| The accuracy of the robot and the rationality of the structure are important factors of the robot performance evaluation standard.The dynamic and static analysis of the robot through digital methods can effectively find out the design defects of the robot,and then optimize and improve the design defect structure can not only improve the rationality of the structure,but also improve the accuracy of the robot to a certain extent.The calibration of robot parameters can eliminate most of the errors caused by the design,manufacture and assembly of robot parts,thereby achieving a significant increase in robot accuracy.This article uses ADAMS,ANSYS and MATLAB software to carry out dynamic,static,modal analysis and multi-method collaborative structural optimization of each structural part of a model of six degrees of freedom welding robot.After ensuring the rationality of the design,the source of the robot's error is analyzed And the robot error identification model is established and calibrated and compensated,which improves the positioning accuracy of the robot.The main conclusions are as follows:(1)The structure and transmission mode of each joint of the robot are analyzed,and a digital prototype is established in ADAMS.Perform dynamic analysis through ADAMS to obtain the force curve and torque curve of the robot wrist,arm,arm mount,arm and swivel during rotation,and determine the joint angle and dangerous position of each robot joint's dangerous position Force and torque.(2)Establish a finite element model of each component of the robot in ANSYS software,using the force and torque of each joint of the robot as a dangerous position as constraints,respectively on the robot wrist,forearm,forearm fixed seat,boom and rotation A static analysis was carried out on the base to obtain the stress,strain and deformation cloud images of each joint of the robot in the dangerous position.Based on this,modal analysis is carried out on the robot wrist,forearm,forearm mount,boom and swivel,and the first six natural frequencies and mode shapes in the constrained mode of each component are obtained and analyzed.The resonance state of each component of the robot.The third-order natural frequency of the cantilever mount is 657.44 Hz,which is similar to the sixth-order natural frequency of the forearm 665.39 Hz,and the vibration modes of both are in the Y-axis direction.It is determined that there is resonance between the two.(4)Based on the results of statics and modal analysis,the shape of the robot arm is optimized,and then the effect of the reinforcement parameters added to the shape optimization on the deformation of the arm is obtained through the orthogonal test statistical method.A ridge regression model is used to analyze the relationship between the factors in the orthogonal test and the amount of deformation of the forearm,and the regression equation between the amount of deformation of the forearm and each factor is obtained,and then the optimal parameters are solved by multi-objective optimization.The optimized model is obtained with the optimal parameters,and the deformation of the forearm is reduced by 15.9% compared with that before the optimization.;Using variable-density material interpolation method to carry out topological optimization of the wrist,boom and swivel parts,under the condition that the strength and rigidity of the parts are sufficient,the weight of the wrist parts is reduced by 18.14%,the mass of the arm is reduced by 6.67%,and the quality of the swivel Decreased by 1.70%,and the difference between the natural frequencies of adjacent parts after the optimization is significantly increased,so that the resonance between the components is avoided.(5)The source of the robot's positioning error is analyzed,and the robot's motion model is established by the DH method to obtain the mapping relationship between the robot parameter error and the absolute distance of the end effector.The PSO algorithm is used to identify the DH parameter error after calibration.The positioning error of the robot is reduced by 3/4. |
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