Abstract:

Abstract:Surface acoustic wave (SAW) resonator used as wireless sensor was characterized and the parameters of its MBVD ((Modified Butterworth-Van Dyke) model were extracted versus temperature. The extracted parameters lead to evaluate the resonator performances in terms of Temperature coefficient of frequency (TCF) and quality factor (Q). An antenna was then associated with the SAW resonator and the entire system has been characterized and modeled. The good agreement experiment-simulation allows to define the optimum operating conditions of the wireless sensor.

Abstract:This paper introduces recent research work in the field of pulsed electromagnetic non-destructive testing/evaluation. These are pulsed eddy current, pulsed magnetic flux leakage and eddy current pulsed thermography. This paper introduces pulsed electromagnetic techniques and their different case studies on defect detection as well as stress characterisation. Experimental tests have been validated and future research plans are discussed. This paper demonstrates pulsed electromagnetic non-destructive testing and evaluation for not only depth information, but also for multiple parameter measurement and multiple integration, which are important for future development.

Abstract:In the X-C linkage grinding of non-circular parts, the computation and control method of contour error in polar coordinates platform is different with that in the XY coordinates platform. To solve this problem, the analysis of the definition and computation methods for contour error and track error in polar coordinates platform will be made. Through the relative lead-lag relation of the linkage axes in the grinding process, the range of the estimation contour error is narrowed and a contour error calculation model is constructed. Then the contour compensation controllers along contour error direction and trajectory tracking error direction are designed respectively, and the error compensation decoupling matrix of the X-C linkage axes is given as well. In the end of this paper, we take the machining of the cylinder contour in Wankel rotary piston engine as an example. A simulation experiment of contour error compensation control based on relative lead-lag quantity is made. The result shows that the designed contour compensation controller can increase the contour machining accuracy effectively.

Abstract:In wireless sensor network, virtual backbone is a cost effective broadcasting method. Connected dominating set formation is proposed to construct a virtual backbone. However, it is NP-Hard to find a minimum connected dominating set in an arbitrary graph. In this paper, based on cross-entropy method, we present a novel backbone formulation algorithm (BFA-CE) in wireless sensor network. In BFA-CE, a maximal independent set is got at first and nodes in the independent set are required to get their action sets. Based on those action sets, a backbone is generated with the cross-entropy method. Simulation results show that our algorithm can effectively reduce the size of backbone network within a reasonable message overhead, and it has lower average node degree. This approach can be potentially used in designing efficient broadcasting strategy or working as a backup routing of wireless sensor network.

Abstract:The accurate measurement of volume fraction of oil-water two-phase flow on line is important in the oil field. This paper presents a new coaxial conductivity sensor for measuring the volume fraction of oil-water two-phase flow. This structure may get the more uniform sensitivity field and the vertical installation may get the more axial symmetry of the flow field, which improve the measurement accuracy. In order to minimize the influence of the edge effect, guard electrodes were designed. An anti-edge effect degree Ae was defined to optimize the length of the guard electrode. Different models of effective conductivity of two materials were used in calculating the oil volume fraction of oil-water two-phase flow. The experimental results indicate that Maxwell model is the best model under the condition of oil volume fraction less than 50% and the mean value of the calculation results using Maxwell model and Bruggeman model possesses higher accuracy in the range of oil volume fraction (50%-70%). The experimental results show that the sensor obtains similar measurement performance in both vertical upward and downward flow conditions. The accuracy of the sensor system is 2% when the oil volume fraction less than 50%, and the accuracy is about 5% when the oil volume fraction between 50% and 70%.

Abstract:As an important and necessary part in the intelligent battery management systems (BMS), the prognostics and remaining useful life (RUL) estimation for lithium-ion batteries attach more and more attractions. Especially, the data-driven approaches use only the monitoring data and historical data to model the performance degradation and assess the health status, that makes these methods flexible and applicable in actual lithium-ion battery applications. At first, the related concepts and definitions are introduced. And the degradation parameters identification and extraction is presented, as the health indicator and the foundation of RUL prediction for the lithium-ion batteries. Then, data-driven methods used for lithium-ion battery RUL estimation are summarized, in which several statistical and machine learning algorithms are involved. Finally, the future trend for battery prognostics and RUL estimation are forecasted.