Analysis And Design Of Plane Three-degree-of-freedom Parallel Mechanism

The three degree of freedom planar parallel mechanism has attracted more and more attention due to its simple structure,strong load capacity and low manufacturing cost.This paper analyzes the structure principle,kinematics,and accuracy of a new type of planar three-degree-of-freedom parallel mechanism for rod space layout,and designs corresponding parameters based on the workspace.According to the structural characteristics of the mechanism,the number and properties of the degree of freedom of mechanism are analyzed.By changing the number and arrangement of the rod in the mechanism,a variety of evolution structures are proposed.Finally,the motion characteristics of the mechanism are verified by software simulationA mathematical model for the positive and negative solutions of a planar three degree of freedom parallel mechanism is established by using the virtual mechanism method.The position positive solution of the mechanism is obtained by the Jacobi matrix method.On the basis of position analysis,the velocity,acceleration and singular position of the mechanism are analyzed.By establishing the mathematical model,the relationship between the structural parameters of the mechanism and the working space of the mechanism was analyzed.On the basis of the structural parameters,the working space of the mechanism is solved by combining the constraints of the stroke limitation of the input slider and the constraints of the ball hinge angle.The influence of the elastic deformation error of the connecting rod,the force and deformation error of the ball screw,the manufacturing error of the connecting rod,the clearance error of the hinge and the driving error of motor on the accuracy of the mechanism are analyzed.By establishing the force balance equation of the mechanism,the influence of the elastic deformation error of the connecting rod and the deformation error of the ball screw pair on the mechanism accuracy is analyzed.The influence of the machining error,the hinges gap error and the motor driving error on the mechanism precision is analyzed by the Monte Carlo error analysis method.