基于平移不变小波变换的多普勒速度声纳输出信号处理

针对水下航行器组合导航系统所使用的多普勒速度声纳输出信号的特点,采用了平移不变小波变换的多分辨率分析的方法,利用Daubechies小波函数,采用了半软阈值去噪的方法,能够在低信噪比的情况下准确地估计多普勒声纳的频移,从含有噪声的多普勒输出信号中提取出原始信号.通过仿真实验表明:采用4层小波分解,算法计算量减小,有效地...     

超空泡航行体纵向运动的鲁棒极点配置控制

由于空泡及滑行力的存在,使得超空泡航行体的建模及控制问题变得非常复杂,在其模型简化过程中会产生一定的建模误差,采用鲁棒极点配置算法进行超空泡航行体控制可以有效克服这一缺点.对超空泡航行体所受的流体动力、尤其是滑行力的动态特性进行了分析整理;建立了超空泡航行体纵平面内的动力学模型;最后利用鲁棒极点配置算法设计了控制器.仿真结果表明,该控制系统具有较强的鲁棒性及稳定性.对各控制变量的控制效果进行了对比分析,分析结果表明空化器比尾舵具有更好的控制效果.     

三轴移动载荷对半刚性路面性能影响分析

为研究多轴车辆移动载荷对半刚性路面性能影响规律,针对半刚性路面的特点,依据弹性层状体系理论,将半刚性路面的沥青层、半刚性基层、半刚性底基层及土基层按线弹性考虑,建立了半刚性路面的三维有限元分析模型,分析了车辆三轴移动载荷对半刚性路面性能影响。结果表明,3轴载荷作用下路面应力变化与车辆轴数有关,当车桥依次驶过路面时,路面应力出现3次突变,沥青层三向压应力、半刚性基层和底基层的垂直压应力、横向拉应力和水平拉应力均增大,最大拉应力出现在半刚性基层和底基层结合处;前轴驶过时轮迹带中心区域各层的横向剪应力最大,后轴驶过时轮迹带边缘区域各层的横向剪应力最大,最大值出现在沥青层底部;中轴驶过时路面各层的水平剪应力最大,最大值也出现在沥青层底部。因此,设计路面结构时,半刚性基层和半刚性底基层应选取抗弯和抗拉强度较高的材料,并应加强沥青面层的抗剪强度。     

基于嵌入式多串口扩展的出租车智能导航终端设计与实现

目前,ARM处理器在嵌入式系统中得到了广泛的应用,但其通常只有3个及以下的串口,难以满足需要多串口设备的系统需求;分析研究基于ARM处理器的智能车载导航终端的多串口扩展问题,提出采用具有单串口扩展为5串口功能的串口扩展芯片GM8125,实现嵌入式系统的多串口扩展需求,并在串口通信中采用分层设计的方法,提高系统的稳定性和运行效率;该出租车智能移动导航终端系统经过实际调试与运行,能够实现预定功能且效果良好,能够应用到新型的智能交通调度系统中。     

基于虚拟现实技术的无人机转角控制仿真

无人机飞行状态具有较强的非线性特征,机体绕X轴的转动惯量较小,副翼的舵效相对较高,受到扰动后滚转角速率变化很快,使得无人机的横侧向控制成为转角控制的难点问题.传统采用转角跟踪器的无人机转角控制方法中,反馈线性化过程较为繁琐,对于模型精度要求较高,无法适应不断变化的无人机飞行状态.提出一种应用虚拟现实技术的无人机转角控制方法,用三维实景仿真塑造虚拟的无人机飞行区域实景,在无人机运动过程中,辅助操纵手在目视距离内,由增稳控制或人工遥控方式对飞机转角进行操作,并通过三维建模来对无人机机体模型和舵面模型进行构建,并导人到相应的环境中,再通过相应程序对无人机的运动和舵面的转角进行有效的控制,从而实现无人机转角的准确控制.仿真结果表明,相比传统控制方法,所提方法控制下的无人机转角的响应速度更快,具有高的控制效率,在各种扰动的情况下,均可以实现无差的控制跟踪.     

