Dynamic Analysis And Structural Optimization Of Adaptive Landing Gear Based On Cable Drive

Helicopters are widely used in transportation,combat,disaster area rescue,and other tasks because of their characteristics of generating lift in a short distance.With the development of the economy and technology,rotorcraft are gradually miniaturized and living and play a wider and wider role in civil fields such as logistics and distribution,seeding,and dispersal.However,the existing helicopter landing gear has limited attitude adjustment capability and can only take off and land on flat ground,which is difficult to adapt to the rugged,slope and real-time swaying dynamic ship surface,which greatly reduces the safety of landing operation and the efficiency of mission execution,so the development of landing gear with terrain adaptability has important engineering and application value.In this thesis,a cable-driven adaptive landing gear is designed based on the UAV landing gear,and the motion space,buffering efficiency,and landing performance of the landing gear are investigated.The main research contents are as follows:(1)By analyzing the current status of landing gear research and the landing characteristics of UAVs,the landing gear landing process planning is carried out for the cable-driven adaptive landing gear.(2)Forward and reverse kinematic theoretical analysis of the adaptive landing gear to determine whether it meets the design requirements of the adaptive landing gear motion space,and establish a virtual prototype kinematic model for analysis and verification.(3)A virtual prototype dynamics model was constructed and the following three aspects were studied.Firstly,the impact of pulley layout and friction between ropes and wheels on the driving torque during adaptive landing gear cable drive was studied,and the optimal design and selection scheme was determined;Secondly,through landing gear shock simulation,the influence of landing gear buffer stiffness and damping coefficient on buffering efficiency was studied,and the optimal stiffness and damping coefficient of landing gear buffer were determined.The buffering efficiency of the landing gear was evaluated using the system power method;Finally,in order to test the landing stability of the landing gear,rough and inclined ground landing simulations were conducted on the virtual prototype of the landing gear,verifying its good adaptability to complex terrain.(4)In order to reduce the overall mass of the landing gear and improve the endurance of the vehicle,the lightweight design of the components is based on the topology optimization method.Firstly,the inertia release method is used to strength-check the components and determine the stress redundancy of the key components of the landing gear.Secondly,the Optistruct module of Hypermesh was used to optimize the topology of the component by combining the location of the stress redundancy and the functional requirements of the component.(5)The landing gear prototype was tested with different landing masses and landing speeds,and the error between the test and simulation results was within 10%,indicating the reasonableness of the virtual prototype construction and buffer efficiency calculation;the landing gear was tested on rugged and inclined surfaces to verify the good terrain adaptability and landing stability of this type of landing gear.