Dynamics model of airdrop process for air transportation cargo

In view of the status that the modeling condition of transport aircraft dynamic model in airdrop process for air transportation cargo was too much simplified, which was far away from the real airdrop project, the current airdrop process dynamic models and their applicabilities were systematic researched, and a separated-body modeling method was established.The forces of airdrop cargoes and aircraft were respectively analyzed without attention on the centroid of cargoes and aircraft, which simplified the modeling process and benefited the qualitative analysis of mechanism of the cargoes to the aircraft.In simulation experiment, the reasonability of dynamic model was verified by using the data of a certain-type transport aircraft.In order to verify the irrationality of small disturbance linearization of aerodynamic parameters, the aerodynamic parameters were processed through 3 modes, the corresponding curves of AOA were comparative analyzed.Under the conditions of different support forces, the application points of traction force, guide models, traction force angle models, and the loading positions of cargo, the built dynamic model of airdrop process was quantitative analyzed and compared with existed models.Simulation result shows that with the assumed conditions including the small disturbance linearization of aerodynamic parameters, assuming the cargoes with known motion law as particles, and ignoring the cabin angle, large model errors are introduced.In the missions of bigtraction ratio and heavy weight airdrop, the influence of the value and direction of traction force on the airdrop dynamic response should be considered.Furthermore, it is significant to install the cargoes near the cabin door of aircraft, which can shorten the moving time of cargoes and reduce the amplitude of interference torque.