Architecture Singularity Analysis of 4-U■S/U■U 5-DOF Parallel Mechanism

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.     

Architecture Singularity Analysis of 4-U PS/U PU 5-DOF Parallel Mechanism

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.     

并联6自由度电动实验教学平台

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.     

一种伸缩杆-水平滑块式并联机器人运动学及静力学计算

文章介绍了一种伸缩杆-水平滑块式三自由度并联机器人机构，根据该机构的结构建立了其运动学方程导出其雅可比矩阵，并对该机构的静力学方程进行了推导。该机器人机构运动学方程正、逆解均具有显式解；其雅可比矩阵在工作空间内不存在奇异点；具有三个平动方向的运动自由度，是一种具有实用价值的机器人机构。     

Mathematical modelling of translational motion of rail-guided cart with suspended payload

In this paper modelling of the translational motion of transportation rail-guided cart with rope suspended payload is considered. The linearly moving cart,driven by a travel mechanism,is modelled as a discrete six degrees of freedom (DOF) dynamic system. The hoisting mechanism for lowering and lifting the payload is considered and is included in the dynamic model as one DOF system. Differential equations of motion of the cart elements are derived using Lagrangian dynamics and are solved for a set of real-life constant parameters of the cart. A two-sided interaction was observed between the swinging payload and the travel mechanism. Results for kinematical and force parameters of the system are obtained. A verification of the proposed model was conducted.     

信息化装备仿真实验室建设初探

在需求分析的基础上，通过系统论证，提出了信息化装备仿真实验室的基本目标、主要功能，为军队武器装备发展和整体建设规划搭建技术演示平台，形成实际战斗力的“孵化器”。     

A novel posture alignment system for aircraft wing assembly

A novel 6-degree of freedom （DOF） posture alignment system, based on 3-DOF positioners, is presented for the assembly of aircraft wings. Each positioner is connected with the wing through a rotational and adsorptive half-ball shaped end-effector, and the positioners together with the wing are considered as a 3-PPPS （P denotes a prismatic joint and S denotes a spherical joint） redundantly actuated parallel mechanism. The kinematic model of this system is established and a trajectory planning method is introduced. A complete analysis of inverse dynamics is carried out with the Newton-Euler algorithm, which is used to find the desired actuating torque in the design and path planning phase. Simulation analysis of the displacement and actuating torque of each joint of the positioners based on inverse kinematics and dynamics is conducted, and the results show that the system is feasible for the posture alignment of aircraft wings.     

Design and Experiments of Ultrasound Image-Guided Multi-DOF Robot System for Brachytherapy

To implant radioactive seeds through a needle precisely and safely, a novel multi-DOF surgical robotic system is presented in this paper for percutaneous prostate intervention through the patient's perineum under real-time ultrasound image guidance. The proposed robot, which is designed with 9-DOF, consists of a 3-DOF automatic location platform for position adjustment, 2-DOF for automatic ultrasonic probe adjustment mounted with electromagnetic trackers, and 4-DOF for manually adjusting the guided template. Meanwhile, a new registration method based on the quaternion algorithm and least square method is developed, and the needle insertion is performed under the realtime guidance of a navigation system. Furthermore, the robot system has undergone some preliminary experiments with a laser tracker to evaluate the repeatability and accuracy of the robot system. The location error of the puncture needle tip can be controlled under 0.7 mm in air for the whole robotic system. The acquired results endorse the precision of the robot system for prostate seed implantation brachytherapy.     

