A novel hand exoskeleton to enhance fingers motion for tele-operation of a robot gripper with force feedback☆

This research describes a robotic system's design, optimization, and implementation processes for tele-operation with haptic feedback using the Hand Exoskeleton of New technologies research center (HEXON) as a novel haptic mechanism and the HEXON robotic gripper to work collaboratively with the exoskeleton. In particular, a force-sensitive robotic gripper is connected to a hand exoskeleton, mimics the user's hand movements, and transfers haptic feedback through the exoskeleton. The two-finger exoskeleton's design process consists of a multi-criteria optimization procedure to simultaneously maximize applied force to the finger and workspace of the attached exoskeleton, optimizing both the Perpendicular Impact Force (PIF) and the Global Isotropy Index (GII), considering worst-case collision avoidance. Due to the tele-operation application and using a robotic arm as a slave in the remote scenario, the gripper can be used as an end-effector for a palletizing 3-DOF robotic arm, and movement of the gripper can be achieved by using a visual sensor to pinpoint the user's hand location in 3D space. With the aim of the stress analysis software, the exoskeleton and gripper designs were analyzed to evaluate the system strength against applied forces. Finally, based on the achieved results, the gripper and two-fingered exoskeleton prototypes were fabricated. Simulations and experimental results are reported, showing the potential of the HEXON in haptics and tele-operation applications, and the exoskeleton is used to operate a robotic arm and gripper while the user can perceive the objects virtually.     

Electromagnetic self-powered low-level vibration energy scavenger with microelectroplated nickel resonator

An electromagnetic self-powered vibration energy scavenger is developed, which can convert low-level vibrational energy into electrical energy. It consists of a magnet-spring system and a two-layer copper coil. The nickel planar spring and the two-layer copper coil are fabricated using UV-LIGA technology and microelectroplating technology. Testing results show that the fabricated vibration energy scavenger can generate a maximum load voltage of 62 mV and a maximum power of 6.4 muW, at an input frequency of 247.5 Hz and an acceleration of 10 m/s².     

Investigation into soft-start techniques for driving servos

Servos (as commonly used in radio controlled vehicles and small scale robotics) are DC actuators which use a potentiometer to provide built-in feedback to localise an actuator arm. To minimise jerky control movements, many servo controllers include velocity and acceleration control which operate using a defined velocity profile resulting in the Pulse Width Modulation (PWM) control value being changed over time. On power-up the initial position of the servo arm is unknown to external controller—resulting in the arm moving to the starting value at maximum speed (which may be mechanically hazardous). In this paper two different techniques for performing a soft-start for servos are described and evaluated, namely: voltage profiling and intermittent drive. The different techniques are implemented and evaluated using four different servos based on measured velocity profiles, current consumption, and peak torque.     

Three‐Dimensional Programmable Assembly by Untethered Magnetic Robotic Micro‐Grippers

Mobile sub‐millimeter micro‐robots have demonstrated untethered motion and transport of cargo in remote, confined or enclosed environments. However, limited by simple design and actuation, they lack remotely‐actuated on‐board mechanisms required to perform complex tasks such as object assembly. A flexible patterned magnetic material which allows internal actuation, resulting in a mobile micro‐gripper which is driven and actuated by magnetic fields, is introduced here. By remotely controlling the magnetization direction of each micro‐gripper arm, a gripping motion which can be combined with locomotion for precise transport, orientation, and programmable three‐dimensional assembly of micro‐parts in remote environments is demonstrated. This allows the creation of out‐of‐plane 3D structures and mechanisms made from several building blocks. Using multiple magnetic materials in each micro‐gripper, the addressable actuation of gripper teams for parallel, distributed operation is also demonstrated. These mobile micro‐grippers can potentially be applied to 3D assembly of heterogeneous meta‐materials, construction of medical devices inside the human body, the study of biological systems in micro‐fluidic channels, 3D micro‐device prototyping or desktop micro‐factories.     

核电站反应堆松脱件模拟撞击技术研究

核电站松脱件撞击模拟系统可在反应堆系统管壁或器壁上制造出松脱件撞击信号,用以在线调试和检测电站松脱部件监测系统,保证核电站的正常运行.利用电容放电特性,产生高能量的脉冲电流;基于电磁效应原理,将脉冲电能转换为机械动能,实现了核电站松脱件撞击模拟技术;通过试验验证,利用该技术可产生0~100g的核电站松脱件模拟撞击信号.     

