三杆柔性机械手运动学分析及仿真研究

在平面内运动的三杆柔性机械手运动学方程的建立是对其动力学分析和进行准确控制的基础.应用浮动坐标系,矢量法和D-H变换矩阵法建立了机械手的运动学模型,通过机械手各构件关节变量求解出机械手末端执行器的笛卡尔坐标空间位姿.使用Matlab软件对机械手末端运动轨迹和角度变化等进行了仿真实验,证明了柔性机械手弹性变形在空间准确定位中的影响,提出了一些减小误差的方法,为进一步研究柔性机械手较为精确的动力学和控制模型奠定了良好的基础.     

双机械手协同运动模型及其工作空间分析

基于双机械手建立协同运动学模型,分析其最佳协调工作空间。首先,采用D-H变换矩阵法建立双机械手运动学模型,揭示机械手末端执行器在不同运动形态下笛卡尔坐标空间位姿与机械手各关节变量之间的转换关系;其次,利用MATLAB中Robotics Toolbox建立双RCX340机械手三维仿真模型,验证运动学模型的可靠性;最后,根据末端执行器的位置向量,采用蒙特卡洛法对双机械手的工作空间进行了分析,得到双机械手末端执行器的最佳协调工作空间,为双机械手协调轨迹规划提供了理论依据。     

危险弹药机器人机械手运动学仿真分析

运用D-H方法建立危险弹药机器人机械手运动学模型;采用蒙特卡罗方法求解机械手末端执行器的位置向量集合;在Matlab环境下,用点云图描绘出机械手工作空间。运用Robotics Toolbox对机械手进行运动学仿真,仿真出机械手末端执行器运动轨迹曲线、关节运动曲线和速度曲线,从而验证参数设计的合理性,也为进一步研究机器人的动力学、轨迹规划打基础。     

基于远心机构的主操作手建模与仿真研究

针对泌尿外科微创手术机器人的末端执行器如何在有限空间中完成给定任务,以提高泌尿外科微创手术的安全性问题,对其主操作手的运动学和工作空间进行了研究。根据泌尿外科微创手术特点和技术要求,基于远心机构,设计了具有6个自由度主操作手,用于控制该手术机器人的末端执行器;采用修正后的D-H参数法,建立了运动学模型,求得了主操作手的末端空间位置与各关节变量之间的函数关系和运动学逆解;利用Matlab和ADAMS软件对主操作手进行了运动学和理论工作空间仿真,并进行了结果对比分析。研究结果表明:该主操作手结构设计合理、模型建立准确、灵活度高,可以完成给定手术任务。     

基于柔性补偿的行星表面采样机械臂控制策略研究

为了适应行星表面较大范围采样及系统减重需求,行星表面采样机械臂通常由细长的臂杆和多个旋转关节串联组成,柔性特征明显。针对4自由度行星采样机械臂,提出基于柔性补偿的控制策略,以提高机械臂的运动精度。基于混合坐标法建立考虑关节和臂杆弯曲变形的机械臂运动学模型,计算机械臂末端柔性偏差;设计机械臂末端笛卡尔空间加速度连续平滑的变加速-匀速-变减速的运动路径,并在期望路径中实时补偿柔性偏差项;基于simulation X软件,建立精细的动力学和关节控制器模型,对机械臂的典型任务进行仿真,验证控制算法的有效性。结果表明,采用柔性补偿的控制策略能够明显提高机械臂的动态跟踪精度及末端定位精度。     

一种基于六构件变胞机构的气动柔性抓取机械手的设计

变胞机构与常见的定自由度机构相比,具有特殊的性能。阐述一种以气体为驱动力的自适应变胞机械手,该机械手简化为两个手指,以一个气缸驱动,每个手指有两个转动关节,在每个手指夹持部位衬以硅胶并贴以力传感器,控制气缸压力,致使夹持力可在一定设定范围内进行调整,是一种具有一定柔性的执行器。该执行器将变胞机构的工作原理和气体柔性驱动技术相结合,是一种基于六构件变胞机构的气动自适应柔性抓取机械手。阐述了该机械手的机构结构原理,并对该机械手进行了运动分析。该机械手在果蔬采摘,人体推拿执行器中具有广阔的应用前景。     

基于ADAMS的桁架式三自由度伺服机械手路径规划和仿真

针对运动规律要求不高的工况,可利用ADAMS动力学仿真技术快速解决机械手轨迹规划问题。以三自由度伺服机械手为对象,构建机械手仿真模型,通过给定机械手末端执行器运动轨迹为空间螺旋线,反求各关节运动参数,并对机械手工作性能做出合理分析。     

自由曲面磨抛机械手末端执行器柔性设计与仿真

通过对自由曲面磨抛的运动分析,设计了一款基于双作用气缸的柔性磨抛机械手末端执行器。利用气动压力的柔顺性,既可以被动贴合曲面实现被动柔顺磨抛,又可主动进行压力调节实现活动台位姿的主动柔顺控制;建立了末端执行器机构的运动学逆解,推导了可磨抛最小曲率半径公式;利用SolidWorks和ADAMS软件建立了虚拟样机仿真模型,并对几种不同磨抛工况进行了仿真分析。结果表明:所设计的柔性末端执行器结构稳定、紧凑,对平面和自由曲面磨抛具有很好的普遍适用性。     

三自由度并联气动柔性执行器工作空间的研究

针对三自由度并联气动柔性执行器的工作空间计算问题,对其工作空间的计算方法和评价标准进行了研究。对该类利用柔性结构和压缩空气实现运动的新型执行器进行了运动学分析。通过对其3个气动柔性元件以及两个圆盘组成的结构进行运动学关系的研究,得到了气动柔性元件的长度和执行器末端位置的数学关系。利用搜索法对该数学关系进行了数值计算,获得了该执行器的工作空间包络面,并对不同参数下的工作空间的变化特点和差异性进行了分析研究。研究结果表明,当选取工作空间的体积、最大工作半径以及最大弯曲角度作为衡量工作空间大小的指标时,上述3个指标均可随柔性元件伸长率k及安装结构参数S的增大而增大。该结论可以对该执行器的结构设计和理论研究提供指导。     

基于橡胶波纹管的柔性机械手臂设计

柔性连续型机器人,相比离散关节型机器人具有高适应性与安全性的特点。针对多种应用领域,介绍一种使用压缩气体驱动的柔性连续型机械手臂原型机,利用其执行器由柔软材料制造装配而成的特点,它在抓取过程中能更好的保护表面脆弱的物体。使用橡胶波纹管,设计、制造并装配为执行器、执行器组及机械手臂,搭建实验台,建立执行器的伸长量与其内部气压的理论模型并通过实验验证,进一步测试柔性机械手臂的形变及运动性能,实现柔性机械手臂在其运动空间内可按照既定顺序工位操作的功能。结果表明,执行器的伸长量与其内部气压的理论模型准确,基于橡胶波纹管的柔性机械手臂具有较大的弯曲角度与一定的负载能力,可应用于识别与定位或物体的抓取移动等领域。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.