Research On Design And Dynamic Characteristics Of Comprehensive Mining Support Equipment With Parallel Mechanism

When the hydraulic support is dismantled,a triangle area will be formed between the end support and the support to be removed,which is the accident-prone place for removing the support.Currently,one or more methods of single hydraulic props,Ibeams,wooden pallets,and shield brackets are generally used for triangular support.However,the existing support methods have problems,such as the inability to adapt to the changing requirements of complex coal seams,low support strength,low production efficiency,and many safety hazards.Based on consulting a large amount of data on triangular support equipment and low degree of freedom parallel mechanisms.In response to issues such as insufficient support strength and weak stability of fully mechanized mining support equipment in environments with the pitched roof or complex changes in coal seam inclination,and combining the advantages of high stiffness,good dynamic performance,good adaptability,and simple structure of parallel mechanisms,that parallel mechanisms are applied to triangular support,and a comprehensive mining support equipment based on the parallel mechanism is formed.It is ensured that the comprehensive mining support equipment has good stiffness and stability.This thesis takes the fully mechanized mining support equipment based on the parallel mechanism as the research object.In order to ensure that the fully mechanized mining support equipment has good support performance under the complex environment with variable dip angle,and it is researched on kinematics,workspace,scale optimization,dynamics,statics and static stiffness.The contents are as follows:(1)A 2RPU-RPS configuration of fully mechanized mining support equipment is proposed,and the degree of freedom of the mechanism is calculated by utilizing screw theory and the modified "G-K" formula.The position of the parallel mechanism is analyzed.The inverse position is solved by coordinate transformation equations and closed vector method,and the forward position is calculated by particle swarm optimization.The model is established and imported into ADAMS,and the degree of freedom is verified.Inverse kinematics solution simulation is carried out and compared with the theoretical simulation results in MATLAB.Forward kinematics solution simulation is carried out in ADAMS.It is proved that the movement trajectory of the top beam of the 2RPU-RPS parallel support equipment can adapt to the coal seam roof under the condition of uneven roof and variable dip angle,and this equipment has good support performance for the triangular working face.(2)The number of workspace point sets is searched by using the boundary numerical search method that meets the constraint conditions.The Control variates are used to analyze the influence of the size parameters of the mechanism on the workspace of the parallel mechanism.The institutional workspace is seted as the optimization objective,and a scale optimization objective function and constraint conditions are established.This thesis uses particle swarm optimization to obtain a set of optimal parameters for institutional size,and the resulting workspace has increased compared to the empirical size.The analysis of the workspace can provide reference for the design of the roof workspace on the 2RPU-RPS parallel support equipment in the future.(3)The Newton Euler method method is utilited to analyze the dynamics of the fully mechanized mining support equipment based on the parallel mechanism.This thesis establishs branch chain dynamics equations and dynamic platform dynamics equations by using Newton Euler equations.This thesis uses MATLAB and ADAMS to simulate the fully mechanized mining support equipment based on parallel mechanisms,and obtains the variation curves of the driving force and constraint torque of the support chain.It is proved that the 2RPU-RPS parallel support equipment under the working pressure of the coal seam roof has good stability and reliability,and meeting the requirements for triangular support use.(4)The statics analysis of the fully mechanized mining support equipment based on the parallel mechanism is carried out by using the bar splitting method,and all the statics equations are obtained.Statics simulation is carried out through MATLAB and ANSYS.Static stiffness analysis is conducted on the parallel mechanisms and a static stiffness model is established.This thesis uses ANSYS software to stress and static stiffness analysis,and it is shown that the stiffness of the mechanism meets the usage requirements.Finally,modal analysis,prestressed modal analysis,and transient dynamic analysis were conducted on the mechanism,that provides good theoretical support for the physical design of the 2RPU-RPS parallel support equipment.It is proved that the 2RPU-RPS parallel support equipment has good statics and stiffness performance under complex conditions.This thesis has 77 figures,12 tables and 108 references.