伺服转台恒温装置结构及控制系统

本文在完成某高精度伺服转台恒温系统的研制任务基础上，全面阐述了伺服转台台面恒温系统的实现措施及理论依据。主要包括结构设计、恒温箱与台面间的非接触密封、恒温箱的设计及模型参数估计、温度检测及控制系统设计     

四轴稳定跟踪转台伺服控制系统的研究与实现

以四轴稳定跟踪伺服转台系统研制的实例出发，从系统总体结构，元、部件选型计算及控制系统的设计与实现等方面进行了详细介绍。针对系统难点，采用基于高速DSP控制器、以采样数字控制和信号滤波技术为基础的全闭环伺服控制方案。实验测试结果均达到了预先制定的设计指标和精度要求，表明了系统设计方案的实用性和有效性。     

三轴陀螺漂移测试转台台体动力学建模及控制系统设计

带宽的保证是三轴陀螺漂移测试转台（以下简称三轴转台）伺服系统设计的主要困难，从使用的角度出发，要求转台伺服系统有较大的带宽，以使三轴转台有较快的响应速度，对干扰有较强的抑制能力，提高三轴转台的跟踪精度，但一些客观因素使带宽指标受到限制，其中机械台体的谐振对带宽的影响是决定性的。本所讨论的三轴转台动力学模型，是三轴转台控制系统设计的依据。     

测试转台陀螺伺服系统全数字控制实现

讨论了测试转台中陀螺伺服状态的构成原理，提出了一种基于全数字控制的陀螺伺服系统实现方案。该方案不仅方便系统参数在线调整，而且可以完成多种不同类型，不同参数的陀螺仪伺服实验，目前已经成功地用于某型空气轴承伺服转台，取得了满意的结果。     

三轴液压仿真转台灰箱辩识研究

三轴液压仿真转台由于伺服阀的非线性及框架间速度和力矩耦合特性使系统的模型非常复杂,常规的理论建模方法建立的数学模型与实际的系统相差较大,这使得鲁棒控制在液压转台中的应用受到一定限制.根据系统模型的结构特征和系统的实际特性对系统进行灰箱辩识是解决这一问题的最好办法.文中通过具体实例说明这种建模方法的有效性.     

测试转台测控系统电磁兼容性设计

本文全面讨论了测试转台测控系统的电磁兼容性问题,针对一般研制过程中常见的干扰及采用PWM数字功率放大电路而引入的调制频率干扰,从设计到装配工艺提出了抑制措施.经在某型单轴伺服转台中的实践证明,文中提出的一系列方法对克服电磁干扰,提高测控系统的可靠性和精度行之有效.     

高精度陀螺漂移伺服转台服精度的实验研究

在由交流力矩电机驱动带滑环系统的气浮转台中,滑环伺服系统对气浮主轴的干扰力矩是主要的干扰力矩。提高滑环伺服系统跟踪精度、选用高柔性的两轴系统之间输电导线,减小它们与轴心的距离是提高主轴伺服精度的有效措施。     

转台伺服系统的H∞设计

—本文将Ｈ∞控制理论用于转台伺服系统的设计，对该系统进行Ｈ∞优化设计作了探讨，重点讨论了权函数的选择问题，并根据系统带有未建模特性的实际情况，给出选择权函数的方法     

机器人无标定视觉伺服控制研究进展

视觉伺服控制是机器人系统重要的控制手段. 相比传统的在标定条件下使用的视觉伺服系统,无标定视觉伺服系统具有更高的灵活性与适应性,是机器人伺服控制系统未来重要的发展方向和研究热点. 本文从目标函数选择、控制器设计、运动轨迹规划三方面综述了无标定视觉伺服控制系统近年来的主要研究进展. 首先根据目标函数的形式,分析了基于位置的视觉伺服、基于图像的视觉伺服以及混合视觉伺服各自的特点与应用;在控制器设计方面,根据是否在设计过程中考虑机器人的非线性动力学特性,分别介绍了考虑机器人运动学与考虑机器人动力学的无标定视觉伺服控制器的设计,重点突出了雅克比矩阵的构造与估计方法;针对无标定视觉伺服系统运动轨迹可能存在的问题,从空间轨迹优化与障碍规避的角度,阐述了已有的可行解决方案. 最后,基于当前的研究进展展望了无标定视觉伺服的未来研究方向.      

