The application of the neural network on Morse code recognition for users with physical impairments.

Morse code is a simple, speedy and low cost means of communication composed of a series of dots, dashes and space intervals. Each tone element (either a dot, dash or space interval) is transmitted by sending a signal for a defined length of time. This poses a challenge as the automatic recognition of Morse code is dependent upon maintaining a stable typing rate. In this paper, a suitable adaptive automatic recognition method, combining the least-mean-square (LMS) algorithm with a neural network, was applied to this problem. The method presented in this paper is divided into five modules: space recognition, tone recognition, learning process, adaptive processing and character recognition. Statistical analyses demonstrated that the proposed method elicited a better recognition rate in comparison with other methods in the literature.     

基于欠驱动机构的仿人机器人手爪设分

通过研究人手的生理结构特点,模仿人手结构,设计出仿人机器人手爪。整个手爪设计有拇指、食指、中指和小指,每个手指有三个关节。采用欠驱动连杆机构设计出结构紧凑的三关节手指机构以实现包络抓取和精确捏取。设计出高度集成的大功率小体积的驱动和传动机构并通过一个电机调整拇指机构的位置,以形成多种抓取模式。最后介绍了该手爪的控制以及抓取实验。     

十自由度假手结构设计及动力学建模仿真

针对传统假手运动不够顺畅和不够灵活的缺点,参考人手的结构,设计了一种五指十自由度的假手。该假手采用模块化的设计思想,除拇指外的四指尺寸结构完全相同,每个手指具有2个屈曲自由度;拇指具有屈曲和侧摆2个自由度。在此结构的基础上,针对拇指和食指进行了动力学建模,并通过Matlab数值仿真和ADAMS虚拟实验的对比,验证了动力学模型的正确性。     

模块化磁吸五指灵巧手结构设计与控制研究

针对目前五指灵巧手自由度低、拆装繁琐等问题,设计出一种模块化、易拆装、直驱式11自由度五指灵巧手.通过永磁铁实现手指关节间的快速拆装,每个手指关节至少有±90°转动范围;通过对大拇指转动角度的特殊设计,可实现灵巧手左/右手模式直接切换以及双侧同时抓取.通过3D打印制作了五指灵巧手样机.针对灵巧手多传感器造成控制系统复杂...     

A biomimetic hand employing a dual actuation scheme

This paper presents a biomimetic hand that employs a hybrid actuation scheme that provides large grasping forces and swift motion. This hybrid hand is made up of a red muscle actuator used for grasping and a white muscle actuator used for fast and accurate movement. A parallel structure utilizing fully back-drivable linear motors has been adopted for the white muscle actuators. The red muscle actuators employ a Micro Hydraulic Compressor Converter (MHCC), hydraulic cylinder, and a tendon. The tendon structure enables a passive shape adaptation during the act of grasping an object. Safety in regards to impact is achieved through the back-drivability. The hybrid hand is comprised of two fingers and a thumb. The fingers and the thumb all have 2 degrees of freedom. The hybrid actuation is only applied to the fingers. The experiment results indicate that a grasping force of 94N is generated through the red muscle actuator and a 3 Hz sinusoidal motion is obtained from the white muscle actuator.     

Development of a hand exoskeleton system for index finger rehabilitation

In order to overcome the drawbacks of traditional rehabilitation method,the robot-aided rehabilitation has been widely investigated for the recent years.And the hand rehabilitation robot,as one of the ...     

Control of whole finger manipulation utilizing frictionless sliding contact—theory and experiment

We propose a whole finger manipulation (WFM) to improve the robustness of manipulation by a multifingered robot hand. The WFM is characterized by enveloping an object by finger links of the multifingered robot hand, and utilizing the frictionless sliding contacts between the surfaces of finger links and the grasped object. Therefore, the WFM can achieve a large manipulation without regrasping the object and can be highly robust in nature because of form-closure due to multiple contact points on the grasped object. This paper discusses the property and control of the WFM. The WFM with frictionless contact is shown to be a manipulable and force closure grasp using kinematics and statics with frictionless sliding contact. We discuss that the force closure for the WFM with frictionless contact can be viewed as form closure. An internal force-based impedance control is proposed for the stable manipulation in consideration of sliding contacts between the object and the finger links. A prototype hand and sensing systems are presented. The validity of the proposed control law is verified through the experiments.     

