机器人力觉示教的力控制及仿真分析

针对机器人传统示教方式逐渐无法满足复杂工业生产需求的现状,提出了一种基于六维力传感器的机器人力觉示教,并介绍了其系统组成。结合一些经典力控制方法及力觉示教实际,对机器人力觉示教的力控制系统展开研究,提出了基于速度的主动柔顺控制策略,从理论上建立了机器人力觉示教时末端工具受力和力矩的运动控制算法。通过Adams仿真软件,对机器人的力觉示教运动进行了仿真分析,最终结果表明该控制算法能够有效地实现机器人力觉示教控制,使力觉示教更加主动灵活,更好地满足复杂工业生产的工艺要求。     

二阶高精度模糊控制系统的设计与仿真

针对常规模糊控制器控制精度较低且稳态品质差的问题,提出一种提高模糊控制器控制精度并能改善稳态性能的方法。首先提出一种提高模糊控制器控制精度的设计方案并给出它的设计方法,然后对这种改进后的模糊控制器进行仿真分析,并和常规模糊控制器进行比较。仿真试验结果表明,这种改进的模糊控制器具有降低系统稳态误差和抑制稳态震颤的作用,提高模糊控制器的精度,改善系统对斜坡输入的伺服性能,而且保持模糊控制器非线性的控制特性。     

控位滑行航行器近水面波浪力计算与运动分析

对控位滑行航行器在近水面波浪作用下进行受力计算和运动分析。介绍了控位滑行航行器的结构特点和工作原理,运用AQWA软件计算了2级海况下航行器所受的波浪力,分别讨论了波浪力对航行器定深和水平控位运动的影响。     

波浪力作用下海洋钻井隔水管随机振动研究

随着海洋钻井向深水海域发展 ,隔水管的受力状态更加复杂。特别是在随机载荷波浪力的作用下 ,隔水管会发生十分复杂的随机振动 ,从而偏离原来的铅垂位置 ,严重时可使钻具受到破坏 ,引起钻井中断。应用随机振动的理论和方法 ,分析了波浪力的随机过程和随机模型 ,指出波浪力是一个均值为零的平稳随机过程 ,隔水管的横向随机位移也是一个均值为零的平稳随机过程。采用模态分析的离散化方法导出了隔水管横向随机振动位移相关函数和均方位移的计算公式 ,编制了计算程序 ,分析了风速对隔水管横向随机振动均方位移的影响。算例表明 :当风速小于 10m/s时 ,均方根值很小 ,可以不予考虑 ;当风速大于 2 0m/s时 ,均方根值与风速成近似的线性关系。本文结果可为隔水管的随机响应计算和工程设计提供一定的理论参考作用。     

钻削力模型的建立及仿真

在研究直线刃标准麻花钻的基础上，建立了有关切削几何参数的数学模型。并对标准麻花钻的几何参数进行了定量的分析。由于钻削过程的复杂性，采用了数学分析和经验值相结合的方法来研究钻削过程机理，建立了动态钻削力和扭矩模型，实现了对动态钻削力和扭矩的仿真。     

一种水下机器人用多轴力传感器的结构设计

水下机器人用多轴力传感器的设计必须首先解决水压力平衡的问题。通过对几种典型的机器人用多轴力传感器结构在水压作用下的应力、应变进行分析，得到这几种结构的特点和适用条件：实心的柱体可以承受深水压力，但由于海水的腐蚀作用，开放式柱体不适合作为弹性体；充油或充气的刚性封闭的薄壁结构不能承受深水压力；带补偿膜的薄壁圆筒结构只能承受浅水压力的作用；用软外囊封包的结构可以承
受深水压力，实现足够大的体积变化而不致被破坏，但存在容易破损以及形状、质心不定的缺陷。提出一种水下机器人用多轴力传感器自适应结构的设计构思，这种结构兼有开放式和封闭式结构的优点。按照这种设计构思已试制出原型样机     

波浪运动机械模拟器设计与仿真研究

为解决实验室环境下波浪输入信号的产生问题,文中结合线性波理论,提出一套可变频率、变波高的凸轮机械式波浪模拟器的设计方案。依据不同海况的波浪特性,采用不同直径的凸轮用以模拟波高变化。以直流伺服电机变压调速方式模拟波频变化,将所需模拟的波频特性转换为转速信号作为输入,伺服电机经由减速器带动凸轮转动,以凸轮实际转速作为输出,通过检测装置实时测定凸轮转速作为反馈,建立波浪运动机械模拟器转速闭环PID控制系统模型。利用ADAMS与MATLAB仿真软件对波浪运动模拟装置的机械系统与控制系统进行联合仿真,通过整定PID控制参数,解决了变频系统输出超调率过大问题。文中研究为实验室环境下研究振荡扑翼波浪能发电装置试验中波浪模拟输入问题提供了新思路、新方法,给海洋工程装备的开发提供重要依据。     

