激振源对高频精密物料输送装置性能影响的试验研究

为研究激振源对高频精密物料输送装置性能的影响,对同一压电输送振子采用不同激振源进行驱动,应用ANSYS软件对激振源参数进行分析,并进行试验。试验结果表明:激振源尺寸变化对压电振子输送性能影响较大,激振源尺寸为24 mm×24 mm×1 mm和24 mm×6 mm×1 mm,驱动电压峰峰值为120 V时,激振频率相差188 Hz,且激振源尺寸与输送振幅成线性关系。研究结果可以为高频精密物料输送装置激振源的设计提供依据。     

基于ANSYS压电输送振子动态设计与数值分析

针对物料输送精确定量给料以及振子输送幅值受行波衰减干扰问题,提出了一种在长度方向与宽度方向输送不受限制,输送面振幅均匀的新型郎之万式压电输送振子。利用ANSYS对输送振子的力学性能进行了分析。实验测试表明:压电振子输送面质点纵向振动幅值分布均匀;振子在激振源作用下激发出一阶纵向振动模态时产生横向弯曲振动变形很小。     

一种新型高频振动压电输送振子的研究

对用于高频振动物料输送装置的压电振子进行了研究,分析了压电输送振子结构参数对输送性能的影响。结果表明:随着轴向尺寸和输送面倾角的增加,振动频率呈递减变化;输送截面尺寸越大,振动频率越大,横向变形越大。为输送装置的设计奠定了基础。     

块体物料的超声振动输送及同步驱动

针对小块体物料的短距离精密输送问题,提出超声振动输送新方法,设计制作了基于弯曲行波的环形压电输送振子。依据模块化设计思想,将输送装置设计成3个单一输送振子的并列组合,采取多个振子的同步驱动。对所设计振子的模态及同步驱动特性进行了理论分析与实际测试,试验结果验证了超声振动输送装置同步驱动的可行性。     

汽车后视镜压电除雨器理论及试验研究

为了解决汽车后视镜雨天视线模糊的问题,提出了一种利用压电振子作为驱动源的汽车后视镜除雨器,设计了除雨器的结构,建立了其有限元模型,并对其整体和关键部件压电振子进行了仿真分析.制作了样机,并对影响后视镜除雨效果的镜面振幅变化规律进行了测试,测试了在对称波正弦波作用下振幅随频率、电压幅值的变化情况.另外,还对除雨效果与Z型振子的角度的关系进行了试验.仿真和试验结果表明,镜面振幅在谐振频率处得到最优除雨效果;镜面振幅随电压增大而增大;除雨器的除雨效果随Z型振子角度增大先增大后减小,当Z型振子角度为60°时除雨效果最佳.     

磁力弹簧式压电共振型气泵的设计

利用压电振子的振动激励相连接的隔膜共振原理,提出了用磁力弹簧式压电共振型气泵来提高压电泵对气体的驱动能力.首先,分析磁力弹簧式共振泵的工作原理,建立了共振泵的动力学模型,计算得出了影响隔膜振幅的主要因素.接着,设计和制作了样机,使用阻抗分析仪和激光位移计分别测得系统的共振频率及压电振子的位移放大倍数.最后,设计了测量共振泵流量和输出压力的实验装置,得出了磁力弹簧轴向间距对输出流量和输出压力的影响.实验测试表明:当输入正弦电压为200 V,系统共振频率为134 Hz,磁力弹簧的轴向间距为9 mm时,压电振子的位移放大倍数约为4.3,其最佳输出流量为524 ml/min,最佳输出压力为9.2 kPa.结果显示,提出的磁力弹簧式压电共振型气泵提高了气体的输送能力.     

一种新型菱形压电振子的设计及其驱动轨迹研究

为了给某型转台提供压电驱动装置,设计了一种新型2自由度菱形压电振子。对此新型振子进行结构设计,并运用ANSYS软件进行了模态分析,根据分析结果确定了振子的激振频率。对菱形振子的驱动轨迹进行理论计算,并运用Comsol软件进行仿真,仿真结果表明驱动轨迹成立,与轨迹理论计算吻合,证明了此压电振子可以提供相应的驱动。进一步对振子的驱动方式进行改变,从而得到了改进的振子,对该改进设计进行Comsol仿真,结果表明驱动轨迹在x-z面内提高了73.3%,在y-z面内提高了128%,此菱形压电振子对后续压电电机的设计提供借鉴。     

环形压电双晶片驱动式振动送料器

为了满足现代工业领域中对轻、薄、小产品平稳输送的要求,提出了一种采用环形压电双晶片作为驱动源的新型振动送料器。设计了振动送料器结构,分析了振动送料器的工作原理,测试了压电双晶片振子的性能,利用有限元软件ANSYS确定了压电双晶片振子的工作模态,研制了送料器样机并进行试验测试。试验结果表明：当振动频率为86.5～91.5Hz时,送料器具备输送物料的能力;当系统共振时,输送速度最快,随着电压的增加,送料速度呈线性关系增加;与同型号的电磁振动送料器相比,研制的环形压电双晶片驱动式振动送料器消耗电流仅为其16%,工作噪声下降22dB,输送稳定性好。     

大深径比微小深孔超声电火花加工工艺研究

针对难加工材料的大深径比微小深孔加工这一工艺难题,设计并制造了基于工件振动的超声电火花复合加工装置。该装置包括一个已优化的压电振子和一台普通电火花机床。为提高加工效率,对压电振子进行了优化分析,使压电振子具有合适的纵振模态、固有频率和较大的振幅,压电振子中陶瓷片具有合理地安装位置。选择模具钢作为加工材料进行大深径比微小深孔的加工实验,比较研究了超声电火花复合加工装置和普通电火花机床加工大深径比微小深孔的加工效率。实验表明,超声电火花复合加工装置的加工效率更高。研究了超声激励电压、脉冲电流、脉冲宽度以及脉冲间隙等参数对大深径比微小深孔加工效率的影响,得出各参数较优的设置值。根据实验结果可以看出,超声电火花复合加工装置可以有效地加工出直径为0.5mm、深径比为60的微小深孔,适用于难加工材料的大深径比微小深孔加工。     

圆形压电振子的理论分析与应用研究

为了研究圆形压电振子的振动与输出性能,对圆形压电振子进行了理论分析与应用研究.首先对圆形压电振子的组成及工作机理进行了阐述;然后对圆形压电振子进行了弹性振动分析,推导出压电振子弹性振动挠度表达式,得到影响压电振子弹性位移的影响因素;最后将圆形压电振子作为气体隔膜泵的驱动力源进行实验测试.结果表明,圆形压电振子用在气体隔膜泵上能实现较好的驱动,系统输出流量高、驱动压力大.验证了用这种圆形压电振子实现微小型系统驱动是可行、有效的.     

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...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.