Research And Design Of AC Servo Motor Position Loop Controller Based On FPGA

With the increasing demand for the motors with high-speed, high precision andhigh response speed in industrial control field, the motor and servo control technologyhave been developed rapidly. Motor is a vital part of industrial control and the mostprimary executive part of industrial control system, only the development of motor andservo control technology can promote the further development of the industrial control.Servo control system is mainly composed of current loop, velocity loop and positionloop, and the position loop is the key to the design of the servo control system, itscontrol performance directly determines the performance of servo control system.Traditional PID control will produce a large overshoot when control the amount ofmutations. Aiming to resolve the deficiency, the thesis designed a kind of improved PIDcontrol method. Combining the high response speed characteristic of feedforwardcontrol, a kind of improved PID control plus feedforward control algorithm wasdesigned. The simulation results show that the algorithm has a smaller overshoot andfaster response compared with the traditional PID.This thesis chooses FPGA as the processing core of position loop controller toachieve the improved PID plus feedforward algorithm and some hardware circuitfunctions. FPGA has a very large scale single chip capacity and high speed parallelprocessing ability as hardware circuit. The designer can also customize a32-bit Nios IIsoft-core processor in the FPGA chip, which supports for common instruction set andcan handle with advanced programming language. A single FPGA chip not only cancomplete logic control as hardware circuit, but also can achieve complex algorithms inNios II soft-core. FPGA can greatly simplify the design of hardware circuit and improvethe efficiency of designers. This thesis designed position loop controller of the AC servosystem based on FPGA and completed the software design work in the FPGA chip ofthe position loop controller. The final test showed that servo motor has good positioningaccuracy and tracking performance under the control of the position loop controllerbased on FPGA.