新型三平移并联机器人动力学优化仿真研究

用ADAMS2007建立了一种新型3RRC型并联机器人机构的参数化运动模型，并对该并联机器人机构进行了初步的位置、运动学、动力学分析，获得了有关运动学及动力学特性曲线，还通过Madab软件计算、分析、比较，验证了用ADAMS软件进行动力学仿真分析的可靠性，最后对该模型进行了动力学优化设计，为新型三平移并联机器人机构的应用打下基础。     

基于ADAMS技术的3-TPT并联机器人机构动态仿真

根据东北大学研制的3-TPT并联机器人机构组成，分析了运动及动力学特性，并在ADAMS上建立了仿真运动模型。获得了有关运动学及动力学特性曲线，为机器人机构设计和动力性能分析开辟了一条新路，解决了运动可视化问题。     

一种新型管道清洁机器人撑开机构动力学分析及其仿真

建立了管道清洁机器人的三维本体结构模型,针对机器人在变径管、弯管、T型管内运动干涉问题,提出了一种新型撑开机构,建立了撑开机构的机构运动简图;利用牛顿欧拉法建立机器人撑开机构的动力学方程并求解;用ADAMS软件建立了撑开机构动力学仿真模型,并进行了动力学仿真分析。仿真结果表明,机器人撑开机构滑块速度方向改变时,机构各杆件受力达到最大。     

惯性冲击式运动原理的理论分析与仿真

利用拉格朗日方程建立基于惯性冲击式驱动原理的微小型机器人的动力学模型，对该模型进行求解与仿真；利用有限元分析方法对机器人机构连行模态分析与瞬态动力学分析。两种分析方法都考虑了双压电膜机构与电场的耦合关系，以及机器人的支撑与管壁之间的接触摩擦。通过对两种方法的分析结果对比，验证了惯性冲击式运动原理的正确性，以及该原理用于管内移动微小型机器人驱动是可行的。     

新型并串联复合机器人KED研究

提出一种由3自由度平动并联机构和放大机构组成的新型并串联复合机器人.从柔性多体系统动力学角度出发,分析了机器人的动力学模型,建立了其动力学方程.运用KED的解题方法,对机器人进行了运动弹性动力学分析,得到了符合实际情况的计算结果.     

燃气管道机器人变径机构设计及动力学分析

燃气管道机器人作为一种集铺设、检测、修复为一体的设备在管道工程领域应用的愈来愈广泛。为了适应不同的管道直径,管道机器人需要设计合理的变径机构。首先设计了两种管道机器人的变径机构,分别对其进行动力学分析,在同等条件下所需理论电机转矩大小比较结构优劣。最后利用ADAMS动力学分析软件进行仿真模拟与动力学分析,设计了更为合理的变径机构,有利于节省成本,同时对于机器人的轻量化研究有重要意义,为管道机器人设计提供了参考。     

6-PTRT并联机构动力学简化策略与稳定性优化

根据6-PTRT并联机器人机构特点及相关文献,推导出此机器人KANE动力学模型。利用四元数法求出刀具在空间曲面上一条加工轨迹,通过空间轨迹规划,实现对并联机器人6个自由度协同控制,分析并联机器人在中低速和高速加工过程中各运动部件对驱动力的影响,得到动力学模型简化策略,提高了运算效率。分析机构启动时动力学响应曲线产生波动的原因,采用Akima插值法对各支链动力学响应进行优化,得到更为平滑的动力学响应曲线,提高机构运行平稳性,为并联机器人结构设计、轨迹规划及实时控制提供理论依据。     

全柔性机器人机构结构动力学分析方法研究

全柔性机器人机构是一种新型机构,多用于高精度的场合。由于其动力学性能会影响其终端的定位精度,因此,有必要对其结构动力学进行研究。具体将全柔性机器人机构作为结构体,分别采用理论简化建模、有限元和试验测试三种方法对其进行了结构动力学方面的研究,并进行了实例分析。首先通过理论简化建模计算出全柔性机器人机构的固有频率,采用商用有限元软件对该机构进行了模态分析,并对该机器人的模态频率进行了试验测试。有限元分析及试验结果均表明了简化模型计算结果有一定的精度。     

