Elastic Dynamics Analysis And Optimization Design Of 3-RUU Parallel Mechanism

3-RUU parallel mechanism compared to DELTA mechanism,with a smaller inertia,have advantages in high-speed operations.However,after the lightweight design of the 3-RUU mechanism,the elastic deformation of the bar and the hinge is larger,which seriously affects the positioning accuracy of the end effector.Therefore,this subject supported by the National Science and Technology Support Program is to research the elastic dynamics of the 3-RUU mechanism and apply the research results to the lightweight and high stiffness design of the 3-RUU parallel robot.The specific research contents are as follows.The research on Kinematics and Workspace of 3-RUU Mechanism.As the basic work of the research on dynamics,the inverse kinematics and working space of 3-RUU parallel robot are studied.The inverse and format kinematics of 3-RUU mechanism are obtained by coordinate transformation and geometric method.The mathematical model of 3-RUU parallel robot is established,and the Jacobi matrix condition number is solved.It is found that the driving and driven arms' parameters the distance between the static and moving platform has a significant effect on the workspace.Increasing the length of the arm can significantly increase the workspace,but it will also bring about the problem in driving torque increase and the stiffness decrease.In the dynamic analysis,the Lagrange equation is used to analyze the multi-rigid body inverse dynamics of the 3-RUU mechanism.On this basis,the finite element elastic dynamic model of each sub-structure is obtained by the sub-structure modeling method.Finally,by integrating kinematics and dynamic constraints,we assembly of the system elastic dynamics model.In this modeling method,the method to converting the Hank hinge dynamics into kinematic constraints is put forward to make the model more simplified.In the aspect of optimization design,combined with the configuration characteristics of 3-RUU parallel mechanism,the parameters of the driving and driven arms and the quality of the moving platform are chosen as the main optimization objects.The robot's natural frequency is optimized as the optimization target and the joint torque is used as the constraint condition,Using the dynamic characteristics and dynamic analysis to work out the mechanism's optimal design.Respectively,considering of the mechanism's driving joint torque limit,the sensitivity of the parameters for the natural frequency of the system was given.Based on the design process of the robot,the rigid body dynamics and the soft body dynamics modeling are carried out.Combined with the CAE software,the optimal design of the mechanism is obtained,and a set of optima l parameters under the given constraints are obtained.After simulation analysis,Dynamic analysis results and optimization of the effectiveness of the design results is verified.