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Yan X.-D.,Northwestern Polytechnical University | Yan X.-D.,National Key Laboratory of Aerospace Flight Dynamics | Wang Z.,Northwestern Polytechnical University
Beijing Ligong Daxue Xuebao/Transaction of Beijing Institute of Technology | Year: 2013

It's an effective way to improve the guidance adaptability for hypersonic glide vehicle (HGV) by applying trajectory planning. First, the target plane coordinate frame was defined. Then, taking the coordinate frame as the reference coordinate frame, dynamic equations with the normalized energy as independent variable were deduced, which have the advantages of fixed integral interval, and cross-range and longitudinal range could be denoted by the equation states. Based on the equations, longitudinal trajectory planning method was put forward as well as lateral trajectory planning method. With the combination of above methods and the trajectory of lateral curvature, a three-dimensional trajectory planning method has been implemented. It is shown that the proposed method can fulfill trajectory planning for HGV rapidly and accurately. Source

Yan X.-D.,Northwestern Polytechnical University | Yan X.-D.,National Key Laboratory of Aerospace Flight Dynamics | Jia X.-J.,Northwestern Polytechnical University | Lv S.,Northwestern Polytechnical University
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2013

Rocket based combined cycle (RBCC) powered vehicles generally climb with constant dynamic pressure at ascent stage in order to provide an optimal or steady condition for the propulsion system. An algebraic equation of height and velocity for constant dynamic pressure climbing was derived. The algebraic equation was used to plan and generate the reference trajectory. Then, a guidance law tracking the reference trajectory was derived via feedback linearization method. Based on the above, the guidance method of constant dynamic pressure climbing for ascent stage of RBCC powered vehicle was implemented. The simulation results show that the method is able to generate the command of attack angle in real-time and complete constant dynamic pressure climbing accurately. Furthermore, the method provides an ascent trajectory design and guidance method for air breathing aerospace vehicle. Source

Fang Q.,Northwestern Polytechnical University | Fang Q.,National Key Laboratory of Aerospace Flight Dynamics | Wang X.,Northwestern Polytechnical University | Wang X.,National Key Laboratory of Aerospace Flight Dynamics
Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University | Year: 2014

Based on the feedback linearization control and the on-line radical base function (RBF) neural network, we design an adaptive BTT missile flight controller. With the on-line weighted value updating algorithm we proposed, the on-line RBF neural network can compensate for uncertainties and disturbances of the BTT missile flight control system through approximating its dynamic inversion errors, thus effectively reducing the coupling of its channels and the inaccuracy of its mathematical model. We simulate the adaptive BTT missile flight controller thus designed; the simulation results, and their comparison, show preliminarily that, compared with the flight control system based on feedback linearization control, the flight controller we designed is more robust and effective for tracking the desired information on angular command. Source

Deng Y.,Northwestern Polytechnical University | Deng Y.,National Key Laboratory of Aerospace Flight Dynamics | Li C.,China Aerospace Science and Technology Corporation | Wang Z.,Northwestern Polytechnical University | Wang Z.,National Key Laboratory of Aerospace Flight Dynamics
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2015

An adapted iterative guidance algorithm is researched for the orbit transfer mission of spacecraft. Based on the traditional iterative guidance method, we directly found the optimal control model on the geocentric inertial frame, use the orient vector of the thrust as the control variable to adapt for the significantly change of attitude angel, found the boundary conditions by using the target orbital elements directly as the terminal constraints, obtain the relationship between the accuracy of the solutions of the constraint equations and the injection accuracy, and then present a concise and effective iterative guidance algorithm using orbital elements as terminal constraints for spacecraft orbit transfer. Numerical simulations have demonstrated the effectiveness and better adaptability than the traditional method. ©, 2015, AAAS Press of Chinese Society of Aeronautics and Astronautics. All right reserved. Source

Wang Z.G.,Northwestern Polytechnical University | Wang Z.G.,National Key Laboratory of Aerospace Flight Dynamics | Zhang N.,Northwestern Polytechnical University | Zhang N.,National Key Laboratory of Aerospace Flight Dynamics
Applied Mechanics and Materials | Year: 2013

Since the traditional parabola trajectory is prone to be head off, wavy trajectory has the flight characteristics of defense penetration ability and increasing range. On the basis of flight characteristics of wavy trajectory missile, a method for flight program angle was designed. A specific formula was given. An optimization model was established. A conjugate gradient optimizing algorithm was used to solve the model and the result is compared with the former trajectory. It shows that optimized wavy trajectory can prove the feasibility of increasing range and valid defense penetration ability. © (2013) Trans Tech Publications, Switzerland. Source

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