可变起跳角度的球形跳跃机器人跳跃分析及其优化

针对跳跃机器人越障时自主控制与调整的局限性，设计了一款可变起跳角的球形跳跃机器人，该机器人采用C₆₀结构镂空外壳和平台调姿机构可实现变角度跳跃目标。通过分析机器人起跳、滞空、落地的运动过程，采用拉格朗日方程对机器人跳跃过程动力学进行建模。建立了起跳角对速度的影响方程，并针对单足跳跃过程，揭示起跳过程中打滑现象的产生与摩擦角之间的关系。基于机器人动力学方程，研究跳跃机器人面对越障时，与障碍物距离和起跳角度对跨越和爬升的影响。最后，利用ANSYS对其动力学进行仿真分析，有效保障了机器人跳跃任务的顺利完成，为球形跳跃机器人规划问题奠定了理论基础。     

一种轮式机器人全方位移动机构的研究

在分析轮式机器人自由度的基础上,给出了自行设计的一种轮式机器人全方位移动机构的结构设计,并对其运动学和动力学进行分析,给出了详细的运动学和动力学模型方程。     

雷诺方程的数值计算方法概述

作为流体力学中的基本公式,雷诺方程的数值求解一直是流体润滑领域研究的重要方向之一。以雷诺方程的基本形式为基础,分别介绍有限差分法、有限元法和有限体积法求解雷诺方程的过程,讨论各自的特点及存在的问题;介绍多重网格法同上述方法结合在求解雷诺方程中的应用,指出多重网格法在求解雷诺方程的高效性方面有了很大程度的突破,但在求解精度上并未有显著改善;讨论等几何分析方法在求解雷诺方程上的应用,指出等几何分析方法求解雷诺方程具有较高的效率和求解精度,但仍存在如样条基函数的不可插值性和IGA在雷诺方程求解方面的普适性等问题,探讨IGA的研究方向,如针对特定雷诺方程引入适于IGA的新型样条表征求解空间、修改IGA理论与雷诺方程的离散模式引入新型边界条件加载模式等;因数值求解雷诺方程时在边界处理、复杂求解域等问题上仍没有一个稳定适用面广的方法,建议可尝试联合IGA与多重网格法来求解雷诺方程,以进一步提高求解效率和精度。     

各种板边条件下大挠度圆板自由振动的分岔解

计及几何非线性,在各种板边条件下,建立圆板自由振动的非线性动力学方程.采用Galerkin法,将圆板的非线性动力学偏微分方程简化成三种标准类型的Duffing方程.提出一类强非线性动力系统的两项谐波法,将描述动力系统的二阶常微分方程,化为以频率、振幅为变量的非线性代数方程组,考虑初始条件补充约束方程,构成频率、振幅为变量的封闭非线性代数方程组.利用Maple程序可以方便地求解.结果表明,两项谐波法不仅适合于对称振动问题,而且适合于非对称振动问题.     

Generalized Reynolds equation for porous boundaries

A generalized form of Reynolds equation has been obtained which permits the variation of relevant quantities across as well as along the lubricant film with porous boundaries. The equation has been derived with a minimum of restrictive assumptions and in particular cases it reduces to the various forms which other workers have developed. It is suggested that the equation derived is applicable to the various models for synovial joints and porous bearings.     

A standard weight equation to assess the body condition of pejerrey Odontesthes bonariensis.

We developed a standard weight equation Ws to aid in the analysis of pejerrey Odonthestes bonariensis body condition over time and across populations using the relative weight index Wr. Weight--length data were compiled from 73 populations of pejerrey (N=16.022) from the Argentine pampas region. We used the regression-line-percentile technique, which provides a 75th-percentile standard by length intervals of 10 mm, to develop the Ws equation. The proposed equation is log 10 Ws=-5,267+3,163 log10 Lst; Ws is weight in grams and Lst is standard length in millimeters. This equation is proposed for use with pejerrey between 120 and 520 mm of Lst. Values for Wr calculated with the Ws equation did not consistently increase or decrease as function of fish length, indicating absence of length bias. We analyze the values and distribution of Wr for pejerrey and suggest how to interpret its results. The equation of Ws that intends to calculate the index of Wr, represents a useful tool of analysis, because not only it allows to statistically compare the physical condition of the pejerrey, independently of its size, capture moment or the individual origin, but also it facilitates to relate it with other variables.     

