Capacitive Electric Quarter-turn Actuator Position Transmitter Design

The electric actuator is a very important drive device in industrial processcontrol system.It is widly used in metallurgy Electric power, petroleum, chemicalindustry. electric actuator includes electric actuating equipment and control valve,electric actuating equipment changes controller’s control signal to output shaft’sangular displacement or linear displacement,control the control valve’splacement,make accused medium changed according to the requirements of thesystem’s state. Control precision of actuator is decided by control performance of theelectric actuator,and position transmitter is an important part of electric actuatingequipment, through this,Research and improvement on position transmitter has veryimportant realistic significance.This paper comes from the practical application,on the basis of checking a largenumber of literature,according to the Present situation and the development tendencyof the electric actuator, analyses the advantages and disadvantages of two mainelectric actuator position transmitter(differential transformer type andpotentiometer)to design an electric actuator position transmitter which usingMSP430F149as the core and sectioning type angle displacement sensor.This paper confirms the Structure and geometry size of sensor which is in baseof research results of some related literature, combined with the internal structure andengineering application of electric actuator position transmitter,and using ANSYSsoftware to do the simulation research and finite element analysis for.according tothe confirmed geometry size,design and make sectioning three layer flat parallel platecapacitance angle displacement sensor,in basis of this, we design hadware circuit andsoftware system of position transmitter. Hardware circuit consists of excitationcircuitry,capacitance measuring circuit,amplifying circuit,filter circuit,microprocessorcontrol circuit、angle showed circuit,analog signal output circuit. software systemincludes the main program module, timer modules and A/D sampling module.thispaper completes the design of the hardware circuit, draws up the relevant softwareand debug the prototype,to achieve the expected goal.