Research On Digital Micro - Injection Technology Based On Piezoelectric Ceramics And Its Application

For now, the widely used digital micro-injection system is always using manual operation or based on the first inverse piezoelectric effect of piezoelectric ceramics for positioning and injecting during micro-flow injection. They have the disadvantages of low control accuracy and complex system structure. For this, researching for a digital micro-injection device which is simple and convenient on operation, accurate on the accuracy of controlling has become an important topic in bioengineering.The subject comes from Professor Shi Li-ping’s State Key Laboratory of Robotics and System Research Project of Harbin Institute of Technology(Item Number: SKLRS-2015-MS-10) and Science Research Project in Heilongjiang Provincial Department of Education(Item Number: 12541624). In this study, the main content is based on theory and application of piezoelectric ceramic digital micro-injection, analyzing the first inverse piezoelectric effect and secondary positive piezoelectric effect of piezoelectric ceramics through theory and experiments, and using its principle to design self-sensing digital micro-injection structure. Mainly including two aspects: on the one hand, theoretical study of self-sensing piezoelectric actuators which is based on the first inverse. On the other hand, secondary positive piezoelectric effect and self-sensing microinjection device design.First of all, this paper introduces piezoelectric ceramics, piezoelectric equations, boundary conditions and so on, theoretical analyzes various times of the piezoelectric effects phenomenon of piezoelectric ceramics under different mechanical and electrical boundary conditions based on the research of classic piezoelectric basic theory.Then establishing the experimental structure of PZT-5 piezoelectric ceramic’s first inverse and secondary piezoelectric effect based on the principle of piezoelectric ceramic’s first inverse and secondary piezoelectric effect, and measuring the displacement of piezoelectric ceramic which is produced in the first inverse piezoelectric effect while the piezoelectric ceramic is applied an external voltage. Separating and decoupling the charge which is generated in the secondary positive piezoelectric effect for realizing the integration of sensor and actuator in the same piezoelectric ceramic. Comparative analyze the experimental output and theoretical value, verify the correctness of the theory and the feasibility of the experimental structure.Finally, in order to apply in practice, this paper design a kind of digital micro-injection device which is based on the first inverse and secondary positive piezoelectric effect by according to the theoretical research and experimental verification of piezoelectric ceramic’s piezoelectric effect. Push the syringe plunger under the action of the piezoelectric ceramic’s first reverse piezoelectric effect to achieve a fluid flowing. At the same time, secondary piezoelectric effect can sense the injection volume to achieve self-sensing microinjection. Designing the overall structure of the program and validate the feasibility of the program is reasonable and practicable through feasibility experiments.