共查询到20条相似文献，搜索用时 15 毫秒
1.
To determine workspace and relationship between the workspace and geometry of parallel manipulator is important for optimum design of parallel manipulators. In this paper, the workspace and the relationship between the workspace and the geometry of 3-UPU parallel manipulators with pure translation axe investigated. Geometric and non-geometric constraints are defined and taken account of in determining the workspace of the translation 3-UPU manipulators. A direct average condition number is used as the global performance index of the workspace. This research shows that there exists an optimal value of the direct average condition number favorable for a good design of parallel mechanisms. The results presented in this paper are useful for the optimum design of 3-UPU parallel manipulators. 相似文献
2.
针对目前基于PLC的机械手控制系统对电机控制的实时性不佳等问题,设计了两自由度并联机械手控制系统,并采用运动控制CPU作为控制器．通过建立数学模型对机械手进行分析,并编制了精简的控制程序,实现了机械手的高速、精确、平稳运行． 相似文献
3.
介绍了并联6自由度电动实验平台实验教学装置的工作原理、设计过程,包括机械结构的设计与建模仿真、控制系统的设计以及人机操作界面的实现等相关内容及实验方法.运行LabVIEW编写的控制程序,可实现并联6自由度电动实验教学平台的6个自由度平动及转动.通过实验平台6自由度的运动以及编写LabVIEW测试程序以达到课程的教学要求.使学生全面熟悉并联6自由度电动实验教学平台的基本工作原理、总体结构、工作特性,同时保证了公共平台大型设备“双6自由度并联机器人空中对接模拟试验台”的有效使用率和节省维修成本,加快培训周期,有利大型设备的共享. 相似文献
4.
Dynamic model and control strategy of parallel mechanism have always been a problem in robotics research. In this paper, different dynamics formulation methods are discussed first. A model of redundant driven parallel mechanism with a planar parallel manipulator is then constructed as an example. A nonlinear adaptive control method is introduced. Matrix pseudo-inversion is used to get a desired actuator torque from a desired end-effector coordinate while the feedback torque is directly calculated in the actuator space. This treatment avoids forward kinematics computation that is very difficult in a parallel mechanism. Experiments with PID together with the descibed adaptive control strategy were carried out for a planar parallel mechanism. The results show that the proposed adaptive controller outperforms conventional PID methods in tracking desired input at a high speed. 相似文献
5.
为培养学生的机构分析能力,在机械原理课程设计中对3-PRR并联机器人机构动力学建模分析进行研究。推导出3-PRR并联机构位置反解、速度反解和加速度反解等方程。基于第2类拉格朗日方程建立3-PRR并联机器人机构逆动力学模型,据此求出各驱动关节的驱动力。在空载和负载两种情况下进行数值计算,经过与Adams仿真结果对比分析,验证了动力学建模的正确性。本研究为平面3自由度并联机器人机构运动学建模和动力学建模分析提供了有效的方法,为实物样机的优化设计奠定了理论基础。 相似文献
6.
给出可重构平面并联机构和空间并联机构的设计原则，概括进行并联机构设计的目的和相应的实验内容，针对不同应用对象，探讨开设此类实验课的途径和方法。通过探索和实践，取得较好的效果。 相似文献
7.
朱彩红 《南通职业大学学报》2011,25(1):88-92
针对一种平面冗余2-DOF并联机器人,分析了其运动学正解和反解,并在运动学反解的基础上讨论了该机构工作空间的约束条件;提出了运用Matcom将Matlab和VC＋＋结合起来进行混合编程的方法,探讨了并联机构工作空间的形状,并得到基于VC＋＋开发的该并联机器人控制系统;仿真结果表明,该机构具有较好的工作空间,可广泛应用于工业装配机器人、虚拟轴并联机床和多维减振平台等领域。 相似文献
8.
