The Research Of Slave Electric Actuator Based On CANopen Protocol

Electric actuator is a kind of important terminal-control instrument in automatic control system. It is widely used to operate and regulate values in modern industrial control system. But traditional electric actuator which is used in many factories have many innate defects,such as ,low precision, operation and maintenance problems, poor reliability, lacking of network communication etc. Therefore, it can't meet modern industry production needs. With the development of intelligent control technology, communication technology and filedbus technology, the electric actuator is developed very fast. Intellectualization, digitization and network are general trend of the electric actuator development. Because of that, the research of the filedbus electric actuator based on CANopen protocol is valuable.Firstly this paper analyzes the shortage of traditional electric actuator, and then presents a CAN bus electric actuator scheme which is based on CANopen protocol. Then provides the the overall structure diagram of bus-type electric actuator. Next details the analysis of the CAN and the CANopen protocol, which lays a good theoretical basis for the software design.Then mainly introduces the controller hardware design of bus-type electric actuator, which includes Power circuit, Position detection circuit, Infrared communication interface circuit, CAN bus communication interface circuit, remote analog input circuit, analog output circuit, power-down protection circuit, etc.Bus-type electric actuator software design is the focus of this paper, it mainly contains the electric actuator control program design and CANopen protocol commuication program design, the latter is as the focus, it mainly includes CAN bus low-level communication,build and access the dictionary object, SDO communication, PDO communication, NMT state machine, Heartbeat message, etc.Finally establish a CANopen network test flatform for the use of testing the electric actuator, the results indicate that the design of bus-type electric actuator is consistent with CANopen standard, and has the following characteristics: intellectualization, informationization and digitization, etc. The intended goal have been realized.