伺服台台面与恒温箱间的隔热方法

本文提出了伺服转台台面恒温箱与台面之间的隔热方法，通过理论计算和实验结果证实，隔热效果显著，能够达到理想的技术指标。     

Technology of fault line selection for single-phase-to-earth fault in small current grounding system

To perfect the existing fault line selection methods and enhance the accuracy in small current grounding system, the fault line selection technology combined the multicriterion with fuzzy theory was proposed. Firstly, the mechanism of single-phase-to-earth fault in small current grounding system was further discussed. For the common neutral nongrounding system and neutral grounding system via arc-suppression coil, the current mathematical models on single-phase-to-earth fault were analyzed respectively. Then the basic principles on three different fault line selection methods were described that were the zero-sequence current frequency analysis, the addition of the integral of multiplying the zero-sequence current and others, and the current injection. Afterwards, the multicriterion fault line selection approach integrated fuzzy decision was advanced, and the efficiency was proved successfully. By using of DSP and PC, the system models were implemented. Through system simulation and a great deal of experiments, the results also have proven the reliability of this novel technology of fault line selection in small current grounding system.     

Parameter tuning of ADRC and its application based on CCCSA

Active disturbance rejection controller can effectively adjust uncertain factors and the disturbance of the model by compensation. However, this advantageous controller has met with a technical bottleneck in its extensive use of engineering application because of its multiplicity of the parameters and the difficulty of integrating them. This paper proposes a chaotic cloud cloning selection algorithm by referring to cloud model and immune cloning selection, generating initial population by employing chaotic initialization to improve the quality of the initial antibodies, realizing mutation with basic normal cloud generator to improve the diversity of antibodies. Then the chaotic cloning selection algorithm is applied to the optimization of parameter integration. This new algorithm is tested and verified as to its convergence speed, convergence precision, and robustness with classic function. The results of simulation experiments for a time-delay system demonstrate that the optimized control system not only possesses excellent control performance but also exhibits strong robustness and anti-interference ability.     

A decision support system for selection of tractor-implement system used on Indian farms

The selection of tractor and its matching implements has now become very difficult in India because of availability of variety of tractor models ranging from 10 to 45 kW. To overcome the problem of matching of tractor-implement system, an expert system modelling approach leading to decision support system (DSS) was adopted to make the step wise decision. The application of DSS was demonstrated in the paper to select either an implement to match the tractor or to select a tractor to match the implement under different soil and operating conditions. The DSS leading to computer software developed in Visual Basic™ programming provided the intuitive user interfaces by linking databases such as specifications of tractors and implements, tractor performance data, soil and operating conditions, to support the decision on selection of tractor-implement system. The programme calculates working width of implement based on input data for the most critical field operation and helps in selection of a suitable implement having width nearer to the calculated value among the commercially available implements. The software calculates the required drawbar power of the tractor based on draft and working speed of the selected implement. Finally, the PTO power requirement of a tractor is calculated by the software. Based on calculated PTO power, the software suggests available makes and models of tractor/machinery from the compiled data bank. The developed DSS was tested with a case study to demonstrate the flexibility of the software. The DSS can be used effectively in selection of a tractor or an implement of particular size from various makes and models of commercially available tractors and implements.     

