Study On Self-tuning Control In CNC Machine

CNC system becomes the core of the modern industry with its high automatic,high accuracy and good flexible. Unfortunately, the parameters tuning of CNCcontrollers is still in the stage of tuning manually. A self-tuning controller is given tosatisfy different performance requirements in three-loop control structure.Modeling of the control plant in position loop is first given, which offer necessaryinformation for the controller design. Next, the choice of input signal is discussed, datacollection is finished by GTS-800motion control card which is produced by GoogolTechnology Company. The final model is got by RMSE evaluation mechanism. Basedon the model, a simplexd method is used in PID self-tuning controller design. At thesame time, the self-tuing mechanism is established using identification and parameteroptimization. It is important to discuss feadible region and the choice of initial value toguarantee the fast calculate and the global result. By compare the step response ofsystem with different optimization criteria, find the suitable optimal controllerparameters to satisfy different requirements.At last, the proposed algorithms and self-tuning method is test on a three-axismilling machine. The experiments show that these control parameters calculated by theauto-tuning method can be used on the actual CNC machining. A software which realizethese algorithms is applied on GTS-800motion control card of Googol TechnologyCompany. The control parameter auto-tuning function can totally replace manual tuningand can reach a better performance.