Study Of Support Platform On Airplane Wings For Damaged Aircraft Trailer

Damaged Aircraft Trailer(DAT) is important equipment in the airport rescuing, the support platform for aircraft wing is an important component of DAT, which plays a role in lifting aircraft and fixing wings. A new type of support platform for aircraft wing is designed in this paper, its main structure consists of an assembled platform and lots of 3-PRS parallel mechanism. The platform has an advantage of higher fit with the curved surface of the wings.In this paper, dimensional synthesis of 3-PRS parallel mechanism, statics, static stiffness analysis, design and selection of main structure, and the finite element analysis of overall structure are researched. The specific content is as follow:Dimensional synthesis of parallel mechanism. The support platform for aircraft wing which is composed of many 3-PRS parallel mechanisms is designed. Based on the established kinematics model, the static jacobian matrix is researched. When load changes, a static performance evaluation index is proposed for minimizing the maximum mean of driving force and constraint force. The static performance of parallel mechanism and the changing rules of constraint conditions with scale parameters are researched by using the method of monotonicity analysis, at last the optimal scale parameters are found in an example.Research on statics and static stiffness of parallel mechanism. Changing rules of driving force of every branched chain in parallel mechanism in the mobile platform movement space are analyzed by using force transfer matrix. Through force analysis of the connecting rod and mobile platform, the transitive relation between the constraint forces in revolute and spherical joint and the external force in the platform is solved, the changing rule of constraint force in movement space is analyzed. Finally, the stiffness matrix of parallel mechanism with constraint force considered is derived using hypothetical mechanism method.Design and selection of main structure. Utilizing the transfer relationship between the driving force and external force, the hydraulic cylinder model is selected and the corresponding dimensions and performance parameters are obtained. In order to meet the requirement of corresponding strength, the combined hinge instead of spherical joint is designed through the analysis of constraint force. Based on the result of dimensional synthesis,the structural design of PRS branched chain and the mobile platform in parallel mechanism is completed. At last the 3D model of support platform for aircraft wing is obtained.The finite element analysis of parallel mechanism. The finite element modeling of parallel mechanism is completed by using the finite element software. According to the actual working condition the direction and magnitude of force are chose, and the effect of hydraulic cylinder elongation on the overall stiffness is analyzed when the mobile platform is in the horizontal posture. Meanwhile the influence of the external force in three directions on the overall stiffness is also analyzed when the mobile is at the limit angle position. Finally,parallel mechanism is proved to satisfy the corresponding stiffness requirements. It provides suggestions for the installation of the support platform for aircraft wing in practical application.