煤炭漏斗车装卸载过程仿真

煤炭漏斗车端、侧墙侧压力是车体静强度校核中的重要作用载荷.运用离散单元法,建立煤炭漏斗车仿真模型,对装卸载过程中车体所受的侧压力进行了仿真分析,并对车体内部的压力场和速度场的分布情况进行了分析.仿真结果表明,装载平衡后,端、侧墙侧压力沿墙高呈非线性分布;卸载过程中,侧墙侧压力呈现明显的波动变化.研究结果说明,离散单元法用于模拟和分析漏斗车车体压力及散粒体流动规律是可行的.仿真结果对漏斗车车体结构的研发具有一定的现实指导意义.     

Profile based routing in vehicular ad-hoc networks

One of the main problems in the VANET(vehicular ad-hoc network)routing algorithms is how to establish the stable routes.The link duration in these networks is often very short because of the frequent changes in the network topology.Short link duration reduce the network efficiency.Different speeds of the vehicles and choosing different directions by the vehicles in the junctions are the two reasons that lead to link breakage and a reduction in link duration.Several routing protocols have been proposed for VANET in order to improve the link duration,while none of them avoids the link breakages caused by the second reason.In this paper,a new method for routing algorithms is proposed based on the vehicles trips history.Here,each vehicle has a profile containing its movement patterns extracted from its trips history.The next direction which each vehicle may choose at the next junction is predicted using this profile and is sent to other vehicles.Afterward each vehicle selects a node the future direction of which is the same as its predicted direction.Our case study indicates that applying our proposed method to ROMSGP(receive on most stable group-path)routing protocol reduces the links breakages and increases the link duration time.     

基于ADSP-2188的铅酸电池智能管理系统研究

针对铅酸电池单体差异性以及对温度、电流、电压敏感等缺陷,设计基于ADSP-2188的智能管理系统.     

Hierarchical inversion‐based output tracking control for uncertain autonomous underwater vehicles using extended Kalman filter

In this study, a hierarchical inversion‐based output tracking controller (HIOTC) is developed for an autonomous underwater vehicle (AUV) subject to random uncertainties (e.g., current disturbances, unmodeled dynamics, and parameter variations) and noises (e.g., process and measurement noises). The proposed HIOTC respectively utilizes a combination of feedforward and feedback controls in a hierarchical structure based on the kinematic and dynamic models of the system. Moreover, to obtain uncontaminated or unavailable states for implementing the proposed control law, the extended Kalman filter (EKF) is employed to estimate the system states. Then, the position outputs, orientation, and velocity of the AUV are reached with guaranteed asymptotic stability. The robustness of the proposed HIOTC is verified through injection of random uncertainties into the system model. The closed‐loop stability of the proposed individual subsystems is respectively guaranteed to have uniformly ultimately bounded (UUB) performance based on the Lyapunov stability criteria. In addition, the asymptotic tracking of the overall system is demonstrated using Barbalat's lemma. Finally, the feasibility and effectiveness of the proposed control scheme are evaluated through computer simulations and it is shown that the overall system achieves good asymptotic tracking performance.     

客户分类下生鲜配送两级路径问题与算法研究

生活水平的提高使得消费者对生鲜产品的需求不断增长,进而促进了冷链物流行业的快速发展。将客户按重要性分为重要客户和普通客户两类,以总配送成本最小为目标,建立考虑客户分类的两级容量有限车辆路径优化模型。提出两阶段启发式算法求解该模型：第一阶段设计改进的遗传-模拟退火算法增强全局搜索能力,其中采用轮盘赌选择机制结合精英保留策略保留优秀个体,部分匹配交叉算子结合自适应交叉率维持种群多样性,Metropolis准则以一定概率接受较差解;第二阶段使用精确方法求解一级配送路径。基于Perboli的Set2算例集和Hemmelmayr的Set5算例集,共30个基准案例,分别将所提出算法与四种现有算法进行对比分析,验证了改进算法的效果,并测试了算法的收敛性。基于模拟数据进行模型分析,验证了所提出模型和算法的有效性和适用性。