Study Of Some Key Problems On Helicopter Emergency Dipping Water Experiment

No matter on military and civilian applications, the study of helicopter emergency dipping water has a practical engineering background. In China about this aspect is still in the blank at present. In view of the test device development of the helicopter and water balloon emergency dipping water,in order to reduce cost, to improve test accuracy, to solve the research key-problems of test equipment development, this paper makes a further research of the technical scheme about the test device.According to the discussion on emergency dipping water experiment,analysis and determine the key problems of the helicopter emergency dipping water experiment The first is the attitude control and maintain of the model elevation and yaw angle and the control of model attitude change of the release process; the second is the impact of fluid-structure interaction of model dipping water; the third is how to control the horizontal speed synchronization of car and the model after the model release. Then makes a deep analysis and research on each of these problems.Firstly, this paper designes the attitude controlling structure of model dipping water according to the test requirements, and solves the attitude control and adjustment problems on helicopter emergency dipping water experiment. Emphatically analysises the influences of the force-bearing point and the mass center bias to the model attitude. Mass center displacement curve and angle change curve are obtained by using MATLAB software, and quantitatively analysises the influence about the different value of e and(?)(0) to the model attitude.Secondly, a simplified treatment about helicopter emergency dipping water problem is made in combination of test requirements. An analysis at the same condition is carried by using theoretical methods and based on ANSYS/LS-DYNA numerical method respectively, and the horizontal speed curve and acceleration curve of the helicopter and balloon. Then the reasons of the error about the theoretical analysis and numerical calculation. The influence degree of the horizontal speed of the helicopter and balloon for the elevation angle,yaw angle and vertical speed are analyzed according to three groups of comparing calculation. These researches provide evidence to the study on horizontal speed synchronization control of the trolley car.Lastly, a general method of the speed synchronization control of the trolley car is presented. The original speed signal curve is generated from the simulation curve by test amendment, after sampling switch sampling, discretization, the control signals is called according to the specific condition,to restore and reconstruct them.In summary,this paper analyses and commences to solve several key-problems in the process of experiment according to the demands of helicopter emergency dipping water experiment. It provides a theoretical guidance to the development of the test device,which has an important research value and practical significance.