Computer simulation of active suspension based on the full-vehicle model

The current method to solve the problem of active suspension control for a vehicle is often dealt with a quarter-car or half-car model.But it is not enough to use this kind of model for practical applications.In this paper,based on considering the influence of factors such as,seat and passengers a MDOF(multi-degree-of-freedom)model describing the vehicle motion is set up.The MODF model,which is 8DOF of four independent suspensions and four wheel tracks,is more applicable by comparison of its analysis result with some conventional vehicle models.Therefore,it is more suitable to use the 8DOF full-car model than a conventional 4DOF half-car model in the active control design for car vibration.Based on the derived 8DOF odel,a controller is designed by using LQ(linear quadratic)control theory,and the appropriate control scheme is selected by testing various performance indexes.Computer simulation 8is carried out for a passenger car running on a road with step disturbance and random road disturbance expressed by Power Spectral Density(PSD).Vibrations corresponding to ride comfort are derived under the foregoing road disturbances.The response results for uncontrolled and controlled system are compared.The response of vehicle vibration is greatly suppressed and quickly damped.which testifies the effect of the active suspenson.The results achieved for various controllers are compared to invesigate the influence of different control schemes on the control effect.     

一种3-7R并联解耦机构的运动学与动力学分析

基于运动副分析,对一种运动解耦的3-7R并联机构进行了构型分析,并对机构的构型特点进行了总结．该机构由3个正交分布的支链组成,机构的运动副均为转动副,构成了机构动平台在x,y,z三个方向的平动解耦．为验证机构的解耦特性,对机构进行了运动学分析,推导了机构的运动学正／反解、输入／输出的速度和加速度,验证了机构的运动解耦特性．采用一种机构支链分解-综合的方法,利用拉格朗日法建立了机构的动力学模型,验证了机构的力解耦特性．这对机构控制策略、机构设计和轨迹规划等方面的研究具有一定的理论意义．     

一种两自由度的压电-电磁复合能量收集器

研究目的：对一种两自由度的压电-电磁复合能量收集器进行发电性能研究。创新要点：建立了一种两自由度压电-电磁复合能量收集器发电性能的数学模型,该数学模型可以评估两自由度压电-电磁复合能量收集器中压电元件、电磁元件以及系统总输出功率。研究方法：对一种两自由度的压电-电磁复合能量收集器进行数学建模,并实验验证数学模型的正确性。基于实验测试得到的系统参数值,理论研究压电元件和电磁元件的机电耦合系数对不同能量收集器发电性能的影响关系,并对几种能量收集器的发电能力进行对比分析。重要结论：对于非强耦合（弱或中间耦合）的两自由度机电转换器,复合能量收集器（压电＋电磁）具有比单一能量收集器（压电或电磁）更高的发电能力。     

论可移动文化遗产及其在信息资源整合中的意义

“可移动文化遗产”一词频频出现在有关国际公约中,其含义已经引起了国内外的关注。然而,通过比较代表性的界定不难看出,其内涵至今尚未达成共识,有必要重新加以认识。基于现有的研究成果,作者探讨了可移动文化遗产的定义,分析了它与馆藏文物、档案、图书和艺术品之间的内在关联,进而剖析了可移动文化遗产在信息资源整合中的意义,即以可移动文化遗产为平台,可以整合部门化的信息资源,提高现有资源的利用率。     

南宁—东盟职业教育网实施策略与平台构建研究

分析东盟职业教育网建设目标和功能定位的基础,提出实施东盟职业教育网建设策略,从数字化教育资源运营、资源服务、资源交易等角度,阐述东盟职业教育网的平台建设机制、资源建设机制、服务机制、运行机制,同时提出平台的模型构建,包括在线学习平台系统、服务管理平台、综合门户平台等。     

Modelling and Simulation of System Dynamics of Hybrid-Driven Precision Press

Different from conventional mechanical systems with single degree of freedom (DOF),the main idea of the system of hybrid-driven precision press is to combine the motion of a constant speed motor with a servomotor via a two-DOF mechanism to provide flexible output. In order to make the feasibility clear, this paper studies theoretically the dynamic characteristics of this hybriddriven mechanical system. Firstly,the dynamics model of the whole electromechanical system is set up by combining dynamic equations of DC motors with those of two-DOF nine-bar mechanism deduced by the Lagrange‘s formula. Secondly through the numerical solution with the fourth Runge-Kutta, computer simulation about the dynamics is done, which shows that the designed and optimized hybrid-driven precision press is feasible in theory. These provide theoretical basis for later experimental research.     