A closed-chain robot has several advantages over an open-chain robot, such as high mechanical rigidity, high payload, high precision. Accurate trajectory control of a robot is essential in practical use. This paper presents an adaptive proportional integral differential (PID) control algorithm based on radial basis function (RBF) neural network for trajectory tracking of a two-degree-of-freedom (2-DOF) closed-chain robot. In this scheme, an RBF neural network is used to approximate the unknown nonlinear dynamics of the robot, at the same time, the PID parameters can be adjusted online and the high precision can be obtained. Simulation results show that the control algorithm accurately tracks a 2-DOF closed-chain robot trajectories. The results also indicate that the system robustness and tracking performance are superior to the classic PID method. 相似文献
9.
This paper proposes a design optimization method for the multi-objective orbit design of earth observation satellites, for which the optimality of orbit performance indices with different units, such as: total coverage time, the frequency of coverage, average time per coverage and maximum coverage gap, etc. is required simultaneously. By introducing index normalization method to convert performance indices into dimensionless variables within the range of [0, 1], a design optimization method based on the principal component analysis and cluster analysis is proposed, which consists of index normalization method, principal component analysis, multiple-level cluster analysis and weighted evaluation method. The results of orbit optimization for earth observation satellites show that the optimal orbit can be obtained by using the proposed method. The principal component analysis can reduce the total number of indices with a non-independent relationship to save computing time. Similarly, the multiple-level cluster analysis with parallel computing could save computing time. 相似文献
10.
一个基于主手的力觉再现和反馈的机器人仿真系统 总被引：1，自引：0，他引：1
介绍了基于5自由度力觉再现装置的虚拟力觉仿真系统的实现方法．此系统中，操作通过主手控制虚拟环境中的从手与虚拟物体相作用，虚拟环境中的接触情况如碰撞响应、形变在图形界面仿真，虚拟力通过主手装置表达．该研究有利于提高遥操作机器人的性能和增强操作的沉浸感． 相似文献
11.
In this paper, a meshless method based on moving least squares (MLS) is presented to simulate free surface flows. It is a Lagrangian particle scheme wherein the fluid domain is discretized by a finite number of particles or pointset; therefore, this meshless technique is also called the finite pointset method (FPM). FPM is a numerical approach to solving the incompressible Navier-Stokes equations by applying the projection method. The spatial derivatives appearing in the governing equations of fluid flow are obtained using MLS approximants. The pressure Poisson equation with Neumann boundary condition is handled by an iterative scheme known as the stabilized bi-conjugate gradient method. Three types of benchmark numerical tests, namely, dam-breaking flows, solitary wave propagation, and liquid sloshing of tanks, are adopted to test the accuracy and performance of the proposed meshless approach. The results show that the FPM based on MLS is able to simulate complex free surface flows more efficiently and accurately. 相似文献
12.
Given the definition of the reference Knudsen number for micro gas journal bearings, the range in the number is related to the viscosity of air at different temperatures. A modified Reynolds equation for micro gas journal bearings based on Burgdorfer＇s first-order slip boundary condition is proposed that takes into account the gas rarefaction effect. The finite difference method （FDM） is adopted to solve the modified Reynolds equation to obtain the pressure profiles, load capacities and attitude angles for micro gas journal bearings at different reference K_nudsen numbers, bearing numbers and journal eccentricity ratios. Numerical analysis shows that pressure profiles and non-dimensional load capacities decrease markedly as gas rarefaction increases. Attitude angles change conversely, and when the eccentricity ratio is less than 0.6, the attitude angles rise slightly and the influence of the reference Knudsen number is not marked. In addition, the effect of gas rarefaction on the non-dimensional load capacity and attitude angle decreases with smaller bearing numbers. 相似文献
13.
