Research On The Control Of Laser Cutting Servo System Based On ADRC

Follow-up control is one of the key technologies of laser cutting system.Improving the control quality of laser follow-up control system plays a vital role in the processing effect and efficiency of laser cutting system.In recent years,with the continuous improvement of laser technology and equipment manufacturing technology,the laser control servo systems are increasingly high requirements.The existing follow-up control algorithm mainly adopts the improved PID control algorithm,and its limitations are gradually emerging.The auto-disturbance-rejection algorithm absorbs the deviations in the classic control algorithm to eliminate the deviations,and at the same time introduces the state-space idea in modern control,which has great advantages in antidisturbance capability and robustness.Therefore,this paper has carried out an algorithm research based on ADRC to improve the performance of laser servo control system.The main work and innovations of the paper are as follows:Firstly,the demand of laser cutting servo control system is analyzed.According to the requirement,the whole hardware scheme,software scheme and control algorithm scheme of laser servo control are designed.The hardware design,selection and control algorithm scheme of laser servo control system are analyzed in detail.The laser cutting servo control system mainly includes upper and lower computer software,servo module,height detection module and so on.Secondly,the height detection scheme based on capacitive displacement sensor is studied.It mainly introduces the principle of capacitive displacement sensor height detection,sensor calibration method,calibration result evaluation method,and disturbance analysis.On the basis of the above research,in order to improve the accuracy of height detection,a height detection method based on Kalman filter is designed.The height detection method based on Kalman filter uses position of encoder and capacitance sensor detection height for data fusion.The detection height of the capacitance sensor is corrected by the feedback position of the encoder,and the corresponding experiment is designed to verify the effectiveness of the method.The Kalman filter is introduced to correct the capacitance detection height,which reduces the deviation between the detection board spacing and the real board spacing due to the capacitance edge effect,and improves the accuracy of the feedback loop.Finally,the auto disturbance rejection control is improved to design the laser servo control method based on the improved auto disturbance rejection control algorithm.The principle of ADRC algorithm is introduced briefly.In order to solve the contradiction between the phase lag of tracking output and the noise amplification of differential extraction,and the complexity of parameter tuning in the tracking differentiator of ADRC,the equivalent linear simplification of tracking differentiator near the zero point and the idea of input compensation are introduced,and the compound tracking differentiator is designed.In order to improve the ease of use of the system,reduce the complexity of parameter tuning,and reduce the complexity of system analysis,linear state expansion state observer is used.Based on the analysis of the performance requirements of the laser servo controller,the relevant simulation and actual measurement experiments are designed according to the usage scenarios of the laser servo control system to verify the performance of the improved auto disturbance rejection control algorithm.Simulation and practical test show that the laser servo control system based on ADRC algorithm can not only meet the normal use scenarios,but also achieve good control effect in complex scenarios such as large external disturbance and large feedback information deviation.Compared with the original improved PID control algorithm,the designed laser servo control algorithm based on auto disturbance rejection controller has stronger robustness,better disturbance rejection ability,wider application scenarios,convenient parameter tuning,and can meet the control performance requirements of laser cutting system.