Design of a hybrid optical image stabilization actuator to compensate for hand trembling

In this paper, a novel hybrid optical image stabilization (OIS) actuator for digital camcorder is proposed. Image stabilization for this hybrid type consists of both radially and tangentially moving components to compensate for hand trembling. The proposed OIS actuator, which uses a voice coil motor method, is divided into two parts: a structure and a magnetic circuit. For the structural part, the driving mechanism consists of two systems: one system is based on a ball guide with a magnetic spring, and the other system is based on a pivot bearing. The former system is typically used as a driving mechanism in mobile devices, whereas the latter system has advantages such as mechanical stability and reduced friction. Overall, a magnetic spring between the magnet and yoke should be considered to select the best magnetic circuit part design and mechanism design. Regarding the electro-magnetic (EM) circuit, two types of EM circuits were designed to satisfy each direction: one circuit is a moving magnet circuit for the radial direction, and the other circuit is a moving coil for the tangential direction. In a digital camcorder, the space for the OIS actuator is limited, and thus, optimized actuator with adequate performances is required. To solve these problems, a sensitivity analysis was performed using the design of experiment procedure. Based on these results, an objective function was defined for the optimization procedure. Finally, the actuator was fabricated, and the dynamic characteristics and feasibility of adapting two types of mechanisms of the suggested OIS actuator were verified. The experimental results indicate that the proposed OIS actuator exhibits sufficient performance for the sensitivity.     

A novel design and fabrication of a micro-gripper for manipulation of micro-scale parts actuated by a bending piezoelectric

In this study, a novel micro-gripper using a piezoelectric actuator was designed and improved by the design of experiments (DOE) approach. Using a bending PZT actuator connected to the micro-gripper by a rigid wedge can be considered as a novel approach in this field. Almost all of the similar grippers in this category were former actuated by a piezo-stack which has some limitations and difficulties like fabrication in MEMS proportions. The basic design was borrowed from compliant mechanisms that are suitable for MEMS application and easy to manufacture in micro-scale because of the intrinsic integration characteristic. Since stress concentration is common in flexure hinge compliant mechanisms, our focus was to consider strength as an important factor in our design. Finite element analysis tools were used to implement the DOE based on two criteria; minimizing stress concentration and maximizing the output displacement in the micro-gripper structure as much as possible with the consideration of the total size of the gripper. The experiment was performed to validate the simulation results and experiment results agreed well with the simulation one. The slight geometrical discrepancy in significant portions of structure like flexure hinges partially contributes to the accumulated error between the simulation and the experiments.

     

Study of the hinge thickness deviation for a 316L parallelogram flexure mechanism fabricated via selective laser melting

3D printing offers great potential for developing complex flexure mechanisms. Recently, thickness-correction factors (TCFs) were introduced to correct the thickness and stiffness deviations of powder-based metal 3D printed flexure hinges during design and analysis. However, the reasons for the different TCFs obtained in each study are not clear, resulting in a limited value of these TCFs for future design and fabrication. Herein, the influence of the porous layer of 3D printed flexure hinges on the hinge thickness is investigated. Samples of parallelogram flexure mechanisms (PFMs) were 3D printed using selective laser melting (SLM) and 316L stainless steel powder. A 3D manufacturing error analysis was completed for each PFM sample via 3D scanning, surface roughness measurement and morphological observation. The thickness of the porous layer of the flexure hinge was independent of the designed hinge thickness and remained close to the average powder particle diameter. The effective hinge thickness could be estimated by subtracting twice the value of the porous layer thickness from the designed value. Guidelines based on finite element analysis and stiffness experiments are proposed. The limitations of the presented method for evaluating the effective hinge thickness of flexure hinges 3D printed via SLM are also discussed.

     

