Huang P.,Zhejiang University |
Wang Q.,Zhejiang University |
Li J.,Zhejiang University |
Ke Y.,Zhejiang University |
Zhang C.,The Military Representative Office of PLA Residing in Xian Aircraft Company
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2014
To improve the safety and reduce the impact on the sensitive direction in an aircraft component trajectory adjustment system, the trajectory of a large component is optimized by a dynamics model of the adjustment system. This model is derived by the Newton-Euler method, and takes into account the rod deformation, screw movement error and deformation in the NC locator. It can evaluate the kinematic characteristics of the component with different movement trajectories. In order to improve the efficiency and reduce the amount of computation in the optimization process, an adaptive kernel principal component analysis algorithm with optimal separability between classes is proposed in combination with pattern recognition methods to predict the performance of feasible trajectories to control the scope of the search. The effectiveness of the proposed method is verified by an example of an adjustment system. After evaluation of 150 feasible trajectories, the maximum translational velocity of the large component during the adjustment process is less than 20 mm/s, and the maximum angular velocity at the end of the adjustment process is less than 0.1 rad/s.
Jing J.-P.,Nanjing University of Aeronautics and Astronautics |
Jing J.-P.,The Military Representative Office of PLA Residing in Xian Aircraft Company |
Guo R.-W.,Nanjing University of Aeronautics and Astronautics |
Sun X.-P.,The Military Representative Office of PLA Residing in Xian Aircraft Company |
He W.,The Military Representative Office of PLA Residing in Xian Aircraft Company
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2012
Experiment of a Ma 4 chin inlet with mixed-compression had been done, the pneumatic performance of the inlet was obtained. The results showed that: (1) When Ma=3.5, angle of attack and angle of yaw are both 0 degree, the total pressure recovery coefficient increased at first and then decreased with the increasing of back-pressure, the total pressure recovery coefficient got its maximum at the critical state. (2) Under the critical states of angle of attack and angle of yaw are both 0 degree. The total pressure recovery of inlet decreased linearly with the increasing of flight mach number. (3) The inlet performance declined under pitch or yaw conditions. (4) The inlet has restarting character in the unstart process caused by back-pressure, phenomenon of hysteresis is not obtained in the loop from start to restart induced by the back pressure during the mass adjustor moving forward/backward process (AFBP).