基于模糊神经网络的机器人关节驱动补偿控制器

本文提出了一种模糊神经网络控制器,该控制器用于工业机器人关节驱动的位置控制,克服了传统PID很难达到对非线性以及不确定因素的控制效果和简单模糊控制不能完全消除稳态误差的缺点,通过神经网络对模糊规则的学习优化,提高了机器人关节末端位置精度,具有较好控制效果。     

基于波变量补偿的阻抗匹配时延双边遥操作

通信时延是遥操作系统中固有的问题,它会严重影响遥操作的性能,降低系统的稳定性和跟踪性。基于无源理论的波变量法可以保证遥操作系统在任意时延下稳定,是解决时延问题的一个重要方法。然而,波变量法带来的波反射会阻扰有用信号的传输,降低了主从端信号的跟踪性,严重时甚至会导致整个系统振荡。针对这一问题,提出了一种基于波变量补偿的阻抗匹配双边遥操作系统结构,旨在减少波反射,提高操作者的临场感和系统的跟踪性。通过仿真实验,结果表明所提方法能够保证固定时延条件下遥操作系统的稳定性,并具有较好的跟踪性。     

基于连杆力矩传感器动态补偿的机器人灵巧手笛卡儿阻抗控制

为了对连杆空间力矩传感器进行动态补偿,提出了适用于求取串联机器人任意连杆中任意一点处所受的内力和内力矩的算法.该算法采用连杆假想截断原理利用牛顿-欧拉方程推导而出.推导过程综合考虑了串联机器人是否处于静态以及末端是否受外力作用的情况,以及串联机器人的关节是否是回转关节的情况.然后利用该算法计算动态补偿值,构建了基于连杆力矩传感器动态补偿的笛卡儿阻抗控制器.最后在HIT/DLR Hand II五指灵巧手上进行了实验验证.实验结果一方面验证了该算法的有效性,另一方面也验证了本文所构建的笛卡儿阻抗控制器的有效性.     

基于LCC-S补偿拓扑MCR-WPT系统的宽范围阻抗匹配研究

针对LCC-S型拓扑网络的实际负载值偏离最优负载的问题,利用后级级联Sepic变换器实现了宽范围阻抗匹配,并由前级直流输入电源控制输出稳压。首先,利用互感模型分析了LCC-S型拓扑谐振状态下的网络特性,得到传输特性及最优负载值;其次,对后级Sepic变换器在开关管导通和断开时的工作模式进行分析,阐释了Sepic电路实现宽范围阻抗匹配的原理,并推导了占空比D表达式;最后,利用MATLAB仿真验证了LCC-S型拓扑的恒压特性以及宽范围阻抗匹配理论和控制方案的可行性。     

飞机飞控作动系统电静液作动技术研究综述

介绍了电静液作动器(EHA)的优势,论述了飞机采用EHA作动技术的收益。介绍了国内外EHA的发展现状,描述了EHA作动技术中高可靠高速液压泵的设计和高效大功率伺服控制器设计的难点,以及高功重比电机技术、电机控制策略和EHA监控器设计的重点。最后结合现有EHA作动技术缺陷以及新时期航空技术装备发展的不足,对EHA作动技术的未来发展趋势进行展望。     

伺服作动子系统的两种可靠性分析方法

飞行控制系统是飞机的重要组成部分,其先进程度已成为飞机性能和作战效能的关键因素,因此有必要对其可靠性进行深入研究。飞行控制系统的可靠性主要由感知对象状态的传感器子系统、实施数据处理和执行控制功能的飞控计算机子系统、操纵舵面运动的伺服作动子系统决定。文章针对飞控系统的伺服作动子系统的特点,引入了故障树分析和马尔可夫过程两种方法分别对传感器子系统建立了模型,通过定性分析与定量计算得出该子系统的故障模式、可靠度、关键重要度,为可靠性设计和故障诊断提供了依据。结果表明,这两种方法都是对伺服作动子系统进行可靠性分析的有效方法。     

A Model for Electrostatic Actuation in Conducting Liquids

This paper presents a generalized model that describes the behavior of micromachined electrostatic actuators in conducting liquids and provides a guideline for designing electrostatic actuators to operate in aqueous electrolytes such as biological media. The model predicts static actuator displacement as a function of device parameters and applied frequency and potential for the typical case of negligible double-layer impedance and dynamic response. Model results are compared to the experimentally measured displacement of electrostatic comb-drive and parallel-plate actuators and exhibit good qualitative agreement with experimental observations. The model is applied to show that the pull-in instability of a parallel-plate actuator is frequency dependent near the critical frequency for actuation and can be eliminated for any actuator design by tuning the applied frequency. In addition, the model is applied to establish a frequency-dependent theoretical upper bound on the voltage that can be applied across passivated electrodes without electrolysis.     

