Development And Research Of Single Bimorph Self Sensing Piezoelectric Pump Based On Circular Bimorph

Piezoelectric pump is an important branch of micropump,which has advantages of good reliability,lower power consumption,structure easily to be miniaturization and integration.Applications range from intravenous introduction of pharmaceutical drugs to bionic underwater propulsion.There is an obvious impact of working conditions on the output flow rate and pressure in practice.Besides excitation voltage and frequency,the performance of the check valves,the pump chamber structure directly affect the output performance of piezoelectric pump and result in the inaccuracy of the output flow rate.Therefore,the additional measuring instruments of flow rate and pressure are still required to perform the real-time monitoring in some fields of precise microfluid transportation and control.Not only the cost but also the volume,quality and complexity of the system are increased.It brings a serious hindrance to the promotion and application of the piezoelectric micropumps using in microfluidic systems and portable products.Funded by the Ministry of Education of Higher Education Science and Technology Innovation Project Major Projects to Foster Capital "Research on the New Piezoelectric Drive Mechanism with Integration of Driven Testing and Control(No.708028)" and the Chinese Nature Science Foundation Project of “Study of self-sensing/self-exciting piezoelectric micro-pumps(No.51205366)”,this dissertation aims to the development of single bimorph self sensing piezoelectric pump.Combine the piezoelectric effect and the converse piezoelectric effect to realize the driving of the pump and sensing of the output flow rate and the output pressure.The work including self sensing analysis of circular bimorph,theoretical analysis of single bimorph self sensing piezoelectric pump,fluid simulation,prototyping and experimental test,and designing of control system.The specific contents are as follows.1.Vibration analysis of self sensing piezoelectric bimorphSelf sensing piezoelectric bimorph is the actuator of piezoelectric pump,and at the same time,it is the sensing unit of output flow rate and pressure.Base on the theory of plates and shells,analysis the deflection of self sensing piezoelectric bimorph under the electric field.The sensing voltage of sensing chip is calculated according to the theory of elasticity and piezoelectricity,to certify the feasibility of self sensing piezoelectric bimorph realizing self sensing.In order to verify the results of theoretical analysis,testing is carried on the self sensing piezoelectric bimorph.Measure the deflection and the sensing voltage of piezoelectric bimorph using suitable equipments.2.Designing of single bimorph self sensing piezoelectric pumpThe dynamic model of single bimorph self sensing piezoelectric pump is established and the main parameters for the influencing trend of piezoelectric bimorph and check valve movements are verified by solving and simulating the dynamic equations,to make sure the output flow rate and the volume change of the pump chamber has function relation.The height of the pump chamber is calculated,and the structure of the pump chamber is simulated using the STAR-CCM+ software,to find out the optimum height for the pump chamber.The check valve of the pump is selected,and the fixing structural parameters of the check valve are analyzed,and the matching design of the inlet check valve and the outlet check valve is carried out.3.Performance testing of single bimorph self sensing piezoelectric pumpThe single bimorph self sensing piezoelectric pump is fabricated.The performance of the pump is tested in the testing system,and the sensing voltages waveform and value are tested.According to the test results,the relationship between sensing voltages and output performances is analyzed.Verify the feasibility of output performance self sensing of single bimorph self sensing piezoelectric pump.4.Designing and testing of single bimorph double acting self sensing piezoelectric pumpSingle bimorph double acting self sensing piezoelectric pump is proposed in order to improve the output performance of single bimorph self sensing piezoelectric pump.Analysis of the working principle of single bimorph double acting self sensing piezoelectric pump,simulation analysis of flow state insingle bimorph double acting self sensing piezoelectric pump using the STAR-CCM+ software.The single bimorph double acting self sensing piezoelectric pump is fabricated.The performance of the pump is tested in the testing system to certify the relationship between sensing voltages and output performances.5.Control system designing of single bimorph self sensing piezoelectric pumpControl system of single bimorph self sensing piezoelectric pump is developed,to construct a precise flow conveying system and to achieve real-time display and quantitative control of single bimorph self sensing piezoelectric pump.The self sensing output precision of single bimorph self sensing piezoelectric pump and single bimorph double acting self sensing piezoelectric pump are tested.This dissertation aims to the development of single bimorph self sensing piezoelectric pump,and the improvement of the performance of the pump.The main work including self sensing analysis of circular bimorph,structure design and performance test of single bimorph self sensing piezoelectric pump and single bimorph double acting self sensing piezoelectric pump,and control system designing.It involves many subjects,such as piezoelectricity,mechanical system vibration,theory of plates and shells and control science.The research results provide a new idea for the output performance detection and control of piezoelectric pump,and widen the application range of piezoelectric pump.It can be used for reference to the development of similar fluid drive device.