Error Analysis And Control Method Of Parallel Robot With Few Degrees Of Freedom

Parallel robots are widely used in special occasions because of their small error accumulation and large stiffness.This paper takes the parallel manipulator as the research background,in order to meet the needs of its bearing stiffness and motion accuracy,the 3UPS\PU parallel manipulator structure is designed,and its mechanism analysis,error analysis and control strategy research are carried out.The research results can be used for parallel robot error analysis and disturbance suppression control strategy.For the 3UPS\PU parallel robot,based on the known structural parameters,the closed-loop vector method is used to analyze its forward and inverse kinematics,and the displacement,velocity and acceleration of the nodes and centroids of the 3UPS\PU robots are established.Model,and use MATLAB to simulate and analyze.The Lagrange method is used to model the main components of the parallel robot,and the dynamic model of the 3UPS\PU robot is obtained.The generalized force is converted into the driving force on the side chain by the principle of virtual work,and the dynamic simulation is performed by MATLAB software.ADAMS software was used to verify the above-mentioned mechanism results.The static error of the 3UPS\PU robot was simulated and analyzed with ANSYS to verify that the structural strength of the robot satisfies the requirements of error accuracy,and the specific relationship between the end effector error caused by statics and its load size and posture was explored.The error analysis model of the parallel robot is established by the method of matrix differentiation,and the simulation is carried out with MATLAB to obtain the connecting pieces that can most influence the error of each degree of freedom of the end effector during the movement of the robot.Based on two different Hooke hinge distribution configurations,an error model is established and simulated,and it is concluded that the Y-shaped distribution is stronger than the T-shaped distribution in terms of error control.On the basis of the robot dynamics model,feedback linearization is carried out based on the inverse dynamics method,which verifies the feasibility of calculating the sentence control.After adding the interference term to the dynamic model,it is concluded that the calculation of the moment method alone cannot control the robot under interference.On the one hand,the sliding mode variable structure method is used to control the 3UPS\PU robot,which can achieve trajectory tracking and interference suppression.On the other hand,in order to avoid the chattering problem,the control method is used to control it,the linear matrix inequality is established and the control parameters are solved by MATLAB,and the robust control has achieved good tracking results.