运用超声电机的燃油调节器活门顶杆机构

设计了一种基于超声电机的燃油调节器活门顶杆机构.该机构通过滚珠丝杆与旋转型行波超声电机(traveling-wave rotary ultrasonic motor,简称TRUM)的输出轴相连,将电机的回旋运动转化成执行元件即活门顶杆的直线运动,通过控制PSoC产生脉冲信号的个数实现了超声电机的步进驱动,可以精确调节油门的大小.针对机构的工作环境对现有的TRUM型超声电机进行了密封性改进,使其可以适用于油压工况.建立了活门顶杆的数学模型,对其进行动力学分析,并通过样机试验进行验证,得到的结果与理论分析基本一致.试验表明,该机构样机可以达到设计要求并实现纳米级的定位精度.     

丰田5S-FE发动机燃油供给系无油压故障现象排除方法浅谈

<正>燃油供给系统简称供油系统,其功用是向发动机各个气缸供给混合气燃烧所需的燃油量。燃油喷射式发动机供油系统的结构主要由燃油箱、电动燃油泵、输油管、燃油滤清器、油压调节器、燃油分配管、喷油器和回油管等组成。燃油分配管又称为供油总管或油架。发动机工作时,汽油泵工作,将油箱内的燃油泵入供油系统,供油系统的油压由油压调节器调节,一般控制在     

单相驻波驱动的旋转型超声电机结构设计与试验研究

单相驱动的超声电机由于其驱动电路简单、设计灵活、结构紧凑等优点,受到越来越多的关注。但单相驱动的超声电机主要以直线型电机为主,且工作模态一般为退化模态,存在能量利用率低、频率易漂移等缺点。此外,现有旋转型单相驱动的超声电机存在输出性能差、不易装夹等问题,严重制约了其应用。为解决上述问题,提出了一种新型单相驻波驱动的旋转型超声电机,通过单一工作模态实现对转子的摩擦驱动。该超声电机的定子主要由压电复合梁和带驱动齿的圆环构成,在两组压电陶瓷片的交替激励下分别产生两相工作模态,并通过两相工作模态相互切换实现电机的双向旋转运动。首先,采用有限元分析方法计算得到了超声电机定子的几何尺寸和两相工作模态(包括共振频率和振型)。其次,通过测振实验对定子原理样机进行了振动特性测试,得到了定子的幅频特性、振型和驱动齿的运动轨迹,并与仿真计算结果进行了比较,验证了仿真分析的正确性。最后,装配了旋转型超声电机原理样机,并开展了性能测试实验研究。结果表明：在300 V激励电压、1 N预压力的条件下,超声电机原理样机在两个工作模态下的最大转速分别为123.9 r/min (顺时针旋转)和450.9 r/min (逆...     

直线型超声电机的发展及应用

概述了直线型超声电机的运动机理，综述了国内外直线型超声电机的发展及其研究现状，列举了一些典型例子，总结了直线型超声电机的应用领域。针对现在直线型超声电机在理论、实验、材料等方面存在的问题，指出了在其研究开发中需要解决的关键技术。     

阶梯圆柱形压电振子直线型超声电机

针对现有直线型超声电机推力较小、效率不高的普遍现状,提出利用阶梯圆柱形压电振子驱动的直线型超声电机.其压电振子包含两组压电陶瓷单元,经逆压电效应激发阶梯形圆柱压电振子在两个正交方向上分别产生5阶弯曲振动,使振子两个圆盘形结构的表面质点形成椭圆运动,经摩擦作用于固定导轨,使振子组件沿导轨产生直线运动,进而构成直线型超声电机.采用有限元仿真方法确定结构尺寸,制作原理样机并进行了相关试验.原理样机获得如下性能:最大输出力为16.2 N;最大速度为180 mm/s;最大效率为38％;响应时间为24 ms;步进分辨率为2μm.     

涡喷发动机转速振荡的模糊控制研究

为保证某型涡喷发动机喷油环小流量雾化性能,燃油控制系统引入了旁路调节器。旁路调节器的引入,给发动机燃油控制系统带来了正反馈效应,从而导致发动机转速振荡。针对上述问题,在不改变执行机构动态特性的前提下,由于找不出合适的PID控制器参数使得系统闭环回路稳定,本文基于模糊控制算法对供油控制系统进行数学仿真分析。仿真结果表明,模糊控制具有响应速度快、超调量较小的动态特性。     

超声电机驱动多关节机器人的类PID小波神经网络控制

针对超声电机驱动多关节机器人的运行特性,提出一种新颖的速度-位置双闭环PID控制模式,有效地抑制了超声电机响应极快所导致的速度变化剧烈的现象,从而提高了机器人的运动平稳性.为了进一步提高超声电机驱动多关节机器人的控制性能,使其能根据超声电机的变化特性对PID控制参数进行实时调节,提出类PID小波神经网络控制器.通过对传统离散型增量式PID表达式各项的合理划分,将速度-位置双闭环PID控制、实践经验、当前的轨迹误差及其变化情况都融入进了类PID小波神经网络控制器中.该控制器参数的在线学习机制采用了δ自适应律并结合了BP算法和梯度下降法,算法简单,计算量大大减少.试验结果证明,所设计的类PID小波神经网络控制器不仅明显优于PID和PID神经网络控制器,而且具有很好的抗干扰能力.     

超声电机微纳驱动参数调节机构设计

为解决超声电机驱动轨迹及微行程纳米定位的可控问题,设计了一种基于双压电陶瓷驱动的调节机构,将双压电陶瓷驱动与超声电机驱动轨迹及微行程纳米定位控制关联起来,并利用ANSYSWorkbench有限元分析软件对调节机构进行了分析。通过对双压电陶瓷施加0～54V调节电压的实验,证实了调节机构能够使超声电机驱动头在x和y两个方向上获得所需的微纳米调节功能,调节范围为,x方向±1.2～±2.36μm,y方向±4.0μm,调节分辨率1～2nm,满足超声电机对驱动轨迹及微行程纳米定位的参数控制要求。     

超声电机驱动的5指灵巧手运动控制系统

为了控制由20个超声电机驱动的关节独立的5指灵巧手实现仿人手的动作,本文建立了5指灵巧手的运动控制系统。系统采用TMS320F1812芯片作为控制器,用EPM7192S芯片实现超声电机正反转控制和片外电路逻辑控制,通过调节DA07724施加在驱动器压频转换器上电压来改变超声电机的工作频率实现对其运行速度的调节,采用PID控制实现了灵巧手位置反馈控制。     

杆式旋转超声电机在精密定位平台上的应用

介绍了一款杆式旋转超声电机,它由一个定子和两个转子构成,利用两个一阶弯曲振动模态工作。将该电机应用于驱动精密定位平台,并构建了基于计算机与GO-400运动控制器的精密定位平台控制系统。对于杆式超声电机,当利用专用驱动器供电,驱动器的输入电压为直流15V时,电机的空载转速为206r/min,堵转力矩为0.273N.m。对于精密定位平台,通过对电机进行正/反转控制、速度PID控制,实现平台的精密定位,定位精度达到2μm。进行了平台步进试验,其正/反向的位移分辨力都为1μm。利用旋转超声电机作精密定位系统的致动器时,可以采用旋转型光电编码器代替昂贵的直线型编码器,从而大大降低整个精密定位系统的价格。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.