Abstract:As increasingly widening gap of computing demand and performance in embedded computing domain, heterogeneous computing architecture which delivers better performance as well as lower power in limited size is gaining more and more attention. At first, the heterogeneous computing model is presented. And the different tightly coupled single chip heterogeneous architectures and their application domain are introduced. Then, task partitioning methods are described. Several programming model technology are analyzed and discussed. Finally, main challenges and future perspective of High Performance Embedded Computing (HPEC) are summarized.

Abstract:Three-dimensional (3D) single-layer microcoils have always been a key element for electromagnetic systems; but they lack an easy and accurate method to calculate the inductance value for their complex 3D micro-structures. This paper employed a curve-fitting process to obtain the associated equation for the inductance value and geometric parameters based on the simulation results. The correction factors regarding helical pitch and wire diameter were reviewed, which are used for compensation in the Nagaoka formula. The simulation process numerically simulated the performance of the 3D microcoils using a FEM electro-magnetic-coupled analysis method. Comparison of the simulated inductance value and the Nagaoka formula was undertaken, which shows that the helical pitch and wire diameter contribute a main role in the calculation error. The derived formula was expressed in a concise form to precisely calculate the inductance value of 3D microsolenoids with single-layer coils.

Abstract:Earth sensors are widely used in spacecraft for attitude determination. They need to have a very large field of view (FOV) (>120°) and relatively low accuracy while being used in the aircrafts around orbit. A triple-FOV infrared earth sensor is proposed in this paper. It uses three pieces of standard infrared detectors with a wavelength range of 14 ~ 16μm, to sense the horizontal circle by detecting the infrared light emitted from the earth. From which, the geocentric vector can be obtained. A mathematic model is established and a validation model is set up to provide input parameters for the mathematic model. The simulation results of the two models show that the output of the mathematic model coincides with the known parameters. Based on the above analysis, a prototype has been built and tested. The test results show that the angle measurement error is about 0.002° and hence such a triple-FOV earth sensor is capable to provide high-precision position information for autonomous navigation.

Abstract:Laser spot thermography is a novel technique for the detection of surface cracks with a laser to heat sample locally and with an IR camera to record the surface temperature distribution. Common methods to characterize cracks are only suitable for the situation that the laser scanning path is vertical to the crack. But due to the randomness of cracks, when the scanning path is parallel to the crack, surface cracks cannot be detected by these methods. To tackle this problem, a method is presented which is suitable for the situation that the scanning path is parallel to crack. The main idea is to evaluate the crack-caused asymmetries of the surface temperature distribution. The effect of temperature gradient and the maximum scanning interval are analyzed by a 2D simulation. A new crack imaging technique is presented that is based on delayed temperature difference at symmetric points to characterize the crack in the thermal image. Compared well with those obtained by the spatial first derivative method, experimental results are shown to efficiently prove this method.

Abstract:This paper presents a design for a magnetic levitation absolute-vibration test system which can be used by vehicles to measure the road surface roughness. The relationship between the vibration test system output voltage and measured speed of the object was obtained through testing, the power spectrum of the measured signal was obtained by virtual instrument analysis, the vibration waveforms of the vehicle over gentle and steep slopes were measured respectively and the road surface roughness was obtained by waveform analysis. Data was saved where the waveforms exceeded threshold. Finally, the steep slope was located using a GPS system. Experimental results show that the magnetic levitation absolute-vibration measurement method has characteristics of high sensitivity and a wide frequency range. This lays the foundation for research into multi-dimensional vibration measurements through magnetic levitation vibration test systems in vehicles.

Abstract:With the rapid development of high-speed-railway, environment around high voltage device on train roof becomes very complicated. Most train accidents happened due to occurrence of flashover on roof insulator, but the insulation condition estimation of insulator in such environment is much difficult. To ensure the insulation property of electric equipment, and guarantee the operation safety of high-speed-train, here established an instrument with high reliability which can on-line monitor insulation condition of roof insulator and give out advanced alarm before the incipient insulator flashover. The instrument consists of three parts, Data Acquisition & Sensor, Data Processing and Back Processing. Anti-interference and protection methods are processed to Rogowski coil sensor for better leakage current signal. To avoid the fluctuation from railway power supply, four modules are set to filter the power supply waveform. Through laboratory measurement, it is shown that the leakage current and the impedance angle can be detected by the instrument accurately. From the comparison of leakage current and impedance angle results under different moisture condition and the alarm operation when leakage current value reached threshold, this instrument can give out enough information for staff to understand the insulation condition of insulator.

Abstract:With the continuous increase of train speed, undulations of catenary and vibrations of the pantograph head result in generating pantograph-catenary arc frequently, intensifying the abrasion between pantograph strip and catenary wire, which has seriously influenced the current collection and safety of electric multi units (EMU). It is necessary to study the pantograph-catenary arc in immediately. Some researchers develop a few pantograph- catenary arc testing equipment, which couldn’t really reflect the operating condition of pantograph-catenary system. In this paper, the pantograph-catenary arc test apparatus was developed, which simulated the flexible and straight contact of pantograph strip and catenary wire, based on the coupling relationship between pantograph and catenary. The equipment was used to research the electrical parameters of the pantograph-catenary arc and the dynamic contact resistance.