水下七功能机械手摆动液压缸的研究

强作业型七功能水下机械手是水下机器人不可或缺的通用水下作业工具。随着对海洋的探索加快，对其需求量将越来越大。我国在强作业型七功能水下机械手的研究上与世界先进水平相差很大。对强作业型七功能水下机械手展开研发工作势在必行。 本论文对七功能机械手的重要关节驱动－摆动液压缸进行研究。首先确定摆动缸的结构选型。然后针对摆动液压缸的组合密封展开研究，以明确组合密封各部分的功能，优化密封件的密封性能。最后对摆动缸进行详细设计，并对其工作性能的参数进行估算。 首先，对组合密封模型进行简化后，用弹性流体润滑（EHL）理论进行分析计算，以得到密封件压缩量与密封油膜厚度、泄漏量、摩擦力的关系。 然后将用有限元(FEM)工具分别建立简化模型、叶片模型和组合密封模型，按接近实际的状态对模型进行约束和加载，以分析其变形和应力分布，并根据最终结果对EHL计算结果进行相应修正，以辅助摆动液压缸的设计。完成以上工作后，根据分析结果确定密封件适当的压缩量。同时，对轴端密封建立模型，用FEM工具对其进行受力变形分析，以改善其密封情况。 对密封件的分析表明，采用论文给出的组合密封结构，其中起支撑作用的Ｏ形圈受液压压力变形产生“自封”效应，强化了密封效果。组合密封的在给定压缩量时的，其O形圈的硬度对密封压力影响很大，应选择更高硬度的Ｏ形圈，以完成对摆动液压缸叶片的密封。端密封受装配后轴沿轴向的游动影响明显，应提高此处Ｏ形圈的直径并适当增加其预压缩量。

偏动式双程SMA驱动器工作机理与能量转换研究

研究了偏动式双程ＳＭＡ驱动器的工作机理，建立了驱动器输出力、输出位移、负载与驱动元件弹性刚度和预变形之间的变量关系。基于热力学基本定律，给出了双程ＳＭＡ驱动器工作过程中能量的周期性流动、转移和转化模型，指出双程ＳＭＡ驱动器双程做功的能量都来源于ＳＭＡ元件的相变弹性势能，能量的一部分用于来程做功，一部分在来程转移给偏置元件，用于回程时做工，还有一部分被释放掉。

越野移动机器人自动驾驶专家系统的研究

本文研究越野移动机器人驾驶专家系统等有关问题．首先介绍了系统的硬件支持环境，然后阐述了自动驾驶专家系统的总体结构，有关知识库的内容以及使用知识的各功能模块的作用与运行机理．该系统已部分得以应用，能够完全代替驾驶员完成各种驾驶操作，并能进行自主导航、运动规划、自动绕障、动态跟踪目标、原路返回以及示教再现等复杂任务。

直驱式容积控制电液伺服系统的建模和仿真研究

电液伺服控制系统以其出力大、响应快、精度高而广泛地应用于国防与民用领域。但是，传统的电液伺服系统由于电液伺服阀对油液精度要求高，抗污染能力弱，从而在一定程度上限制了它更广泛的应用，随着技术的进步，出现了一种新型的电液伺服系统—直驱式容积控制电液伺服系统，它是由交流伺服电机驱动的液压泵与执行元件组成，它具有伺服电动机控制的灵活性和液压系统出力大的双重优点，具有高效节能、体积小、可靠性高等显著优点，在一定程度上弥补了传统电液伺服系统的不足，从而被认为是未来电液伺服控制系统的重要发展方向之一。本文的研究内容是以中国科学院沈阳自动化研究所与日本石川岛播磨重工业株式会社的合作项目“电液混合驱动系统（Hybrid Actuator System）研究与开发”为基础，开展原理与特性研究，主要研究内容有以下一些项目：研究直驱式容积控制电液伺服系统的工作原理、设计理论与控制方法，建立直驱式容积控制电液伺服系统的性能试验系统，进行该系统的静、动态性能仿真与分析，研制一套直驱式容积控制电液伺服系统的原理样机。 第一、直驱式容积控制电液伺服系统的原理与机械结构研究，研究直驱式容积控制电液伺服系统的工作原理与结构方案，详细分析比较与传统电液伺服系统的优缺点，研究基与双向定量泵集成阀体的一体化设计技术，进行直驱式容积控制电液伺服系统的系统设计。 第二、直驱式容积控制电液伺服系统的建模与控制算法研究，研究直驱式容积控制电液伺服系统的建模方法，建立直驱式容积控制电液伺服系统的数学模型，研究满足系统性能指标的PID控制策略，使系统在稳定的前提下具有良好的动态品质和高的稳态精度。 第三、直驱式容积控制电液伺服系统集成技术研究，该直驱式容积控制电液伺服系统是由交流伺服电动机、双作用定量泵、方向控制阀、液压缸，以及多个传感器共同组成的。研究系统模块化设计方法，研究系统集成技术，建立直驱式容积控制电液伺服系统与液压系统性能的最佳匹配方法，研究直驱式容积控制电液伺服系统的实现技术。 第四、直驱式容积控制电液伺服系统的性能仿真研究，在上述建立的伺服系统模型基础上，利用MATLAB内的动态仿真库SIMULINK，仿真分析直驱式容积控制电液伺服系统的静、动态性能，研究改善系统性能的措施方法。 第五、直驱式容积控制电液伺服系统的补油性能状态研究，详细分析系统在各种工况下的内部油液流动状态，并基于此研究补油阀体的集成设计，建立补油设备的数学模型，仿真分析该补油装备的静、动态运行性能，研究补油阀的设计技术，在上述分析基础上，设计加工满足系统运行性能状态的叠加式液控补油阀。 第六、在上述工作基础上，研制一套直驱式容积控制电液伺服系统，验证系统设计原理，控制算法，及系统集成技术、研究高性能直驱式容积控制电液伺服系统的设计方法和实现技术。 关键词 液压技术；交流伺服电动机；直驱式容积控制；动态特性；叠加液控补油阀

