Robust Circular Formation Control of Dubins Vehicles Under Input Saturation and External Disturbances

This article studies the problem of circular formation control for multiple Dubins vehicles with an identical constant speed and heading angle being the only control input. When moving around a stationary target, each vehicle is assumed to receive information only from a single neighbor. The key contribution of this article is the development of a robust circular formation controller that addresses the issues of input saturation and external disturbances for Dubins vehicles while achieving a desired target-centric formation. Specifically, the monotonic variation intervals of the relative distances between the vehicle and its virtual vehicle are first identified by analyzing the relative motion. Then, an angle smooth-switching strategy is designed to regulate the relative distance between vehicles and reduce the chattering caused by abrupt control switches. Finally, a finite-time angle-tracking controller is proposed that uses a smooth Sigmoid approximation function and a disturbance observer to handle input saturation and external disturbances, respectively. Both numerical simulations and real-world experiments are conducted to validate the effectiveness of the proposed controller.