三肢体机器人足部力传感器弹性体分析

提出将传感器传递矩阵条件数和行范数两项指标综合的方法,对一种三肢体机器人的足部三维力传感器弹性体结构进行优化,使传感器在具有低传递误差的同时具有较高的灵敏度.并应用有限元法分析了弹性体各结构尺寸对传感器性能的影响,得到了弹性体在单向受力时的应力、应变分布状态及其静、动态特性,为传感器的结构设计和进一步分析提供了依据.     

基于远程数据传输的空间网架结构风荷载识别

风荷载是空间网架结构的主要设计荷载。正确识别作用在空间网架结构土的风荷载是对其工作状态评估的重要前提条件。本文设计了基于远程数据传输技术的空间网架结构风荷载识别系统．只要安装好传感器就不必在工程现场采集数据，可通过Internet传输数据，使得工程人员在实验室就可实时分析数据，对网架结构进行在风荷载作用下的动力分析。     

Force sensor based on discrete optoelectronic components and compliant frames

In this paper, a novel force sensor based on commercial discrete optoelectronic components mounted on a compliant frame is described. The compliant frame has been designed through an optimization procedure to achieve a desired relation between the applied force and the angular displacement of the optical axes of the optoelectronic components. The narrow-angle characteristics of Light Emitting Diode (LED) and PhotoDetector (PD) couples have been exploited for the generation of a signal proportional to very limited deformation of the compliant frame caused by the external traction force. This sensor is suitable for applications in the field of tendon driven robots, and in particular the use of this sensor for the measurement of the actuator side tendon force in a robotic hand is reported. The design procedure of the sensor is presented together with the sensor prototype, the experimental verification of the calibration curve and of the frame deformation and the testing in a force feedback control system. The main advantages of this sensor are the simplified conditioning electronics, the very high noise-to-signal ratio and the immunity to electromagnetic fields.     

一种应变式多维力传感器的优化设计

针对一种十字梁多维力传感器进行了应力—应变分析,建立了这种传感器的应力—应变模型,并对这种传感器的结构尺寸和应变计贴片位置进行了优化设计,优化设计以传感器获得最大精度为目标,结果显示:传感器优化后其顺应矩阵的条件数下降,传感器测量精度提高。     

A novel six-component force sensor of good measurement isotropy and sensitivities

In this work, a novel six-component force sensor with its force-sensing member in the form of four identical T-shaped bars is presented. The force-sensing member is subjected to finite element analysis in conjunction with a design optimization for high measurement sensitivities. Although significant measurement couplings exist in this six-component force sensor, however, they distribute only in a few sparse places in the calibration matrix, making the calculations for the force components relatively easy and quick. The condition number under the full rated loading conditions for this sensor is 1.543, which represents a rather good measurement isotropy, as compared to approximately 2–4 for a Maltese crossbar sensor under similar conditions. In addition, only 20 strain gauges are required in the design, which is less than that used in a Maltese crossbar type sensor, in which at least 24 strain gauges are used.     

内置式电容层析成像系统传感器优化设计

电容层析成像系统重建图像的质量主要依赖于系统的观测矩阵,即灵敏度矩阵,灵敏度矩阵的特性又由传感器的结构参数所决定的。本文提出了采用反映灵敏度矩阵特性的条件数作为主要的电容传感器优化设计指标,结合表示传感器电极总体灵敏程度的电容变化量指标,兼顾最大、最小电容测量值满足测量范围的要求,进行综合优化设计。通过有限元方法,分析了内置式传感器电极结构参数对电容测量值和灵敏度矩阵的影响,并利用综合指标进行了优化,获得了一组内置式传感器的优化结构参数。     

A new edge-detected lift force flow sensor

A lift force gas flow sensor which uses the force normal to the fluid flow to measure the flow velocity has recently been introduced. Two thin plates mounted at an angle are deflected when they are subjected to fluid flow. For most mechanical flow sensors the flow sensitivity is closely connected to the time response. A weaker structure gives higher flow sensitivity but a lower natural frequency, i.e., a slower response time. The lift force sensor is designed for measurements of respiratory gas flow in ventilators, where, in addition to low flow restriction, both high sensitivity and fast response are required. A new type of suspension has now been realized for the lift force flow sensor. The detection is separated from the suspension of the airfoil plate with the strain gauges placed on separate detector beams. This leads to separate parameters for optimization of the lift force concept with "independent" control of flow sensitivity and natural frequency. This paper presents an analytical model, simulations and measurements on the new structure. The new edge-detected sensor has been experimentally evaluated for different lengths (100-600 /spl mu/m), widths (20-100 /spl mu/m) and thicknesses (8-20 /spl mu/m) of the detector beams. In accordance with the theory, the measurements show that the new structure has approximately three times the natural frequency of the old, center detected structure and similar or improved flow sensitivity. The evaluation has also resulted in a design scheme for optimal performance. A flow sensitivity of 0.65 /spl mu/V/V/(l/min)/sup 2/ has been obtained for the best edge-detected sensor with a natural frequency of 3.2 kHz.     