Research on the operating characteristics of parallel 4-DOF electric platform with 4TPS-PS structure

The 4TPS-PS parallel platform designed for a stabilization and automatic tracking system is a novel lower-mobility parallel mechanism. In the first part of this paper, the structure of the platform is described and the kinematics model is built. The workspace of the platform is defined as the full reachable rotation workspace when the Z coordinate dimension of the upper plate varies continuously. A fast searching method of the full reachable workspace is presented, after which the inverse kinematics of the platform is deduced. The forward and inverse solutions of the speed and force of the platform are deduced. According to the characteristic of the 4TPS-PS platform’s structure, a fast searching algorithm of the maximum generalized speed and maximum generalized force output by the upper plate is put forward based on the forward and inverse solutions of the platform’s speed and force. The 4TPS-PS platform prototype built by the State Key Laboratory of Fluid Power Transmission and Control of China is taken as the research subject. The full reachable rotation workspace of the prototype is computed out and analyzed. The curves of maximum generalized speed and maximum generalized force of the prototype are computed out and plotted. Finally, the com- puting and analyzing results of the operating characteristics are confirmed through the experiment.     

新型双楔式侧抽芯机构的研制

新型双楔式侧向抽芯机构既不同于斜导柱等机械抽芯机构，又不同于纯液压抽芯机构，而是采用机械与液压相结合的方式，利用液压为动力驱动机械抽芯机构，从而实现合模锁紧与开模抽芯。这种新型侧抽芯机构可大大减小液压缸尺寸，结构紧凑，避免了与注射成型机有关部件的干涉。同时方便侧抽芯型芯的制造、修配和调整。     

论活动在涉农高职学生思想政治教育中的价值

活动是人获取知识、发现真理和检验真理,改造主客观世界的实践过程。人通过活动进行各种信息和能量的交换,实现着人们活动的目的。活动是人的一种常态化的生活方式,自然也就是开展教育的有效平台。本文从活动是高职学生思想政治教育的起点、有效平台和发展机制三个方面,论述了活动在涉农高职学生思想政治教育中的价值。     

主动学习:在线教学的新目标与实施策略

主动学习近年来演变为在线教学的重要议题,它为在线学习提供了新的视角.该研究从在线教学背景下主动学习的内涵与研究特征出发,首先提出了在线教学目标经历的嬗变,即信息由"自由渗透"到"自主重建",认知由"洗耳恭听"到"自我调节",行为由"约定俗成"到"躬体力行",情感由"人造物"到"人";其次检视了主动学习面临的困境,即师生...     

基于VC++的三自由度直升机控制实验系统的设计与实现

根据三自由度直升机实验平台,分析了其固有的特征,即:典型多输入-多输出特性、非线性和强交叉耦合性。在此基础上,建立了系统的数学模型并设计了适合该实验的PID控制器。利用VC 编程环境,对直升机飞行的高度及速度控制进行了实现。实验结果表明,其控制效果达到了预定的指标。     

无人机飞行控制半实物仿真系统设计与实现

为保证无人机飞行试验的安全性,提升无人机飞控系统设计的可靠性,自主研发了无人机飞行控制半实物仿真系统。结合准确的无人机6自由度非线性数学模型和xPC实时系统模块模拟生成无人机飞行状态信息,根据地面站控制指令、传感器故障模注入指令解算获得不同飞行模式和飞行状态下的舵面偏转量,实现了实时系统闭环反馈控制,并驱动舵面偏转检验控制系统的响应速度。该系统不仅能验证飞控系统的逻辑性和实时性,而且借助虚拟现实技术和航迹地图显示,具备在线整定控制律参数的功能。该系统模块化程度高,相关硬件和软件对无人机平台和飞控计算机通用性广,依据多平台实验和多架次试飞的实验流程实用性强,为无人机飞控系统开发提供了切实可行、高效可靠的途径。