Research On The Design And Realization Of Sensors Based On The Magnetoresistance/Magnetoelectric Effects And The Self-Sensing Actuator

As the important supports of advanced manufacturing,industrial automation and information technology,precision actuation and sensing technologies are widely applied in ultra-precision machining,vibration control,power engines and other fields.The current injectors in engines are mainly used for actuation,lacking the functions of sensing and controlling the flow rate or stability,which can largely affect the quality of injection.Indices like flow rate or stability also affect the working efficiency,economy and emission of the engines.Self-sensing actuator integrates the functions of sensing and actuation,which is an important direction of the development and fusion of sensing and actuation technologies.With the advantages of high precision,small volume and intelligence,the self-sensing actuator is suitable for precision control of the flow rate and stability of the injectors.Therefore,this dissertation aims to research on the sensors based on the magnetoresistance and magnetoelectric effects,design the self-sensing actuator,realize the function of integrating sensing and actuation,and conduct relevant applications.The main works are abstracted as follows:The displacement sensor based on tunnel magnetoresistance(TMR):A non-contact and high-precision displacement measurement sensor based on TMR is proposed.The principle is based on the interactions between the TMR component and the permanent magnet.The variation of the displacement is converted into the variation of the magnetic field,which causes the change of the output of the TMR component.The theoretical model is developed and the optimal sensitivity with corresponding parameters of the sensor are determined.The performance indices of the sensor are determined with experiments and are compared with the current displacement sensors.The proposed sensor is of high precision and low volume,which is suitable for integrating with the actuation part and act as the sensing part of the self-sensing actuator.The resonant pressure sensor based on magnetostrictive/ piezoelectric magnetoelectric effect: a resonant pressure sensor is proposed with the magnetostrictive/piezoelectric composite.The composite is a part of the resonant component.The natural frequency of the resonant component varies with the external pressure,which can be measured by the variation of the magnetoelectric response.The theoretical model of the sensor is developed with the nonlinear constitutive model of the magnetostrictive phase and the magnetoelectric equivalent circuit analysis.The parameters are optimized;the performance of the sensor is tested and compared with theoretical results.The proposed sensor enlarges the application fields of the magnetoelectric effect.Also,it has the potential of integrating with the actuation part.The actuation system based on the giant magnetostrictive material:The nonlinear model of the actuation system is developed;the magnetic circuit is analyzed and the structure parameters are optimized based on the principle of minimal energy loss.This actuation system is of high precision and compact structure,and suitable for integrating with the sensing part.The design and optimization of the self-sensing actuator: the displacement sensor based on TMR and the actuation system based on the giant magnetostrictive material are integrated and the self-sensing actuator is designed.The flexible magnifying mechanism in the self-sensing actuator is theoretically modeled and optimized.Its strength is checked and the frequency response is analyzed.The sensing part of the self-sensing actuator are modeled and the parameters are optimized.Next,the model of the whole system is developed and the frequency response is studied.The prototype realization and experimental studies: The prototype of the self-sensing actuator is manufactured and its performance is tested.It is applied to precisely control the flow rate and fluctuation of the valve.Firstly,the amplification factor of the magnifying mechanism is determined.Next,the performance of the self-sensing actuator is tested.The open-loop performance of sensing and actuation,the frequency response and the positioning and tracking performance of the self-sensing actuator are studied by experiments.It is concluded that the function of self-sensing actuation is well achieved.Finally,the self-sensing actuator is applied to control the flow rate and fluctuation of the valve.It has effects on controlling of the flow rate,and improves the stability of injection by controlling the fluctuation of the valve.