Dynamic Characteristic Analysis And Control Strategy Research Of Linear Servo Mechanism

As a common transmission element,ball screws are widely used in aerospace,industrial intelligent manufacturing,weaponry and other fields.Therefore,the position control technology of servo motors + ball screws is becoming a huge demand as the basic and significant part of the industrial field.Especially in some aerospace equipments,the working conditions and performance requirements of ball screws are more stringent.Aiming at the problems of low tracking accuracy and poor anti-interference ability of the position servo system under special and complex working conditions,the ball screw position servo system should be deeply studied.The drive-transmission pattern of "servo motor + ball screw pair" is designed and built as the position servo system.The rigid dynamic model of the position servo system is completed based on physical property analysis;Through the analysis of the force and the force transmission path of the transmission components in the system,the system motion coordination relationship is established,and the construction of the flexible body dynamic model of the position servo system is completed.At the same time,the simulation model is established by MATLAB/Simulink software,providing a simulation verification platform for the design of subsequent control algorithm;The factors that affect the transmission accuracy of the system are explored,and the influence of structural parameters such as moment of inertia and stiffness is specifically analyzed;Considering the influence of friction,a nonlinear model of the system is established,and the specific influence law is explored.The servo control algorithm is designed for the rigid model of the position system.The traditional PID controller and adaptive sliding mode controller are designed;the nonlinear disturbance observer is designed to estimate the external disturbance of the system;Combining backstepping control with sliding mode control methods,and introducing disturbance observers,completed the design of an improved adaptive backstepping sliding mode controller;Simulation and comparison experiments have verified that the adaptive backstepping sliding mode controller based on nonlinear disturbance observer has higher position tracking accuracy and the best disturbance suppression effect.The servo control algorithm is designed for the flexible model of the position system.Aiming at the elastic deformation of system components,the feedforward control algorithm is selected to compensate the deformation;In view of other interference factors of the system,combined with the simulation results of the rigid body model,an adaptive backstepping sliding mode control algorithm based on a nonlinear interference observer is selected to suppress these factors;The feedforward and backstepping sliding mode are integrated into a hybrid controller,and the rationality and effectiveness of the hybrid controller are verified through simulation experiments.The design and construction of the position control system are completed based on the Lab VIEW and PXI platform,On the basis of this experimental device,the displacement accuracy experiments under no-load,constant load and inertial load is completed.According to the experimental results,the improved backstepping sliding mode controller under the rigid body model is significantly better than the traditional PID controller and sliding mode controller in improving the tracking accuracy and motion stability of the system.Compared with the rigid body model controller,the tracking accuracy and the robustness of the hybrid controller,which was designed for flexible bodies,is better.