A behavioral model for optically powered OCT endoscope with a micro electrostatic vertical‐comb optical scanner

This paper presents a novel device architecture for optically actuated microelectromechanical systems (MEMS) endoscopes for optical coherence tomography (OCT) measurement. A 10‐mW infrared light beam at a wavelength of 1.5 µm is transferred through the single‐mode fiber to provide a scanning MEMS mirror with the drive voltage (maximum 11 V) by exciting a photovoltaic cell, while also providing with a secondary light beam at a wavelength of 1.3 µm for the OCT measurement. An electrostatic vertical comb‐drive optical scanner (1.5 mm × 2.0 mm × 0.5 mm) has been developed by using the deep reactive ion etching (DRIE) of a silicon‐on‐insulator (SOI) wafer. The design of the scanner module is discussed, along with the experimental results of electrostatic operation. An equivalent circuit model for the optical scanner is developed to explain the behavior of the optically powered actuation mechanism, including the hysteresis loop in the frequency response and the voltage dependence of oscillating angle (mechanical peak ±3.2°/7 V around the resonance frequency of 250 Hz). OCT measurement of a tissue is demonstrated to reconstruct the cross‐sectional image of a fingerprint at a resolution of lateral 40 µm × vertical 8 µm and penetration depth of 2.5 mm. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Characteristics of a two‐dimensional integrated magnetic sensor for position sensing and motor control

Two‐dimensional integrated magnetic sensors for position sensing were designed and fabricated with the standard 0.35‐µm CMOS process on silicon. One such type is the n‐type Hall sensor that uses an inversion layer under the gate oxide of the MOSFET. The Hall sensors were arrayed (64 × 64), and the control digital circuits and output amplifier were also integrated into the same chip. ‘One pixel’ was 50 × 50 µm, and the entire chip was 4.9 × 4.9 mm. The sensitivity of one of these sensors was 2.7 mV/(mA·kG). The two‐dimensional magnetic flux distribution was measured from the 5‐mm diameter Nd–Fe–B rare‐earth permanent magnet. About 42 s was required to measure one frame. The position of the magnet could be detected with the fabricated sensors. Magnetic sensors using an inversion layer in MOSFETs are useful for position sensing systems, but their noise characteristics, such as poor sensitivity, should be improved. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

螺旋传动蠕动式内窥镜机器人的设计和实验

针对现有胃肠道检测方法的被动运动方式的缺点,设计出了基于蠕动方式的胃肠道内窥镜机器人。该机器人由两个径向钳位机构和一个轴向伸缩机构组成,钳位机构和伸缩机构都是基于螺旋传动原理并由直流电机驱动。机器人通过步态的配合完成前进、后退和驻留。加工装配后的机器人在收缩状态时尺寸大小为Φ13mm×75mm,径向最大伸长5mm,轴向步距29.2m,理论运动速度2.92mm/s。基于双螺旋传动的机器人可以实现在肠道内主动运动。     

基于内嵌式SMA电机的柔性机械手研制

该文描述了一种新型柔性机械手的研制，这种新型机械手能够实现拟人抓取中的平滑运动，手指外径10mm，由两个弯曲部分，一个连接部分组成，弯曲部分为偏心嵌有线性SMA驱动器的单元电机，介绍了SMA丝和弹性手指的尺寸规格设计和制作方法，详细研究了弯曲部分的机械特性并给出了基于电阻反馈的控制系统，最后设计制作了一个三指机械手，抓取实验证明，机械手能较好完成平滑拟人抓取。     

Multi‐template approach to realize central pattern generators for artificial locomotion control

Biologically inspired control of artificial locomotion often makes use of the concept of central pattern generator (CPG), a network of neurons establishing the locomotion pattern within a lattice of neural activity. In this paper a new approach, based on cellular neural networks (CNNs), for the design of CPGs is presented. From a biological point of view this new approach includes an approximated chemical synapse realized and implemented in a CNN structure. This allows to extend the results, previously obtained with a reaction‐diffusion‐CNN (RD‐CNN) for the locomotion control of a hexapod robot, to a more general class of artificial CPGs in which the desired locomotion pattern and the switching among patterns are realized by means of a spatio‐temporal algorithm implemented in the same CNN structure. Copyright © 2002 John Wiley & Sons, Ltd.     

