气动人工肌肉外骨骼机器人位置跟踪控制

针对以气动人工肌肉作为关节驱动器的外骨骼机器人关节位置跟踪控制问题进行了研究。首先,在动力学模型的基础上,设计了上层控制器,并结合自适应控制和滑模控制方法降低了动力学参数不准确和扰动项未知对外骨骼机器人的影响;其次,基于无模型方法设计了底层关节力矩控制器,调整外骨骼机器人的关节力矩;最后,针对上述控制方案设计仿真实验与外骨骼机器人的穿戴实验。结果表明,该控制方法对气动人工肌肉外骨骼机器人的关节位置跟踪控制是有效的。     

带修正因子的自组织模糊PID控制在气动人工肌肉位置控制中的应用

作为气动人工肌肉并联机器人关节研究的核心内容，首次对单支气动人工肌肉的位置控制做深入的研究。研究表明，一种带修正因子的自组织模糊控制与PID控制的混合控制器对单支气动人工肌肉的位置控制有明显的控制效果。     

气动人工肌肉驱动关节PID位置控制研究

气动人工肌肉是一种具有柔顺性的新型驱动器。文章在对人工肌肉及其驱动关节进行实验研究及建模的基础上，采用PID方法对人工肌肉驱动的关节进行了位置控制的研究，取得了较为理想的控制效果。     

气动肌肉驱动的康复机器人关节建模及位置模糊控制

肢体康复机器人运动速度低、位置精度要求不高,但柔顺性和安全性要求高.气动肌肉是一种新型柔性驱动器,适合于康复机器人的驱动.气动肌肉具有时滞、非线性等特点,关节位置控制难度增大.由此建立了关节模型,采用了模糊控制技术,借助MATLAB的Simulink,得到模糊控制查询表.实验表明,本控制算法较好地实现了关节位置控制.     

柔性气动连续体机器人关节结构设计与运动学分析

基于气动人工肌肉和缆绳组合驱动,提出了一种三自由柔性气动连续体机器人关节,该关节具有结构紧凑、柔顺性高、控制简单等特点。通过分析该机器人关节结构特性,采用修正的D-H法,建立了其正反解运动学模型,求解了其位置运动学解和速度运动学解,通过仿真验证了关节结构的合理性和运动学方程的正确性。     

仿生跳跃机器人气动串联弹性关节的位置/刚度控制

设计了一种气动人工肌肉驱动的串联弹性关节,基于气动人工肌肉Chou模型,建立了串联弹性关节的动力学模型,推导出关节刚度,获得了关节刚度与肌肉内部气压、弹性体刚度的关系。设计反向传播（back propagation,BP）神经网络整定PID参数的BP-PID控制算法,开展了气动串联弹性关节的位置与刚度控制研究。仿真结果表明BP-PID控制优于PID控制,关节位置跟踪精度由0.58°变为0.10°,关节刚度跟踪精度从0.026 N·m/rad变为0.005 N·m/rad。实验结果表明关节位置跟踪平均误差由0.347°减小到0.117°,关节刚度跟踪平均误差从0.024 N·m/rad减小到0.019 N·m/rad。     

仿人型机器人腿的探讨

提出一种用气动人工肌肉驱动的仿人型机器人腿。首先描述了气动人工肌肉的结构与工作原理，人工肌肉具有变刚度特性，它的刚度可通过控制橡胶管内的气压实现，调节管内气压的大小就可改变肌肉的刚度。它的刚度大小决定肌肉的驱动力。然后提出了用气动人工肌肉驱动的机器人腿的结构形式以及机器人腿的摆动控制方式，腿的驱动力和行走运动全由工控机控制实现。     

气动人工肌肉驱动关节特性研究

气动人工肌肉是一种具有良好柔性、出力/重量比大的新型气动执行器。该文研究了由一对气动人工肌肉的组成的关节模型，分析了它的静特性，并进行了实验研究。实验结果表明气动肌肉关节具有一些独特的特性。     

