The kinematics and force analysis of a new leg mechanism for multi-legged wall-climbing robot

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Wavelet network solution for the inverse kinematics problem in robotic manipulator

INTRODUCTION The inverse kinematics problem (IKP) for a ro- botic manipulator involves obtaining the required manipulator joint values for a given desired end-point position and orientation. It is usually complex due to lack of a unique solution and closed-form direct ex- pression for the inverse kinematics mapping. The forward kinematics problem (FKP) is to find the po- sition and orientation of the end-effector based on given joint values which can be easily obtained by analyzing the …     

A novel method for mobile robot simultaneous localization and mapping

INTRODUCTION A key prerequisite for a truly autonomous robot is that it can simultaneously localize itself and accu-rately map its surroundings (Kortenkamp et al., 1998), which is known as Simultaneous Localization and Mapping (SLAM), which, when phrased as a state estimation problem, involves a variable number of dimensions. Murphy and Russell (2001) adopted Rao-Blackwellized particle filters (RBPFs) as an effective way for representing alternative hypotheses on robot paths and ass…     

基于无网格法的一维薛定谔方程的特解新算法

基于径向基函数和有限差分方法,利用无网格方法的特解新算法给出了一维薛定谔方程的数值解,同时给出了数值例子来说明这种方法良好的准确性。并取得了比较好的数值结果。     

曲面柔性制孔机器人末端执行器及其法向姿态调整的一种新算法(英文)

设计了一种曲面柔性制孔机器人末端执行器,并针对该末端执行器提出了一种法向姿态调整的新算法.空间不共面四点可以确定一个与之相切的球面,求出该球面的半径及球心位置,以该球面近似代表制孔点区域的曲面,联结制孔点与该球面球心的矢量即可近似代表制孔点曲面的法矢量.根据这一原理,该算法首先用4个位移传感器测量出曲面上制孔区域内4个点的坐标,并由此计算出制孔位置的法向矢量,然后计算出此法向矢量与末端执行器上电主轴的轴线矢量的误差.根据该误差,进一步计算出末端执行器上2个旋转轴的旋转角度及制孔机器人另外3个直线移动方向的移动距离,从而实现调整主轴在制孔点与曲面垂直的功能.针对2种类型曲面的仿真结果表明,根据该算法可以实现较高的调整精度和效率.     

一种新的遗传算法及其在机器人变结构控制中的应用

A novel genetic algorithm (NGA) is proposed, which possesses micro-regulation and renascence operation. The optimized variable searching interval is regulated gradually according to the sub-group of excellent individuals. The NGA is used to optimize the parameters of the variable structure control (VSC), which satisfies the new reaching law and sliding mode. It is used in robot control systems. Simulation results are given.     

Virtual local target method for avoiding local minimum in potential field based robot navigation

A novel robot navigation algorithm with global path generation capability is presented. Local minimum is a most intractable but is an encountered frequently problem in potential field based robot navigation. Through appointing appropriately some virtual local targets on the journey, it can be solved effectively. The key concept employed in this algorithm are the rules that govern when and how to appoint these virtual local targets. When the robot finds itself in danger of local minimum, a virtual local target is appointed to replace the global goal temporarily according to the rules. After the virtual target is reached, the robot continues on its journey by heading towards the global goal. The algorithm prevents the robot from running into local minima anymore. Simulation results showed that it is very effective in complex obstacle environments. Project (No. 69904009) supported by the National Natural Science Foundation of China     

智能机器人综合路径规划算法在Matlab中的实现

在充分考虑了运动障碍物随机性的基础上,研究了随机运动障碍物的位置分布规律,并结合随机运动障碍物具有惯性的特点,提出了对机器人运动路线进行逐步判别的一种综合路径规划方法。仿真结果表明,该算法正确、高效、实用,对机器人绕过随机运动障碍物具有一定的参考价值。     

Virtual local target method for avoiding local minimum in potential field based robot navigation

INTRODUCTIONAutonomousnavigationisoneofthemostimportanttopicsinthemobilerobotareaandcanbecategorizedintotwoparts:reactivenavigation(Haddadetal.,1998)andpathplanning.Thefirstoneislocalpathplanningbasedandthesecondoneplansapathintheglobalworkspace .Localpat…     

估测湿样品空气渗透系数的近似解析解

利用文献[1]的自然降压法测量非饱和材料的空气渗透系数,推出一个估测湿样品空气渗透系数的近似解析解.通过解析方法和数值方法验证解析解的理论值和实验数据吻合.若忽略可预计的误差,在给定条件下,运用自然降压法得到的近似解析解可求湿样品的空气渗透系数.     

基于Backstepping的双臂空间机器人惯性空间轨迹的鲁棒神经网络跟踪控制

讨论了基于BackStepping方法,载体位置与姿态均不受控制的双臂空间机器人跟踪惯性空间期望轨迹的控制问题．首先基于拉格朗日第二类方法,结合系统动量（动量矩）守恒关系,推导得到了系统动力学方程,并转化为系统状态方程．基于Backstepping方法,针对具有不确定性的双臂空间机器人系统,设计了鲁棒自适应神经网络控制规律,保证了具有不确定性的双臂空间机器人系统末端手爪在惯性空间跟踪期望轨迹的控制．仿真实验证明了该方法的有效性．     