基于水下作业系统阻抗力控制水下目标定位

提出了基于水下作业系统阻抗力控制的水下矩形围壁定位方法.水下作业系统末端执行器跟踪期望运动轨迹,通过与水下矩形围壁环境表面接触力反馈信息的变化获得与环境接触的特殊点,计算得到矩形围壁环境相对水下作业系统的位姿.以带有三自由度机械手的水下作业系统为例进行水下矩形围壁目标表面恒力跟踪的计算机仿真,仿真结果表明定位方法可以很好的获得矩形围壁环境的位姿,控制策略县有很好的表面跟踪和力控制能力.     

大直径直孔套管起拔力仿真计算

目前套管起拔力分析均是针对于岩土中简化计算,得出的起拔力与真实情况有很大差别。基于此,应用非线性有限元软件,分析计算真实复杂工程状况下即边注浆加固边起拔套管的拉拔力,得出桩浆间摩擦系数对套管起拔力影响最大,摩擦系数为0.2与摩擦系数为0.6对应的套管起拔力峰值相差高达70000N;摩擦系数越小,套管起拔过程越平稳;套管壁厚一般选取10mm对应较小的套管起拔力;仿真计算为工程上大直径套管起拔力的确定、动力选取提供了一定理论指导。     

随机波浪力谱及结构件裂纹扩展研究

根据Jonswap谱确定随机波浪功率谱,进而由同一功率谱使用Shinozuka方法计算生成10个随机波浪力谱,应用雨流计数法对波浪力谱进行循环计数处理,最后使用基于能量释放率的Paris公式方法对构件进行疲劳裂纹扩展计算.可为海洋结构物的疲劳设计及疲劳寿命评估提供一定的参考.     

欠驱动多指节机器人手的抓力分析

对欠驱动多指节机器人手的抓力进行了分析,给出了直指和曲指抓取物体时的抓力方程,并对手指抓力作了动态仿真。手指抓力分析为多指节手的机构与力控制设计提供了理论基础。     

Design of minimum multiplier fractional order differentiator based on lattice wave digital filter

In this paper, a novel design of fractional order differentiator (FOD) based on lattice wave digital filter (LWDF) is proposed which requires minimum number of multiplier for its structural realization. Firstly, the FOD design problem is formulated as an optimization problem using the transfer function of lattice wave digital filter. Then, three optimization algorithms, namely, genetic algorithm (GA), particle swarm optimization (PSO) and cuckoo search algorithm (CSA) are applied to determine the optimal LWDF coefficients. The realization of FOD using LWD structure increases the design accuracy, as only N number of coefficients are to be optimized for Nth order FOD. Finally, two design examples of 3rd and 5th order lattice wave digital fractional order differentiator (LWDFOD) are demonstrated to justify the design accuracy. The performance analysis of the proposed design is carried out based on magnitude response, absolute magnitude error (dB), root mean square (RMS) magnitude error, arithmetic complexity, convergence profile and computation time. Simulation results are attained to show the comparison of the proposed LWDFOD with the published works and it is observed that an improvement of 29% is obtained in the proposed design. The proposed LWDFOD approximates the ideal FOD and surpasses the existing ones reasonably well in mid and high frequency range, thereby making the proposed LWDFOD a promising technique for the design of digital FODs.     

起重机轨道压板受力计算

分析了起重机轨道的受力,推导出了起重机轨道压板所受的外力,再由有限元素法求出了压板各部位的应力分布,以此来判断压板的安全性。     

Calculation of the Bloch wall contrast in magnetic force microscopy

The magnetic force microscope (MFM) is a promising analytical tool for the mapping of magnetic microfield distributions on a nanometre scale. The detailed interpretation of experimentally obtained data requires a rigorous micromagnetic analysis of the underlying magnetostatic tip-sample interactions. We have performed model calculations yielding the MFM image contrast obtained for 180° Bloch walls using ferromagnetic microscope tips. The actually observed wall image is shown to depend critically upon the mesoscopic tip design. The spatial resolution and also values for the resulting interaction forces and tip-sample compliances are derived.     

