Applied Mechanics and Materials Vols. 226-228

Abstract: The application filed and characteristics of flexible tactile sensor are introduced in this paper. Main technologies including microelectronics mechanical system and other new material of flexible tactile sensor are proposed. The structure and the working principle of microelectronics mechanical system used in flexible sensor are described and explained. The principle of piezoresistive of strain gauge is researched on. The piezoelectric properties of polyvinylidene fluoride is also narrated. The coupling effect of the dielectric mechanical properties and the dielectric mechanical properties are discussed. The conductive mechanism and the piezoresistive effect of flexible tactile sensor based on conductive rubber are analyzed. Physical properties of main technology of flexible tactile sensor are proposed summarily. Moreover, advantages and disadvantages of technologies above are analyzed. Some problems to be solved and research contents of flexible tactile sensor are put forward.

Abstract: In this paper, a three-stage algorithm for raw LIDAR data filtering has been presented. Firstly, the raw data is re-sampled to grid, which size should take into consideration of raw data density and usage intention. Then a slope adaptive region growing is used to segment grid cells to different surface patches. Secondly, segmentation adjacency is established based on topological analysis. Two perceptual cues, that is, connection and elevation are computed for every pair of the adjacent segmentations. By the cues, the upper segmentations are classified as terrain, building, vegetation and others. Finally, the grid cells classified as terrain are used to build approximation of the terrain surface. Raw data are accepted as terrain within a given distance from the surface. To illustrate the effectiveness of the new procedure for DTM production, a series of data sets from ISPRS are tested. The results show that the method can discriminate terrain points from non-terrain points correctly.

Abstract: The paper selected the ZIGBEE technology to build river model wireless network by analogy, and based on mesh network structure of ZIGBEE, integrated the velocity data transmitting apparatus and router, to make the data transfer farther, and the reliability higher, to meet velocity collection need of the large scale river model . Herein a collection system on flow velocity was developed based in Visual Basic, which established the corresponding relationship of the velocity measurement position and actual measurement section and improved automation of data management by the automatic identification on the ZIGBEE number. The practical application revealed that the river model collection system on flow velocity based on the ZIGBEE would meet the needs on the velocity collection with a wider scope, showed more flexible networking and higher reliability, and finally improved the efficiency of the river model experiments.

Abstract: The performance of the automatic level control（ALC） system determines the stability of the microwave signal source output power, accuracy and linear flatness in each frequency range, directly determining the signal generator power characteristic indicators. This paper gives an implementation of a high-performance feed-forward ALC circuit, the negative feedback loop consists of the power detector circuit, logarithmic amplifier, the integral hold circuit, attenuator driving circuit, PIN attenuation circuit and so on.

Abstract: We have researched the residual stress in super-smooth glass ceramics using nano-indentation technology, according to the characteristic that the residual stress in the process of pressure is sensitive to the pileup around the indenter, we can determine the changing area, then combine this with the elasto-plastic contact theory, thus the residual stress calculation formula is obtained. By the continuous strain obtained by a spherical indenter and the research on the yield stress and stress-strain curves of microcrystalline glass through spherical indentation experiments, we can get the rule which can tell us how the residual stress of the microcrystalline glass changes with the depth from surface. This research helps to improve the processing quality as well as the performance of the super-smooth surfaced microcrystalline glass, obviously it has a wide application prospect.

Abstract: Abstract: Timber is a typical orthotropic material, of which the accurate measurement of elasticity modulus and Poisson ratio is important. In this article, the test samples are manufactured according to GB 1943-1991 and 1935-1991. An electronic testing machine is employed to add longitudinal load on samples and the longitudinal and transverse strains are measured via Wheatstone bridge. Then, the compressible elasticity modulus and Poisson ratio of Ziziphus montana wood in three directions is obtained. The results show that the elasticity modulus measured is of similar magnitude to those with similar dry density and of great importance to finite element calculation.

Abstract: The measurement of spray characteristics especially the droplets thermal and hydrodynamic properties is very important for many industrial applications. In this paper, a developed global rainbow thermometry method is applied to measure droplets temperature and size distribution in a flat fan air-blast atomizer spray. The spray droplets is illuminated by a continuum laser with the wavelength of 532nm and power of 14mW, and the rainbow light formed by the droplets is received by a linear CCD. To get accurate result, a calibration method for the relation of scattering angle and CCD pixels is designed, which can effectively reduce the error of the measured temperature. Experiment is taken under different temperature at a fixed gas-liquid ratio conditions, and results shows the method is feasible and has a relatively good precision.

Abstract: Micro-gyroscope is a typical representative of MEMS development, and relative measuring and testing may acquire some important performance parameters, which facilitate analysis and mastery of the operating characteristics further. However, accuracy and reliability of the results or data from measuring system become the key problem for almost all measuring systems. Based on results produced by micro vision measuring, principles about driving and operating of micro-gyroscope are analyzed, and the theory function between input excitation and vibration response is established. With further study on the whole process of dynamic response analysis, resonant amplitude and frequency are finally defined as two decisive factors influencing the accuracy of micro-gyroscope measuring system. Focusing on experiment design and calculation analysis of the two parameters, accuracy and reliability of the system are well verified, which presents important references for other relative measuring systems of micro-gyroscope.

Abstract: Being relatively new to the field, electromechanical actuators of Stewart platform in vibration control and motion simulation applications lack the knowledge base compared to ones accumulated for the other actuator types, especially when it comes to characterization and system identification. This paper focuses in the modeling of an electromechanical linear actuator to be used in a heavy load six-degrees-of-freedom platform application intended for motion control technology. The paper keeps the main kinematic and dynamic parameters unaffected, ignoring others. After obtaining the structure of model, parameters is derived by system identification. Provides a comparison of output of real system and simplified model by same input signal, the experimental result shows that the method is accurate and have good ability.

Abstract: Reliable predictions of ship wakes scattering strength are required for laser radar modeling. In this paper, far-field light scatter of wake bubbles is firstly simulated by CST software and used linearly polarized light at a frequency of 563THz (wavelength 532nm,blue light) as probe light; Analyzed the far-filed radar cross section performance of effect factors such like bubbles radius, absorption coefficient in sea water with the method of finite integral of CST. The experiment result shows scatter strength and depolarization characteristics are great variable on conditions of forward and backward scattering, and affected by the bubble radius and seawater absorption coefficient as well, this method all directions of the scatter strength and depolarization characteristics that also can be get in figures. These results provides important basis for subsequent research.