气动人工肌肉驱动器的动态跟随控制研究

研究了气动人工肌肉驱动器的动态位置跟随控制技术,构建了控制实验系统,设计了控制系统软件,并运用BP神经网络PID控制算法对其进行实验控制研究。实验结果表明,能够较好地实现气动人工肌肉驱动器的位置定位控制和动态跟随控制。     

编织型气动人工肌肉迟滞现象建模与应用

气动人工肌肉被广泛应用于柔性机器人、仿生机器人等多种机器人研究领域。但气动肌肉具有很强的非线性与明显的迟滞现象,直接限制了气动肌肉的精确控制。针对气动肌肉动力学建模问题,建立包含理想项与非线性迟滞项的完整气肌模型。通过仿真分析证明加入滞回模型后气肌的精度得到了提升：去程时精度提高了10%,回程时精度提高了33%。进一步,将该模型应用于机器人力控制关节上。通过曲面轨迹跟踪试验证明力控制精度从±15 N提升到了±5 N,同时将回程段控制精度提高了40%,并有效解决了力控制关节回程输出力不准确的问题。为进一步提高机器人柔性加工和装配领域的力控制精度提供了理论依据。     

Dynamic response-based characterization of ring-based vibratory angular rate sensors

Dynamic response behaviour of a rotating ring is investigated in order to better understand the achievable performance improvements as well as system limitations. For this purpose, the governing equations that represent the transverse as well as the tangential in-plane motion of a rotating ring are derived via the Hamilton’s principle. These equations are then discretized to represent a two-degree-of-freedom time-varying gyroscopic system. The asymmetry effects are considered important and are included by considering mass mismatch in the system mass matrix. In order to predict dynamic behaviour of a ring system subjected to external excitation and body rotation, time and frequency response analyses are performed. The natural frequency variations due to the gyroscopic coupling presented in the system are first characterized for varying input angular rates. The effects of system parameters such as damping and mass mismatch on the sensor sensitivity and operating range are quantified via suitable time and frequency response analyses.     

Ultrasonic Resonator Techniques for Broad-band Spectroscopy and for High-resolution Sound Velocity Measurement of Liquids

This review gives a short introduction into the principles of ultraconic measurement techniques for liquids, using cavity resona-tors. Guidelines for the resonator design in broad-hand ultrasonic spectroscopy as well as in high-resolution singie-frequency or narrow-band applications are presented. Deviations of the field configuration in real cells from that in an ideal resonator are discussed and relations for the mode spectrum of cavity fields are given. Recent resonator measurement procedures and methods of data evaluation are men-tioned briefly. Some examples of measurements show the extended usability of ultrasonic resonator techniques in basic science and in a wide range of applications for materials characterization, in manufac-turing processes, as well as in control routines.     

The geometry of trochoid envelopes and their application in rotary pumps

A method is described for finding the envelopes of trochoids which perform a planetary motion. Envelopes are obtained which have continuous slopes and curvatures, as well as some with apexes, which are already well-known. The curves have the property that at all times the envelope is in contact with the trochoid at several points, while the gaps between the envelope and the trochoid vary in size as the curves are rotated, so the shapes are potentially applicable in pumps or engines.     

基于四维聚类的R*-树结点分裂算法

针对R*-树应用到逆向工程领域时遇到的适用性差等问题,提出一种新的R*-树结点分裂算法,该算法以R*-树结点最小边界矩形外接球半径为权值,对点、三角形、矩形等多种三维几何对象进行加权处理,将其统一表示为四维点对象,选定距离最远的两个四维点作为初始分簇中心,根据点到两分簇中心的距离进行分簇,结合k-means算法以结点外接球半径为权值计算新的分簇中心,并迭代分簇过程,直到各分簇中心不再变化,结束R*-树的结点分裂过程。试验证明,采用该结点分裂算法可处理复杂数据对象的分簇,并在提高建树效率的同时,优化R*-树结构,提高空间查询效率,对提高逆向工程数据预处理效率具有重要意义。     