Series Elastic Actuators

This thesis presents the design, construction, control and evaluation of a novel force controlled actuator. Traditional force controlled actuators are designed from the premise that "Stiffer is better''. This approach gives a high bandwidth system, prone to problems of contact instability, noise, and low power density. The actuator presented in this thesis is designed from the premise that "Stiffness isn't everything". The actuator, which incorporates a series elastic element, trades off achievable bandwidth for gains in stable, low noise force control, and protection against shock loads. This thesis reviews related work in robot force control, presents theoretical descriptions of the control and expected performance from a series elastic actuator, and describes the design of a test actuator constructed to gather performance data. Finally the performance of the system is evaluated by comparing the performance data to theoretical predictions.

The Effect of Transmission Design on Force-Controlled Manipulator Performance

Previous research in force control has focused on the choice of appropriate servo implementation without corresponding regard to the choice of mechanical hardware. This report analyzes the effect of mechanical properties such as contact compliance, actuator-to-joint compliance, torque ripple, and highly nonlinear dry friction in the transmission mechanisms of a manipulator. A set of requisites for high performance then guides the development of mechanical-design and servo strategies for improved performance. A single-degree-of-freedom transmission testbed was constructed that confirms the predicted effect of Coulomb friction on robustness; design and construction of a cable-driven, four-degree-of- freedom, "whole-arm" manipulator illustrates the recommended design strategies.

Control of Vibration in Mechanical Systems Using Shaped Reference Inputs

Dynamic systems which undergo rapid motion can excite natural frequencies that lead to residual vibration at the end of motion. This work presents a method to shape force profiles that reduce excitation energy at the natural frequencies in order to reduce residual vibration for fast moves. Such profiles are developed using a ramped sinusoid function and its harmonics, choosing coefficients to reduce spectral energy at the natural frequencies of the system. To improve robustness with respect to parameter uncertainty, spectral energy is reduced for a range of frequencies surrounding the nominal natural frequency. An additional set of versine profiles are also constructed to permit motion at constant speed for velocity-limited systems. These shaped force profiles are incorporated into a simple closed-loop system with position and velocity feedback. The force input is doubly integrated to generate a shaped position reference for the controller to follow. This control scheme is evaluated on the MIT Cartesian Robot. The shaped inputs generate motions with minimum residual vibration when actuator saturation is avoided. Feedback control compensates for the effect of friction Using only a knowledge of the natural frequencies of the system to shape the force inputs, vibration can also be attenuated in modes which vibrate in directions other than the motion direction. When moving several axes, the use of shaped inputs allows minimum residual vibration even when the natural frequencies are dynamically changing by a limited amount.

Intelligent Assembly Systems

Lee, M.H. and Rowland, J.J. (eds.), 1995, Intelligent Assembly Systems, 239pp, World Scientific series in Robotics and Intelligent Systems - Vol. 12, World Scientific, ISBN 981022494X.

