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Wang X.-P.,Shanghai Electro Mechanical Engineering Institute
Jisuan Lixue Xuebao/Chinese Journal of Computational Mechanics | Year: 2013

Several separation trajectories of statically unstable air-to-air missile by rail launch were computed by combination of flow simulation based on N-S equations solver with 6-DOF motion equations of missile and control law. The computational results show that the pitching angles and the yawing angles of missile change rapidly, even the rolling angles are divergent quickly, due to the lateral aerodynamic interference from the aircraft, if no control strategy is adopted. While attitude control is introduced, missile attitudes during the separation from aircraft are steady, and safety on aircraft is greatly improved.

Xie L.,Northwestern Polytechnical University | Xu M.,Northwestern Polytechnical University | An X.,Northwestern Polytechnical University | Cai T.,Shanghai Electro Mechanical Engineering Institute | Chen W.,Northwestern Polytechnical University
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2013

To carry out research of nonlinear aeroelasticity, this paper presents a nonlinear time-domain aeroelastic simulation program which adopts computational fluid dynamics/computational structural dynamics (CFD/CSD) couple method. The program couples the nonlinear structural finite element software NASTRAN with a multi-block structured grid-based CFD solver developed by myself. Radial basis function (RBF) is used to transfer information between the two solvers and deform grid. To improve the efficiency of the RBF method, a space point reduction algorithm based on multi-level interpolation is constructed. For the purpose of reducing the number of space points, the interpolation object of each interpolation step is the error of previous step, and interpolation region is limited simultaneously. Results of some mesh deformation examples show that this way can support the movement of large deformation with high computational efficiency. With the use of this program, flutter computation of AGARD 445.6 wing is completed, static aeroelastic computation of a wing with a large aspect ratio is performed and a dynamic aeroelastic simulation of limit-cycle-oscillation (LCO) of a cropped delta wing is carried out. Results demonstrate that structural nonlinearity has strong influences on aeroelastic phenomenas when the aspect ratio of the wing is large or the amplitude of response is great.

Hui F.,University of Jinan | Qin F.,Shanghai Electro Mechanical Engineering Institute
Proceedings - 2016 8th International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2016 | Year: 2016

Most global navigation satellite system (GNSS) receivers cannot work in high dynamic scenarios because of poor navigation satellite acquisition in these environments. Hence, inertial navigation system (INS) is used to aid the GNSS signal acquisition and improve the acquisition capability of the receivers. In this paper, an ultra-tight integration system using the low-cost IMU is proposed to achieve navigation for high dynamic applications. To verify the effectiveness of the ultra-tight integration, an experiment system is built and a high dynamic scenario is simulated. The results prove that the designed ultra-tight integration system has perfect tracking and navigation performances for high dynamic applications. © 2016 IEEE.

Hui F.,University of Jinan | Qin F.,Shanghai Electro Mechanical Engineering Institute
Proceedings - 2016 8th International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2016 | Year: 2016

In GNSS/INS navigation integrated systems, the selection of inertial sensors is a factor which can impact their system performances implicitly. Unfortunately, the research of the relationship between the inertial sensor errors and the navigation performances is not sufficient yet. In this case, the mathematical relationship between the sensor quality and the INS (Inertial Navigation System) performance is firstly derived in details based on a 6 DOF (Degree of Freedom) model. Since the INS is a part of the GNSS/INS system, the influence of the sensor errors on the total performance is further analyzed. By simulating an integrated system using three different grade IMUs (Inertial Measurement Units), the influence mechanism is proved. © 2016 IEEE.

Zhang J.,Jiangsu University | Zhao D.-A.,Jiangsu University | Wang M.,Shanghai Electro Mechanical Engineering Institute
Yuhang Xuebao/Journal of Astronautics | Year: 2011

A robust decoupling control method is presented for nonlinear attitude dynamics of hypersonic vehicle with model uncertainties and external disturbances. The dynamics is separated into fast loop and slow loop as attitude angular velocity and attitude angle in terms of the singular perturbation theory. In the outer-loop, the simple analytical control law based on second order model reference adaptive control theory is used to suppress the coupling of attitude kinematics and external disturbances without inverse operation. In the inner-loop system, the affine control with tight couping aerodynamic coefficients is used, control vector is solved explicitly by nonlinear dynamic inverse, the desired dynamics is in proportional plus integral dynamics form, trajectory linearization-aided time-varying controller is designed based on model predictive control policy with input constraint, to improve system robustness. Lastly, simulation result demonstrates effectiveness of the proposed method.

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