Research On Modeling And Solving Rules And Performance Evaluation Of Constant Jacobi Mobile Parallel Mechanism

The mobile parallel mechanism with constant Jacobian matrix has the advantages of constant mapping relationship between input and output velocities,convenient control and high precision.Generally speaking,for most of these parallel mechanisms,we use the influence coefficient method to solve their kinematics and dynamics equations.If the solving process can be simplified to a certain extent,it will play an important role in giving full play to the advantages of the constant Jacobian matrix parallel mechanism and promoting the application of the constant Jacobian matrix parallel mechanism.Aiming at the mobile parallel mechanism with constant Jacobian matrix,this paper puts forward a simple modeling and solving law,and chooses typical mechanism for modeling and simulation verification.Finally,the influence of Jacobian matrix constant and local constant on kinematics and dynamics analysis of the mechanism is studied.The main research work is as follows:Firstly,the Jacobian matrix of the moving parallel mechanism with constant Jacobian matrix is solved based on the Jacobian matrix solution formula of the moving parallel mechanism,and the kinematics modeling and solving law of the inverse position solution equation of the moving parallel mechanism with constant Jacobian matrix is put forward by combining Solidworks software;the general solution of the dynamic equation of the moving parallel mechanism with constant Jacobian matrix based on the constant characteristic of Jacobian matrix and the influence coefficient method is given.In the process,the solving law of dynamic modeling for this kind of mechanism is put forward.Secondly,the degree of freedom and Jacobian matrix of symmetrical 3-CPR mechanism are analyzed as numerical examples.According to Jacobian matrix integral inverse position solution equation,the unknown parameters of position solution equation are obtained by combining Solidworks software,and compared with the results of vector method.The working space of the mechanism is drawn;the dynamics equation of mechanism is solved by using the above-mentioned dynamic modeling law in MATLAB software.And dynamic modeling and simulation verification are carried out.Thirdly,the asymmetric three-dimensional moving CRR-CPR-PPRR mechanism is taken as a numerical example for kinematics analysis and theoretical calculation to obtain the position solution equation,which is verified by comparison with the results of vector method;the three-dimensional workspace diagram of the mechanism is drawn;finally,the dynamic analysis is carried out,and the dynamic equation of the mechanism is solved by using the dynamic modeling method combined with MATLAB software,and the simulation experiment is carried out by Adams.Finally,the input selection of CRR-CPR-PPRR mechanism is analyzed,and the kinematics and dynamics characteristics of CRR-CPR-PPRR mechanism under Jacobian constant and local constant are compared and analyzed according to different input selection conditions.The kinematics and dynamics simulation analysis of different input combinations of CRR-CPR-PPRR mechanism under Adams environment is completed,and the displacement,velocity,acceleration and driving force curves of the mechanism are solved and compared.The influence of Jacobian matrix invariance and local invariance on kinematics and dynamics analysis of mechanism.