efficacy enclosing solution, whilst the non-orthogonal property between axial and tangential speed components, non-ignorable environmental perturbations, and strict assignment requirements empower elliptical encircling control to be more challenging, and the relevant investigations are still open. Following this line, an appointed-time elliptical encircling control rule capable of reinforcing circumnavigation performances is developed to enable Unmanned Aerial Vehicles (UAVs) to move along a specified elliptical path within a predetermined reaching time. The remarkable merits of the designed strategy are that the relative distance controlling error can be guaranteed to evolve within specified regions with a designer-specified convergence behavior. Meanwhile, wind perturbations can be online counteracted based on an unknown system dynamics estimator (USDE) with only one regulating parameter and high computational efficiency. Lyapunov tool demonstrates that all involved error variables are ultimately limited, and simulations are implemented to confirm the usability of the suggested control algorithm.