Precision Positioning System Based On FPGA

The traditional PID controller algorithm for computing speed is too slow and overshoot. It can not be applied to drive a large part in some of the instruments (dial indicator) and special equipment (CNC). To improve the performance of the controller's operation, we often use control systems such as single-chip and DSP chip, we design implementation by software form, but this approach has disadvantage as a long development cycle and low cost.This article was based on motion control FPGA technology research, and research on automatic positioning system for the existence of overshoot .This article studies AC servo motor, and uses of top-down design puts an FPGA chip as the control digital circuit design and builds a PC + FPGA-based high-precision motion control system, This article work out the experimental test platform for repeat positioning accuracy, positioning performance and other aspects . The purpose is to develop a one-way approach to the target location high-precision positioning system. Thesis completed the following tasks:(1) It analysis and comparison of the servo motor and stepper motor performance characteristics, the structure of a variety of advantages and disadvantages of the master motion control. It composite integrated motion control system accuracy, cost and other factors, It proposed implementations based on PC + FPGA AC servo closed-loop control system;(2) It analysis of the motion control system characteristics of each module and conducted a selection of motion control system hardware modules (motor, motor drive, precision linear rails, grating and other mechanical devices) to achieve high-precision, high-precision parts as standard to choose, It is the basis for follow-up to achieve high-precision systems; of hardware modules to FPGA , AC servo system control device, and uses Quartus II development environment, and Verilog HDL language top-down design methodology. It designs and simulate the optional parameter PID controller, bus interface , grating signal processing, PWM generator and auxiliary control modules and some other functions. It is responsible for motion control algorithms and motion planning, etc. It hangdles the output speed and direction signals, and rasters signal processing, It needs the host through the serial bus PC machine communication;(4) It builds and tests the AC servo motion control experimental test platform. To aimed at the features of experimental platform, debugs optional parameter PID controller, so that the motor can run smoothly, The platform were repeated positioning accuracy, positioning performance and other aspects of performance tests. Its results show that using the optional parameter PID controller is better than a fixed parameter PID controller. The system has a high repeatability, and the positioning error is in the [-3, +3] (μm ).This development of high-precision positioning system based on FPGA and FPGA realization of motion control functions. It full use of FPGA resources, with high precision, fast response, high reliability, suitable for approaching the target requires a one-way controlled object location device have a good prospect.