形状记忆合金在驱动器上的应用研究

随着新技术的快速发展,形状记忆合金作为一种重要的智能材料在制造、医疗和航空航天等领域有着越来越广泛的应用。形状记忆合金易于实现驱动器微型化和自动化,有着传统驱动器不可比拟的性能优点。本文总结基于智能材料的驱动器,探讨NiTi形状记忆合金驱动器的制造和驱动触发等问题以及新的研究方向。     

机构学研究现状与发展趋势的思考

在人类文明和社会发展的进程中,制造业始终是创造社会财富的主要来源,是衡量国家综合国力的重要指标。当今世界经济全球化,各国的综合国力和竞争能力体现于机械产品的设计能力。因为制造业的灵魂是设计,而制造和被制造机械的灵魂是机构,所以现代机构学的理论研究是制造业的基础,是现代机械产品发明创造的源泉,是提高国家制造业水平和国际竞争能力的关键。机构创新设计决定了产品的创新性。如果机构的设计有缺陷,则制造出的将会是先天不足的产品或称之为“有残疾的机械”。对产品的创新而言,机构拓扑创新设计具有原创的特征性质,是机械发明中最具有挑战性和发明性的核心内容。所以,现代机构学的研究对提高我国机械产品的自主设计、创新和国际竞争能力有着十分重要的意义。机构学研究的发展趋势应该是研究现代机构设计的新理论和新方法、实现特殊功能的机构设计理论以及应用关键技术、微操作和微尺度机械的机构学、机构与机器人动力学、新型移动与操作机器人、仿人与仿生机器人和微纳机器人等。现代机构学研究的最高任务是揭示自然和人造机械的机构组成原理,创造新机构,研究基于特定性能的机构分析与设计理论,为现代机械与机器人的设计、创新和发明提供系统的基础理论和有效实用的方法。     

PyxosTM技术介绍

Pyxos嵌入式控制网络平台，是美国埃施朗公司推出的又一种控制网络技术，它是一种专门应用于扩展I／O总线的技术，使用该技术可以使得任何机器内部的各个组成部分之间形成智能的数字控制网络，它是一种低成本的、网络自安装的技术，而且能够和现有的基于GB／Z 20177的LONWORKS控制网络平台技术结合，构成任意规模的自动控制网络。     

Empirical modeling of dynamic behaviors of pneumatic artificial muscle actuators

Pneumatic Artificial Muscle (PAM) actuators yield muscle-like mechanical actuation with high force to weight ratio, soft and flexible structure, and adaptable compliance for rehabilitation and prosthetic appliances to the disabled as well as humanoid robots or machines. The present study is to develop empirical models of the PAM actuators, that is, a PAM coupled with pneumatic control valves, in order to describe their dynamic behaviors for practical control design and usage. Empirical modeling is an efficient approach to computer-based modeling with observations of real behaviors. Different characteristics of dynamic behaviors of each PAM actuator are due not only to the structures of the PAM actuators themselves, but also to the variations of their material properties in manufacturing processes. To overcome the difficulties, the proposed empirical models are experimentally derived from real physical behaviors of the PAM actuators, which are being implemented. In case studies, the simulated results with good agreement to experimental results, show that the proposed methodology can be applied to describe the dynamic behaviors of the real PAM actuators.     

微小机器人的移动方式

微小机器人是微机电系统研究开发的重要分支,各种微小机器人的研究成果不断涌现.受自身尺寸和作业空间的限制,微小机器人难以采用常规机器人的驱动器、传动机构和执行机构.根据移动方式的不同,将微小机器人分为腿足式、轮式、蠕动式和游动式等类型.讨论了各种移动类型的例子,分析研究了它们新颖的驱动机构.认为驱动器的微型化是实现微小机器人的关键,高效合理的驱动方式可降低对微小驱动器的要求.     

[学科发展]5D打印——生物功能组织的制造

生物制造是制造技术与生命科学技术交叉融合产生的新兴学科方向,这一学科方向的发展将为巨大的人体组织与器官市场提供新技术,同时也给制造技术变革带来新机遇。面向生物制造未来发展,提出5D打印制造概念,论述了5D打印的内涵,分析了其关键技术。结合生物制造技术的现有进展,介绍了研究团队在心肌组织支架的制造、类脑神经组织制造、爬行生命机械混合机器人方面取得的初步研究进展,为生物制造技术拓展新方向提供新思路。     

Force control of hybrid actuator using learning vector quantization neural network