图G的一个k全染色是用k种颜色对图G的顶点集和边集进行染色使得相邻接的或相关联的元素染不同的颜色,图G的全色数χ＂（G）为图G的k-全染色中的最小k值.Behzad和Vizing猜想任意简单图G的全色数都不超过Δ（G）＋2,已经证明了此猜想对最大度不是6的平面图成立,而且最大度不小于9的平面图G的全色数为Δ（G）＋1.本文利用差值转移方法研究了最大度小于9的一些情况,证明了最大度为4,5,6,7,8的平面图G,如果其围长不小于8,则其全色数也为Δ（G）＋1. 相似文献
14.
Forward position analysis is one of the importantand difficult issues in the kinematic analysis of paral-lel manipulators and has been extensively investiga-ted[1—3]. Most of the approaches for solving forwardposition problems of parallel manipulators with six de-grees of freedom (6-DOF), the Stewart platform forinstance, can be classified into two categories, i.e.closed-form analytical method using polynomial ap-proach and numerical method using iterative algo-rithm. Although the polynomial… 相似文献
15.
马瑞雪 《兰州石化职业技术学院学报》2008,8(1):73-76
基于课堂动态发展评估理念,通过调查英语专业学生在一年之内学习兴趣、策略以及成绩的发展变化,探讨了学生在这三项指标上的发展状态。得出的结论为：学习者的兴趣、策略以及成绩各项指标朝着积极的方向发展;学习者兴趣、策略的显著发展出现在不同的学习阶段,成绩发展较为缓慢;兴趣、策略与成绩相关性较低,兴趣与策略无相关性。 相似文献
16.
Jeffrey Buckley Niall Seery Donal Canty 《European Journal of Engineering Education》2019,44(1-2):164-178
ABSTRACTA substantial degree of empirical evidence has illustrated the correlation between spatial skills and performance in engineering education. This evidence has been foundational in the construction of educational interventions which have resulted in both increased levels of spatial ability and increased educational performance and retention. However, the cognitive faculty of spatial cognition is widely recognised as multifactorial and a number of factors exist within this domain which have not been examined as potential influences on educational success. A number of factors have been identified within the pertinent literature which do not appear in any formal framework of spatial cognition. This paper presents a review and synthesis of this work with the amalgam presented as a model to support the further integration of spatial ability into engineering educational practices. 相似文献
17.
截面数据的多指标综合评价问题已有不少研究,而对于时间序列/截面数据(又称为平行数据)的多指标系统进行综合评价目前研究较少,利用主分量分析法和理想点法给出平行数据系统综合评价的一种计算方法,并通过实例分析说明了此方法的合理性. 相似文献
18.
截面数据的多指标综合评价问题已有不少研究,而对于时间序列/截面数据(又称为平行数据)的多指标系统进行综合评价目前研究较少,利用主分量分析法和理想点法给出平行数据系统综合评价的一种计算方法,并通过实例分析说明了此方法的合理性. 相似文献
19.
Architecture singularity of a parallel mechanism with five degrees of freedom (DOF) is analyzed. Such mechanism consists of a movable platform connected to the base by five active limbs. Four of them are identical 6-DOF limbs and the last one has the same DOF as the specified DOF of the movable platform. Based on the kinematics analysis, two categories of architecture singularities for such mechanism are proposed. Then the sufficient condition for each singularity is researched. Results show that the mechanism is singular when it employs each category of the proposed architecture, provided that it satisfies the corresponding sufficient condition. It can be concluded that the proposed two categories of architecture singularities should be avoided with the following dimensional synthesis of such mechanism. 相似文献
20.
Architecture singularity of a parallel mechanism with five degrees of freedom (DOF) is analyzed. Such mechanism consists of a movable platform connected to the base by five active limbs. Four of them are identical 6-DOF limbs and the last one has the same DOF as the specified DOF of the movable platform. Based on the kinematics analysis, two categories of architecture singularities for such mechanism are proposed. Then the sufficient condition for each singularity is researched. Results show that the mechanism is singular when it employs each category of the proposed architecture, provided that it satisfies the corresponding sufficient condition. It can be concluded that the proposed two categories of architecture singularities should be avoided with the following dimension-al synthesis of such mechanism. 相似文献