Study On Trajectory Optimization And Guidance Approach For Hypersonic Glide-reentry Vehicle

The hypersonic glide-reentry vehicle is a new maneuverable vehicle for the long-range precise strike mission or military delivering. For the purpose of developing reentry trajectory optimization and guidance technology of the hypersonic glide-reentry vehicle, this dissertation studies the properties of the reentry trajectory, the schematic of reentry angle-of-attack, trajectory optimization, on-board trajectory generation, reentry guidance and the penetration capability of glide-reentry. The main results achieved in this dissertation are summarized as follows:Based on the planar reentry dynamic model, the rudimental properties of the glide-reentry trajectory and the angle-of-attack scheme are studied. 1) The influence of the initial trajectory parameters and the maximum lift-to-drag ratio on the trajectory shape is analyzed; 2) The physical programming method is employed to solve multi-objective reentry trajectory optimization problem, and the physic characteristic of the optimal trajectory shape is analyzed; 3) Then the optimal parameterized angle-of-attack scheme of reentry is proposed.A rapid trajectory optimization approach using Gauss Pseudospectral Method (GPM) for hypersonic glide-reentry vehicle is developed. Aimming at deficiencies of traditional trajectory optimization method in initial value determination and computation efficiency, a pipelining and segmenting trajectory optimization approach base on GPM, containing an initial guess generator, is proposed. Then this appoach is applied to compute the optimal trajectories of reaching a point target, an area target and the attainable region of reentry flight. The feasibility of this approach is validated by comparing the GPM results with that of the numerical integration. An optimal trajectory with a range of ten thousand kilometer and the attainable region of reentry flight both can be generated in about 3 minuets on a desktop computer. It indicates the rapidity of the presented approach.An improved on-board three-degree-of-freedom (3DOF) constrained entry trajectory generation method is proposed. 1) With the defined angle-of-attack profile and path constraints, the mathematical model of reentry corridors are biult; 2) An improved qusi-equilibrium glide condition is presented and utilized to convert all path constraints to the constraints of control variables, and the control variables are parameterized. Employing the approximate relationship between the velocity and the range, the parameters of control variable and the longitudinal reference trajectory satisfying terminate constraints can be solved; 3) Then the 3DOF trajectory generation method is completed by the heading error corridor control strategy in lateral motion and longitudinal trajectory tracking control based on the linear quadratic regulator (LQR); 4) The numerical simulation indicates that the algorithm is able to generate a reentry trajectory with a range of ten thousand kilometer satisfying all path constraints in about 2-3 seconds on a desktop computer.A mixed reentry guidance of predictor-corrector with defined way-points and trajectory tracking is proposed. In the solution process, the reentry trajectory is divided into the predictor-corrector part and the retargeting and tracking part which is near to the target. In the first part, the predictor-corrector method is applied to solve the guidance problem between the defined way-points. In the second part, reference trajectory is regenerated on-board and tracked. 1) The method of way-points determination is presented. 2) In the predictor-corrector part,the control variables are parameterized and the predictor-corrector algorithm is developed using the brain emotional learning based intelligence controller. 3) In the retargeting part, the trajectory is regenerated on-board and the LQR theory is employed for trajectory tracking. 4) The effectivity of the mixed guidance strategy is validated by simulations in conditions of the nominal case, the dispersed case, which consider deviations of reentry point parameters, air density, vehicle mass, lift coefficients and drag coefficients, and the target moving case. Comparing with the general predictor-corrector guidance method, the mixed guidance strategy has advantages in guidance precision and the time cost of trajectory predictionThe radar tracking performance for conventional reentry trajectory and the glide-reentry trajectory is studied respectively. Based on the Unscented Kalman Filter and target dynamics model, the tracking error considering the measure yawp of radar is calculated and the tracking performance is compared. The simulation results indicate that the glide-reentry trajectory excels the conventional trajectory in breaking the radar tracking.This dissertation has some theoretical significance in extending the research domain of current numerical trajectory optimization method, exploring a new idea of reentry guidance, and importing a new controller of intelligence control. The obtained properties and performance of glide-reentry trajectory based on theoretical researches are a good reference to the development of the new type of hypersonic glide-reentry vehicle in the future.