基于ObjectARX的轻型木桁架节点模拟软件

为克服轻型木桁架设计过程中计算工作量大、手算难以实现的问题,利用ObjectARX编写豪式桁架和芬克式桁架的任意外形建模及计算模型自动生成程序.该程序采用规范推荐的节点模拟法体现齿板连接而产生的节点半刚性特征：用多根模拟弦杆、腹杆和若干分节点构成模拟节点;所有杆件数据通过Xdata扩展数据形式集成在杆件单元中,便于后续程序进行内力计算、简化轻型木桁架的工程设计计算过程.经豪式桁架试算实例,验证该程序生成的模型满足规范要求,易于调整,数据结构良好,且能体现齿板连接引起的刚度修正结果.     

基于正弦力激励的预紧压电式力传感器的研究

为了校准预紧的压电式力传感器动态灵敏度并研究其频响特性和预紧结构的设计,首先介绍了正弦力激励的方法并建立校准数学模型。分别在传感器正立和倒立安装方式下进行测试,通过对比试验研究传感器端部等效质量引入的惯性力对传感器动态灵敏度的影响。然后根据传感器固有频率的落球测试方法,将传感器和附加质量块安装于振动系统。通过白噪声激励得到系统安装谐振频率,进而研究传感器有效频率范围和测量精度与安装谐振频率的关系。最后通过理论分析,说明传感器非对称设计的原因。试验结果表明,当附加质量块质量约为传感器质量的121倍时,可忽略端部等效质量对灵敏度标定的影响;压电式力传感器固有频率高达46kHz,但其有效使用频率范围受安装谐振频率限制,当试验频率与安装谐振频率比 时,压电式传感器精度等级为1%;传感器两端等效质量不同,预紧结构是非对称的,用于动态测试时要将端部等效质量轻的一端连接到被测物体。本研究结果可为开展传感器的现场标定和预紧结构的设计提供理论依据。     

六维力传感器的结构设计分析

为了改善现有六维力传感器的动态性能，提出了一种新型的六维力传感器弹性体结构。建立了结构模型，并采用有限元方法进行了静力学分析以及模态分析，分析了该传感器弹性体在各工况下的应变分布特征；随后对弹性体的关键尺寸参数进行了详细的设计，基于响应面分析法对数值计算结果进行拟合，建立了各工况下响应值与弹性体关键尺寸的回归方程。分析结果表明，该传感器具有良好的动态性能，其一阶固有频率高达3196.3 Hz，各个力分量的灵敏度均有提高，其中x方向力的灵敏度提高了26.09%。通过实验验证了该设计方案的可行性，该传感器的研制为高速作业机器人用多维力传感器的发展奠定了基础。     

A high sensitive MEMS capacitive fingerprint sensor using slotted membrane

In this paper a novel single-chip microelectromechanical systems (MEMS) capacitive fingerprint sensor with slotted membrane is developed to improve the sensitivity. The capacitive sensor consists of a thin, flexible membrane and a rigid back plate with air gap. In this study with making slots in upper electrode to decrease the mechanical stiffness of the membrane, using proportional T-shaped protrusion on diaphragm in order to concentrate the force from finger ridges, making holes in lower electrode to reduce the air damping and using low stress material for diaphragm, we have been succeeded to design a novel MEMS fingerprint sensor with high sensitivity compared with the previous works (Sato et al., IEEE Trans Electron Devices 52:1026–1032, 2005; Damghanian and Majlis, 2008 IEEE International Conference on Semiconductor Electronics (ICSE 2008), pp 634–638 2008). The behaviors of the fingerprint sensor with clamped and slotted membranes are analyzed using the finite element method (FEM). The results yield a sensitivity of 1.44 fF/Mpa for the clamped and 3.22 fF/Mpa for the slotted fingerprint sensor with a 50 × 50 μm² diaphragm. The sensitivity of the slotted structure is increased 2.236 times.     

On automatic selection of redundancies

In the finite element force method the stresses are related to the external loads by the matrix equation of equilibrium. This equation allows the reduction of total number of variables since a stress field can be described in terms of independent (redundant) parameters. Such a selection is used in the elastic force method as well as in the limit analysis. An optimal choice of redundancies which corresponds to the best accuracy of a numerical procedure solving the underdeterminate system of equilibrium equations is sought. The results of a numerical comparison between the various techniques used for an automatic selection of redundancies are presented for a series of frame and truss problems.     

An optimality criteria based method for discrete design optimization taking into account buildability constraints

This paper presents a heuristic design optimization method specifically developed for practicing structural engineers. Practical design optimization problems are often governed by buildability constraints. The majority of optimization methods that have recently been proposed for design optimization under buildability constraints are based on evolutionary computing. While these methods are generally easy to implement, they require a large number of function evaluations (finite element analyses), and they involve algorithmic parameters that require careful tuning. As a consequence, both the computation time and the engineering time are high. The discrete design optimization algorithm presented in this paper is based on the optimality criteria method for continuous optimization. It is faster than an evolutionary algorithm and it is free of tuning parameters. The algorithm is successfully applied to two classical benchmark problems (the design of a ten-bar truss and an eight-story frame) and to a practical truss design optimization problem.     