Hydraulic actuators are important in modern industry due to high power, fast response, and high stiffness. In recent years, hybrid actuation system, which combines electric and hydraulic technology in a compact unit, can be adapted to a wide variety of force, speed and torque requirements. Moreover, the hybrid actuation system has dealt with the energy consumption and noise problem existed in the conventional hydraulic system. Therefore, hybrid actuator has a wide range of application fields such as plastic injection-molding and metal forming technology, where force or pressure control is the most important technology. In this paper, the solution for force control of hybrid system is presented. However, some limitations still exist such as deterioration of the performance of transient response due to the variable environment stiffness. Therefore, intelligent switching control using Learning Vector Quantization Neural Network (LVQNN) is newly proposed in this paper in order to overcome these limitations. Experiments are carried out to evaluate the effectiveness of the proposed algorithm with large variation of stiffness of external environment. In addition, it is understood that the new system has energy saving effect even though it has almost the same response as that of valve controlled system.     

柔性滚弯技术在国外的应用进展

利用弹性介质对钣金件进行柔性滚弯成形,是一种先进的钣金制造工艺,将弹性介质的冲压优势和传统滚弯原理结合,成为钣金成形领域的一个新的发展方向.文章介绍了柔性滚弯技术在国外的应用进展,并以通用机床、专用机床、自动化机床和CNC机床为例,简要说明各类柔性滚弯机的工作原理和运转流程,为我国专业工作者提供参考和帮助.     

CIMT’97主要展品的技术特点综述

两年一度的中国国际机床展览会是国际机床界和我国机械制造业的一件盛事。第五届中国国际机床展览会(CIMT’97)又一次荟萃了国内、外各机床厂及相关配套件厂和工具厂的精华,既可看到一些名牌企业享有盛名的产品,也会发现一些脱颖而出的新秀企业所展示的精品。从展览会上我们能深刻地领会到机床工具行业的发展动向,也能生动地观察到琳琅满目的新产品和新结构。从中既反映了丰富多采的世界先进实用制造技术和最新制造技术,也展示了中国机床工具行业通过“三大战役”在增强开发能力和竞争实力方面所取得的可喜的巨大进步。     

微分注塑成型创新技术及装备

采用基于熔体齿轮泵的微分注塑成型创新技术,可以用一台微分注塑成型装备达到多台微型注塑机的效果,最终实现微塑料制品高效率、低成本、大批量的生产.     

大型旋转机械振动监测与故障诊断培训系统的开发与应用

基于ISO18436标准,研究大型旋转机械振动监测与故障诊断理论,并结合设备故障诊断专家的现场经验,开发一套大型旋转机械振动监测与故障诊断培训系统,将多媒体软件Authorware与数据库结合起来进行数据交换,并运用Flash技术,提高系统的生动性、交互性及高效性,为机械故障诊断提供了一种新的培训思路.     

细小管道内爬行的微机器人

基于现代精密加工技术制造的微机械,有着广阔的应用前景。特别是直径Φ10～20mm(1英寸)的细小管道,要求研制新型微机器人用于无损检查管壁和维修。考虑到电磁驱动器,具有结构简单、单位行程长、动作灵敏、控制方便等优点,研制了一种电磁式微机器人,外形尺寸Φ15×30mm,自重25g,它可以在Φ20mm金属管内爬行,移动速度6～8mm/s,有垂直爬坡能力。所加电压16～20V,频率30～70Hz.     

Loop shaping design for tracking performance in machine axes

A modern interpretation of classical loop shaping control design methods is presented in the context of tracking control for linear motor stages. Target applications include noncontacting machines such as laser cutters and markers, water jet cutters, and adhesive applicators. The methods are directly applicable to the common PID controller and are pertinent to many electromechanical servo actuators other than linear motors. In addition to explicit design techniques a PID tuning algorithm stressing the importance of tracking is described. While the theory behind these techniques is not new, the analysis of their application to modern systems is unique in the research literature. The techniques and results should be important to control practitioners optimizing PID controller designs for tracking and in comparing results from classical designs to modern techniques. The methods stress high-gain controller design and interpret what this means for PID. Nothing in the methods presented precludes the addition of feedforward control methods for added improvements in tracking. Laboratory results from a linear motor stage demonstrate that with large open-loop gain very good tracking performance can be achieved. The resultant tracking errors compare very favorably to results from similar motions on similar systems that utilize much more complicated controllers.     

