Research And Implement Of Numerical Control Machine Tool Servo Drive Parameters Tuning Technology

The accuracy and response speed of the NC machine tool depends a lot on the servodrive system, whose performance is closely related to its working state and parameters. Toget satisfactory performance, the parameters of the servo system must be tuned. In thisthesis, the performance test and parameters auto-tuning technology are researched, aimedto the NC machine tool servo drive parameters tuning technology researching, in order toget a better motion control performance of the NC system.In this thesis, the step response test, contouring errors test and frequencycharacteristics test of the servo drive system are researched aimed to the performance testtechnology researching. After analyzing the contouring errors of typical contour parts,lines and arcs, a method called minimum distance method is designed to calculate thecontouring errors. And with well understanding of the servo system frequencycharacteristics, a method called segment sine wave single-step method is designed to getthe frequency characteristics in a single step, which use a signal whose frequency changessegment by segment as the input of the servo system.In this thesis, after researching and analyzing the existent PID auto-tuning methods,an improved PID auto-tuning method is designed to tune the PID controller parametersautomatically and efficiently, which use least-square method to identify the math model ofthe servo drive system, use integral of errors as a performance target to judge theperformance of the system and use the rotating coordinate method to find the optimizedPID controller parameters.A servo drive parameters tuning system is designed and realized based on theresearch and analyses before. This system can help the worker to efficiently tune the servodrive parameters with performance tests such as step response test, contouring errors testand frequency characteristics test, or by auto-tuning the PID controller parameters. The experiments results demonstrated that this system can present vivid performance testingcurves and tune the PID controller parameters automatically. Meanwhile, after auto-tuning,the performance of the servo drive system is much improved. The servo drive parameterstuning software designed in this thesis has already been applied in several servo drivesystem performance optimizing cases. The results proved that the methods designed in thisthesis are effective and efficient, can meet the demands of the application of the NCmachine tool.