The development of power supply technology has always been associated with the need for further miniaturization. One aspect of this trend is a design based on mathematical and physical principles and ...the implementation of magnetic components. The use of planar inductors and transformers offers the best preconditions for realizing this objective as they allow the windings to be integrated directly in the circuit board. Even when only a single series of planar cores is used, exactly identical winding configurations may have different air-gap positions. Different winding losses then result as a function of this position. The following paper presents a procedure for determining the effect of the air-gap position on the winding losses in planar inductors and its practical applicability on the basis of real examples.
Quadrotor Helicopter or simply quadrotor is rotorcraft that has four lift-generating propellers. Two of the propellers spin clock wise and the other two counter-clockwise. Control of the machine can ...be achieved by varying relative speed of the propellers. Quadrotor concept is not new, however the modern quadrotors are mostly unmanned. Advancement in miniaturized IMU technology, availability of high speed brushless motors and high power to weight ratio Li-Polymer battery technology, quadrotors can now be successfully designed and fabricated. This paper proposes a mathematical model of quadrotor dynamics. A simplified approach is adopted using momentum theory, where the gyroscopic effect and air friction on frame of machine has been neglected, resulting in a simplified model, which is useful for designing a controller to stabilize the machine in hover state. Proposed model is non-linear since the rotor dynamics are a function of square of motor inputs.
A linear parallel compliant XY-stage for ultra-precision motion is proposed. The prismatic joints of the compliant stage are implemented by three kinds of flexural joints. Among the flexural joints, ...a modified double compound linear flexural joint has the function of linear motion guide and displacement amplification so that the compliant mechanism has compact structure. The parallel linear compliant mechanism is analyzed, designed, machined by wire electric discharge machining, and then integrated with stack type piezoelectric elements for driving forces and capacitance-type displacement sensors into an ultra-precision stage for 2-DOF linear motions. Experiments demonstrate the characteristics of the ultra-precision stage implemented by the compliant mechanism.
Rain Removal Using Kalman Filter in Video Wan-Joo Park; Kwae-Hi Lee
2008 International Conference on Smart Manufacturing Application,
2008-April
Conference Proceeding
In outdoor environment vision system, weather effects are complex noise. They degrade the performance of vision algorithm such as feature detection, segmentation and object recognition. Rain scene ...has property that an image pixel is never always covered by rain throughout the whole video. Even though we can only see a short distance ahead because of heavy rain, each pixel of the scenes taken by camera is not always covered by rain. If pixel is affected by rain, this pixel has large intensity but this pixel has original chromatic information. Consequently we make a recovery to original color value via decreasing intensity to original value. Proposing recursive data processing, we can estimate the intensity value of each pixel. And this method needs the periodic reset. If unsuitable estimated mean value is determined because of heavy noise, henceforth cleanly captured scene has little weight effect for estimated mean value. Accordingly we reset the weighted value between estimated intensity and new captured one. Additionally, the proposed method has big advantages, including small equation by repeatedly estimating the mean of intensity and handling in real-time and benefits that too simple and it can implement to real time processing. And we obtain more pure scene than existing methods.
Nanoimprint lithography has been demonstrated as a high-throughput, high-resolution and low-cost manufacturing method on nano scale pattering since it was first proposed by Dr. S.Y. Chou in 1995. In ...this article we presented a general literature review on the roller-type nanoimprint tithography (RNIT), a continuous nanoimprint lithography process. Several kinds of typical Roller-type Nanoimprint Lithography process have been briefly introduced and some examples are also introduced to gain a clear general view and perceive.
In the European funded project E3Car (ENIAC) the available power module technologies for Electric Vehicles (EV) are evaluated and tested. Up to now there are some automotive qualified power modules ...mostly for Hybrid electric vehicle applications on the market with rated blocking voltage up to 600V. But there are almost no 1200V automotive power modules available. This paper describes the optimization of an industrial power module by using the Finite-Elements-Method (FEM) for an improved thermal management. Starting with existing industrial power modules in this paper the baseplate design was investigated in general with simulations and thermal measurements. Then the baseplate thickness was varied in simulation in order to get a thermal optimum due to e.g. heatspreading. Then power modules with optimized baseplate design were realized and thermally investigated. Finally power cycling tests have shown that the lifetime compared to an original industrial power module was almost doubled.
Rapid prototyping (RP) processed parts are mainly fabricated by layered manufacturing process. Hence stair steps occur at surface of the part and affect the quality of the surface. Also, the surface ...roughness by the stair step depends on surface angle. Therefore, prediction of the surface roughness distribution by the change of surface angle for a part to be processed is required on the process planning stage of the RP. This paper proposes a methodology to express surface roughness distribution of the part which is processed by the FDM. In order to reflect actual roughness distribution in computing, a surface roughness distribution equation is presented based on interpolation using measured roughness values. And, the computing accuracy by the number of the measured roughness data is analyzed. The implemented results show that the proposed methodology can be practical.
Cutting fluid in machining is important due to their role in reducing tool wear and improving surface finish. However, controlling the usage is imperative due to the ecological and/or economical and ...reasons. Minimum quantity lubrication (MQL) has recently emerged as a viable option to minimize the amount of fluid used in machining without sacrificing its lubrication and cooling in machining. This paper presents our effort to understand the parameters in the MQL process in order to expand its effectiveness in cutting operations. Although some literature regarding the influence of flow rates and nozzle directions is available, this information is insufficient. This paper studies three new parameters in the MQL process, namely the droplet size, the droplet size distribution, and the wetting angle. Confocal laser scanning microscopy (CSLM), wavelet filtering, and image processing algorithms were used to calculate the droplet geometry and distribution for various commercially available MQL oils. The wetting angles of the oils were measured by depositing oil droplets onto TiSiN and TiAIN coated inserts. The parameters studied are important to estimate the comparative performance of lubricant-coating pairs.
The development of power supply technology has always been associated with the need for further miniaturization. This means that power semiconductors must be mounted at short distances on the same ...heat sink. Adjacent power semiconductors have an increasing influence on the chip temperature. The maximum junction temperatures, which are specified by the manufacturer under all operating conditions, may not be exceeded. As a rule, the chip temperatures are calculated on the basis of the losses and thermal impedance of a power semiconductor according to manufacturer's specifications. The following paper presents a procedure for determining the junction temperatures of power semiconductors in switch-mode power supplies, considering common heat-sink and arbitrary power-loss functions.
This paper describes a new approach to analyze road images which often contain vehicles and extract license plate (LP) from natural properties by finding vertical and horizontal edges from vehicle ...region. The proposed technique consists of three main modules: (a) segmentation technique named as sliding concentric windows (SCW) on the basis of a novel adaptive image for detecting candidate region, (b) refining by using HSI color model on the basis of using hue and intensity in HSI color model verifying green and yellow LP and white LP, respectively and (c) finally, verify and detect VLP region which contains predetermined LP alphanumeric character by using position histogram. In the proposed method, input vehicle images are converted into gray images. After then the candidate regions are found by sliding concentric windows. We detect vehicle license plates (VLP) region which contains predetermined LP color by using HSI color model and LP alphanumeric character by using position histogram. Experimental results show that the proposed method is very effective in coping with different conditions such as poor illumination and varied weather. Experimental results also show that the distance from the vehicle varied according to the camera setup.