Triaxial MEMS accelerometer with screen printed PZT thick film

Piezoelectric thick films have increasing interest due to the potential high sensitivity and actuation force for MEMS sensors and actuators. The screen printing technique is a promising deposition technique for realizing piezoelectric thick films in the thickness range from 10–100 μm. In this work integration of a screen printed piezoelectric PZT thick film with silicon MEMS technology is shown. A high bandwidth triaxial accelerometer has been designed, fabricated and characterized. The voltage sensitivity is 0.31 mV/g in the vertical direction, 0.062 mV/g in the horizontal direction and the first mode resonance frequency is 11 kHz. A Finite Element Method (FEM) model is used to validate the measured sensitivity and resonance frequency. Good agreement between the model and the measurements is seen.     

A new fast‐response buck converter using accelerated pulse‐width‐modulation techniques

A new fast‐response buck converter using accelerated pulse‐width‐modulation techniques is proposed in this article. The benefits of the accelerated pulse‐width‐modulation technique is fast‐transient response, simple‐compensation design, and no requirement for slope compensation; furthermore, some power management problems are minimized, such as EMI (Electro Magnetic Interference), size, design complexity, and cost. The traditional voltage‐mode speed is slower with the transient response, so an accelerated pulse‐width‐modulation technique is used to solve the problem of slowed transient response in this article. The proposed buck converter has excellent conversion efficiency with a wide load conditions. The proposed buck converter has been fabricated with TSMC 0.35 µm CMOS 2P4M processes, and the total chip area is 1.32 × 1.22 mm². Maximum output current is 300 mA when the output voltage equals 1.8 V. When the supply voltage is 3.6 V, the output voltage can be 1–2.6 V. Maximum transient response is less than 5 µs. The simulation and experimental results are presented in this article. Copyright © 2011 John Wiley & Sons, Ltd.     

Dynamic modeling and adaptive robust boundary control of a flexible robotic arm with 2‐dimensional rigid body rotation

This paper investigates the control of a single‐link flexible robot manipulator with a tip payload appointed to rotate about 2 perpendicular axes in space. The control objective is to regulate the rigid body rotation of the manipulator with guaranteeing the stability of its vibration in the presence of exogenous disturbances. To achieve this, a Lyapunov‐based control design procedure is used and accomplished in some steps. First, the partial differential equation (PDE) dynamic model governing the rigid‐flexible hybrid motion of the arm is derived by applying Hamilton's principle. Next, based on the developed PDE model, an adaptive robust boundary control is established using the Lyapunov redesign approach. To this end, an adaptation mechanism is proposed so that the robust boundary control gains are dynamically updated online and there is no need for prior knowledge of disturbance upper bounds. The actuators and sensors are fully implemented at the arm boundary without using distributed actuators or sensors. Furthermore, in order to avoid control errors resulting from the spillover, control design is directly based on infinite‐dimensional PDE model without resorting to model truncation. Simulation results illustrate the efficacy of the considered method.     

MEMS PIEZOELECTRIC ACOUSTIC TRANSDUCER

ABSTRACT

This paper presents the fabrication process and measurement results of microelectro-mechanical (MEMS) piezoelectric acoustic transducers. To increase the output sound pressure, a dome-shaped multi-layer diaphragm is designed and fabricated by adjusting the residual stress in the individual layers. Transducers work in either audio or ultrasonic frequency range if diaphragm is designed in different size. In the frequency range from 100 Hz to 7 kHz, the output sound pressure of audio transducers with 3 mm × 3 mm diaphragm is higher than 0.1 Pa. The maximum output reaches 1.1 Pa at 3.8 kHz. For ultrasonic transducers with 1 mm × 1 mm diaphragm, the maximum output is 1.26 Pa at resonant frequency of 54 kHz. All transducers show acceptable linearity over a wide range of input drive voltage.     

Development of Corrosion‐Resistant Pressure Sensor with Semiconductor Strain Sensor

In automotive and industrial fields, pressure sensors are a key component for precisely controlling the mechanical systems. Conventional micro electro mechanical system (MEMS)‐based pressure sensors have an advantage in noise resistance, because both strain gauges and control circuits are integrated in one chip. However, the MEMS‐based pressure sensors are generally fabricated on an Si substrate, and have a low stability against various active gases. Thus, we have newly proposed a pressure sensor which consists of an Si‐based strain sensor set on a stainless steel diaphragm with a high stability against the active gases. The key technology is that a Koval plate is inserted between the strain sensor and the stainless steel diaphragm, for preventing the breakage or the delamination of the strain sensor at the bonding interface due to a difference in thermal expansion. Structure of the sensor including the shape and the size of Koval plate and the assembly position of the strain sensor were designed using structural simulation and experiments. Eventually, the 2.8 mm wide and 0.17 mm thick Koval beam was bridged on the stainless steel diaphragm for efficiently transmitting the diaphragm deformation to the strain sensor. The strain sensor was assembled at the edge of Koval beam with a glass bonding technique. Consequently, the developed pressure sensor has achieved a small dispersion of less than 1% F. S. in a temperature range from 0 °C to 85 °C.     