旧车床改制缠绕机

针对目前国内缠绕式垫片生产专用设备－缠绕机普遍结构简陋,工艺落后,生产出的垫片质量不高,而研制出的新型缠绕机价格偏高的状况,采用旧的C618或C620车床,经改造并添加自制的控制仪器后,成功地制造出了较普通密封件厂先进的缠绕机。经产品性能对比试验和现场使用,该机完全可与新型缠绕机相媲美,得到了用户的好评。     

Linear motor for ejector mechanism

Ejector mechanism actuators in electric injection moulding machines require large thrust and low operating rate. Although the ordinary linear synchronous motor (LSM) is unfit for this machine, the linear motor presented in this paper is suitable for this use as it is compact in size and more cost effective compared to LSM.This paper contains the new linear motor that can generate large thrusts for a short time: its mechanical design, simulated flux profile and experimental results of motor size and thrust output relationship are presented. The described linear motor has an approximate volume of 250 mm×250 mm×250 mm and generates a maximum thrust of about 20 kN at a current of 250 A. This revised version was published online in October 2004 with a correction to the issue number.     

Developing a location–inventory model under fuzzy environment

Process analytical technology encourages the industry to adopt innovative technologies to increase quality. The key components of this approach are better understanding the product manufacturing process, data analysis, process analytical tools, process monitoring, and continuous feedback during the manufacturing process. Remote process analytical technology over public IP networks can significantly reduce the cost of maintenances and technical support, and simplify the classical OPC-like architecture based on multiple server gateways. The requirements for using remote process analytical technology for high-speed processes are mainly concerned with cyber security and high data refresh rate on the remote monitoring machine. This work intends to evaluate a new, open application protocol named CyberOPC dedicated to CNC machines. The CyberOPC version presented in this paper supersedes the first version presented in previous papers, which had no streaming features. The CyberOPC technology is not only an open alternative to other data exchange protocols, but it also introduces streaming capabilities to gain high refresh rate on remote control stations. It is based on the Client/Server Model, where a software layer is introduced between CNC and the remote monitoring station, on the Server side of CyberOPC. Even if the case study adopts a tunneling Schema that includes server gateways, the requirements to develop protocols in embedded devices and modern CNC are fulfilled by several devices that include a TCP/IP stack.     

Long-term lubrication of momentum wheels used in spacecrafts—An overview

Momentum wheels are spacecraft actuators of large angular momentum used for the attitude control and stabilization of spacecrafts. The on-orbit performance of spacecrafts depends largely on the performance of the momentum wheels which in turn depends on its bearings and its lubrication. Currently, the life cycle of spacecrafts are aimed to be around 20–30 years. However, the increases in size, complexity and life expectancy of spacecrafts demand advanced technologies especially in tribology and in turn the development of more innovative lubrication systems for long-term operation. This article reviews the tribological requirements of momentum wheels and the various lubrication systems used in the past and raises a necessity to develop a new system to cope with the new requirements.     

Practical and intuitive controller design method for precision positioning of a pneumatic cylinder actuator stage

The present paper describes a practical and intuitive controller design method for precision positioning of pneumatic cylinder actuator stages. Pneumatic actuators are easy to use and have numerous advantages, which has led to these actuators having a wide variety of applications. However, pneumatic actuators have notable nonlinear characteristics, which make precision positioning difficult to achieve. The purpose of the present study is to clarify a practical and intuitive controller design procedure for precision positioning of a pneumatic cylinder actuator. In addition to positioning performance, the present study focuses on the realization of easy controller design without the need for the exact model parameters or knowledge in control theory for general-industrial-use pneumatic cylinder actuators with friction characteristics. These considerations are important in order to fully exploit the advantages of pneumatic cylinder actuators in a wide variety of applications. As such, three elements are added to the conventional continuous-motion nominal characteristic trajectory following (CM NCTF) controller. A new design procedure of the improved CM NCTF controller for pneumatic cylinder actuator stages is introduced, and the positioning performance of the designed control system is examined experimentally under several conditions. The positioning results generally indicate a positioning error of 50 nm, which is equal to the sensor resolution.     

一种新型的现场连接技术——IO-Link

IO-Link已经成为可编程控制器标准IEC61131第9部分的公共可用规范了。它是一种用于小型传感器和执行器的单点数字通信接口。很多自动化厂家已经支持这个规范了。本文对该技术做了一个简要介绍。     

Optimal placement of sensors and actuators using measures of modal controllability and observability in a balanced coordinate

In this paper, a method for optimal placement of sensors and actuators is presented by using new measures of modal controllability and observability defined in a balanced coordinate system. The proposed new measures are shown to have a great advantage in practical use when they are used as criteria for selecting the locations of sensors and actuators, since the most controllable and observable locations can be obtained to be identical. In addition, they are more accurate than the measures of Hamdan and Nayfeh in that the effects of the eigenvector norm are considered into the magnitude of measures. In simulations, to verify the effectiveness of the proposed measures and optimal placement method, the closed-loop response of a simply supported flexible beam, in which the number and locations of actuators are determined by using the proposed measures and optimal placement method, has been examined and compared with the case of Hamdan and Nayfeh’s measures.