多路本质安全型LiFePO4矿用电池充电仪

LiFePO4电池因其稳定性高,安全性能优越,在矿用领域得到了广泛应用。多路本质安全型LiFePO4矿用电池充电仪专为LiFePO4电池设计,充电严格按照LiFePO4电池的充电曲线,对电池伤害小;由单片机控制,为充分利用单片机资源,设计成多路输出,可同时对多个电池进行充电;电路设计为本质安全型,使LiFePO4电池在井下充电更安全。     

基于DCT变换的数字水印算法研究

提出了一种基于离散余弦变换(DCT)域的数字水印算法,该算法从DCT域的中频开始嵌入代表0和1的不相关的高斯随机序列.实验结果证明,该算法具有良好的不可见性,对噪声、滤波、剪切和旋转攻击都有良好的鲁棒性.     

Automatic 3D model reconstruction of cutting tools from a single camera

Collision detection by machining simulation requires the 3D models of rotating cutters. However, the 3D models of a cutter and holder are not always available. In this paper, a new method is proposed to design an automatic vision-based 3D modeling system, which is able to quickly reconstruct the 3D model of a cutter and holder when they are installed onto the spindle. Only a single camera is mounted on the machine tool to capture the image of the rotating cutter and holder. By viewing the rotating cutter and holder as an object of surface of revolution, the contour of the imaged cutter and holder can be used to reconstruct the 3D model as a stack of circular cross-sections. Then the complete generating function of the cutter and holder can be recovered from the cross-sections. Finally, the 3D model of the cutter is built by rotating the generating function around the spindle axis. The effectiveness and accuracy of the proposed method are verified by experiments on-machine using 12 kinds of cutters and holders, which can satisfy the requirement of collision detection.     

超空泡水下航行器定深控制研究

极高的航速使得对超空泡水下航行器的控制变得异常复杂. 为了对其深度进行有效控制, 必须对其纵平面运动特性进行研究. 本文首先建立了超空泡水下航行器的纵平面运动模型, 分析了其纵平面运动特性; 然后进行了控制算法的综合; 最后, 仿真及试验结果均验证了所设计的航行器纵平面运动控制算法的有效性. 试验结果表明该控制系统具有较高的控制精度. 本文的研究成果为进一步研究水下超空泡航行器的运动控制提供了必要的理论基础.     

Preventive maintenance scheduling for repairable system with deterioration

Maintenance as an important part in manufacturing system can keep equipment in good condition. Many maintenance policies help to decrease the unexpected failures and reduce high operational cost such as conventional preventive maintenance. But these conventional preventive maintenance policies have the same time interval T that may easily neglect system’s reliability, because the system deteriorates with increased usage and age. Hence, this study has developed a reliability-centred sequential preventive maintenance model for monitored repairable deteriorating system. It is supposed that system’s reliability could be monitored continuously and perfectly, whenever it reaches the threshold R, the imperfect repair must be performed to restore the system. In this model, system’s failure rate function and operational cost are both considered by the effect of system’s corresponding condition, which helps to decide the optimal reliability threshold R and preventive maintenance cycle number. Finally, through case study, the simulation results show that the improved sequential preventive maintenance policy is more practical and efficient.     

基于ARM9的分散式数据采集系统的研究

针对传统数据采集系统采集精度与数据处理能力的不足,结合当前广泛应用的嵌入式系统技术和总线技术,基于ARM9处理器S3C2440设计了一种分散式数据采集系统.底层数据采集系统采用了模块化的设计结构,各模块采用统一的总线把数据传送给主控器;最后系统利用ARM9强大的数据处理能力对所有数据进行分析、处理.实际试验证明,该系统数据处理速度快、控制精度高,可满足一般工业现场的要求.     

主动连接的广播教学解决方案

同一VLAN下的2个物理机房,其中一个机房在使用广播软件教学时会对另一个机房产生干扰,并且学生接受教师屏幕时是被动模式．该文介绍了一种使用VNC远程控制软件,实现学生主动连接教师机并且在2个物理机房同时教学时不产生广播教学干扰的方法     

测试软件启动口令的简单实现

介绍了一种基于LabWindowsCVI测试软件启动口令的实现方法。这种方法简单有效,具有一定的实际应用价值。同时,还对这一方法所存在的问题及解决办法作了阐述。     

微机群并行计算机安全开机系统的研发

随着计算机技术的飞速发展,并行计算机用户环境的设计日益成为一个至关重要的问题;并行计算机用户环境的优劣将直接影响到高性能计算机的发展和应用;论文就MPMD型微机群并行计算机的开机方式进行了有意义的改进;MPMD型微机群并行计算机在开启时,需经人工按压开关开启各个节点,多达64个;改进后系统利用MCS-51单片机系统,在实验的基础上确定了开启节点的最佳时间段,实现了利用微处理器开肩多节点的程控开关,可方便地实现了多节点的自动安全连续启动.     

电能质量数据的DCT压缩方法研究

变换编码对于电能质量数据压缩的提高是一项很重要的技术。文章首先介绍了离散余弦变换（DCT）的基本概念,然后对电能质量数据进行映射变换,并利用MATLAB进行仿真研究,利用离散余弦变换将原始电能质量数据映射到离散余弦空间,产生了更有效更紧凑的系数,但是直接对采样数据进行DCT处理,压缩比与精度成反比。提出数据复制组合方法进行改进,实验证明此方法有利于熵编码压缩码率和数据精度的提高。