Performance Analysis And Optimization Design Of 2-R (SS) ₂-R (RR) ₂ (RR) ₂ High-speed Parallel Robo

In this paper,closely combining the needs of high-speed material handling,picking and placement of materials in the automated production lines of food,medicine and other light industries,a new type of 2-R(SS)2-R(RR)2(RR)2 new horizontal high-speed parallel robot mechanism is invented,and take the robot mechanism to systematically study its kinematics and dynamics modeling and analysis,trajectory planning,integrated optimization design and other issues.The main results of the full text are as follows:In terms of kinematics modeling and analysis: complete the degree of freedom analysis of the 2-R(SS)2-R(RR)2(RR)2 new horizontal parallel mechanism with the help of displacement subgroups;use the vector method to establish the kinematics inverse solution model,Two types of kinematic performance evaluation indicators,namely the pressure angle within the chain and the pressure angle between the chains,which can reflect the singular characteristics of the mechanism,are proposed,and the influence of scale parameters on the kinematic performance is revealed;the limit work of the mechanism is completed based on geometric interference conditions and kinematic performance constraints Space search and task space planning lay the foundation for optimized design later.In terms of dynamic modeling and analysis: the rigid body dynamics model is established using the principle of virtual work,and the driving torque is divided into three performance indicators of inertia,speed and gravity,and the inertia based on the global maximum value of the single-axis driving torque is proposed.The three components of,velocity,and gravity are used as dynamic performance evaluation indicators,which reveals the change law of the three types of dynamic performance with scale parameters,and completes the preliminary screening of scale parameters based on this.The natural frequency analysis model is established based on Ansys workbench,and the distribution law of the low-order natural frequencies of the mechanism is revealed in the working space.Based on this,the first-order frequency of the mechanism at the middle position is selected as the elastodynamic performance evaluation index.Combined with Solid Works and Ansys workbench,a structure size parameterized model was established,which can be used to solve the next-order natural frequency of different structure parameters,laying the foundation for the integrated optimization design of the design parameters later.In terms of trajectory planning: Based on the motion law of 3-4-5 polynomials,combined with the motion characteristics of the 2-R(SS)2-R(RR)2(RR)2 parallel robot mechanism,the trajectory position on the cylindrical surface is proposed.Space gate type trajectory.The arc transition curve and Lame curve are used to replace the corner transition respectively,and combined with the movement characteristics of the trajectory on the plane,the velocity and acceleration models of the above two types of curves are established.The comparative analysis draws the following conclusions: the trajectory length and operating period of the two types of curves are almost the same,and the grabbing frequency meets the work requirements;the Lame curve has a smoother change in the end acceleration and active arm torque than the arc transition curve,and finally The Lame curve is preferred as the grasping trajectory.In the aspect of mechanism integration optimization design: design an optimization design method of scale parameters,structure size iterative optimization until convergence,and give an optimization process.Among them,the optimization of scale parameters is based on geometric interference conditions and kinematics performance as constraints,and the driving torque required for the branch chain active arm torque in the working space is small as the optimization goal;the structural parameter optimization is optimized by the minimum first-order natural frequency of the mechanism Target.The calculation example shows that the mechanism under the optimized size meets the geometric interference conditions in the working space;the maximum values of the two types of pressure angles in the working space are less than 60°,which meets the kinematics performance requirements;the maximum during the grasping process of the three-branch active arm The torque is obviously smaller than the torque value under the initial size,and the first-order natural frequency of the mechanism has achieved the maximum value in the experimental data,which has good dynamic performance.