锥杆中应力波传播的放大特性

从变截面杆中一维应力平面波的无量纲控制方程组出发,采用特征线数值解法分析了应力波在锥形杆段中的传播特性,讨论了无量纲参数λ、τ_r和R对透射波放大系数和波形的影响,为应力波放大器的合理设计提供了理论依据。在Hopkinson压杆装置上对锥杆中的应力波传播进行了实验研究。理论分析计算和实验研究结果一致地表明原先由Leftheris提出的计算公式和有关结论是错误的。     

Numerical approach for a system of second kind Volterra integral equations in magneto-electro-elastic dynamic problems

INTRODUCTION In scientific and engineering problems, Volterra integral equations are always encountered and have attracted much attention (Christopher and Baker, 1977; Delves and Mohamed, 1985; Brunner and van der Houwen, 1986; Kress, 1989; Oja and Saveljeva, 2002; Maleknejad and Shahrezaee, 2004; Maleknejad and Aghazadeh, 2005; Zerarka and Soukeur, 2005). Generally, exact solutions are very difficult to find and solutions have been obtained for only some few special cases (Yan and …     

深埋圆形富水隧道应力与位移的弹塑性解

研究目的：推导获得深埋圆形富水隧道应力场与位移场分布的弹塑性解析解。创新要点：皋于弹性力学厚壁圆筒受均布压力的拉姆解答和Mohr—Coulomb屈服条件,推导了考虑渗流作用和应力释放时含衬砌深埋隧道的弹塑性解,并采用FLAC3D有限差分程序验证了其正确性。研究方法：通过理论分析建立考虑渗流作用和应力释放的含衬砌深埋圆形隧道的解析模型（图1）,然后推导了基于Mohr-Coulomb屈服准则的隧道同岩与衬砌渗流场、位移场和应力场计算的弹塑性解析公式,并通过数值模拟程序（图2）验证了推导公式的正确性。重要结论：基于前人研究皋础,推导获得了深埋富水隧道应力与位移场分布的理论解析解,并通过数值模拟方法验证了其正确性。该解析解一方面可以用于深埋高水头隧道的预设计,如预测隧道周围的水压力、应力场和位移场分布规律,另一方面可用于校核大型复杂数值模型的正确性。     

A new local ablation for unresectable primary liver tumor： effect of electrothermal and electrochemical therapy on rat liver

Background： Electrochemical therapy （ECT） has been used to treat unresectable hepatic tumor. In order to improve its efficacy, we combined ECT with hyperthermia induced by electrothermal needle （ETN） （ETECT）. The aim of this study is to investigate the destructive effect of ETECT on normal rat liver. Methods： Twenty rats were randomized into 4 treatment groups （n=5 in each group）： control, ECT alone, hyperthermia alone and ETECT. Following the treatment, sections of the livers were histologically examined by light microscopy and the destructive volumes were measured with micrometer. Results： We found that the destructive volumes in ETECT group were the largest （P〈0.01）. In ETECT group coagulative necrosis was found in both anode and cathode areas, around which transition zones existed. The transition zones can only be seen when coulomb was increased in ECT group. Conclusion： ETECT was demonstrated to enhance the destructive effect of ECT. This study provides theoretical and experimental basis for a new local ablative treatment for unresectable primary liver tumor.     

A transition model for placement of handicapped children in regular and special classes

Mainstreaming and deinstitutionalization are current phenomena which call for a variety of handicapped children to be transitioned to a range of educational settings not previously available to them. A model is presented in which critical transition parameters are conceived as functionally related continua, indicating degrees of readiness for both special and regular classroom settings. The model is based upon actual experience in placement of disturbed, learning disabled, and retarded children into school settings after discharge from a psychiatric hospital.     

一个强耦合捕食模型正解的先验估计

讨论了一个强耦合的Holling-Tanner型捕食模型,利用Harnack不等式和最大值原理给出了它正解的上、下界估计.     

一类球内奇异非线性椭圆型方程边值问题的正的径向对称解

运用打靶法研究一类球内奇异非线性椭圆型方程△u=f(|x|,u,|(?) u|)的边值问题,得到了一个存在正的径向对称解的充分和必要条件,部分的推广了H.Usami于1989年所得的结果.     

侨校各类学生心理健康状况调查研究

文章旨在了解侨校学生心理是否健康的问题,采用SCL-90量表,作为测试工具对四个年级学生进行测量,包括饮食与睡眠、躯体、人际关系敏感、抑郁、焦虑、敌对、偏执、强迫、恐怖、精神病等10个方面,还有针对性地对大学生最受影响的10个方面进行调查。     

As2O3纳米粒的制备、表征和体外治疗人肝癌细胞的研究

研究了As2O3 纳米粒的制备方法、表征及其抗肝癌细胞的作用.采用溶胶凝胶法制备As2O3 纳米粒,并用透射电镜、能谱仪和图像分析仪等方法对其进行表征及特性检测.通过MTT法和流式细胞仪法研究了不同浓度As2O3 纳米粒对人肝癌细胞株的影响,并与传统的As2O3 溶液进行了比较.实验中制备了2种粒径大小的As2O3 纳米粒子,其平均直径分别为80nm和40nm,通过能谱仪的测试证实所制备的纳米粒为As2O3,且无其他成分.体外细胞实验发现,As2O3 纳米粒处理细胞48 h后,人肝癌细胞的存活率明显低于同浓度的As2O3 溶液处理组(P<0.05).研究结果显示,通过溶胶凝胶法可将As2O3 制备成纳米粒子;体外细胞实验表明,与传统的As2O3 溶液相比,As2O3纳米粒子可对肿瘤细胞产生更强细胞毒作用.