THIN-FILM PIEZOELECTRIC ACTUATORS FOR BIO-INSPIRED MICRO-ROBOTIC APPLICATIONS

ABSTRACT

Biologically-inspired autonomous micro-robots have a variety of anticipated applications resulting from their unique scale and cooperative potential. To achieve locomotion comparable to biological systems, these micro-robots will require actuators substantially stronger than most existing MEMS actuation technologies. Piezoelectric thin-films can meet these specifications while drawing limited power and contributing little mass to micro-robotic systems. Theoretical actuation requirements for micro-robotic applications show that lead-zirconium-titanate (PZT) thin-film actuators can meet these requirements, including a new thin-film PZT lateral actuator developed by the United States Army Research Laboratory. Experimental results and a comparison to other common lateral actuation technologies are presented.     

Fabrication of a microelectromechanical system mirror array and its drive electrodes for low electrical interference in wavelength‐selective switches

This article describes the fabrication of a microelectromechanical system (MEMS) mirror array and mirror‐drive electrodes with high‐aspect‐ratio gold walls that reduce electrical interference in a wavelength‐selective switch (WSS). The MEMS mirror array, in which a lot of closely spaced adjacent mirrors are electrostatically operated, can be fabricated with a high yield by encapsulating the mirrors with an organic film that protects them from process damage. The gold walls with a high‐aspect ratio are formed in the narrow space between adjacent mirror‐drive electrodes by using thick‐multilevel interconnection technology. Because of these walls between adjacent electrodes, each MEMS mirror operates with low electrical interference. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Development of multi‐analyte DNA microchip using 3D nanoprototyping fabrication method

The importance of microfluidics systems for high‐throughput postgenome analysis has been steadily increasing. We conceived and fabricated an integrated six‐microchip capillary electrophoresis unit on a small area of 30 × 30 mm for high‐throughput DNA analysis. The design of the structure was performed using a fluid dynamics simulation of electrophoresis to improve the DNA separation resolution. A narrow width of the micro channel at the corners was adopted. For simple fabrication of the microchip, we developed the PMMA structure of the micro fluid channel using lithography, molding, and fusion bonding techniques. It was demonstrated that the proposed integrated structure of micro channels results in good performance of on‐chip DNA separation in a small one‐unit area of 9 × 9 mm. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(1): 32–36, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21156     

Development and Control of Multi‐Degree‐of‐Freedom Mobile Robot for Acquisition of Road Environmental Modes

The acquisition of information about the environment around a mobile robot is important for purposes such as controlling the robot from a remote location and in situations such as that when the robot is running autonomously. In some research, audiovisual information has been used. However, the acquisition of information about force sensation, which is included in environmental information, has not been well investigated. The mobile‐hapto, which is a remote control system with force information, has been proposed, but the robot used for the system can acquire only the horizontal components of forces. For this reason, in this research a three‐wheeled mobile robot consisting of seven actuators was developed and a control system was created for it. The robot can acquire information about horizontal and vertical forces without using force sensors. By using this robot, detailed information on the forces in the environment can be acquired and the operability of the robot and its ability to adjust to the environment are expected to improve.     

Switching characteristics of vacuum gap switch employing UV‐laser triggering

The switching time and arc‐ignition probability of a sustained main discharge in a laser trigger vacuum gap were measured. The third harmonic beam of an Nd:YAG pulse laser (wavelength 355 nm, energy 5 mJ/pulse, power density 4 × 10⁷ W/cm²) was used to trigger the gap. The main electrodes 85 mm in diameter were made of oxygen‐free copper. The gap length was 1.6 mm and the experimental chamber was evacuated to about 1.3 × 10⁴ Pa by a turbomolecular pump. The UV beam from the laser was focused at normal incidence onto the grounded cathode. The switching time decreased and the arc‐ignition probability increased with increasing applied voltage. The switching time was 326 ns at 15 kV with a circuit inductance of 107 μH. Its jitter was 24.8 ns. The advantageous results obtained with the UV beam are compared to the previously reported data on triggered vacuum gaps. © 2000 Scripta Technica, Electr Eng Jpn, 132(3): 8–13, 2000     

