Design of a hybrid magnetomotive force electromechanical valve actuator

We propose a novel axis-symmetric modified hybrid permanent magnet (PM)/electromagnet (EM) magnetomotive force actuator for a variable valve timing camless engine. The design provides a large magnetic force with low energy consump-tion, low coil inductance, PM demagnetization isolation, and improved transient response. Simulation and experimental results confirm forces of about 200 N (in the presence of coil current) at the equilibrium position and 500 N (in the absence of coil current) at the armature seat. We compared our proposed design with a double solenoid valve actuator (DSVA). The finite element method (FEM) designs of the DSVA and our proposed valve actuator were validated by experiments performed on manufactured prototypes.     

创伤手指康复外骨骼手关节力传感器研究

为使创伤手指康复外骨骼手能够反馈手指的力觉信息,根据应力测量原理设计了外骨骼手基关节二维力传感器.应用ANSYS软件对传感器弹性体进行了有限元分析,针对手指弯曲和内收/外展两个方向研究了传感器的应变原理,设计了传感器信号采集电路,并对传感器进行了静态标定.传感器在手指弯曲方向具有0.325 V/N的灵敏度和1.4%的线性度,在手指内收/外展方向具有0.346 V/N的灵敏度和2.9%的线性度.实验结果表明传感器能够满足康复外骨骼手系统的要求.     

机电误差互补法在力传感器中的应用

介绍了机电误差互补法的基本原理和给出了应用于力传感器的试验结果。这种方法能有效地提高力传感器的实测精度 ,在传感器安装尺寸受限的情况下 ,更显示出其优越性 ,因而在应用工程中有实用意义。工艺方法是发展这一技术的关键。     

Wide-bandwidth electromechanical actuators for tunnelingdisplacement transducers

A series of displacement transducers have been demonstrated which are based on the detection of electrons that quantum-mechanically tunnel across a narrow gap between electrodes. These transducers have important applications due to the sensitivity of the tunneling mechanism to sub-Å variations in the electrode gap. In this paper, we describe the recent development of wide-bandwidth electromechanical actuators and simple feedback circuitry which have been adapted for use in tunneling displacement transducers. With these actuators and circuits, we have built tunneling transducers with control bandwidths well in excess of 10 kHz. The design, fabrication, operation, and applications of these actuators are described     

电动舵机的复合自适应非奇异终端滑模控制

非奇异终端滑模控制（NTSMc）能够实现误差的有限时间收敛,但一般NTSMC的控制律采用高增益项来消除系统不确定性的影响,具有较强的保守性．为了降低这种保守性,本文采用复合白适应律对系统的不确定参数进行估计,按照估计值设计复合自适应非奇异终端滑模控制（CANTSMC）,对不确定参数引起的系统动态进行补偿．本方案曾经应用于电动舵机,以补偿不确定参数对模型动态性能的影响．本文证明了闭环稳定性,以及输出跟踪误差在有限时间内的收敛性．通过仿真验证了该方法的有效性．     

叉指式加速度计的一种仿真法分析

微电子机械系统的快速发展对其建模仿真也提出了较高要求。首先介绍了一种微电子机械系统原理级描述仿真方法,它基于成熟的微机械元件库,提供微器件的原理级描述,使得仿真更简单、更高效,但目前其适用范围有限。然后介绍了用这种方法分析叉指式微电容加速度计的结果。     

Implicit slicing for functionally tailored additive manufacturing

One crucial component of the additive manufacturing software toolchain is a class of geometric algorithms known as “slicers.” The purpose of the slicer is to compute a parametric toolpath and associated commands, which direct an additive manufacturing system to produce a physical realization of a three-dimensional input model. Existing slicing algorithms operate by application of geometric transformations upon the input geometry in order to produce the toolpath. In this paper we introduce a new implicit slicing algorithm based on the computation of toolpaths derived from the level sets of arbitrary heuristics-based or physics-based fields defined over the input geometry. This enables computationally efficient slicing of arbitrarily complex geometries in a straight forward fashion. Additionally, the calculation of component “infill” (as a process control parameter) is explored due to its crucial effect on functional performance fields of interest such as strain and stress distributions. Several examples of the application of the proposed implicit slicer are presented. Finally, an example demonstrating improved structural performance during physical testing is presented. We conclude with remarks regarding the strengths of the implicit approach relative to existing explicit approaches, and discuss future work required in order to extend the methodology.     

