Design And Research Of Mining Shovel Excavating Mechanism

As the mainstream mining equipment in open-pit mining,electric shovels are mainly used for the stripping and loading of ore materials,with broad development space.Although traditional two degree of freedom electric shovels have advantages such as high operating efficiency and adaptability to harsh mining environments,they also have drawbacks such as clumsy excavation actions,low full bucket rate,and high energy consumption.Therefore,this thesis relies on the key support project of the National Natural Science Foundation of China: Research on Collaborative Design and Intelligent Operation of Large Mining Shovel Suitable for Complex Environments(project number: U21A20125),A new three degree of freedom mining mechanism is proposed,and its kinematics and dynamics are analyzed.Simulation analysis is carried out in ADAMS,and a small test bench is built to complete relevant experiments,which establishes the foundation for the subsequent research and development of physical prototype.The specific work completed in this thesis is as follows:(1)Analyze the traditional mining shovel excavation device and propose new design goals;Based on topological graph theory,a new type of mining mechanism configuration is obtained using the linkage class matching synthesis method;Determine the final configuration through screening conditions and draw a schematic diagram of the mechanism through specific transformation of the kinematic chain;Analyzed the structural composition and different operating conditions of the excavation mechanism;(2)Based on the closed loop vector method,the kinematics model of the mining mechanism is established,and the forward and inverse solutions of the pose,velocity and acceleration of the mechanism are obtained;Conduct singularity analysis on the mining mechanism to obtain the corresponding singularity positions;The working spatial analysis of the mining mechanism is analyzed,and the boundary conditions of the working space are obtained according to the existence theorem of implicit function;By using scale synthesis to determine a set of size parameters that meet the operating conditions,the correctness of the mechanism motion model was verified using MATLAB programming,and the workspace of the mining mechanism was obtained;(3)Analyze the centroid coordinates,centroid velocity,and centroid acceleration of each member;Analyze the excavation resistance in the excavation conditions and calculate the maximum excavation resistance based on empirical formulas;The dynamic statics model of the mining mechanism is established based on the dynamic static method,and the force balance equation of each link is obtained;List the motor power expression to provide a theoretical basis for the subsequent development of the prototype;(4)Based on ADAMS,the kinematics and dynamics simulation analysis of the mining mechanism is carried out,and the displacement,velocity and acceleration curves of the output reference point and the driving torque curves of each active link are obtained;Build a small experimental platform and introduce the hardware composition and software program of the platform;The rationality and feasibility of the new excavation mechanism were verified through excavation experiments under no load conditions.This thesis has 78 figures,17 tables and 111 references.