Design of moving magnet type pickup actuator using inserted coil

Recently, the demand of the information storage devices with large storage capacity such as Blu-ray Disc and high-definition television is increased. In keeping with this trend, the optical storage devices are also required to have high data transfer rate and large storage capacity. To satisfy these requirements, the actuator for optical disc drive should have a high servo bandwidth to compensate the vibration of optical disc. The servo bandwidth is limited by some flexible modes of the actuator, thus it is essential to make these frequencies of flexible modes to high frequency region. The frequency of flexible mode depends on materials and shape. Stiff materials and simple shape is useful to increase the frequency of flexible mode. In this paper, we suggested a moving magnet type actuator having flexible modes which are happened at high frequency region. Generally, the moving magnet type actuator has an advantage to increase the frequency of flexible mode because the moving magnet type actuator has simple structure and the Young’s modulus of magnet is high. However, large moving mass and inefficiency of Electromagnetic (EM) circuit cut down driving sensitivities of actuator. To improve driving sensitivities, we designed the model with the closed EM circuit for tracking actuation. The design of experiments (DOE) procedure is applied to get proper design parameters and the variable metric method (VMM) which is a technique of optimization is used to improve driving sensitivity. The lens holder is also improved based on the optimization result of EM circuit. And to make up for the low efficiency of EM circuit, the thermal stability is checked on condition that the input current is very high. At last, the final design of moving magnet type actuator is suggested and it is verified that the driving performance and the structural stiffness of the final design is sufficient.     

Design of swing arm actuator for small and slim optical disc drives

Recent advancements in mobile devices have fueled a requirement for information storage systems with characteristics such as subminiature size, low cost, and minimum power consumption. Small optical disk drives could provide a good solution, because their storage media is cheaper than those of hard disk drives or flash memories. In this paper, we proposed the miniaturized swing arm type actuator that had a new focusing mechanism for small and slim optical disk drives (ODD). Initial model was designed by EM and structural analyses. Based on results of DOE, optimization procedures of EM circuits were performed with design variables using variable metric method (VMM). And, structural parts were designed to maintain the high sensitivity of the actuator. Finally, the swing arm type actuator for small and slim ODDs was suggested and its dynamic characteristics were checked.     

Design and performance evaluation of a novel stick–slip piezoelectric linear actuator with a centrosymmetric-type flexure hinge mechanism

Microsystem Technologies - A stick–slip actuator with a centrosymmetric type flexure hinge mechanism was presented in this paper. The dimension of the actuator is approximately...     

A parasitic type piezoelectric actuator with an asymmetrical flexure hinge mechanism

A parasitic type actuator with an asymmetrical flexure hinge mechanism has been proposed in this study to achieve linear motion with a large working stroke. The principal output direction of the piezoelectric stack is vertical to the motion direction of the mover to obtain a large output load. The composition of the parasitic type actuator and working process are introduced and parasitic motion is explained. Finite element method has been applied to analyze the parasitic motion of the proposed asymmetrical flexure hinge mechanism. Moreover, an experiment system of the parasitic type actuator is set up, and experiments show that the positioning resolution of the actuator is around 0.1 μm; the maximum motion speed could achieve to 2850 μm/s when the input frequency f = 500 Hz and the input voltage U_e = 100 V; the maximum output force F_g is up to 750 g when the input frequency f = 1 Hz and the input voltage U_e = 100 V. This study indicates that the asymmetrical flexure hinge mechanism could achieve parasitic motion for the design and application of piezoelectric actuators with a large working stroke.

     

Design of hybrid type’s optical pickup actuator for system stability in high density reading and recording

Recently, there has been a trend to have large capacity and high data transfer rate in optical disk drive. Pickup actuator also should have high performance for satisfying this trend. Since moving magnet type actuator has more simple and robust structure than moving coil type one, we designed moving magnet type to accomplish high flexible mode frequency. However, the driving sensitivity of moving magnet type actuator was low because of its characteristics as following. At first, moving parts including magnets are heavy and electromagnetic (EM) circuits are not closed-loop owing to yoke composed of paramagnetic materials. Therefore, in order to increase the driving sensitivity without the degradation of the other dynamic characteristics, EM circuits were redesigned by adding solenoid coils on existing mechanism. As a result, the hybrid type actuator composed of moving magnet type and moving coil type was suggested to obtain high sensitivities and high flexible mode frequency. Design variables of EM circuits and structure parts were decided through parametric study and design of experiments procedure. Optimization algorithm using variable metric method was used to improve performance. Based on these results, the final model was presented.     

基于有限元分析的ICF靶半自动装配系统的微夹钳设计

根据惯性约束聚变(ICF)靶零件的特点,确定用于ICF靶半自动装配系统微夹钳的技术指标,并完成其结构设计.该微夹钳采用柔性铰链机构和压电陶瓷驱动,可根据需要更换不同形状和开口距离的夹口,以适应夹持不同靶零件.以压电陶瓷的2种极限参数为载荷,分析了微夹钳的张合量、应力分布、应变量,并采用非线性接触分析对夹持力和夹持效果进...     