液压伺服作动系统力纷争敏感度及机理研究

液压伺服作动系统存在的力纷争问题会引起作动系统性能下降、飞机舵面结构疲劳,影响飞机安全。为解决上述问题,建立了考虑较完整电液伺服阀模型以及飞机舵面结构参数的并联作动系统数学模型,提出了对液压伺服作动系统力纷争关键敏感参数及形成机理的研究方法。将潜在影响力纷争的因素整合为控制器参数、电液伺服阀参数、作动系统结构参数、气动力参数四类,并研究了各类参数变化对力纷争的影响。结果表明,控制器参数和电液伺服阀参数是影响力纷争的关键因素,此外,通过对伺服阀位移、作动器位移/速率和力纷争之间作用关系和影响模式的研究,找到控制器差异和伺服阀差异形成力纷争的不同机理。分析结果对液压伺服作动器的设计及力纷争的解决提供了理论依据。     

核电多样性驱动系统硬件设计

为实现第三代数字核电保护系统AP1000的国产化,对多样性驱动(DAS)系统进行了研究开发。该系统包括调理模块、定值模块、通信模块和显示模块,在安全通道内采用FPGA代替CPU,实现UART异步通信、SPI串行通信、定值比较以及RAM数据可读标志等功能。经过长时间运行证明,基于FPGA构架的DAS系统能够准确、可靠地实现数据采集、通信和输出等功能,满足核电保护系统的安全需求。     

A Novel Actuation Concept for a Multi Rotor UAV

This paper proposes a novel strategy to improve the performance and fault tolerance of multi-rotor vehicles. The proposed strategy uses dual axis tilting propellers and thus enables three different actuation mechanisms, namely, gyroscopic torques, thrust vectoring and differential thrusting. Unlike the conventional quadrotor, the proposed strategy offers a wider range of control torques by combining the three actuation mechanisms. Conventional quadrotors cannot be reconfigured if one of rotors fails. However, the proposed strategy is still able to reconfigure the vehicle with complete failure of one rotor and a pair of adverse motors. In order to prove this concept, a dual axis tilting UAV is first designed and prototyped. Next, a mathematical representation of the prototyped vehicle is modelled and verified using experiments. Then, a control system is developed based on a PD controller and pseudoinverse control allocator and validated through tests on a rig and flight tests. The tests show that the vehicle is faster than a conventional counterpart and that it can resist the failure of two rotors. Finally, this paper suggests how to lead further substantial improvements in performance.     

一种自动阻抗匹配算法

阻抗匹配是射频系统中的重要组成部分,良好的阻抗匹配能够避免功率反射和优化射频源输出。针对梯度算法在自动阻抗匹配过程中的不足提出一种改进方法。介绍自动阻抗匹配器的系统结构,并对基于反射系数模的梯度信息的阻抗匹配算法进行讨论。对2种算法得到的结果进行比较,结果表明,该方法能够缩短匹配时间。     

Command-Shaping Techniques for Electrostatic MEMS Actuation: Analysis and Simulation

Precision positioning of microelectromechanical systems (MEMS) structures using electrostatic actuation has been widely used for optical and radio-frequency MEMS. How to achieve fast switching without exciting excessive residual vibration or structural impact is an important issue for these applications. This paper presents the analysis and simulation of applying command-shaping techniques for controlling MEMS electrostatic actuation. According to the nature of application fields, electrostatic actuators are classified into three categories: 1) lateral linear actuation; 2) vertical nonlinear actuation; and 3) pull-in actuation. Their corresponding linear or nonlinear command-shaping schemes are developed and presented. Both lumped element and continuous models of typical MEMS electrostatic actuated structures are simulated using Simulink and the finite-element method, and results indicate that the shaped command would yield a much superior response than that by the unshaped commands. Essential sensitivity studies are also conducted to examine the robustness of these shaping schemes, and results shows that within a certain level of parameter variation, these shapers are robust enough to retain the performance.     

聚酰亚胺悬臂MOEMS电磁光开关的优化设计

利用聚酰亚胺(PI)优良的机械、绝缘、耐热等性能,设计出基于PI膜的磁控光开关.给出合理的线圈宽度与间隙宽度,提出了八边形的线圈绕组结构,计算得出PI膜悬臂梁光开关驱动电压与工作距离的关系,并对悬臂梁长度、宽度、厚度进行优化.在驱动电压为2V时,自由端位移达到2mm.     