柔性铰链转动刚度计算公式的推导

柔性铰链作为无摩擦的支点有着成千上万的应用，以力学的基本公式和微积分为基础，给出了一般柔性铰链转动刚度计算公式的推导过程。在此基础上，得出了常用的直圆柔性铰链的设计计算公式，计算公式是精确的推导结果，且在表达上较迄今沿用的Paros给出的柔性铰链精确设计计算公式来得简洁，有利于柔性铰链及其机构的计算和分析。当直圆柔性铰链的切割半径与最小厚度相当时，Paros给出的简化公式存在一定的误差，这里的计算公式尤其适用于该类直圆柔性铰链。     

一种新的计算机层析方法研究

提出了基于有限元的层析图像重建技术,该方法使用单元顶点上的目标值计算信号投影,详细推导了信号衰减也即目标物理量在检测线上的投影与单元节点值的关系,同时推导了单元刚度阵的计算公式,并提出了整体刚度阵、方程右边常向量的计算方法。最后还使用此方法对一仿真检测结果进行了重建分析,从分析结果来看,因此方法得到的系数矩阵对称正定,可以用ICCG等大型稀疏方程组求解方法求解,图像重建过程较经典ART方法效率更高,精度也更高。     

Control design of a pneumatic cylinder with distributed model of pipelines

In this paper, the control design with distributed model of pipelines is proposed to make the cylinder side be free of pressure sensors. In this research, long connected pipelines are used. The pipeline is designed as a one dimensional distributed model. The model of pipelines is based on the discretization of four equations, as state equation of air, motion equation, continuity equation, and energy equation. The distributed model estimates the pressure losses and time delay through long connected pipelines in real time. To confirm the control method with distributed model of pipelines, a simulation model of the whole system is designed. Compared simulation and experimental results, it has been found that the model represents the real system well. In the experiments, the pressure values in the cylinder chambers estimated by the distributed model in real time played as control signals. Compared with the estimated and measured pressure values in the cylinder chambers, it is found that with this distributed model, the pressure values in the cylinder chambers is precisely estimated in real time using the measured values at the control ports of the servo valve. The experimental results demonstrate that the position accuracy is almost the same with that of using the measured pressure signals in the cylinder chambers. The cylinder side is free of pressure sensors with the proposed control method.     

弹性连杆机构动力分析的一种新方法

介绍了一种新的运动弹性动力学分析方法,从严格的柔性多体系统动力分析理论出发,建立了柔性单元及系统运动方程,并将方程表为与常规 KED(kineto-elastodynamic analysis)方法相近似的形式,以便利用 KED 方法对其求解,以曲柄连杆机构为例进行运动弹性动力分析,结果表明,这一方法求解方便,且具有与多柔体系统动力学方法相近的精度.     

The effect of off-end tip distance on the nanomanipulation based on rectangular and V-shape cantilevered AFMs

The AFM system, which is used as a nanomanipulator, includes a probe consistent of a cantilever and a tapered tip. In cantilevers, the tip can be located in different distances from the cantilever free end. This causes to change in stiffness of the cantilever and therefore changing in pushing force of the nanomanipulation. In this paper, the effect of the tip distance on the cantilever stiffness is studied using the equations of Hazel, and Neumeister and Ducker (ND), and a new equation to correct the torsional stiffness of V-shaped cantilevers (VSC) is proposed, which is based on the ND equation. Then, the effect of distance on pushing force of AFM-based nanomanipulations with rectangular cantilevered (RC) and VSC AFMs is simulated. The obtained results using proposed equation show that increasing of distance causes to non-linear increment of torsional stiffness of VSC. Error of the proposed equation is achieved less than 3% in comparison with result of torsional stiffness equation of ND. Moreover, it is observed that the torsional stiffness of VSC predicted by Hazel’s equation is considerably inaccurate. In nanomanipulation studies, the necessary pushing forces of nanoparticle motion are increased by increment of distance, for both types of cantilevers (RC and VSC). Moreover, critical time for RC AFM increases, but in the case of VSC AFM, the critical time decreases at first, then it is almost constant at a limited range of d, and finally it starts to increase by increasing the distance.     

Synthesis of four-bar mechanisms by Freudenstein–Chebyshev

A new dimensional synthesis method is described in the paper. The position function of the four-bar mechanism is presented by the Freudenstein’s equation and it is minimized by the Chebyshev’s best approximation theory. The target function is used as an exactly satisfied equation and the Freudenstein’s equation is considered as a Chebyshev’s polynomial. In some cases the method provides possibilities to find simple solutions of the synthesis tasks. These solutions are known as the best Chebyshev’s approach of the weighted target function. This approach is near the best one for the original target function. A numerical example given here explains the essence of the method.