基于旋量理论的三指机器人灵巧手逆运动学分析

为提高三指机器人灵巧手逆运动学的求解效率,提出了基于旋量理论的逆运动学新的求解算法。以Shadow三指灵巧手为例,在无法直接利用单纯的Paden-Kahan 子问题求解逆运动学的条件下,食指（无名指）的逆解采用Paden-Kahan子问题与代数解相结合的算法,拇指的逆解采用数值法与Paden-Kahan子问题相结合的算法。最后通过计算实例证明了算法的有效性和可行性。该算法在保证精度的前提下,几何意义明显,耗费时间短,效率高。     

基于相关匹配的QR码识别方法

QR码图像识别是QR码应用中的关键技术.Hough变换、曲面拟合去背景、控制点变换等方法为QR码识别过程中图像预处理的基本方法,针对图像预处理后图像识别率低的缺点,提出了一种基于相关匹配法的QR码识别方法.基于曲面拟合的改进自适应阈值法分割图像.采用Hough变换和控制点变换方法校正图像的几何失真变形.利用模板对QR码进行相关匹配,对相干系数阈值处理得出取样网格.实验表明,本文算法能有效提高QR码识别效率和效果.     

Influence of blank profile on the V-die bending camber process of sheet metal

The finite element simulation is now widely used in the design of stamping tools. A trial and error procedure has been replaced by a simulation in which defects associated with sheet forming processes are predicted and evaluated. This paper aims to clarify the process conditions of the V-die bending of a sheet metal. It provides a model that predicts not only the correct punch load for bending, but also the precise final shape of the products after unloading. An incremental elastic-plastic finite element computer code, based on an updated Lagrangian formulation, was developed to simulate the V-die bending of sheet metal. In particular, the assumed strain field (ASF) element was used to formulate the stiffness matrix. The r-minimum technique was used to deal with the elastic-plastic state and solve contact problems at the tool-metal interface. A series of experiments were performed to validate the formulation in the theory, leading to the development of the computer codes. The predicted punch load in the finite element model agrees closely with the experimental results. The whole history of deformation and the distribution of stress and strain during the forming process were obtained by carefully considering the moving boundary condition in the finite element method .A unique feature of this V-die bending process is the camber after unloading. The computer code successfully simulates this camber. The simulation was performed to evaluate the effects of the size of the blank on the camber process. The results in this study clearly demonstrate that the computer code efficiently simulated the camber process .     

基于XBee的无线数据采集系统开发和应用

为了及时、方便地获取车间现场数据,研究开发了一种基于XBee模块的无线数据采集系统,包括手持式数据采集器及连接数据服务器的接收器。手持数据采集器以8052单片机为控制核心,集成了XBee无线通信模块以及满足PS/2协议的条码阅读模块,可通过数字小键盘、条码阅读器在车间现场采集各种工票及其进度等离散数据,并实现实时无线传输。介绍了该数据采集系统的设计原理及其软硬件系统,以及在某企业生产车间的实际应用。实际应用结果表明,该系统使用方便,安全性好,适用于生产现场的离散数据采集和无线传输。     

Detection of kinematics parameters of index finger movement with high-speed video camera

Synergic movement of finger＇s joints provides human hand tremendous dexterities, and the detection of kinematics parameters is critical to describe and evaluate the kinesiology functions of the fingers. The present work is the attempt to investigate how the angular velocity and angular acceleration of the joints of index finger vary with respect to time during conducting a motor task. A high-speed video camera has been employed to visually record the movement of index finger, and miniaturized （5-mm diameter） reflective markers have affixed to the subject＇s index finger on the side close to thumb and dorsum of thumb at different joint landmarks. Captured images have been reviewed frame by frame to get the coordinate values of each joint, and the angular displacements, angular velocities and angular acceleration can be obtained with triangle function. The experiment results show that the methods here can detect the kinematics parameters of index finger joints during moving, and can be a valid route to study the motor function of index finger.     

Estimating the surface area of nonconvex particles from central planar sections

In this paper, we present a new surface area estimator in local stereology. This new estimator is called the ‘Morse‐type surface area estimator’ and is obtained using a two‐stage sampling procedure. First a plane section through a fixed reference point of a three‐dimensional structure is taken. In this section plane, a modification of the area tangent count method is used. The Morse‐type estimator generalizes Cruz‐Orive's pivotal estimator for convex objects to nonconvex objects. The advantages of the Morse‐type estimator over existing local surface area estimators are illustrated in a simulation study. The Morse‐type estimator is well suited for computer‐assisted confocal microscopy and we demonstrate its practicability in a biological application: the surface area estimation of the nuclei of giant‐cell glioblastoma from microscopy images. We also present an interactive software that allows the user to efficiently obtain the estimator.     

