摘要：AbstractThe aim of this paper is to develop a simple and powerful control design-oriented model for re-entry vehicle during the ground roll-out phase. Pitching motion is absent in this phase and the yaw-roll dynamics of the vehicle is highly non-linear and coupled due to the aerodynamics and friction. Main contribution in this paper is that highly nonlinear dynamics is represented conveniently by a simple control design oriented linear model. To study the effect of rolling on yaw motion and vice versa a lateral-directional coupled model is developed. The 2-DoF bicycle model is a well known model used to study the lateral behaviour of vehicles and aircraft on runway. The bicycle model is augmented with 1-DoF roll dynamics which is modelled using torsional springs. The proposed model considers the effects of aerodynamics, tire-ground interaction, parachute drag and wind. The integrated model gives a mathematical description of the vehicle’s interactions with runway. Nose wheel steering and rudder are used for directional control and differential elevon deflection is used for lateral control post touchdown. A simple PID controller is designed for the yaw dynamics in order to bring the vehicle to the runway central line and a rate damping control is used in the roll plane. A suitable control allocation strategy is developed for rudder and nose wheel and the efficiency of the algorithm is demonstrated through simulations.
