基于DS-LCC拓扑抗偏移性的建模与优化

针对无线电能传输(WPT)系统中线圈偏移导致功率及效率波动问题,提出基于双边LCC(DS-LCC)拓扑WPT系统的改进模型。首先,对该模型进行传输特性分析,推导出不同横向偏移条件下线圈互感与传输特性间对应的函数式。其次,引入归一化方法并确定偏移后线圈匝数与耦合强度及线圈内阻的线性关系。在上述基础上通过对系统进行参数优化设计,实现特定横向偏移范围内系统输出功率和传输效率抗偏移性的提升。最后,搭建一台100 W的实验样机对理论分析进行验证。结果显示在0~20 cm的横向偏移范围内系统的输出功率始终高于80 W,传输效率始终高于70%。     

Improved inter-view correlations for low complexity MV-HEVC

The more advanced multi-view extension, MV-HEVC, effectively exploits visual similarities between multi-view videos and enables high compression efficiency. Each view in the multi-view sequence depends on the captured scene, the distance between cameras and recording angles. Increasing the distance between dependent viewpoints generates an inter-view disparity. This impacts the inter-view similarities, affects the disparity estimation and further increases the computational complexity of the MV-HEVC encoder. In this paper, an efficient earlier disparity estimation is proposed for low complexity MV-HEVC. This algorithm is based on reducing the complexity of disparity estimation by eliminating the inter-view offset. Moreover, the inter-view similarities are controlled by considering the reliability of each coding unit size in the search range. This reliability is estimated by reducing the number of searching points within a new limited window. For reliable motion estimation, we further proposed an earlier decision of coding units splitting in the dependent views according to those in the reference views. Experimental results show that the proposed algorithm can achieve an average encoding time saving of 20.37%–40,61% with marginal performance degradation.     

采用超低失调运放的集成积分器的设计与实现

采用特殊技术方法控制二级运放中特定MOS管尺寸,设计出一种超低失调电压的运算放大器,并将其应用到集成积分器的设计.然后基于理想积分器的工作原理,用一种新的方法,设计并实现了一种有超低失调运放的集成积分器.设计采用HHNEC0.18μm CMOS工艺,在Cadence环境下利用Hspice进行仿真,结果显示,运放失调为556nV,增益以及相位稳定裕度较大;积分器在1kHz频率工作时显示出良好的工作特性.版图设计考虑了失配与匹配的问题,并且通过了DRC和LVS规则检查.     

On the effect of tool offset in hybrid-FSW of copper-aluminium alloy

Tool offset is one the most significant parameters in joining of dissimilar materials by friction stir welding (FSW) process. An investigation is carried out on the effect of tool offset toward thermal history, material flow pattern, mechanical properties, welding force, and weld joint morphology. It was found that offsetting toward aluminum side along with a plasma-assisted heat source is an efficient approach to address one of the most important apprehensions in aluminum-copper solid-state welding process. The offset influences the amount of intermetallic at the joint interface and in-effect impacts on final strength and material flow behavior. The optimum and continuous layer of intermetallic produces the maximum weld joint strength. The specimen welded with optimum tool offset shows the highest strength using 55 A plasma current in hybrid friction stir welding process.     

时频域联合校正的PN码相干捕获算法

受多普勒频偏和本地时钟漂移的影响,接收信号中存在频偏且码字不同步。针对该问题,提出一种时频域联合校正的PN码相干捕获算法。从接收信号的循环平稳特性出发,进行载波频率和码字同步的联合校正,使校正后的信号与本地PN信号具有近似相干性。基于设计的相关特征函数,实现较长相关长度下的相干检测,完成PN码捕获。仿真结果表明,该算法在低信噪比、大频偏条件下,具有较高的检测概率。     

Linear offset-free Model Predictive Control

This work addresses the problem of offset-free Model Predictive Control (MPC) when tracking an asymptotically constant reference. In the first part, compact and intuitive conditions for offset-free MPC control are introduced by using the arguments of the internal model principle. In the second part, we study the case where the number of measured variables is larger than the number of tracked variables. The plant model is augmented only by as many states as there are tracked variables, and an algorithm which guarantees offset-free tracking is presented. In the last part, offset-free tracking properties for special implementations of MPC schemes are briefly discussed.     

无线传感器网络整合时钟同步方案

针对多数无线传感器网络时钟同步方案存在的仅纠正时钟偏移问题,提出一种新的解决方案,整合时钟偏移同步和时钟速率同步,通过3个连续的消息传输实现单跳同步,采用分层的生成树实现多跳同步。仿真实验结果表明,与现有的同步方案比较,该方案的同步错误更小,能够获得更长的再同步周期。     

微球探针制备工艺的优化

为了解决现有激光微球探针加工技术中存在的探针尖端微球球心偏离针杆中轴线的问题,提出了一个两步法加工策略.以CO2激光光束为热源,对探针针杆尖端进行加热,使针杆尖端受热融化产生微球.然后将带有微球的探针针杆绕其中轴线旋转180°,再使用CO2激光光束辐照带有微球的探针尖端,对尖端微球偏移量进行补偿.实验结果表明:采用“熔球-旋转再熔球”的两步法加工策略,能明显降低探针尖端微球相对于针杆的弯曲程度,缩小探针尖端球形球心和针杆中心线的偏移距离.     

低信噪比下基于新型变步长LMS的自适应滤波算法

为了提高现有的变步长LMS算法在低信噪比环境下的滤波性能,提出了一种新的变步长LMS自适应滤波算法。该算法利用加入补偿项的误差相关值估计与前一时刻步长因子的组合来调节步长,提高算法的抗噪声干扰能力和收敛速度;并将步长因子的传统固定约束范围改为动态约束范围,使步长变化趋于平滑,降低系统的失调误差;同时对系统的权向量迭代公式进行更新,提高了算法的输入范围。从理论分析和仿真实验两方面可以看出,新算法与现有的变步长算法及标准LMS算法相比,在信噪比较低的条件下收敛速率、抗扰能力、稳态失调噪声方面都有很大的改善,证明所提算法是有效、可行的。     

基于GL847的扫描图像校正

扫描仪在扫描成像过程中,诸多因素会给扫描图像带来误差和扭曲,因而必须对其加以校正。在分析扫描仪误差产生原理的基础上,详细讨论了基于GL847的扫描图像增益与偏移校正机制,提出了一种有效的扫描图像校正参数获取方法。