关键词： 球形机器人   动力学   凯恩方法  

摘要： 利用凯恩方法建立了非理想条件下球形机器人的动力学模型。分析了关节摩擦、滚动摩阻力矩、球壳不圆对球形机器人运动特性的影响,给出了球形机器人运动过程中球壳打滑问题产生的原因,仿真结果为球形机器人控制策略和机械设计提供了理论依据。

关键词： 柔性杆柔性铰机器人   载荷   刚-柔耦合   动力学  

摘要： 为了研究柔性机器人在做大范围运动时关节铰的柔性以及杆端载荷对机器人运动响应的影响,对带有载荷的柔性机器人进行了刚柔耦合动力学建模。将柔性铰的柔性简化为线弹性扭簧,计及柔性铰质量。考虑柔性杆横向弯曲变形和纵向拉伸变形,且在纵向位移中计及由于横向变形而引起的纵向缩短项,即非线性耦合变形项。采用假设模态法描述柔性杆变形,运用第二类Lagrange方程推导得到了带有载荷的柔性杆柔性铰机器人的刚柔耦合动力学方程。求解这组方程得到柔性机器人的动力学性态。将带有载荷的柔性杆柔性铰机器人与不带载荷的柔性杆柔性铰机器人对比发现,柔性杆末端载荷增大了系统的响应幅值,降低了响应频率。将柔性杆柔性铰机器人与柔性杆刚性铰机器人对比发现,铰的柔性作用同样使系统的响应幅值增大,响应频率减小了。

关键词： Dynamics modeling   Kinematics   Lagrange equations   Parallel mechanism   Virtual work  

摘要： Recursive matrix relations for kinematics and dynamics analysis of two known parallel mechanisms: the spatial 3-PRS and the planar 3-RRR are established in this paper. Knowing the motion of the platform, we develop first the inverse kinematical problem and determine the positions, velocities, and accelerations of the robot's elements. Further, the inverse dynamic problem is solved using an approach based on the principle of virtual work, and the results can be verified in the framework of the Lagrange equations with their multipliers. Finally, compact matrix equations and graphs of simulation for power requirement comparison of each of three actuators in two different actuation schemes are obtained. For the same evolution of the moving platform, the power distribution upon the three actuators depends on the actuating configuration, but the total power absorbed by the set of three actuators is the same, at any instant, for both driving systems. The study of the dynamics of the parallel mechanisms is done mainly to solve successfully the control of the motion of such robotic systems.

摘要： Highlights ► Robotic surgery may offer potential advantages over laparotomy in patients with gynecologic cancer. ► Advantages of robotic surgery over traditional laparoscopic surgery remain to be defined. ► Guidelines for robotic surgery credentialing and training should be defined and future development encouraged.

关键词： Proactive visual attention   Multiple time recurrent neural networks   Premotor theory of visual attention   Multiple objects manipulation task  

摘要： The current paper proposes a novel model for integrative learning of proactive visual attention and sensory-motor control as inspired by the premotor theory of visual attention. The model is characterized by coupling a slow dynamics network with a fast dynamics network and by inheriting our prior proposed multiple timescales recurrent neural networks model (MTRNN) that may correspond to the fronto-parietal networks in the cortical brains. The neuro-robotics experiments in a task of manipulating multiple objects utilizing the proposed model demonstrated that some degrees of generalization in terms of position and object size variation can be achieved by organizing seamless integration of the proactive object-related visual attention and the related sensory-motor control into a set of action primitives in the distributed neural activities appearing in the fast dynamics network. It was also shown that such action primitives can be combined in compositional ways in acquiring novel actions in the slow dynamics network. The experimental results presented substantiate the premotor theory of visual attention.

关键词： 并联机器人   动力学模型   计算机辅助方法   凯恩方法   单刚体   PID控制器  

摘要： 为了对六自由度并联机器人动力学模型进行充分验证和分析,并提高建模与分析的效率,提出在Simulink和SimMechanics环境下进行动力学建模与分析的计算机辅助方法.将六自由度并联机器人描述为单个刚体,采用凯恩方法建立其单刚体动力学模型,设计了基于铰点空间控制策略的经典PID控制器,并在Simulink和SimMechanics这2种环境下进行了动力学建模仿真,六自由度并联机器人的动力学响应完全一致,说明了在Simulink和SimMechanics 2种环境下的动力学模型都是正确的,并且所提出的方法也可应用于所有机械系统的动力学建模与分析.

