ABSTRACT: Bird's formation flight is one of the best types of cooperation in nature. The bird's flight was the motivation of humans for flying. After one century of flight development, bird's formation flight was the motivation of humans for aircraft's formation flight. The closeness of aircrafts in formation flight and the effect of disturbances such as vortex make the formation flight control a challenging issue for control designers. This paper introduces a novel integration between guidance commands and system controller inputs. In recent papers the control system inputs were derived from approximate equations, and this approximation caused maneuver limitation. To tackle this problem, a new method is introduced, which employs proportional-integral-derivative (PID) controller in the integration block. This integrated guidance and control system employs the pure pursuit guidance to determine the unmanned aerial vehicle's acceleration command. A two-loop dynamic inversion technique is used for designing attitude and velocity controller, while the acceleration feedback control is used between the guidance system and attitude controller, which leads to increase in maneuverability of unmanned aerial vehicle's formation flight. The simulation results show that the proposed method can control the UAV's formation with sufficient accuracy in severe maneuvers.

The polysaccharide, kappa-carrageenan (kC), has been chemically modified by graft copolymerization of 2-hydroxyethylmethacrylate (HEMA) in an aqueous medium using ceric ammonium nitrate (CAN) as an initiator under argon atmosphere. A plausible reaction mechanism of grafting has been suggested. Evidence of grafting was obtained by comparison of FTIR spectra of kC and homopolymer-free kC-g-poly(HEMA) as well as solubility characteristics and gravimetric analysis of the products. The optimum reaction conditions affording maximum grafting ratio and add-on value have been determined. The grafting parameters have been found to increase with increasing in kC, CAN, and HEMA concentrations as well as polymerization time and temperature, up to a certain value, but these parameters decrease on further increasing in reaction conditions.