Research Of Linear Electric Intelligent Actuator Drived By A High-power Linear Motor

Electric valve is a very important part of ductwork which is used to stop or regulate the flow of medium in the pipe. Electric actuator is just the controlling and driving part of electric valve. The performance of electric actuator is very important for the controlling of electric valve, even for the ductwork.The traditional electric linear actuator is bulky, low precision, unconvenient to control its speed and easy to damage its motor. After a great deal of research of status quo and developing trend of existing electric linear actuator, a new method of driving actuator by a new linear step motor is worked out. And then, a control system based on singlechip is designed to intelligentize the actuator.After total design of the system, the main part of the system is particularly described. Under the guidance idea of minimization, the author designed a new high-power linear step motor for the actuator, in which the rotation of rotor could be directly turned to the linear movement of screw. The motor adapts to run in low speed. So the system has no rotation-line transition and gear down equipment that exist in traditional one. Additionally, rotation preventing equipment, manual equipment and other equipments are designed, which make the actuator more compact. The new actuator is two-third as large as the traditional one. Considering the demands and the development trends of electric intelligent actuator, the author designed the hardware and the software of the the controller system, in which the structure of principal and subordinate controlling system is adopted. The upper computer is the interface between man and machine. The lower computer controlls the step motor directly in real time. USB is used in the communication between upper and lower computer. The upper computer program is designed in VC++. It is used to set the movement parameter, transmit the data, and show the running status of actuator. The lower computer is designed based on AT89C51 and a special USB chip. The controller program is designed in singlechip language C. It receives the command of upper computer and controls the step motor in opening ring mode. The controller can open or close the vale completely or set the valve at any position in any speed exactly.At last, the laboratory and local debugging of the prototype is introduced, in which the system ran very well. The system is a entirely numerical control system. Itis convenient to be controlled, easy to be regulated in speed, and has high control precision. It satisfies all the demands of valve controlling very well.