A new impedance force control of a haptic teleoperation system for improved transparency

In this study, a new impedance force control model of a haptic device for teleoperation is developed and analyzed. A new contact force model for the haptic device and the human hand is provided. Movements of the human hand give additional force disturbances to the force control system. Disturbance force model by haptic dynamics and hand movements is fully analyzed and included in the control system design. An adaptive control scheme is proposed to improve system transparency by achieving good force tracking performance, while simultaneously compensating human hand disturbances and sensor noises. A separate reference model for every DOF is proposed to satisfy tracking performances. Adaptive control gains cover force tracking performance and compensates for human hand disturbances while providing robustness to sensor noises.

     

Evaluation of a three-dimensional single-point turning at atomistic level by a molecular dynamic simulation

In this paper, a molecular dynamic simulation study was performed to study 3D single-point turning of a monocrystalline copper workpiece with rigid diamond tools at nanometric scale. Morse potential energy function was applied to model the copper/diamond and copper/copper interactions. Two-groove cutting was employed to simulate the surface creation in 3D single-point turning operations. Multiple machining conditions were investigated by considering the effects of rake angle, machining speed, depth of cut, and feed rate. Not surprisingly, in machining both grooves, the tool forces increase with the increase of feed rate and depth of cut, as well as the use of a smaller rake angle. These general observations are consistent with the conventional metal machining at longer length scales. On the other hand, it was found that the increase of machining speed also significantly causes the rise of tool forces. Moreover, the stress and instantaneous temperature distributions in the workpiece were analyzed. It was discovered that for all conditions investigated, the equivalent stress and temperature distributions actually resemble these reported for conventional machining. All cutting parameters affect the magnitude and distribution of stresses to a certain extent, while the machining speed appears to be the dominant factor for the machining temperature.     

Numerical multilevel investigation for the evaluation of pressure distribution in ehl circular contacts from film thickness measurements

An analysis of circular contacts under elastohydrodynamic lubrication using a hybrid technique is presented. In particular, attention has been focused on the pressure distribution calculation. A versatile code has been developed to evaluate the pressure distribution starting from three‐dimensional film thickness maps obtained from the analysis of interferometric images. The code has been developed in C++ and is based on the multigrid technique. This hybrid technique has a basic advantage over the full numerical approach in that the pressure is obtained without making any assumptions about the lubricant itself. The main drawback of the method is that high‐resolution interferometric images are required.     

具有形状自适应的欠驱动拟人机器人手指

为了实现使用较少驱动器获得较多的自由度,从而在不增加控制难度的前提下,更好地抓取物体以及增加手的拟人化,需要研究欠驱动机械手指装置。提出了一种新的设计思想,以此为指导设计了一种机械手指装置,并对其主要设计参数进行了详细分析。试验证明,该装置可以作为机器人拟人手的一个手指或手指的一部分,用以实现机器人拟人手较少驱动器驱动较多的手指关节自由度,并具有抓取不同形状、尺寸的物体的自适应性,降低了装置对控制系统的要求。该装置外形与人手的手指相似,结构简单、可靠、易加工、体积小和重量轻。     

基于MATLAB/RTWEC自动代码生成技术整车控制器快速原型开发

介绍了整车控制器快速原型的系统架构。在Simulink的软件平台上搭建了整车控制器仿真模型,利用仿真数据对算法原理进行错误检查和修正。介绍了利用MATLAB/RTWEC实现了基于模型的自动代码生成机制,并将应用层代码与控制器硬件TTC-90底层代码进行了集成,用于整车实验。整车实验结果证明了快速原型的正确性和MATLAB自动生成代码的可靠性、快速性。     

G92指令在FANUC-OM系统中的灵活运用

在数控加工中，一般习惯上使用G54来设置工件坐标系的零点，实际上FANUC-OM系统中的G92指令的功能有一定的灵活性，在G54失效或不使用G54的情况下同样可以使数控机床正常使用。     

G92指令在FANUC-0M系统中的灵活运用

在数控加工中,一般习惯上使用G54来设置工件坐标系的零点,实际上FANUC-OM系统中的G92指令的功能有一定的灵活性,在G54失效或不使用G54的情况下同样可以使数控机床正常使用.