| Industrial robots are an important tool in modern manufacturing,and the development of high-speed and high-precision industrial robots is a key link in realizing the upgrading of high-end manufacturing industries.In the process of rapid positioning of the robot servo system,due to the flexible deformation of the joint transmission structure and arm structure of the robot,the rapid start and stop will cause the robot servo to vibrate during the positioning process.Vibration will reduce the positioning accuracy of the robot,generate noise and reduce the service life of the system.Therefore,it is of great significance to study the vibration problem of the robot servo system.This article firstly carries on the modeling analysis to the robot flexible arm servo system.The flexible links in the flexible arm servo system specifically include flexible joints and flexible mechanical arms.The flexible joint system is equivalent to the linear spring system,and the flexible manipulator is equivalent to the EulerBernoulli beam system analysis.Due to the difficulty of modeling complex mechanical systems,the Simmechanics toolbox combined with the electrical control model was used to establish an electromechanical hybrid simulation model.Secondly,the vibration mechanism of the robot servo system is analyzed.The impact component contained in the given position command will excite the vibration of the positioning end.Combining the servo response speed and the severity of the positioning end vibration,the positioning end response performance evaluation index is proposed;the natural frequency of the flexible joint,the speed loop gain and the discrete error will all affect the system speed oscillation.In order to extract the characteristics of the rotational speed oscillation frequency,the chirp sweep signal is used to realize the natural vibration frequency identification of the flexible joint;the end vibration signal is located by the sensor feedback,and the adaptive identification of the end vibration frequency is realized based on the improved PLL method simulation.Then,in view of the vibration problem of the positioning end,the frequency domain characteristics and vibration suppression principles of the four typical trajectory planning motion curves are analyzed,and compared with the input shaper.The trajectory planning curve is equivalent to a trapezoidal curve combined with a special filter.Compared with the input shaper,the zero points of the special filter can only be distributed on the imaginary axis,but the response lag time is easier to obtain.The vibration suppression performance of the four motion curves is simulated and analyzed in combination with the positioning terminal response performance evaluation index.Although the Cosine motion curve causes the longest lag time,the overall positioning time is the shortest and the vibration suppression effect is the best.Aiming at the problem of speed oscillation,this paper proposes to set active damping in the position control loop to suppress speed oscillation,and analyzes the influence of damping coefficient on speed oscillation through simulation.Finally,based on the laboratory algorithm verification platform,the experiment verified the suppression effect of the motion curve on the vibration of the positioning end.The results show that the vibration suppression effect of the Cosine motion curve is the best.Based on the robot servo swing arm platform of Guangzhou CNC Company,the experiment verifies the Cosine motion curve.Effectiveness of restraining the vibration of the robot servo terminal.In the active damping experiment,the effect of speed oscillation suppression under different damping coefficients is verified.Increasing the active damping coefficient can effectively suppress the speed oscillation,but it will slow down the system dynamic response speed. |
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