| The research and application of parallel mechanism has been more and more widely and paid more and more attention,and the parallel mechanism with six degrees of freedom is studied most.However,the parallel mechanism with few degrees of freedom can give full play to its advantages in specific situations.Compared with the parallel mechanism with six degrees of freedom,the parallel mechanism with few degrees of freedom is easier to control and more stable in structure.At the same time,compared with the serial mechanism,the advantages of the parallel mechanism will be more obvious.But the parallel mechanism also has shortcomings,such as small workspace,difficulty in solving positive solutions,complex control and so on.This is also a problem that many scholars need to study and solve.Based on the research foundation of the majority of scholars in the field of mechanism,two kinds of four-degree-of-freedom parallel mechanisms were analyzed and studied.First of all,its configuration,kinematics and workspace were analyzed for the theoretical research.Afterwards,it was applied to the hydraulic support to form a parallel hydraulic support for actual surrounding rock coupling simulation.It not only provided a new way for the innovation and development of hydraulic support,but also provided reference for the feasibility of parallel hydraulic support.First,the degrees of freedom and azimuth feature sets of 2RPS/2SPS and 2RPC/2SPC parallel mechanisms were analyzed in detail.At the same time,the choice of mechanisms' driving pairs were also analyzed.Then,the coupling degree analysis was performed by using the principle of basic kinematic chain composition,and the coupling degree of the two mechanisms were obtained,which directly indicated the complexity of the two mechanisms.Second,the kinematics analysis of the parallel mechanism is one of the important research contents.The inverse positional solution equations were established through the space coordinate transformation equation and the closed vector method,and the forward positional solution analysis was performed by using the Newton iteration method.The first-order influence coefficient matrices were established by using the dummy mechanism method,and the numerical examples were verified by differential method and ADAMS simulation.The correctness of the first-order influence coefficient matrix was determined.Finally,based on ADAMS,the forward and inverse kinematics simulation of the two were performed in steady state,and the displacement,velocity,and acceleration curves of each component were obtained.Third,the numerical method was used to analyze the workspace of the two parallel mechanisms,and the analysis flowchart was drawn.The points of each workspace were obtained based on MATLAB.In order to further study the sensitivity characteristics of workspace,by changing the value range of each influencing factor and the change curve of the number of workspace points with each factor was obtained.Fourth,the two mechanisms were applied to the hydraulic support and the surrounding rock coupling model of the parallel hydraulic support was established.The static surrounding rock coupling analysis and the dynamic rigid-flex coupling analysis were performed based on ANSYS,and the deformation and stress diagrams of each component were obtained,as well as the maximum shape variable and maximum stress change curve of each component under the dynamic condition.In this paper,the configuration,kinematics and workspace of two parallel mechanisms with 2RPS/2SPS and 2RPC/2SPC were analyzed.And the new type of parallel hydraulic support was proposed,and its existence and feasibility were verified through the surrounding rock coupling simulation.At the same time,the new directions for the development of hydraulic support were expanded. |
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