Controlled Thermophoresis as an Actuation Mechanism for Noncantilevered MEMS Devices

A microelectromechanical system actuator based on thermophoretic, or Knudson, forces is proposed using analytical calculations. It can potentially execute scanning or spinning motions of a body that is not mechanically attached to the reference substrate. For a silicon device of 100-$muhbox{m}$ diameter, it is calculated that it can be levitated at a distance of about 0.5 $muhbox{m}$ from a substrate and that it can execute scanning motion and use quasi-springs by laterally acting thermal forces. In this way, an engine with spinning motion of a floating body having a diameter of 200 $muhbox{m}$ with up to 5 kHz can be achieved.$hfill$[2008-0013]      

异构作动系统的平稳切换控制方法

为充分发挥异构作动系统在能量特性和控制特性上的双重优势,建立了液压作动器和电动静液作动器的仿真模型,并在此基础上,通过Matlab和AMESim联合仿真的方式,分析了能量特性;以能量特性为依据,提出了"主动切换"的管理方法.仿真结果表明,该方法可以实现能量特性的优化,但引入了位置跟踪曲线的"抖动"问题.针对"抖动"问题,提出了"设置最小切换时间"和"输出力柔性过渡"的系统性解决方案.仿真结果表明,该方案在保证跟踪特性的同时,实现了能量特性的显著提升.     

基于云规则的驱动级主动防御系统

主机的安全性主要体现在主机的防御系统方面,而最重要的技术就是系统行为监控技术。通过云规则的动态加载,获取互联网中恶意程序的最新信息,并对操作系统的重要资源进行访问控制。利用进程隐藏和进程终止保护技术对操作系统中重要进程进行保护;采用驱动隐藏和驱动卸载保护技术保护操作系统中的重要内核模块,同时可以阻止内核级和后门的恶意加载行为。实验结果表明,该防御系统具有良好的监控能力,不但可以阻止未知或者未授权的应用运行,还可以防止恶意程序修改正常的应用,从而达到对系统的安全性进行加固和扩展的目的。     

Mechanism and Control of Continuous-State Coupled Elastic Actuation

Focusing on the physical interaction between people and machines within safety constraints in versatile situations, this paper proposes a new, efficient, coupled elastic actuation (CEA) to provide future human-machine systems with an intrinsically programmable stiffness capacity to shape the output force corresponding to the deviation between human motions and the set positions of the system. As a possible CEA system, a prototype of a two degrees of freedom (2-DOF) continuous-state coupled elastic actuator (CCEA) is designed to provide a compromise between performance and safety. Using a pair of antagonistic four-bar linkages, the inherent stiffness of the system can be adjusted dynamically. In addition, the optimal control in a simple various stiffness model is used to illustrate how to find the optimal stiffness and force trajectories. Using the optimal control results, the shortest distance control is proposed to control the stiffness and force trajectory of the CCEA. Compared to state-of-the-art variable stiffness actuators, the CCEA system is unique in that it can achieve near-zero mechanical stiffness efficiently and the shortest distance control provides an easy way to control various stiffness mechanisms. Finally, a CCEA exoskeleton is built for elbow rehabilitation. Simulations and experiments are conducted to show the desired properties of the proposed CCEA system and the performance of the shortest distance control.     

MEMS Electrostatic Actuation in Conducting Biological Media

We present design and experimental implementation of electrostatic comb-drive actuators in solutions of high conductivity relevant for biological cells. The actuators are operated in the frequency range 1-10 MHz in ionic and biological cell culture media, with ionic strengths up to 150 mmol/L. Typical displacement is 3.5 mum at an applied peak-to-peak signal of 5 V. Two different actuation schemes are presented and tested for performance at high frequency. A differential drive design is demonstrated to overcome the attenuation due to losses in parasitic impedances. The frequency dependence of the electrostatic force has been characterized in media of different ionic strengths. Circuit models for the electric double layer phenomena are used to understand and predict the actuator behavior. The actuator is integrated into a planar force sensing system to measure the stiffness of cells cultured on suspended structures.     

A Nonlinear Model-based Variable Impedance Parameters Control for Position-based Impedance Control System of Hydraulic Drive Unit

In this paper, aimed at the problem of control accuracy when the traditional position-based impedance control is applied in the hydraulic drive unit (HDU)