A design flow for micromachined electromechanical systems

I present a design flow for integrated microelectromechanical systems (MEMS), with particular focus on electromechanical devices. Several design examples of real-world devices are given     

Improve the refractive index sensitivity of gold nanotube by reducing the restoring force of localized surface plasmon resonance

The core refractive index sensitivity of a gold nanotube was investigated by calculating the shift of local surface plasmon resonance (LSPR). It was found that the core refractive index sensitivity can be improved by reducing the wall thickness or the surrounding refractive index. The sensitivity increases exponentially with decreasing wall thickness, but increases linearly with decreasing surrounding refractive index. This multi-factor controlled sensitivity of gold nanotube enlarges the ability of optimizing the refractive index sensors. The physical origin of this tunable refractive index sensitivity of gold nanotube was also investigated based on the plasmon hybridization and repulsive effects on the restoring force of plasmon oscillation. This physical mechanism can be used for designing core-shell metallic nanostructures for effective LSPR chemical and biological sensing.     

Investigation of nonlinear dynamic behavior of a capacitive carbon nano-tube based electromechanical switch considering van der Waals force

Microsystem Technologies - In this study, nonlinear dynamic behavior of a capacitive carbon nano-tube switch is investigated considering van der Waals (vdW) force. The carbon nano-tube is...     

Automatically producing tailored web materials for public administration

Public administration organizations commonly produce citizen-focused, informational materials describing public programs and the conditions under which citizens or citizen groups are eligible for these programs. The organizations write these materials for generic audiences because of the excessive human resource costs that would be required to produce personalized materials for everyone. Unfortunately, generic materials tend to be longer and harder to understand than materials tailored for particular citizens. Our work explores the feasibility and effectiveness of automatically producing tailored materials. We have developed an adaptive hypermedia application system that automatically produces tailored informational materials and have evaluated it in a series of studies. The studies demonstrate that: (1) subjects prefer tailored materials over generic materials, even if the tailoring requires answering a set of demographic questions first; (2) tailored materials are more effective at supporting subjects in their task of learning about public programs; and (3) the time required to specify the demographic information on which the tailoring is based does not significantly slow down the subjects in their information seeking task.     

A neural network learning algorithm tailored for VLSIimplementation

This paper describes concepts that optimize an on-chip learning algorithm for implementation of VLSI neural networks with conventional technologies. The network considered comprises an analog feedforward network with digital weights and update circuitry, although many of the concepts are also valid for analog weights. A general, semi-parallel form of perturbation learning is used to accelerate hidden-layer update while the infinity-norm error measure greatly simplifies error detection. Dynamic gain adaption, coupled with an annealed learning rate, produces consistent convergence and maximizes the effective resolution of the bounded weights. The use of logarithmic analog-to-digital conversion, during the backpropagation phase, obviates the need for digital multipliers in the update circuitry without compromising learning quality. These concepts have been validated through network simulations of continuous mapping problems.     

改进非线性亮度提升模型的逆光图像恢复

针对因为拍照时光线不足或拍摄角度不佳而拍出逆光图像影响肉眼观察或计算机识别的问题,提出一种改进的非线性亮度提升模型的逆光图像恢复手段。已有的非线性亮度提升方法虽然能够提高逆光区域的亮度,但往往由于过度提升导致高亮度区域失真。在已有的图像亮度处理算法基础上,提出基于非线性亮度提升模型的自适应逆光图像恢复方法,采用对数函数的转换关系对图像亮度进行分段处理,其分段阈值由Otsu阈值分割决定,其转换函数中逆光区域的调节系数由逆光区像素面积比计算得到。仿真结果显示,新方法提升了图像质量且确保了整幅图片自然不失真,与利用对数函数转换关系,并在HSI空间模型下对图像亮度进行调节的方法相比,提升了处理性能。     

