Design And Simulation Of Plateau Cushion Vegetation Collection Mechanism

There are some scattered alpine cushion vegetation with high scientific research value in the plateau area.However,due to the severe environment of the plateau,the complex terrain,the harsh and changeable climate,and the uneven distribution of cushion vegetation,the collection of cushion vegetation is facing great difficulties.Traditional collection mechanisms are basically used in flat,regular and single-controllable agricultural sites,and it is difficult to complete the plateau cushion vegetation collection requirements.Based on this,a cushion vegetation collecting mechanism suspended under the drone is developed in this subject.The collecting mechanism adopts a 3 DOF parallel mechanism and a space-continuous flexible robotic arm,and each carries a gripper.The two mechanisms are used together to complement each other,and are used to realize the cushion vegetation grabbing function of the harsh plateau environment.First,according to the use requirements and technical indicators of the plateau cushion vegetation collection mechanism,the structural design of the relevant mechanical system was carried out.The parallel cushion vegetation collecting mechanism and the space continuous cushion vegetation collecting mechanism are designed.The structural design schemes of the main components of the two collection mechanisms are introduced in detail.Secondly,the kinematics analysis of the plateau cushion vegetation collection mechanism was carried out.First,the forward and inverse kinematics modeling,position analysis and numerical solution of the parallel vegetation collection mechanism were performed.The forward and inverse kinematics of the single-joint and three-joint segments were analyzed respectively,focusing on the kinematic coupling relationship and decoupling between the three-segment joints.Based on this,a numerical algorithm for inverse kinematics solutions was proposed.In MATLAB environment,the forward and inverse kinematics of the single-joint and three-joint segments of the spatial continuous vegetation collection mechanism were simulated and verified.The experimental results verified the feasibility and effectiveness of the forward and inverse kinematics derivation and the proposed algorithm.Finally,combined with the improved Monte Carlo method,the workspaces of the single-joint flexible arm and the three-joint flexible arm were simulated and analyzed respectively.The results show that the reachable workspace of the three-joint flexible arm issignificantly increased and the working capacity is significantly enhanced.Third,the finite element analysis software Workbench was used to analyze the static stiffness and modal analysis of the main structure of the plateau cushion vegetation collection mechanism.The static stiffness analysis shows that the parallel mechanism has better rigidity than the continuous flexible arm,but the flexibility is slightly worse.The modal analysis shows that compared with the parallel mechanism,the continuous flexible arm is slightly less resistant to vibration and deformation.Therefore,it is possible to strengthen the static platform of the parallel mechanism or the chassis of the flexible arm,appropriately increase the cross-sectional area of the driven rod or the flexible pillar,improve the material selection of the driven rod or the flexible pillar,improve the link stiffness between the moving platform and the driven rod or between the supporting discs.These methods can further improve the performance of the plateau cushion vegetation collection mechanism.Finally,ADAMS software and MATLAB software were used to simulate and analyze the kinematics and dynamic characteristics of the designed plateau cushion vegetation collection mechanism.The simulation data results show that the positions,speeds,and acceleration simulation curves of the two mechanisms are generally consistent with theoretical expectations,which can verify the correctness of Chapter 3kinematics theoretical analysis and ADAMS modeling.Through comparison,it is found that the speed and acceleration peaks of the continuous flexible arm are much higher than the parallel mechanism,and the efficiency may be higher in the actual cushion vegetation collection process,but the requirements and control of the motor are also more complicated.During the entire simulation process,no singularity appeared,and it can be preliminarily judged that the designed cushion vegetation collection mechanism has good motion performance.Finally,the positional precision test and bending rotation test of the principle prototype of the space continuous cushion vegetation collection mechanism were carried out.The results show that the prototype can basically meet the accuracy requirements of the cushion vegetation collection task,and the prototype has flexible bending rotation performance,which is better satisfy the task of gathering the cushion vegetation growing in a small hidden area.