Research On The Communication Strategy Of BLDC Motor Control System

The transmission way and processing method are quite limited to the information in tradition motion control system. The field bus provides a new channel which can realize the entire digital, bidirectional information transmission. The control system based on the field bus standard can transmit the information to each kind of data display and processing unit. It also realize equipment resources unitizing and raises equipment utilization rate. This thesis takes BLDC Motor control system as a background. Utilizing the field bus technology in the motion control system is focused. The communication connection between PC and DSP controler is established. Motor movement is Controled through the HMI on PC. Consider of the motor control system's distributional control structure, not high request of data transmission speed as well as the low degree of network complex, The General and High-open field bus such as Modbus and CAN are choosed as the Object of study.This theis includes all frame types of Modbus protocol as well as software and hardware interface designed between PC and DSP controller. Bidirectional Command/data transmission between PC and DSP controller is realized Through this connection. Some function codes to control the statu of motor is designed. Modbus protocol has certain flaw in transmission speed and reliability. Therefore higher reliability, timely and flexible CAN bus structure is use to make the improvement. First, the Hardware circuit and driver design of parallel-CAN interface card which is based on EPP protocol are completed. Realizing CAN message communication between PC and DSP controller In the physical and data link layer. Second, High-level protocol CANopen is mainly researched In application layer. Basic communication object and custom parameters such as Motor control/condition aiming at motor control system are realized. Results show that the use of fieldbus in motion control system is reasonable and practical. The operability and expansibility of monitoring software developed in Windows-based operating system are also vertified.