小型软件项目RUP裁剪模型的研究

依据RUP统一过程模型,结合小型软件项目的特点,对RUP模型进行了适当的裁剪,从而建立了一个适用于小型软件项目开发的模型.为综合评价RUP裁剪模型的功效,对该模型在电信公司的电话自动停机复机系统中进行了应用研究,应用该模型完成了电话自动停机复机系统的开发,实践表明:该模型相对瀑布、喷泉、螺旋等模型有明显的优势,大大提高了电话自动停机复机软件的开发效率,保证了电话自动停机复机系统的开发质量,实现了对该软件的优化生成,做到了软件的按期交付.     

Disassembly sequence and cost analysis for electromechanical products

For companies, the improvement of the recyclability performance of their newly designed products is becoming an integral part of product development process. The concept of environmental conscious design (ECD) has been adopted to assist the environmental performance of the products at the early stage of designing. This new trend requires that the design strategies need to be modified by integrating the environmental constraints. This paper provides the disassembly sequence and cost analysis for the electromechanical products during the design stage. The disassembly planning is divided into four stages: geometric assembly representation, cut-vertex search analysis, disassembly precedence matrix analysis, and disassembly sequences and plan generation. The disassembly cost is categorized into three types: target disassembly, full disassembly, and optimal disassembly. The result of this approach shows that the electromechanical products can be disassembled systematically and economically.     

Optimal electrode shaping for precise modal electromechanical filtering

This paper addresses the optimal shape design of segmented spatial sensors and actuators that isolate selected mode shapes and perform modal filtering. Electromechanical filters have reappeared with the new manufacturing capabilities of micro-electro-mechanical structures (MEMS). In such small dimensions it proves essential to treat their elastic behaviour as continuous rather than discrete systems that require suitable design methods, some of which are developed here. In MEMS filters, the input signal is converted to external electrostatic forces and in order to perform the desired filtering, the electrodes need to be shaped such that they excite only a desired part of the dynamics. An optimization scheme that shapes these electrodes to achieve optimal filtering is developed. In order to enhance the filter’s performance and minimize energy lost to the supporting structure, a special support tuning method is proposed. Several simulated examples examine the effectiveness of the proposed optimization methods.     

Area decomposition for electromechanical models of power systems

Coherency and time scale properties of power system models are shown to be related by the dichotomic solution of a matrix Riccati equation. A grouping algorithm is proposed which reduces the area decomposition problem to obtaining a basis for the slow subsystem and performing a Gaussian elimination. Since the slow coherency measure allows for a lack of coherency in fast parts of machine transients, the resulting area decomposition is independent of fault locations. The procedure is illustrated by a 16-machine example.     

Composite stacking sequence optimization for aeroelastically tailored forward-swept wings

A method for stacking sequence optimization and aeroelastic tailoring of forward-swept composite wings is presented. It exploits bend-twist coupling to mitigate aeroelastic divergence. The method proposed here is intended for estimating potential weight savings during the preliminary aircraft design stages. A structural beam model of the composite wingbox is derived from anisotropic shell theory and the governing aeroelastic equations are presented for a spanwise discretized forward swept wing. Optimization of the system to reduce wing mass is undertaken for sweep angles of ?35° to 0° and Mach numbers from 0.7 to 0.9. A subset of lamination parameters (LPs) and the number of laminate plies in each pre-defined direction (restricted to {0°,±45°, 90°}) serve as design variables. A bi-level hybrid optimization approach is employed, making use of a genetic algorithm (GA) and a subsequent gradient-based optimizer. Constraints are implemented to match lift requirements and prevent aeroelastic divergence, excessive deformations, airfoil stalling and structural failure. A permutation GA is then used to match specific composite ply stacking sequences to the optimum design variables with a limited number of manufacturing constraints considered for demonstration purposes. The optimization results in positive bend-twist coupling and a reduced structural mass. Results are compared to an uncoupled reference wing with quasi-isotropic layups and with panel thickness alone the design variables. For a typical geometry and a forward sweep of ?25° at Mach 0.7, a wingbox mass reduction of 13 % was achieved.