Design of a robot gripper with force feedback control

The design of a two-jaw robot gripper using a D.C. servomotor with optical encoder is described. Force control of the gripper is achieved using armature current sensing as a means of detecting motor torque and hence the force applied between the gripper jaws.The motor was modelled mathematically to obtain the second order equation relating armature current to the applied motor voltage. This relationship was used to develop a proportional plus integral digital control algorithm enabling force feedback to be achieved.Two-way communication between the ASEA robot controller and the IBM-XT gripper controller enables a range of gripping forces to be accessed throughout the robot programme cycle, any one of which may be selected at a particular time. Anticipated problems associated with the thermal drift and transient responses have largely been overcome by repeatedly recalibrating the gripper throughout a work shift.     

增程式电动车恒功率控制方式的仿真分析

增程式电动车有多种发动机控制策略,本文针对一款新能源电动汽车改制的增程式电动车动力参数匹配问题,以AVL Cruise为仿真平台,采用增程器恒功率控制策略构建整车模型,计算了所设计的增程式电动车经济性能.研究结果表明,最大爬坡度、加速时间、最高车速满足车辆动力性要求.     

激光尾场中被加速电子的动能研究

为了研究在激光驱动的尾场中被加速电子的动能,采用粒子模拟方法,得到了决定电子最大动能的尾场势的最大值和最小值,讨论了等离子体尾波静电势的最大值和最小值及其与激光脉冲长度和强度之间的关系。结果表明,捕获电子最大能量与脉冲激光强度成正比,激光脉冲长度是激光波长的10倍时电子获得的能量最大。     

Design and Fabrication of a Four-Arm-Structure MEMS Gripper

This paper is focused on the design and fabrication of a four-arm-structure microelectromechanical systems gripper integrated with sidewall piezoresistive force sensors. Surface and bulk micromachining technologies are employed to fabricate the microgripper from a single-crystal silicon wafer (i.e., no silicon-on-insulator wafer is used). A vertical sidewall surface piezoresistor etching technique is used to form the side direction force sensors. The end effector of this gripper is a four-arm structure: two fixed cantilever arms integrated with piezoresistive sensors are designed to sense the gripping force. The resolution of the force sensor is in the micronewton range and, therefore, provides feedback of the forces that dominate the micromanipulation processes. An electrostatically driven microactuator is designed to provide the force to operate the other two movable arms. In this way, it creates a deflection of 25 mum at the arm tip, and the range of the operation is 30-130 mum. Experimental results show that it can successfully provide force sensing and play a main role in preventing the damage of microparts in micromanipulation and microassembly tasks.     

Velocity and acceleration estimation for optical incremental encoders

Optical incremental encoders are extensively used for position measurements in motion systems. The position measurements suffer from quantization errors. Velocity and acceleration estimations obtained by numerical differentiation largely amplify the quantization errors. In this paper, the time stamping concept is used to obtain more accurate position, velocity and acceleration estimations. Time stamping makes use of stored events, consisting of the encoder counts and their time instants, captured at a high resolution clock. Encoder imperfections and the limited resolution of the capturing rate of the encoder events result in errors in the estimations. In this paper, we propose a method to extend the observation interval of the stored encoder events using a skip operation. Experiments on a motion system show that the velocity estimation is improved by 54% and the acceleration estimation by 92%.     

Tactile sensing with accelerometers in prehensile grippers for robots

Several pneumatic grippers with accelerometers attached to their fingers have been developed and tested. The first gripper is able to classify the hardness of different cylinders, estimate the pneumatic pressure, monitor the position and speed of the gripper fingers, and study the phases of the action of grasping and the influence of the relative position between the gripper and the cylinders. The other grippers manipulate and assess the firmness of eggplants and mangoes. To achieve a gentle manipulation, the grippers employ fingers with several degrees of freedom in different configurations and have a membrane filled with a fluid that allows their hardness to be controlled by means of the jamming transition of the granular fluid inside it. To assess the firmness of eggplants and mangoes and avoid the influence of the relative position between product and gripper, the firmness is estimated while the products are being held by the fingers. Better performance of the accelerometers is achieved when the finger employs the granular fluid. The article presents methods for designing grippers capable of assessing the firmness of irregular products with accelerometers. At the same time, it also studies the possibilities that accelerometers, attached to different pneumatic robot gripper fingers, offer as tactile sensors.     

一种WCDMA第三方探测系统目标信号快速捕获算法

针对第三方探测系统对WCDMA系统中上行PRACH捕获的实时性要求,分析传统前缀同步算法的不足,本文设计一种基于能量累加和最大似然相结合的前缀快速捕获算法,并根据消息的帧结构特点设计一种基于控制部分的频偏估计算法。快速捕获和频偏估计共同构成第三方探测系统目标信号快速捕获算法,经实测数据验证,该算法能够快速、准确对目标手机用户RACH信息进行捕获、解码。     

一种非谐振式MEMS电磁能量收集器

介绍了一种新型非谐振式微电子机械系统(MEMS)电磁振动能量采集器的设计、微加工和表征测试.该能量收集器由MEMS结构、线圈、小型化NdFeB磁体和陶瓷基板组成.建立结构模型对结构固有频率、位移和应力进行仿真.利用MEMS技术制备能量收集器结构和Al线圈等关键部件,并结合嵌有永磁体的陶瓷基板进行组装,在组装过程中使用C...     