An eigenvalue method on group decision

I.ThePrincipleofGEMInthefollowing,wewi1levaluatenobjectsB,,B1,"-,B,bygroupdecisionsupportsystemGwhichconsistsofmexpertsS,,S,,..',S..Letx',E[I,J](f=1,2'...,mlj=l,2,"',n)betheevaluationvalueofthejthobjectBjestimatedbythei-tllexpertS'.Thelargerxqis,themoreop…     

基于MEMS-IMU辅助的高动态GPS选星方法设计

一般的GPS选星方法通过搜索选取使几何精度衰减因子最小的4颗卫星,对于高动态应用特别是在水平姿态角较大的情况下,传统的选星方法存在许多局限性。针对低成本的MEMS-IMU/GPS组合导航系统,提出了基于MEMS-IMU辅助的GPS选星方法;针对高动态载体姿态变化较大的问题,采用MEMS-IMU输出的高速率姿态信息压缩卫星搜索范围,通过选取不超过6颗可见卫星来降低几何精度衰减因子,从而提高定位性能。使用半实物仿真数据,验证了所提出的方法。测试结果表明,与传统的选星方法相比,基于MEMS-IMU辅助的GPS选星方法在飞机高动态大机动条件下,优化了卫星星座,具有精度高、计算量低、可靠性高等优点。     

Objectivity requirement for fluid dynamics

IntroductionAsextensionoftheNewtonsecondlaw ,thefundamentaltheoryofclassicalfluiddynamicsconsidersthefluidelementwithdensityρasfluidparticle,anddescribestherelationbetweenthevarietyanddistributionofvelocityVoverspace_timevolumeelementdv ∧dt,namely ,themomentum_impulseequationsbyρdV dt=ρf - P+ ·σ(V , V ,…) ,(1 )wheref,P ,σareexternal (body)force ,pressureandviscous (area)force ,respectively .Therepresentationsofmotionandforceusuallyneedspecificframeofreference.Forinstance,inthehomog…     

嵌入式控制技术在定位定向系统中的应用

介绍了基于RTLinux和PC104单板机的嵌入式控制模块在定位定向系统中的应用实例，阐述了系统开发对实时嵌入操作系统的选择策略，并分析了系统软件的结构和实现方法。     

重力辅助导航匹配区域选择准则

通过在重力场区域中移动局部计算窗口的方法,计算了实测重力场各个局部的多种统计特征并使用填色等值线图进行了对比和分析,以局部重力场的标准差和经纬度方向相关系数作为匹配区域选择的数量指标,给出了重力匹配区经验选择准则。采用均方误差和平均绝对差算法在实测重力图上对重力辅助惯性导航系统进行了仿真研究,计算结果表明,在满足重力匹配区选择准则下进行的重力辅助导航,其导航系统定位误差小于一个重力图网格,匹配率大于90%。     

SELECTION OF OBJECTIVE FUNCTIONS AND APPLICATION OF GENETIC ALGORITHMS IN DAMPING DESIGN OF PIPE SYSTEM

The vibration failure of pipe system of aeroengine seriously influences the safety of aircraft. Its damping design is determined by the selection of the design target, method and their feasibility. Five objective functions for the vibration design of a pipeline or pipe system are introduced, namely, the frequency, amplitude, transfer ratio, curvature and deformation energy as options for the optimization process. The genetic algorithms (GA) are adopted as the optimization method, in which the selection of the adaptive genetic operators and the method of implementation of the GA process are crucial. The optimization procedure for all the above objective functions is carried out using GA on the basis of finite element software-MSC/NASTRAN.The optimal solutions of these functions and the stress distribution on the structure are calculated and compared through an example, and their characteristics are analyzed. Finally we put forward two new objective functions, curvature and deformation energy for pipe system optimization. The calculations show that using the curvature as the objective function can reflect the case of minimal stress, and the optimization results using the deformation energy represent lesser and more uniform stress distribution. The calculation results and process showed that the genetic algorithms can effectively implement damping design of engine pipelines and satisfy the efficient engineering design requirement.     

强脉冲载荷作用下端盖法兰结构的螺栓预紧力设计方法

为研究承受强脉冲载荷的端盖法兰结构的螺栓预紧力设计方法,利用实验室霍普金森杆平台,基于液压原理设计了一套实验装置,并结合数值模拟结果,对强脉冲载荷下端盖法兰结构的动态响应进行研究。通过研究发现:由预紧力和脉冲载荷引起的螺栓总拉伸应变随载荷峰值变化的曲线上存在最小极值点,并总结了最小极值点随载荷峰值、载荷脉宽的变化规律,为强脉冲载荷下法兰结构和预紧力设计提供了依据。