基于压电陶瓷驱动的腹腔手术微型机器人

本文简要介绍了一个基于压电陶瓷驱动的腹腔手术用微型机器人系统，重点叙述了 微型机器人关节驱动部件的结构设计方案及其实现，对所设计的柔性铰链进行了定量力学分 析，并通过实验证明采用柔性铰链来实现驱动位移的放大是确实可行的．     

Design of a new triple electro-magnetic optical image stabilization actuator to compensate for hand trembling

Recently, the demand for a new two-axis driving actuator for optical image stabilization (OIS) system has increased in mobile devices such as digital cameras and digital camcorders. In this paper, we proposed a novel OIS actuator with triple electro-magnetic (TEM) circuits and a three-ball supporting mechanism for a digital camcorder and considered the driving force, magnetic spring, and moment equilibrium of the TEM circuits. To design the TEM circuits with the high sensitivity and adequate magnetic spring, the electro-magnetic circuit was improved. At first, a sensitivity analysis was performed using the design of experiment procedure. Based on these results, effective design parameters were selected and an objective function was defined and gradient-based optimization was carried out. Finally, the improved TEM OIS actuator was fabricated for a digital camcorder and the feasibility of the OIS actuator with the TEM circuits and three-ball supporting mechanism was verified and the performance was investigated experimentally. The experimental results indicated that the proposed OIS actuator exhibits sufficient performance with respect to sensitivity.     

Development of symmetric type slim optical pickup actuator for flexible disk system

Recently, in information storage devices, several characteristics such as high data transfer rate, large storage capacity and small drive size are required as high-definition television (HDTV) broadcasting, mobile devices, and notebook personal computer (PC) were popularized. In optical disk drive (ODD), several actuators have been developed to satisfy these specifications. In this paper, we presented the symmetric type slim actuator with efficient tracking magnetic circuits for the flexible disk system. At first, electromagnetic (EM) circuits were designed to have big driving force for high sensitivities through design of experiments (DOE). And, in structural parts, we designed the actuator that had proper control bandwidth through several redesigns of moving parts. Consequently, the final model was fabricated and dynamic tests were experimented. And, it was checked that our actuator had a very high tracking sensitivity and could be applied to the flexible disk system.     

Design and testing of a microgripper with SMA actuator for manipulation of micro components

The extremely high work-to-volume ratios of the SMA actuators make them suitable to be used as a powerful actuator in micro-scale manipulation. In this study, an easily manufacturable micro-gripper with shape memory alloy (SMA) wire actuator was designed and manufactured. The concept of the designed micro-gripper was based on flexible hinge structures to increase the deflection efficiency and strength. The size of microgripper was a significant criterion in our design. Also, innovative layout in locating of SMA wire caused the microgripper to gripe and manipulate a boarder range of objects. The finite element method was used to analyze and calculate the stress distribution and jaw’s deflection in the gripper. In order to verify the modeling results, an experimental analysis by building a set-up for micro-gripper and running tests were implemented and it showed a good agreement with the modeling results. The approximate size of the micro-gripper is about 12 × 10 mm and its maximum achievable deflection is 200 μm which is perceptibly higher than SMA actuated micro-grippers with the same size.

     

Charge control of parallel-plate, electrostatic actuators and the tip-in instability

Controlling the charge, rather than the voltage, on a parallel-plate, electrostatic actuator theoretically permits stable operation for all deflections. Practically, we show that, using charge control, the maximum stable deflection is limited by 1) charge pull-in, in which the actuator snaps due to the presence of parasitic capacitance and 2) tip-in, in which the rotation mode becomes unstable. This work presents a circuit that controls the amount of charge on a parallel-plate, electrostatic actuator. This circuit reduces the sensitivity to parasitic capacitance, so that tip-in is the limiting instability. A small-signal model of the actuator is developed and used to determine the circuit bandwidth and gain requirements for stable deflections. Four different parallel-plate actuators have been designed and tested to verify the charge control technique as well as to verify charge pull-in, tip-in, and the bandwidth requirements. One design travels 83% of the gap before tip-in. Another design can only travel 20% of the gap before tip-in, regardless of whether voltage control or charge control is used.     