真空微电子加速度传感器结构的有限元分析

论述了真空微电子加速度传感器的结构及工作原理 ,应用有限元方法对加速度传感器进行了静力学和动力学分析 ,拟合出悬臂梁的长宽厚与质量块最大位移量的关系曲线和谐振频率的关系曲线以及质量块受迫振动的谐响应曲线。这些分析为此类加速度传感器的设计提供了理论依据     

基于光纤Bragg光栅的地震检波器的理论与实验研究

提出了一种新型的基于光纤Bragg光栅(FBG)的地震检波器。FBG地震检波器传感头由平面弹簧片、质量块和FBG构成。给出了该检波器的力学模型,理论推导与分析了该检波器的幅频特性和加速度灵敏特性,并讨论了影响该检波器灵敏度的主要因素。实验结果表明,该检波器具有良好的线性度、稳定性和耐受性;检波器的频率响应范围为10～140 Hz,传感器灵敏度为25.9pm/g,共振频率为167 Hz,较符合理论值;最高可检测加速度值大于30g。     

基于压电材料的引线键合微夹持器设计

引线微夹持器是IC/LED键合系统的关键模块.该文综合采用压电智能材料与柔性联接的组合结构,设计了键合系统的引线微夹持器.利用有限元法,计算了微夹持器的振动模态与静力特性,获得了系统的固有频率、振动模态及电信号驱动下的支臂端部张开量.在实验上,通过高速摄像系统的跟踪实验,捕获了系统支臂端部的运动行为,获得了系统张开量与驱动电压的关系;并用激光非接触测量技术,获得系统端部的振动特性.该文计算与实验均为引线微夹持器的可靠性应用提供基础.     

PASER 在混合气体激活介质中的理论计算

在受激辐射粒子加速中（PASER）, 受激介质中处于激发态的电子跃迁到基态时辐射的光子能量直接以量子形式转移给从它旁边经过的电子。本文首先对单个电子束团穿过受激介质时产生的电场进行了理论推导，并分别对受激的二氧化碳混合气体和受激氟化氩混合气体进行了计算。计算结果表明加速梯度可以达到1GV/m，比现有的普通的加速器加速梯度20~30MV/m高两个数量级。此外，通过二维模型进一步分析了电子微束团串穿过受激的混合气体介质获得的能量增益。结果表明电子束团串可以显著地吸收受激介质中的量子态能量，且吸收的能量与相互作用长度成正比。在相互作用长度等于0.5m时对束团参数和其它的量对能量交换的影响进行了分析。通过理论计算给出了电子获得最大能量增益时的优化参数。     

正弦三角激光脉冲尾场加速正电子模拟

为了研究正弦三角激光脉冲和低密度的等离子体相互作用时加速正电子的运动,采用数值模拟方法进行了数值计算,得到了被加速正电子的动能.结果表明,由于正弦三角激光脉冲激发产生的Raman散射原因,使得被尾场捕获的正电子数增多及相应的初速度增大;非对称正弦三角脉冲的前沿比对称正弦三角脉冲更陡,具有更强的有质动力势,能够产生更强的尾场,因此非对称正弦三角激光脉冲比对称激光脉冲驱动尾场中正电子的能量高.该研究结果说明,非对称正弦三角激光脉冲能够有效地提高正电子的加速效果.     

Single-port robotic manipulator system for brain tumor removal surgery: SiromanS

The paper presents a new single-port robotic manipulator system (SiromanS) for brain tumor removal surgery. SiromanS is designed to minimize the size of surgical incisions compared to those needed for existing brain tumor removal surgeries. SiromanS consists of two robotic arms, a stereo-endoscope with a light source, and a cylindrical insertion part to house the arms and the endoscope. The stereo-endoscope is used to provide a 3D view of the surgical site to surgeons. The insertion part possesses three channels, through which the two robotic arms and the stereo-endoscope are integrated into SiromanS. One robotic arm of SiromanS has a gripper end-effector and the other has a suction end-effector to remove the brain tumor. This paper presents the robotic arm controlled by a wire-driven mechanism for distal dexterous motion and its miniaturization, and illustrates an actuating module that is separable from the robotic arm for sterilization and tool exchange. The forward/inverse kinematics analysis is also presented. A series of experimental results show that SiromanS’ performance capabilities are promising for brain surgery applications.