Robust Design Of Frequency Reliability Of Loading-unloading Robot Manipulator

With the industrial robots play an increasingly important role in many fields of production,demand for the improvement of the performance of the robot,the robot must have a good reliability,and its dynamic characteristics directly affect the robot reliability and the stability.The random geometric dimensions of the structure will influence the dynamic characteristics of the system,and the robot manipulator is the main supporting components of the robot,therefore,it is very important to analyze the natural frequency of the whole robot,and study the influence of the structural parameters of the manipulator on the dynamic characteristics of the whole machine,and it is of great significance to the robust design of the frequency reliability.The main contents of this paper are as follows:(1)The parametric modeling of robot is carried out,and the structure of robot is simplified.The modal analysis is carried out by using ANSYS Workbench software,the natural frequency and corresponding vibration modes are obtained.The static and modal analysis of the robot manipulator under the limit working condition is carried out.Then the maximum stress value,the maximum deformation amount and the natural vibration mode of the manipulator are obtained.(2)Experimental design(DOE)is obtained by combining software ISIGHT and Workbench,according to the experiment results,the important geometric parameters of the robot manipulator are selected as the design variables.Based on the experimental design database,the BP neural network is used to fit the functional relationship between the minimum natural frequency of the whole machine and the variables of the robot manipulator,then the reliability limit state equation of robotic frequency is obtained.Based on the theory of reliability method,subsequently,the frequency reliability and sensitivity of the robot are calculated by using the first order second moment method,the influence of the random variables of the robot manipulator on the reliability of the whole machine is analyzed,then the results of reliability are verified by Monte-Carlo method.(3)Based on the theory of reliability-based robust design,the random variables which obviously affect the natural frequency are robust optimized.Through the robust optimization design,the quality of the whole machine is reduced,and the reliability sensitivity of frequency is reduced.The reliability of the system is no longer sensitive to the change of design parameters,and the purpose of robust reliability design is achieved.