履带式移动机器人轨迹跟踪控制技术研究

随着移动机器人在工业、农业、军事等领域中的广泛应用,对其自主运动控制技术的需求逐渐增大.为了实现履带式移动机器人的轨迹跟踪控制,建立了运动学模型和轨迹跟踪动态误差模型.基于Lyapunov稳定性理论,提出了一种状态反馈控制律,并通过Lyapunov函数对控制律的稳定性进行了证明.为了评估所提出控制律的性能,在Matlab/Simulink环境下分别进行了直线轨迹跟踪和圆形轨迹跟踪仿真实验.仿真实验结果表明,所设计的控制律能够快速有效地实现直线轨迹跟踪与圆形轨迹跟踪,具有较好的控制效果,可应用于履带式移动机器人轨迹跟踪控制的实际项目中.     

Structure and permanent magnetic properties of SmFex （x=3-8） melt spun ribbons during heat treatment

Compounds with the composition SmFex（x=3–8） were prepared by melt spun method at a velocity of 40 m/s and subsequent annealing at temperature between 600–1000 ℃. The crystal structures of the as-quenched and as annealed powders were investigated by XRD methods with following Rietveld analysis. The glass forming ability could be enhanced by the increase of Sm content to x≤5.Metastable Sm5Fe17-type structure existed when 3≤x≤5 and temperature was lower than 800 ℃. SmFe2-type structure could be stable up to 1000 ℃ when x〉3 and temperature was under 800 ℃. The content of SmFe2-type decreased with the increase of x value and increased with temperature lower than 800 ℃, from which SmFe2-type started to bring the transition to SmFe3-type. As for Sm5Fe17-type compounds with x=3.4, the highest coercivity of 33.6 kOe could be obtained under a velocity of 30 m/s and heat treated under 700 ℃×1h.     

矿用带式输送机多目标参数协同优化控制储能方法

利用超级电容储能是实现矿用带式输送机节能的有效方法,但仅靠负载功率预测控制存在能量利用率低的问题。为此,提出了一种多目标参数协同优化控制策略。在负载功率预测基础上,综合考虑储能单元和电机能量流传递规律,设计了不同运行工况下的功率优化算法,实现了储能单元和电机能量的优化传递,实时求解约束条件下超级电容的目标电流和电机的目标转速,从而实现多目标参数协同优化。研究表明,采用提出的策略能有效提高矿用带式输送机的能量利用率。     

玉米须水提物改善高脂饮食诱导大鼠非酒精性脂肪性肝病的研究

非酒精性脂肪性肝病(NAFLD)可增加肝硬化和肝癌的发病率,然而目前却没有特定的治疗药物.采用高脂饮食(High Fat Diet,HFD)喂养建立NAFLD大鼠模型,并同时灌胃给予玉米须水提物(corn silk aqueous extract,CSAE)进行干预,考察CSAE对NAFLD的抑制作用.实验结束后收集血...     

Crystal structure and hard magnetic properties of TbCu_7-type Sm_(0.98)Fe_(9.02–x)Ga_x nitrides

The compound Sm0.98Fe9.02–xGaxNδ(x=0, 0.25, 0.5, 0.75, 1) were prepared by melt-spun method and subsequent annealing and nitriding. The Rietveld analysis showed that the lattice expansion played an important role in improving the Curie temperature. An obvious development of the Curie temperature was obtained with the increased Ga content from x=0–1(ΔTc=90 oC). The optimum coercivity of nitrides was obtained at x=0.25 with the value Hcj=652 kA/m(8.15 kOe) after annealing, which corresponded to a reasonable distribution of grain sizes of both TbCu7-type SmFe9Nδ and α-Fe. However, an excess of Ga doping might lead to an abnormal growth of α-Fe, which in turn deteriorated the magnetic properties. It was concluded that a moderate Ga content was very effective in raising the coercivity and Curie temperament in the TbCu7-type Sm-Fe-N.     

新型煤水分离及水循环再利用成套装备设计

为解决煤矿井下水力冲孔作业时煤水分离不彻底、水循环利用不高效的问题,设计了一种以脱水筛为主要装置的煤水分离及水循环利用成套装备。新型煤水分离装备主要由液压系统、脱水筛、泥浆泵、文丘里射流器及其他附件组成,通过渣浆泵将煤水混合物导入脱水筛,在脱水筛的作用下实现煤水分离,水流入储水箱以备循环使用,煤泥自动装袋,较好地对水煤进行了实时分离,改善了作业环境,提高了工作效率,经济效益良好。     

TD-LTE多用户双流波束赋型技术分析和评估

文章评估了TM8MU－BF和SU－BF的性能,并提出多项提高BF性能的实现优化方案,包括上行探测参考信号（SRS）的多小区协调分配方案和多用户配对的优化方案等。仿真结果显示,在目前的产品能力下,MU－BF相比SU－BF约有20％的性能增益;而引入优化的实现方案后,SU－BF性能进一步提升约10％,MU－BF性能进一步提升约25％。     

竞争对手会影响你的定价吗？

影响中国酒店业盈利的因素有很多,其中最直接、力度最大者是成功的定价策略,这个看似简单的业务决定其实纷繁复杂,同时有潜在的风险。     

MMC-HVDC站内交流母线故障特性和保护策略

为了保证模块化多电平换流器型直流输电的高效和稳定运行,需要对于MMC-HVDC系统的故障形式和故障机理进行详尽的分析,对其继电保护原理及保护判据进入深入的研究。简要介绍了MMC-HVDC保护系统的保护分区、不同保护的动作方式及所需数据的测量方式。深入分析了MMC-HVDC系统站内交流母线故障(接地短路和相间短路)的故障暂态响应,研究了站内交流母线故障后采用的保护策略,提出采用比率制动特性的电流差动保护,能够可靠躲开外部故障时由于电流互感器饱和等因素引起的不平衡电流,同时又能可靠保证站内交流母线内部故障时的灵敏度。在RT-LAB实时仿真平台中验证所做分析和所提保护策略的有效性。