Research On Theory Of Structure's Design And Control System For Micro-Piezoelectric Pump With Active Valve

The application of piezoelectric pump in micro-electro-mechanical system is an important branch of piezoelectric drive technique. The performance of piezoelectric pump is not only depends on the actuator of piezoelectric pump chamber, but also depends the working modes of the inlet one-way valve and outlet one-way valve. Therefore, In recent years, the research on the valve has been growing up in the piezoelectric pump's research field. In this paper, based on analysis and summarize present research findings for piezoelectric pump with active valve, design and make a new micro-pump with bimorph. it dissertate the central part- finite element analysis for piezoelectric component.and through optimize a number of testings to verificate the rationality of this component, make this connect of two chamber , based on their different performance's comparison by test, it is a new direction for future research.The main content of this dissertation is as belows:1. Introduction of piezoelectric pump with active valveBased on the research and analysis for current research work on micro pump and micro valve, this paper focused on present current conditions and development of piezoelectric pump with active valve. Currently, the principal achievements of the study on piezoelectric pump are piezoelectric pump with check valve, piezoelectric stack pump, piezoelectric pump without check valve and piezoelectric ultrasonic pump and they are already widely used in biological gene, chemical analysis, aero and space areas. The piezoelectric pump with active valve was a new concept which was brought forward in recent years. The main achievements are only piezoelectric membrane, peristalsis and piezoelectric stack drive piezoelectric pump with active valve. Hence, understanding working conditions deeply and improving the performance of piezoelectric pump with active valve are new emphasis of the study on piezoelectric pump.2. Theory and simulation analysis of piezoelectric vibrator used for pumpBased on knowages of the fundamental theoretical for piezoelectric ceramics, piezoelectric material,piezoelectric effects,vibration's module,resonance characteristic,and etc. Consider its structural difference and different driving signal's characteristic, decide to using circle piezoelectric bimorph as actuator of piezoelectric pump's research. Because of circle piezoelectric bimorph's deformation was similar with Cylinder, So it roughly match with the basic hypothesis of Kirchhoff. This article uses the cylindrical form, establishes the circular piezoelectric vibrator's theoretical model, the strain and the amount of deflection has been listed, uses the Rayleigh-Ritz law to solve, derived a new delta function for circular piezoelectric vibrator's natural frequency and the dynamic displacement, which is under first order bending vibrations condition, as shown in the formula, When the natural frequency and deflection of circular piezoelectric vibrator under a certain electric field,it was effected very big by piezoelectricity potsherd thickness, piezoelectricity potsherd, metal foundation plate material attribute, piezoelectricity potsherd diameter, metal foundation plate thickness The metal foundation plate diameter and so on. Considered the usable request in the furture, this article selected the piezoelectricity ceramic with following size: The foundation plate diameter isΦ35mm, piezoelectricity ceramic's diameter isΦ30mm, foundation plate thickness is 0.1mm, ceramic thickness is 0.3mm.And the piezoelectric vibrator performance test system has been established. Based on the experimental test to its piezoelectric vibrator static characteristic and the dynamic characteristic, and also take the high voltage's damage to the piezoelectric vibrator in consideration, so take 90V as the suitable voltage. It studied the relation between the piezoelectric vibrator oscillation amplitude and the pretightening up force, so it made full preparation for next research.3. Micro active valve finite element analysisBased on flow formula's introduction and calculation, summarize three main parameters, which is affect on flow rate.these are flux's parameter valve port's opening h, the valve port radius and valve seat width w. Therefore, use ANSYS software to analyze the effect on housing flow's field distribution and intensity of pressure lose when the valve port thickness w and valve port opening hv's under different parameters. and checked by experiment, it will provided the basis Principle to optimized the design on circular active valve's structure.4. Micro pumps and flow analysis of the structural designFrom the theoretical analysis of factors affecting performance of piezoelectric pump to study the fluid flow's formula, and analysis the fluid's characteristics, The relationship between thickness of the cavity and flow will be analyzed, Through the analysis results of flows at the radial direction and the axial directions, it easy to know that the import and export position should be set near to piezoelectric vibrator's center.We can also find out the better size of import's diameter and export's diameter through analysis on them.Based on compare result of performance-to-price,chose the streamline shape. Then analysised it's phase difference characteristic and the boundary condition. It provides the theory basis to optimize design of the piezoelectricity pump's body structure with above studies.5. Research of Micro-pump's Experiment based on differefent DesignsI have done the optimize design for the structure's parameter of piezoelectric pump with single-cavity.we can got a better data combination,and designed three kinds of piezoelectric pump with fully different structure.Through the analysis of the flux and pressure for this three pumps, The test results indicated:The variety of flux is different even if under same working conditions, dual-chamber pump's max output is 260ml/min ,The max flux for special single-chamber pump with two active valve's is 110 ml/min ,single-chamber pump with two valve's best output is 60ml/min ,dual-chamber pump's best pressure is 42 kPa ,special single-chamber pump with two valve's best pressure is 26Kpa,single-chamber pump with two active valve's best pressure is 16Kpa. Though the max fluency has a bit diffenence,the out pressure of dual-chamber pump is a little higher then other two.it was answer for the theoretical analysis result.It will be provided a new thread for future research.6. Research on Micro-pump's control systemWe have designed a special drive and control system for the Micro-Piezoelectric pump with active valve, including both of hardware design and software design. First of all, in order to meet the requirement of Micro-Piezoelectric Pump's deformation, select the SCM as the core part, used the modulization designing idea as principle to design the hardware. It mainly includes: SCM periphery module, serial communication interface module, drivingcircuit module, reactive circuit module. Then we developed the software by use of assemble language and VS C# for the drive and control system, including the PC and SCM programs. The PC programs mainly include: communication module, original parameter setting module, working parameter setting module, calculation control module, current working status display module. The SCM programs mainly include:main program module, serial port interruption sub-program module, frequency and phasic difference adjustment sub-program module, timing interruption sub-program module and other small sub-program modules. The PC software is responsible for sending the command according to the parameters set by the user and vibration feedback signal from the SCM to SCM. And the SCM software is responsible for controlling hardware according to the command from the PC program and sending the vibration feedback signals to PC. The drive and control system has the following main functions: It has achieved to adjust the output signal, phasic detention, voltage manually.It has achieved the function for timing, fixed quantity and fixed speed feeder. It can detect the resonance frequency automatically.It can achieved real-time watching and displaying the current status. Finally, We have tested the performance of the drive control system for Micro-piezoelectric pump with active valve, including the output voltage, frequency, phasic difference and the deformation for the closed loop of this control unit. After many times tests and applications.it was proved that this control system can meet requirements for the higher precision of flux transmit.