Hydrolysis of a Disiloxane/Ester Fluid in a Simulated Hydraulic System at 275 F

Data are presented on the changes in the properties of a disiloxane/ester fluid resulting from water concentrations as small as 200 ppm while undergoing mechanical stress at 275 F in a simulated aircraft hydraulic system. The response of fluid flash point, viscosity, neutralization number, and hydraulic system filter differential pressure are discussed for hydraulic fluid water concentrations as high as 18,900 ppm. The efforts of previous investigators, employing bench tests and simulated systems, are reviewed. The limitations and sources of error of methods of determining fluid degradation and level of water contamination, as determined by this study, are noted. Attention is given to the importance of reacted water, for which no routine method of determination has been developed, as apposed to free water as determined by the Karl Fischer method of analysis.     

Energy-efficient machining systems: a critical review

Sustainable machining as a critical part in sustainable manufacturing has been valued by manufacturing enterprises of all sizes. The traditional short-term financial considerations are substituted by longer-term sustainable strategies to ensure the competitiveness, and ultimately, the survival of the company. Energy-efficient machining system, which promotes sustainable machining, is the focus of this paper. The energy-efficient machining system requires a comprehensive understanding as well as optimisation of energy consumption. Literature in this field is carefully reviewed and summarised. Energy consumption models, which are regarded as the core of the energy-efficient machining systems, are grouped into four categories, i.e. theoretical, empirical, discrete event-based, and hybrid models. Then, energy optimisation methodologies and strategies are discussed for energy-efficient process planning and production scheduling. The applications such as tool condition monitoring can employ energy information as useful input. Research inspired by energy-efficient machining studies is briefly introduced. The main elements of an individual energy-efficient machining system are then summarised. Discussions, research suggestions, and future directions are given at the end.     

Feasible workspace regions for general two-revolute manipulator

In this paper, a topology is presented for feasible workspace regions in general two-revolute manipulators. The design problem and concept of feasible workspace regions have been discussed as linked to each other. Design equations are formulated by arbitrarily prescribing four workspace boundary points. The so-called feasible workspace regions are the intersection of three different sub-regions, which are given by constraint curves as function of the relative positions of three workspace boundary points. By using a parametric study, all topologies for three sub-regions are figured out. Corresponding areas in cross section plane are determined for prescribing the position of a feasible workspace point as function of the topology for sub-regions. A classification has been proposed to determine and to characterize the combination of the topologies for those sub-regions. All topologies for feasible workspace regions are figured out and they are discussed as a design tool. Three general cases are analyzed in details to characterize workspace design capabilities for general two-revolute manipulators.     

CAPP系统的智能开发工具

分析了CAPP系统的研究与发展状况;论证了研制具有智能的CAPP系统开发工具的必要性与可行性;给出了构造该工具的设计思想、逻辑结构和关键技术;提出了构造CAPP系统开发工具的策略和主要措施。     

Laminar Flow in a Recess of a Hydrostatic Bearing

The flow in a recess of a hydrostatic journal bearing is studied in detail. The Navier-Stokes equations for the laminar flow of an incompressible liquid are solved numerically in a two-dimensional plane of a typical bearing recess. Pressure- and shear-induced flows, as well as a combination of these two flow conditions, are analyzed. Recess friction, pressure-ram effects at discontinuities in the flow region, and film entrance pressure loss effects are calculated. Entrance pressure loss coefficients over a forward-facing step are presented as functions of the mean flow Reynolds number for pure-pressure and shear-induced laminar flows.     

波相色谱-质谱联用技术

本文简要介绍了LC-MS及其接口的基本原理技术和发展,对影响LC-MS分析结果的诸多因素作了一一说明。并对常见的质谱技术和仪器进行了比较。