Papers by Author: Shi Qiao Gao

Abstract: Harvesting ambient vibration energy through piezoelectric (PE) means is a popular energy harvesting technique. The merit of applying PE means to supply energy for microelectronic devices is that they can reduce the battery weight and possibly make the device self-powered by harvesting mechanical energy. This investigation will examine the energy generating performance of miniature PE cantilever beam through theoretical modeling, simulation and experiment testing. Through the theoretical analysis of the piezoelectric energy harvesting structure, the expression of open circuit voltage output is obtained. Using ANSYS software, the working performance of piezoelectric cantilever beam is analyzed. On the basis of theoretical analysis and simulation optimization, a set of experimental system is established to test the energy harvesting performance of the piezoelectric cantilever beam. The testing result shows that the harvested energy by the piezoelectric cantilever beam could supply electrical power to some micro electrical devices.

Abstract: Based on the pull-off force calculation model with the liquid bridge capillarity force theory, analysis of the circumstance of the liquid bridge, puts forward an pull-off force calculation model with the consider of the edge effect. More experiment test results show, the model is effective and it can use for the exactitude calculate.

Abstract: A low frequency energy harvesting structure was studied, describing the process of its manufacture. The natural frequency was obtained by modal analysis of the structure. It obtained the relationship between the magnitudes of the voltage generated from the piezoelectric energy harvesting device and the size parameters of structure, so that the energy harvesting structure can operate at the resonant frequency in order to obtain the maximum energy.

Abstract: Based on the electrostatic comb drive structure, the comb will do relative motion when it is driven up, and the space between them will be less than 1μm. Considering the micro-scale effect, the Van der Waals force and the Casimir force is used to analyze the influence on the micro-structure, compared with the electrostatic force. The van der Waals force and the Casimir force is almost equivalent to the electrostatic force when the initial gap of the micro-structure and the relative displacement between the micro-structure is relatively small. Therefore the van der Waals force and the Casimir force play an important role in the micro-structure and cannot be ignored.

Abstract: In MEMS, the size of micro-structure is usually in the micron and even nanoscale. It's easier to form capillary phenomenon than the macroscopic system. In view of this phenomenon, this article is based on the micro-mechanical gyroscope as the research object, to analyze the occurrence of capillary condensation of adhesion phenomenon. Firstly, we derive the Kelvin equation for capillary condensation, and then combination of the Kelvin equation introduce the capillary condensation of the adhesion phenomenon; Secondly, it analyzes the dynamics characteristics of its structure existing the liquid bridge, and analyzes the causes of the liquid bridge; Finally, it analyzes the capillary adhesion phenomena on the performance of the micro-mechanical gyroscope,as well as how to avoid the generation of capillary condensation adhesion.

Abstract: As a typical inertial sensor, vibration micro-gyro is extensively studied. According to its working principle, drive control system is an important element for the gyro system. The role of drive control system is to keep the drive modal stability including stable vibration frequency and amplitude. The PLL method is usually used to realize the drive system. However, it has some shortcomings used to high Q vibration micro-gyro. In this paper, the problems of the PLL method are analyzed, and a PID & AGC control system is introduced. By simulating and measuring, it is indicated that this method is fit for driving high Q vibration micro-gyro.

Abstract: Fuze is an important component element of penetration weapons, for fuze tests in shot fields are expensive and can’t grasp the entire process, therefore a method of simulating the projectile penetrating into concrete target using Virtual Instrument Software LabVIEW combined with computer simulation is proposed here. Firstly the constitution of the hardware-in-the-loop simulation system is introduced, then the variation of acceleration when projectile penetrates into concrete is imitated, finally the whole system is tested, and the results indicate that the system can simulate the process of projectile penetrating into concrete target precisely and reliably.

Abstract: This paper introduces the working principle of the micromacined gyroscope, and establishes the drive equation of it. By solving the differential Equation, the analytical solution and the amplitude-frequency characteristics of the driving mode are obtained. By the visual measurement based on high-speed photography and the post image processing, it measures the vibration of the drive mode of the micromachined gyroscope. And it puts forward a novel displacement detect algorithm that based on the image processing, and with Matlab it verifies the analytical solution and the amplitude-frequency characteristics of drive mode of the micromachined gyroscope. This helps the study on the vibration of the micromacined gyroscope, and provides a new way to measure MEMS.

Abstract: Based on the calculation and analysis of three kinds of elastic beam’s stiffness coefficient in micro machined gyroscope, the results show: in the condition of small displacement，forces and displacement are linear relationship in clamped-clamped beam, crab-foot beam and bow beam; but as the displacement increases, the relationship between forces and displacement are obvious non-linear in clamped-clamped beam. When the displacement is three times the length of beam’s width, the bow beam’s force and displacement are linear relationship. By ANSYS crab-foot beam and bow beam’s stiffness is obtained, the simulation results and the polynomial fitting coefficient are all credible.

Abstract: A detailed analysis of the concept of strain energy density and strain gradient on the material microscale effect in a micro-machined gyroscope is carried out. By analysis, the material microscale effect mainly influences its elastic modulus. The analytical expression of the valid elastic modulus on the micro elastic beam structure of the micro-machined gyroscope is deduced. When considering the valid elastic modulus and not, respectively compare the natural frequency of the elastic beam with the actual measurement results. The error of former is far less than the latter. By the theoretical derivation and experiment test, the influence of the material microscale effect on the micro-machined gyroscope is analyzed.