Design And Analysis Of Adaptive And Robotic Landing Gear Of Helicopter

Helicopter has been widely used in combat,rescue,exploration,tourism and other fields due to its unique characteristics of good flexibilit y,strong maneuverabilit y,high concealment,wide range of activities and abilit y t o take off and land vertically.Although the helicopter has the advantages described above,the ground requirements for landing are very high.At present,most of the helicopters in the world need stable and flat ground when landing.When performing missions under complex terrain,most of them are hovering to transport personnel or airdrop materials,which may cause damage to personnel or materials.If an emergency landing,it may cause irreversible damage to the helicopter.Therefore,in order to solve the difficult problem of helicopter landing on the complex ground,this paper designs a helicopter adaptive robotic landing gear which can land on the complex terrain.The main research work and conclusions are as follows:Firstly,according to the helicopter landing requirements,a four-point landing gear layout that can better adapt to the terrain was selected;a four-leg hinge structure landing gear capable of adapting to the terrain was designed;and the hydraulic circuit of the landing gear system was designed.The parameters of the buffer system are given.Then,according to the mechanical structure and hydraulic system of the helicopter's adaptive robotic landing gear,the forward and reverse kinematics analysis of the helicopter landing gear was carried out,and according to the forward kinematics analysis,the working space of the single leg was analyzed by the Monte Carlo method;The helicopter body dynamics model was constructed,and the single-leg dynamics model of the landing gear was established using the Lagrangian method,and the dynamics characteristics of the landing gear system were analyzed;the damping force model and the ground contact force model in the buffer stage were given.Finally,according to the helicopter landing process,the landing gear landing control strategy is given.The entire landing process is divided into two stages: the first stage is the pre-adjustment stage of the landing gear under the helicopter hovering state;the second stage is the helicopter landing and buffer stage.For the first stage of the landing process,a cont rol strategy was designed in combination with the earth observation technology,inertial navigation and attitude measurement techno logy and PID control method,so that the landing gear can be adjusted as expected;then for the second stage of the landing p rocess,combined with Passive-off and The Passive-on control method designed a variable damping control strategy to enable the helicopter to successfully complete the buffer landing stage;finally,Adams were used for simulation to verify the effectiveness of the control strategy and the feasibility of the adaptive machine landing gear system.The results show that the helicopter adaptive robotic landing gear studied in this paper can make the helicopter land in complex terrain.Therefore,this landing gear system can broaden the application field of the helicopter and has great application potential in the field of helicopter.