Research On Perfect Function And Bus Communication Rate Improve Of High Performance NC Servo Drive

Servo drive system is the important function unit of the NC machine tools and is one ofthe critical infrastructures of NC machine tools to the development of high-precision, highspeed and high efficiency, which performs motion commands from the CNC systems anddrives the machine axis feed operation. Servo drive system performance indicators determinethe processing effect of NC machine tools in some ways. Based on success of the keytechnology in servo system, the versatility is improved through adding some new features. Inthis paper, several important issues are attached; including fault diagnosis and protection ofthe serve drive, speed external setting, SERCOS bus interface communication rate improve.The overall framework of the servo drive system and the SVPWM control strategyadopted by permanent magnet synchronous motor are introduced. Its control elements areTMS320F2812DSP and FPGA. Its power drive part adopts intelligent power module (IPM)and communication circuits are RS232and SERCOS. In addition, the structure of the deviceis redesigned to comply with requirements of product.Fault diagnosis and protection function plays an important role for the safe operation ofthe device and the personal safety of operators. In view of the complex operation environment,some common faults are combined and classified. By analyzing the failure phenomenon andits reason, the fault signal acquisition circuit is designed. Through the judgment of FPGA andDSP, it makes the corresponding protective action in time and displays the alarm information.It is researched how the servo drive runs without CNC. In the CNC system, the servodrive is controlled to run by accepting the motion control instruction from the host computerCNC. As an independent motor control device, how is it applied in the other motion controlsystem? Simulation speed setting circuit based on linear circuit and digital speed settingcircuit based on external I/O are designed. The motor speed can be set by the externalpotentiometer or digital encoder. The versatility of the servo drive is improved.Compared to traditional pulse communication mode, SERCOS field-bus has manyadvantages in CNC and servo drive communication. Based on the successful running in2Mbit/s rate, the communication rate is improved to4Mbit/s through modifying and testingthe hardware circuit and software parameters.Finally, the servo drive is installed on the NC machine tools (XKHL650) to process avariety of tests pieces. The test results show that the development of servo drive meets thedesign requirement.