A Six-Axis MEMS Force–Torque Sensor With Micro-Newton and Nano-Newtonmeter Resolution

This paper describes the design of a six-axis microelectromechanical systems (MEMS) force-torque sensor. A movable body is suspended by flexures that allow deflections and rotations along the x-, y-, and z-axes. The orientation of this movable body is sensed by seven capacitors. Transverse sensing is used for all capacitors, resulting in a high sensitivity. A batch fabrication process is described as capable of fabricating these multiaxis sensors with a high yield. The force sensor is experimentally investigated, and a multiaxis calibration method is described. Measurements show that the resolution is on the order of a micro-Newton and nano-Newtonmeter. This is the first six-axis MEMS force sensor that has been successfully developed.     

MEMS Sensor for In Situ TEM Atomic Force Microscopy

Here, we present a MEMS atomic force microscope sensor for use inside a transmission electron microscope (TEM). This enables direct in situ TEM force measurements in the nanonewton range and thus mechanical characterization of nanosized structures. The main design challenges of the system and sensor are to reach a high sensitivity and to make a compact design that allows the sensor to be fitted in the narrow dimensions of the pole gap inside the TEM. In order to miniaturize the sensing device, an integrated detection with piezoresistive elements arranged in a full Wheatstone bridge was used. Fabrication of the sensor was done using standard micromachining techniques, such as ion implantation, oxide growth and deep reactive ion etch. We also present in situ TEM force measurements on nanotubes, which demonstrate the ability to measure spring constants of nanoscale systems.     

平面框架结构地震力的设计敏度和海森矩阵的计算

提出一种平面框架结构地震力的设计敏度和海森矩阵的精确计算方法.在有限单元法和纽马克-β法的基础上推导了平面框架结构地震力的设计敏度和海森矩阵的计算公式,用matlab语言编制了平面框架结构地震力的设计敏度和海森矩阵的计算程序,实现了平面框架结构地震力的设计敏度和海森矩阵的精确计算.最后给出一个二层平面框架结构算例,数值结果表明本文所提的地震力的设计敏度和海森矩阵的计算方法是有效的和高效的.     

Force density method for simultaneous optimization of geometry and topology of trusses

A new method of simultaneous optimization of geometry and topology is presented for plane and spatial trusses. Compliance under single loading condition is minimized for specified structural volume. The difficulties due to existence of melting nodes are successfully avoided by considering force density, which is the ratio of axial force to the member length, as design variable. By using the fact that the optimal truss is statically determinate with the same absolute value of stress in existing members, the compliance and structural volume are expressed as explicit functions of force density only. After obtaining optimal cross-sectional area, nodal locations, and topology, the cross-sectional areas and nodal coordinates are further optimized using a conventional method of nonlinear programming. Accuracy of the optimal solution is verified through examples of plane trusses and a spatial truss. It is shown that various nearly optimal solutions can be found using the proposed method.     

基于ANSYS的压电四维力传感器一种优化设计方法

在压电式多维力传感器设计过程中,传感器结构对性能的影响难以准确把握,提出一种基于ANSYS的传感器优化设计方法.把不同切型的石英晶片按照特定的双环结构排列实现空间四维力的测量.运用ANSYS有限元软件,研究压电式四维力传感器弹性膜对传感器灵敏度与固有频率的影响规律.分析结果表明:该方法能够有效的平衡传感器灵敏度与固有频...     

Simulation of thermal flying height control slider with built-in contact sensor

This work investigates the piezoelectric contact sensor in the thermal flying height control (TFC) slider. A finite element model is built for the thermal flying height control slider with a piezoelectric contact sensor, which is used to detect the contact between the slider and disk. A constant force is applied at the maximum thermal protrusion point of air bearing surface. The simulation results show that the ZnO sensor with shear-mode is more sensitive to contact force than that with transverse-mode. The sensitivity of contact sensor can be increased by reducing the cross-sectional area of sensor, increasing the thickness of sensor, and choosing a short distance of sensor to air bearing surface. In addition, the thermal-stress effects from TFC heater on contact sensor are significantly large and the amplitude of thermal-stress inducing output voltage is orders larger than that induced by contact force. However, by optimizing the distance of sensor to ABS, it is possible to eliminate the thermal-stress effects. Finally, the response time of thermal-stress induced electrical voltage of contact sensor is about 0.3?ms.     

一种小型光电式力传感器的研制

以扑翼飞行机器人飞行动力性能测试应用为目标,研究了一种高灵敏度小型(满量程50N)力传感器的设计方法.基于红外光电二极管具有响应速度快、线性范围宽、安装方便、接口电路简单等特点,设计了一种光电式力传感器.对设计的弹性体进行了力-应变有限元分析,试制了传感器样机并进行了传感器静态性能测试.测试结果表明,设计制造的光电式力传感器的非线性度小于0.3％,具有较高的综合性能.