The Study Of CNC Tool Servo Drive System Based On DSP

This paper brings forward a close loop servo drive system of CNC machine tool based on DSP (Digital Signal Processing) , according to to the update request for all-numeral control system of CNC machine tool.The system can run by two control mode which are SVPWM (Space Vector Pulse Width Modulate) and non speed-sensor DTC(Direct Torque Control).It also has basical interpolation such as date sampling linear and arc interpolation.Meanwhile the system is studied and tested. Expercialy filtering measured current is emulated and taken some experiments.The studied filter way makes sure that the gained current has high quality when the system is run by DTC mode. And it also shows that the non speed-sensor DTC mode is much better than the SVPWM one.This paper firstly shows buildup, work principle and servo drive system of CNC machine tool, then gets the close-loop servo drive system of CNC machine tool based on DSP.The system adopts both SVPWM and DTC theory which are introduced in detail. The theory includes the relation of MI and using rateof voltage in SVPWM mode and the non speed-sensor DTC technology which units both vetor control and direct torque control.On this base,this paper makes out the hardware design in detail about the servo drive system.It explains how to design the voltage type inverter based on MOSFET tube, drive circuit, outside circuit of DSP and filter circuit, and how to choose the voltage and current sensor.Because of the great importance of the checked current in rough estimation of rotae speed, the current checked by current sensor not only is filtered by hardware, but also filtered by adaptive notch filter. Experiment tells that the adaptive notch filter is not practical for its filter not keeping up with the step of the real current wave. So it adopts a new tracking differentiator filter whose theory is wroted in detail. For good use in the servo drive system, several parameters are changed in formulation. It gives a new arithmetic of velocity in non speed-sensor DTC, after analyzing the function of the TD fileter, and simulates and makes experiment about the new arithmetic, the results show that it brings the expected good.effect..This paper also gives the design of DSP software.It shows how to carry out the DTC speed estimation.in software. Bascal interpolation arithmetics is studied simply.It tells how to carry out the date sampling linear and secanting arc interpolatons in software.At last, it analysiss the experiments' results about booth SVPWM and DTC modesLimited by the fund and time, the experiment system is a studied one,it amis at if the system is useful,and it gives a good condition to its unborn stiudy and production development.