基于C8051的误差检测在圆网壁纸机中的应用

基于满足大型圆网壁纸印刷机高精度、高速度和高稳定性等工艺要求的目的,从分析误差的产生、计算误差的方法和误差的处理出发,系统采用了色标检测的方法。通过对光电编码器所产生的脉冲信号进行分析,控制各圆网的同步状态,以C8051单片机为核心的误差检测系统实现了伺服电机的闭环控制,最终达到了对各圆网单元的精确控制。介绍了基于单片机的误差检测在圆网壁纸机伺服控制系统中的工作原理、应用、硬件组成和软件的实现。     

Lead-free NKN-5LT piezoelectric materials for multilayer ceramic actuator

As a candidate for lead-free piezoelectric materials, Li₂O excess 0.95(Na_0.5K_0.5)NbO₃–0.05LiTaO₃ (NKN-5LT) ceramics were developed by conventional sintering process. Sintering temperature was lowered by adding Li₂O as a sintering aid. Abnormal grain growth in NKN-5LT ceramics was observed with varying Li₂O content. In the 1 mol% Li₂O excess NKN-5LT samples sintered at 1000°C for 4 h in air, electromechanical coupling factor and piezoelectric constant of NKN-5LT ceramics were found to reach the highest values of 0.37 and 250 pC/N, respectively. Lead-free piezoelectric ceramic, Li₂O excess NKN-5LT, multilayer ceramic actuators (MLCA) were fabricated. 10?×?10?×?1 mm³ size MLCAs were fabricated by conventional tape casting method. The displacement of Li₂O excess NKN-5LT MLCA with 3 mm thickness was ~1 μm at 150 V.     

Circuit and system design for an 860–960 MHz RFID reader front‐ends with Tx leakage suppression in 0.18 − µm CMOS technology

This paper presents an RF Front‐END for an 860–960thinspaceMHz passive RFID Reader. The direct conversion receiver architecture with the feedback structure in the RF front‐end circuit is used to give good immunity against the large transmitter leakage and to suppress leakage. The system design considerations for receiver on NF and IIP3 have been discussed in detail. The RF Front‐END contains a power amplifier (PA) in transmit chain and receive front‐end with low‐noise amplifier, up/down mixer, LP filter and variable‐gain amplifier. In the transmitter, a differential PA with a new power combiner is designed and fabricated in a 0.18‐µm technology. The chip area is 2.65 mm × 1.35 mm including the bonding pads. The PA delivers an output power of 29 dBm and a power‐added efficiency of 24% with a power gain of 20 dB, including the losses of the bond‐wires. Copyright © 2011 John Wiley & Sons, Ltd.     

Fabrication and evaluation of PZT/Ag composites and functionally graded piezoelectric actuators

Metallic Ag as the second phase was added into PZT ceramic matrix to fabricate piezoelectric composites and functionally graded actuators by gradually altering Ag concentration, aimed to improve mechanical properties and to solve possible interfacial debonding usually observed in conventional bimorph-type piezoelectric actuator. The PZT/Ag composites were obtained by directly co-firing PZT and Ag powders at 1200^∘C for 1 h. The fracture strength σ _f and fracture toughness K _IC , as well as the corresponding piezoelectric properties, were firstly evaluated upon the PZT/Ag composites for Ag concentrations of 0–30 vol%. The mechanical properties for the PZT/Ag composites were found to be greatly enhanced compared with pure PZT ceramics: from 69 to 129 MPa for σ _f and from 1.0 to 3.7 MPa.m^1/2 for K _IC . With increasing Ag concentration, the piezoelectric constant d ₃₃ of PZT/Ag composites was found to decrease from 419 to 86 pC/N. Then, a functionally graded actuator was fabricated and evaluated in terms of electric-induced curvature k. The PZT/Ag FGM actuator with size of 12 mm × 3 mm × 1 mm has a curvature k of 0.03–0.17 m⁻¹ that corresponds to applied voltages of 100–500 V. A comprehensive comparison was made on the mechanical property enhancements by the metal particles dispersion, and the bending displacements produced by the FGM actuators between the PZT/Ag and previously fabricated PZT/Pt systems.     

Development of a Peristaltic Crawling Robot Using Planar Link Mechanisms

The field of bio‐mechanisms, which develops new machines that use motion and control of organisms as a model, is attracting attention. We examined the peristaltic crawling of an earthworm as a transport function in place of wheels or ambulation, and have developed a robot running inside a tube. In this robot, a joint corresponding to the earthworm's segment is driven by a DC motor. This paper presents the experimental result of the peristaltic crawling of an actual earthworm and the evaluation result of the transport mechanism of a prototype robot. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.