关键词： 轮式移动机器人   轨迹跟踪   动力学模型   自适应滑模控制   反演技术  

摘要： 通过对一类质心和几何中心不重合情况下轮式移动机器人控制问题的研究,提出了一种具有全局渐近稳定的自适应滑模轨迹跟踪控制律。首先针对系统的运动学模型,设计了一个运动学控制器;然后基于动力学模型和运动学控制器,利用反演技术和积分滑模控制的思想设计了自适应滑模控制器,该控制器能有效地克服未知扰动的影响。并利用Lyapunov稳定性理论证明了系统的稳定性且跟踪误差收敛,满足了移动机器人的轨迹跟踪要求,且具有设计方法简单、鲁棒性强的特点。最后通过2个仿真算例验证了所提控制律的有效性和正确性。

关键词： 胶囊机器人   空间旋转磁场   磁驱动力矩   流体力矩   随动效应  

摘要： 为了实现旋进式胶囊机器人在充满黏性液体弯管内的无碰撞转弯行走,提出一种离散逼近的空间万向旋转磁场控制策略,采用与机器人相连的赖柴坐标系确定机器人的姿态,建立旋转磁场与机器人内驱动器耦合所产生的空间磁力矩模型和弯管液体环境对机器人转弯运动响应的流体力矩模型,对转弯过程中磁力矩和流体力矩的动态响应特性进行理论研究。结果表明在转弯过程中外旋转磁场使机器人发生随动效应,流体力矩使磁力矩诱导的摆动响应迅速衰减现象有利于机器人在弯曲环境内的非接触式驱动。

关键词： prostatectomy   robotic surgery   centralization   RALP   prostate cancer   surgical volumes  

摘要： BACKGROUND: Robotic surgery has been widely adopted for radical prostatectomy. We hypothesized that this change is rapidly shifting procedures away from hospitals that do not offer robotics and consequently increasing patient travel. METHODS: A population-based observational study of all prostatectomies for cancer in New York, New Jersey, and Pennsylvania from 2000 to 2009 was performed using hospital discharge data. Hospital procedure volume was defined as the number of prostatectomies performed for cancer in a given year. Straight-line travel distance to the treating hospital was calculated for each case. Hospitals were contacted to determine the year of acquisition of the first robot. RESULTS: From 2000 to 2009, the total number of prostatectomies performed annually increased substantially. The increase occurred almost entirely at the very high-volume centers (>= 106 prostatectomies/year). The number of hospitals performing prostatectomy fell 37% from 2000 to 2009. By 2009, the 9% (21/ 244) of hospitals that had very high volume performed 57% of all prostatectomies, and the 35% (86/244) of hospitals with a robot performed 85% of all prostatectomies. The median travel distance increased 54% from 2000 to 2009 (P<.001). The proportion of patients traveling >= 15 miles increased from 24% to 40% (P <.001). CONCLUSIONS: Over the past decade, the number of radical prostatectomies performed has risen substantially. These procedures have been increasingly centralized at high-volume centers, leading to longer patient travel distances. Few prostatectomies are now performed at hospitals that do not offer robotic surgery. Cancer 2012;118: 54-62. (C) 2011 American Cancer Society.

关键词： 球面机构   动力学分析   并联机器人   ADAMS仿真   运动性能  

摘要： 球面机器人是机器人研究领域的一个重要分支,在机器人的肩关节、腕关节、腰关节、髋关节设计中应用广泛,还可以用于摄像机、显微镜的空间定位和卫星天线的空间方位跟踪系统等。传统的球面机构受到机构本身的一些限制,存在设计上的不足。本文通过对其结构的详细分析,以工作空间为研究对象,进行了机构改进。\n 本文提出了一种新型的两自由球面解耦机构,对其进行了深入分析,主要内容为:\n 1.对一种球面机构进行了运动分析和工作空间分析,了解了其存在的缺陷,逐步提出了新型球面解耦机构。\n 2.对改进机构进行了运动学分析,建立了机构的位置方程,并进行了正解分析和工作空间分析,得到了机构的正解方程和雅克比矩阵J。\n 3.分析了机构的动力学问题,应用拉格朗日-欧拉法建立了机构的动力学模型。\n 4.应用Solidworks软件对机构进行了三维建模,并导入ADAMS中进行了机构的运动学仿真,给出了运动轨迹输出曲线,验证了机构的合理性和有效性,证明机构具有良好的运动性能。\n 5.利用ADAMS软件对机构进行了动力学仿真和结构参数优化,这将为机构的控制和伺服电机的选取提供动力学参数。\n 本文的研究工作为球面机器人控制方面的研究奠定了基础。