Advanced Materials Research Vols. 712-715

Abstract: According to the simulation by Finite Element Analysis (FEA) for rings with different sizes, how thickness vibration resonance frequency varying as piezoelectric ring structure changing is studied. The relation between thickness vibration mode and height, thickness and radius is obtained. The bandwidth of single circle being narrow has been obtained at the same time, so the method that two high frequency piezoelectric ring oscillators are stacked in axis direction and their structure are optimized to get two times as much as the monocyclic bandwidth is researched, according to the trend of single ring.

Abstract: This paper discusses the design, implementation and analysis of a system analysis for wireless sensor network. Current testing systems have low efficiency on software environment. We proposed a service oriented software approach, and gave out an experimental analysis of reliability. The testing system greatly decreases the development workload on server. Experiment reveals that the result of reliability analysis is accurate and the testing system is effective.

Abstract: According to IEC61000-4-2, the influence of ESD EMP on the wireless antenna is studied by the injection experiments and radiation experiments in this paper. The results of experiments show that the ESD EMP has significant influence on the wireless antenna, and various kinds of failures such as breakup, restart may be occurred. In order to solve this problem, a wireless protection program has been designed, in which the TVS diode was used as the first lever for protection and the π-type high pass filtering network as the second lever. This program not only has the traditional function of ESD protection, which can avoid the high voltage damage to the internal circuit, but also achieve the purpose of load matching, ensuring the signal source not distortion.

Abstract: For wireless sensor network (WSN), without full consideration of the influences of unknown nodes distribution and density when planning beacons moving path, most of existing localization methods have lower efficiency. In this paper, beacon model is presented according to the theory of equal distance 3-optimal-coverage, a new heuristic path planning method is proposed for the ROI in which unknown nodes distribute randomly and the node density is limited, this proposed method can make on-line decision for the moving direction and distance over every step. Simulations show that the proposed scheme is efficient.

Abstract: Localization and navigation algorithm is the key technology to determine whether or not an AGV (automatic guided vehicle) can run normally. In this paper, we summarize the popular navigation technologies first and then focus on the positioning principle of Nav200 which is adopted in our AGV system. Besides that, the map building method and the layout of the reflective board is also introduced briefly. This paper introduced two navigation methods. The traditional navigation method only uses the sensor data and the electronic map to guide AGV. To improve positioning accuracy, we use the Kalman filter to minimize the error of localization sensor. At last some simulation work was done, the results shows that the localization accuracy was improved by adopting Kalman filter algorithm.

Abstract: According to the problem of petrochemical heat equipment status inspection and fault diagnosis, a method based on threshold value of infrared image segmentation was presented. Studying the infrared image segmentation based on threshold value we can get the relationship between threshold value and the target area, threshold value and the temperature. Categories of differential variance method and optimal threshold value method of the experimental results were compared, and feasibility of this method was verified.

Abstract: To solve the unknown faults diagnosis online for analog circuit, a novel faults diagnosis strategy based on improved kernel fuzzy c-means (IKFCM) is proposed. simultaneously, the high-performance recognition tree structure of the improved kernel fuzzy c-means itself can decrease the train sample and eliminate wild value, the training speed and precision of classifier can be done well in this way. The realizing of precision fault diagnosis, firstly, via confirming exact class centers from the data of known faults, and then the mean value can be obtained relying on the faults data of each class, meanwhile, setting this mean values as the thresholds for judging faults and each data point is issued with a class label. During the whole faults diagnosis, each detection data will be compared with the thresholds, the high similarity detection data will be fall into the known faults classes while the low similarity detection data will be labeled as unknown faults. Simulation proved the well performance effectively of the proposed IKFCM method .

Abstract: To resolve the problems that the initial state of charge (SOC) and the available capacity of batteries are difficult to estimate when using the Ah counting method, in this paper An improved SOC estimation method was proposed that combined with the open circuit voltage (OCV) method and Ah counting method based on the analysis and consideration of the battery available capacity variation caused by charge and discharge current, environment temperature and battery state of health (SOH). The precision of the proposed method was validated by using Federal Urban Driving Schedule (FUDS) test of a Lithium iron phosphate (LiFePO4) power battery. The SOC estimate error using the proposed method relative to a discharge test was better than the Ah counting method.

Abstract: Space infrared early warning satellite is an important platform for detecting ballistic missile launch and trajectory. This paper established observation satellite motion model, and the motion state of the satellite at any time was gotten based on its initial information by numerical integration methods. According the theory of double satellites location and satellite observation data of ballistic missile, the observation trajectory of ballistic missile was fitted. The trajectory was used to build the motion model of ballistic missile, and the position, speed and other parameters of the ballistic missile can be inferred. Finally, simulation experiment was conducted.

Abstract: This paper presents a tolerance analog circuit hard fault and soft fault diagnosis method based on the BP neural network and particle swarm optimization algorithm. First, select the mean square error function of BP neural network as the fitness function of the PSO algorithm. Second, change the guidance of neural network algorithms rely on gradient information to adjust the network weights and threshold methods, through the use of the characteristics of the particle swarm algorithm groups parallel search to find more appropriate network weights and threshold. Then using the adaptive learning rate and momentum BP algorithm to train the BP neural network. Finally, the network is applied to fault diagnosis of analog circuit, can quickly and effectively to the circuit fault diagnosis.