The Research And Design Of Scanning Control System Based On DSP And FPGA

Microwave infrared scanner is important portable equipment in meteorological Satellites. Scanning control system is the Electrical Control Actuator of the scanner, and its performance decides the imaging accuracy of the scanner and the task completion of the satellites. According to the high precision requirements of the microwave infrared scanner, the servo control system based on DSP (Digital Signal Processor) and FPGA (Field Programmable Gate Array) is presented and the structure, control scheme and the hardware and software design of the system are analyzed. The brushless DC motor is used in the system as its driven motor, and dual-loop control tactic composed by current loop, velocity loop is designed to implement a high inertia load drive control at a slow speed and the balance of the moment of inertia.In this paper, the brushless DC motor's working principles and mathematical models[0] is briefly introduced. Besides that, the causes of the torque ripples and how to reduce the torque ripples are analyzed. The whole system control structure is consisted of two DSP chips and one FPGA chip, One DSP is used to control drive motor and the other DSP is used to compensate motor[0], with the FPGA assisting DSP to accomplish the function of communication, data sampling, and speed calculation. In the hardware part, some peripheral interface circuits such as electrical power driving unit, feedback sampling unit, serial communication and power supply module are designed. DSP and FPGA subsystem modules with the center of TMS320F2812 and EP2C20 are also configured. In the software part, the communication between DSP and FPGA, speed calculation of drive motor, PWM adjusting, signal sampling, speed and current control are completed. Furthermore, some beneficial practical researches about the dual-loop algorithm based on PID controller whose parameters are self-modified by neural network theory have been done in the velocity loop design.The practical scanning control experimental system has been implemented, and the result shows that the hardware and software are reasonably designed; system works stably with a high control precision and meets the design performance indicators.