A Study On A Novel 3-DOF Force-Controlled End-Effector

The traditional force-controlled end-effector based on the parallel mechanism mainly adopts the 2T1 R parallel mechanism configuration,which can quickly adapt to the curvature change of the complex curved surface,but it is difficult to achieve the active compliance control of the lateral force.For the inner surface of the workpiece with the narrow hole.Processing is not applicable.In this paper,the three-parallel parallel mechanism configuration is used for the design of the force-controlled end-effector.The active compliance control of the lateral force is realized by the translation along the x and y-axis directions,which can solve the problem of automatic grinding and polishing of the inner surface in a narrow space.At the same time,the axial force active compliance control by the translation along the z-axis direction can also meet the grinding and polishing requirements of the outer surface of the workpiece.The performance of the force-controlled end effector is mainly determined by the parallel mechanism.For this purpose,the parallel mechanism is mainly studied.The main work contents are as follow:According to the requirements of grinding and polishing,the 3T parallel mechanism with parallel four-bar mechanism is constructed based on the screw theory,and the configuration is selected from the aspects of motion performance and assembly precision.This article establish a positional positive solution model and a position inverse solution model for the mechanism.The velocity Jacobian matrix of the mechanism is established using the velocity vector method,the derivation method and the screw theory method,respectively.The acceleration model of the mechanism is established by deriving the velocity model.The static model of the mechanism is established by the principle of virtual work,and the dynamics model of the mechanism is established by the two methods of virtual work and Lagrange equation.Performance analysis on the singularity,workspace and dexterity of the mechanism are addressed.The design is optimized according to the influence of each parameter on the performance of the mechanism.The virtual prototype structure is designed,and the simplified virtual prototype is imported into the adams software for simulation,and the simulation results are compared w ith the theoretical model.Set up an experimental platform to verify the kinematics model of the organization.