GENESI: Wireless sensor networks for structural monitoring

The GENESI project has the ambitious goal of bringing WSN technology to the level where it can provide the core of the next generation of systems for structural health monitoring that are long lasting, pervasive and totally distributed and autonomous. This goal requires embracing engineering and scientific challenges never successfully tackled before. Sensor nodes will be redesigned to overcome their current limitations, especially concerning energy storage and provisioning (we need devices with virtually infinite lifetime) and resilience to faults and interferences (for reliability and robustness). New software and protocols will be defined to fully take advantage of the new hardware, providing new paradigms for cross-layer interaction at all layers of the protocol stack and satisfying the requirements of a new concept of Quality of Service (QoS) that is application-driven, truly reflecting the end user perspective and expectations. The GENESI project will develop long lasting sensor nodes by combining cutting edge technologies for energy generation from the environment (energy harvesting) and green energy supply (small form factor fuel cells); GENESI will define models for energy harvesting, energy conservation in super-capacitors and supplemental energy availability through fuel cells, in addition to the design of new algorithms and protocols for dynamic allocation of sensing and communication tasks to the sensors. The project team will design communication protocols for large scale heterogeneous wireless sensor/actuator networks with energy-harvesting capabilities and define distributed mechanisms for context assessment and situation awareness. This paper presents an analysis of the GENESI system requirements in order to achieve the ambitious goals of the project. Extending from the requirements presented, the emergent system specification is discussed with respect to the selection and integration of relevant system components.The resulting integrated system will be evaluated and characterised to ensure that it is capable of satisfying the functional requirements of the project

Prism coupler with variable coupling gap

The construction and operation of a prism/variable-gap/sample system (or variable-gap Otto coupler) for the excitation of surface electromagnetic modes is reported. This system has been used for the observation and characterization of surface plasmon polaritons on thin film structures. The initial alignment of prism and sample is performed under gravity and the subsequent gap variation is performed by means of a single actuator operating a flexure stage on which the prism is mounted. The flexure stage ensures the maintenance of good parallelism between sample and prism as the gap dimension is varied. The coupler has also served as a prototype, in terms of design principle, for the construction of a more sophisticated, variable-gap Otto coupler that can operate in vacuum at temperatures from ambient to 85 K. (C) 2000 American Institute of Physics. [S0034-6748(00)02311-X].

Internal model control for shape memory alloy actuators using fuzzy based Preisach model

This paper investigates a possible application of Preisach model to control shape memory alloy (SMA) actuators using an internal model control strategy. The developed strategy consists in including the Preisach hysteresis model of SMA actuator and the inverse Preisach model within the control structure. In this work, an extrema input hystory and a fuzzy inference is utilized to replace the classical Preisach model. This allows to reduce a large amount of experimental parameters and computation time of the classical Preisach model. To demonstrate the effectiveness of the proposed controller in improving control performance and hysteresis compensation of SMA actuators, experimental results from real time control are presented.

Predictive position and force control for shape memory alloy cylinders

In this paper, a linear lightweight electric cylinder constructed using shape memory alloy (SMA) is proposed. Spring SMA is used as the actuator to control the position and force of the cylinder rod. The model predictive control algorithm is investigated to compensate SMA hysteresis phenomenon and control the cylinder. In the predictive algorithm, the future output of the cylinder is computed based on the cylinder model, and the control signal is computed to minimize the error and power criterion. The cylinder model parameters are estimated by an online identification algorithm. Experimental results show that the SMA cylinder is able to precisely control position and force by using the predictive control strategy though the hysteresis effect existing in the actuator. The performance of the proposed controller is compared with that of a conventional PID controller

A Strain-Driven Morphotropic Phase Boundary in BiFeO3

Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.

Development tools for opportunistic pervasive computing

The goal of the POBICOS project is a platform that facilitates the development and deployment of pervasive computing applications destined for networked, cooperating objects. POBICOS object communities are heterogeneous in terms of the sensing, actuating, and computing resources contributed by each object. Moreover, it is assumed that an object community is formed without any master plan; for example, it may emerge as a by-product of acquiring everyday, POBICOS-enabled objects by a household. As a result, the target object community is, at least partially, unknown to the application programmer, and so a POBICOS application should be able to deliver its functionality on top of diverse object communities (we call this opportunistic computing). The POBICOS platform includes a middleware offering a programming model for opportunistic computing, as well as development and monitoring tools. This paper briefly describes the tools produced in the first phase of the project. Also, the stakeholders using these tools are identified, and a development process for both the middleware and applications is presented. © 2009 IEEE.

Tangible applications for regular objects:An end-user model for pervasive computing at home

This paper describes an end-user model for a domestic pervasive computing platform formed by regular home objects. The platform does not rely on pre-planned infrastructure; instead, it exploits objects that are already available in the home and exposes their joint sensing, actuating and computing capabilities to home automation applications. We advocate an incremental process of the platform formation and introduce tangible, object-like artifacts for representing important platform functions. One of those artifacts, the application pill, is a tiny object with a minimal user interface, used to carry the application, as well as to start and stop its execution and provide hints about its operational status. We also emphasize streamlining the user's interaction with the platform. The user engages any UI-capable object of his choice to configure applications, while applications issue notifications and alerts exploiting whichever available objects can be used for that purpose. Finally, the paper briefly describes an actual implementation of the presented end-user model. © (2010) by International Academy, Research, and Industry Association (IARIA).