Correction of distortion due to thermal drift in scanning probe microscopy

A common source of distortion in scanning probe microscope (SPM) images is “thermal drift,” the slow thermal expansion of different materials in the sample and microscope due to small changes in temperature over the course of a scan. We describe here a method for correcting this distortion by immediately following each image scan with a rescan of a small, narrow portion of the same area with the slow and fast scan axes reversed. The original, full image is corrected using a low-order polynomial mapping function, with coefficients determined by a pixel-wise comparison between the original full and rescanned partial images. We demonstrate here that this method can correctly remove distortion from a wide range of images with a precision of better than one pixel, and is also robust to common imaging artifacts. We also address some of the programming considerations that have gone into implementing this computationally intensive technique, which can now be performed using standard desktop hardware in times that range between a few seconds and a few minutes.     

空间光学遥感器偏流机构控制单元的闭环实时模拟检测

摘要：为了实时地检测空间偏流机构驱动单元的功能、性能和可靠性,提出了一种应用FPGA并行闭环实时高速检测驱动单元的方法。结合计算机技术,设计了偏流驱动单元的检测系统。该系统应用高速AD电路将驱动信号采入FPGA中进行分析,获取控制脉冲,同时模拟编码器信息反馈给驱动单元,并将控制脉冲和模拟编码器信息传送给计算机进行检测。对控制脉冲频率为1.2kHz、编码器最小反馈间隔10ms和反馈偏差在±1码值之内的偏流驱动系统进行实际检测,结果表明：可实时准确地监视空间相机偏流驱动单元的工作状态,检测出各种驱动错误,完全适用于空间相机偏流驱动单元的闭环实时检测需要     

Force control compensation method with variable load stiffness and damping of the hydraulic drive unit force control system

Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit (HDU), and the contacting between the robot foot end and the ground is complex and variable, which increases the difficulty of force control inevitably. In the recent years, although many scholars researched some control methods such as disturbance rejection control, parameter self-adaptive control, impedance control and so on, to improve the force control performance of HDU, the robustness of the force control still needs improving. Therefore, how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper. The force control system mathematic model of HDU is established by the mechanism modeling method, and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived, considering the dynamic characteristics of the load stiffness and the load damping under different environment structures. Then, simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform, which provides the foundation for the force control compensation experiment research. In addition, the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping, under which the force control compensation method is introduced, and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment. The research results indicate that if the load characteristics are known, the force control compensation method presented in this paper has positive compensation effects on the load characteristics variation, i.e., this method decreases the effects of the load characteristics variation on the force control performance and enhances the force control system robustness with the constant PID parameters, thereby, the online PID parameters tuning control method which is complex needs not be adopted. All the above research provides theoretical and experimental foundation for the force control method of the quadruped robot joints with high robustness.     

一种核管道机器人结构设计与驱动力分析

针对人工方式进行核电管道检测与维护存在效率低的问题,将管道机器人技术应用到核电站管道维护中,代替人工进行现场故障监测、异物探测和清理。设计了直径为300 mm的管道机器人的机械结构,分析了机器人在管道中的受力情况以及驱动特性。同时设计了一种全新的单电机全驱动机构,这种设计使机器人整体结构更为紧凑,提高了机器人行进速度以及驱动负载能力。并利用ADAMS动力学仿真软件对机器人驱动特性进行了研究和分析。结果表明,机器人的驱动能力能够满足实际作业需求,并且其驱动能力与摩擦系数、斜坡度有关;其中驱动力与摩擦系数成正比,即摩擦系数越大机器人的驱动力越大;驱动力与斜坡度成反比,即斜坡度越大驱动力越小。该研究结果可为后续机器人优化设计提供理论依据。     

基于二代小波的光纤陀螺实时降噪方法研究

在以光纤陀螺为主要惯性敏感元件的捷联惯导系统中,陀螺输出信号中的非确定性随机漂移的实时滤除,对提高实际系统的初始对准精度及导航精度均具有重要的意义。考虑到传统小波阈值法的去噪性能及实时性问题,提出了一种基于第二代小波变换,并结合硬阈值、强制降噪和带滑动数据窗的光纤陀螺信号实时降噪改进方案。利用MATLAB进行了正弦信号和光纤陀螺输出信号的模拟实时降噪实验,并与一代小波实时降噪方案进行了比较,验证了改进方案在理论计算速度大幅提升的前提下,降噪性能得到提高,进而减小了系统输出的姿态误差。     

Robust finite time cooperative control of second order agents:A Multi-input Multi-output higher order super-twisting based approach

This paper studies the formation of multiple mobile agents with double integrator dynamics and their target tracking. An algorithm consisting of an observer and a feedback control law of the nonsmooth type is proposed for the purpose of achieving finite-time formation and target tracking. The development is based on the Multi-input Multi-output (MIMO) super-twisting like approach aiming at finite time convergence without chattering. In addition to the formation; tracking, chattering prevention and robustness is also provided by the sliding mode mechanism which is demonstrated by simulations.