Design of swing arm type actuators considering thermal and dynamic characteristics

The present state of the design of swing arm actuators for optical disc drives is to obtain the highly efficient dynamic characteristics within a very compact volume. As a necessary consequence, the need of the small form factor (SFF) storage device has arisen as a major interest in the information storage technology. Due to the size constraint, the thermal stability of the optical pick-up head is important: therefore, the actuator is designed to emit the heat, which is generated by the optical pick-up, along the structural body easily. In this paper, we suggest the miniaturized swing arm type actuator that has effective heat emission quality as well as satisfies the dynamic requirements for the SFF optical disk drive (ODD). The actuator is targeted to be installed in CF-II card size drive to be competitive with flash memory or mini hard disk drive used in mobile electric devices; therefore the dimension of the actuator is required as 11.0 mm × 2.5 mm × 25.0 mm (width × height × length). Because of its small size, the dynamic requirements are severe to ensure the enough gain-margin for the system control together with satisfying the DC/AC sensitivity conditions. Moreover, due to the small size, the maximum pick-up temperature is critical in design because the system has high possibility to reach the shut-down temperature. For the operating mechanism, it uses a tracking electromagnetic (EM) circuit for the focusing motion together and the initial model is designed and promoted by the design of experiments (DOE) only considering the dynamic characteristics. New concept design is suggested based on the topology optimization method considering the thermal conductivity. Furthermore, the new design is modified by DOE to maintain the high sensitivity and to have wide control bandwidth and decreasing mass and inertia. The final design of a swing arm type actuator for SFF ODD is suggested and its dynamic characteristics are verified.     

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.     

EM‐based yield optimization exploiting trust‐region optimization and space mapping technology

Design centering is a design problem which looks for nominal values of circuit parameters that maximize the probability of satisfying the design specification (yield function). Direct yield optimization of electromagnetic (EM)‐based circuits is obstructed by the high expense of EM simulations required in the yield estimation process. Also, the absence of any gradient information represents an obstacle against the optimization process. In this article, a new approach for design centering and yield optimization of EM‐based circuits is introduced. In the proposed approach, the generalized space mapping (SM) technique is incorporated with a derivative‐free trust region optimization method (NEWUOA). Moreover, a variance reduction sampling technique is implemented in the yield estimation process. Two techniques suitable for the microwave circuit design centering process are introduced. The first technique exploits the surrogate developed using any circuit optimizer, for example, minimax optimizer, in the yield maximization process. While the second technique iteratively constructs and updates an SM surrogate during the yield optimization process. Our novel approach is illustrated by practical examples showing its efficiency. One of the examples is entirely designed within the sonnet em environment. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:474–484, 2015.     

基于柔性铰链的热驱动微夹钳的实验和仿真分析

微执行器在整个微机电系统中直接面对其应用对象,需要满足定位精度高,稳定性好,响应速度快,控制方便的要求.柔性铰链以其特殊的性能广泛应用于操作执行器的设计应用中.以一种基于柔性铰链的电热驱动微夹钳为研究对象,通过实验和ANSYS有限元仿真分析对微夹钳的机械性能进行了分析,发现微夹钳端部的输出位移与输入电压基本呈线形关系.通过仿真分析探讨了柔性铰链结构尺寸变化对微夹钳性能的的影响.     

Optimal design of a micro-positioning Scott-Russell mechanism by Taguchi method

In this paper, main features in kinematics of a micro-positioning Scott-Russell (SR) mechanism associated with two flexure hinges are its displacement amplification and straight-line motion, which are widely needed in practical industries. Without increasing the radial displacement, the SR mechanism is optimally designed by Taguchi method to obtain a maximum amplification of a small displacement driven by a lead zirconate titanate (PZT) actuator. According to kinematic characteristics of the SR mechanism the control factors include the direction, radius, width and offset of flexure hinges. It is found that the directions and offsets of flexure hinges have obvious effects on the amplifying factor and linearity ratio. The software ANSYS is utilized to obtain the numerical simulations, which are compared with the experimental results for the SR mechanism with and without offset of flexible hinges. Finally, some conclusions about the effects of control factors on the performance of the SR mechanism are drawn.     

基于CAN总线的航空发动机智能执行机构的设计

分布式控制是未来航空发动机控制系统的重要发展趋势.作为航空发动机分布式控制系统的主要组成部分,提出了一种基于CAN总线的智能执行机构的设计方案,并给出了具体的硬件电路和软件算法.DSP实现智能执行机构的程序控制和自诊断,CAN总线完成发动机中央处理器与DSP的数据交换,步进电机实现精确的自整角机传感器位置控制.实验结果表明,对比目前的发动机执行机构,提出的智能执行机构克服了相位移动明显、误差大、响应速度慢等缺点,取到了良好的控制效果,对提高系统的测量精度及保证航空发动机的控制品质具有重要意义.