Research On Kinematic Performance And Simulation Of A Spatial Three-translation Parallel Mechanism

Three-degree-of-freedom parallel mechanism is one of the important branches of parallel mechanisms.Compared with six-degree-of-freedom parallel mechanism,this kind of parallel mechanism has the advantages of small movement limbs,high carrying capacity and easy control.Three-degree-of-freedom parallel mechanisms are widely used in microelectronics,high precision machining,medical machinery and other fields.This paper takes spatial 3-PRC three-translation parallel mechanism as the research object.The kinematics,dynamics and virtual prototype simulation of the 3-PRC parallel mechanism are mainly studied.Firstly,the degree of freedom of 3-PRC parallel mechanism is analyzed based on screw theory.Three-dimensional translation movements of the moving platform of 3-PRC parallel mechanism are verified.The position positive solution equation and inverse solution equation are established according to the geometric constraint relationship of 3-PRC parallel mechanism.N umerical examples verify the correctness of the positive and inverse solutions of the position.Based on the solutions of the position,the variation laws of velocity and acceleration are analyzed using the method of kinematic influence coefficients.The singularities are also analyzed by using the Jacobian algebra method.The position relations among the links are obtained when positive singularity and reverse singularity occur.Secondly,the work space of 3-PRC parallel mechanism is searched using numerical search method based on position inverse solution and geometric constraint conditions.The motion simulation is carried out using SimMechanics module of MATLAB.The correctness of the workspace solution is verified.Finally,the influence of the angle between the driving rod and the static platform on the workspace is analyzed.Thirdly,the particle system and the Kane equation of rigid body are established using Kane equation method.The generalized velocity and partial velocity of each link of 3-PRC parallel mechanism are obtained by dynamics modeling.The dynamic Kane equation of 3-PRC parallel mechanism is established.Fourthly,the virtual prototype model of 3-PRC parallel mechanism is created using 3D modeling Pro/E and ADAMS software.The kinematics of 3-PRC parallel mechanism is simulated.The ADAMS post-processing module is used to measure the variations of displacement,velocity and acceleration of the terminal reference point of the moving platform.The dynamics is simulated of 3-PRC parallel mechanism.The variation of the consumed power and the driving forces are obtained.The results can provide theoretical guidance for selection of the motor.Finally,the finite element analysis of 3-PRC parallel mechanism is carried out using Pro/E and ANSYS Workbench software.The biggest part of deformation and stress suffered are determined when the moving platform is in two kinds of positions and orientations.The weak places of the whole structure are found.