In this paper, we will try to find a universal theoretical model and approximate solutions which can be applied to both mode shape and normal shape actuators and sensors, and which can be predicted the gain of the fir...In this paper, we will try to find a universal theoretical model and approximate solutions which can be applied to both mode shape and normal shape actuators and sensors, and which can be predicted the gain of the first three modes of the mode shape and normal shape actuators and sensors, finally through computer simulation analysis to validate. In order to prove the feasibility of the theory and as well as convenient to use on the electro-mechanical engineering, we will try to simplify the three-dimension structure problem into an one-dimension structure problem. Furthermore we will design one kind of bimorph type piezoelectric cantilever beam, so that it can be used as with the actuator and sensor simultaneously, but also conducive to the theory and simulation analysis. As for the simulation analysis, we will use the ANSYS code.展开更多
The structure and rheological properties of carbon-based particle suspensions, i.e., carbon black（CB）, multi-wall carbon nanotube（MWNT）, graphene and hollow carbon sphere（HCS） suspended in polydimethylsiloxane（...The structure and rheological properties of carbon-based particle suspensions, i.e., carbon black（CB）, multi-wall carbon nanotube（MWNT）, graphene and hollow carbon sphere（HCS） suspended in polydimethylsiloxane（PDMS）, are investigated. In order to study the effect of particle shape on the structure and rheological properties of suspensions, the content of surface oxygen-containing functional groups of carbon-based particles is controlled to be similar. Original spherical-like CB（fractal filler）, rod-like MWNT and sheet-like graphene form large agglomerates in PDMS, while spherical HCS particles disperse relatively well in PDMS. The dispersion state of carbon-based particles affects the critical concentration of forming a rheological percolation network. Under weak shear, negative normal stress differences（ΔN） are observed in CB, MWNT and graphene suspensions, while ΔN is nearly zero for HCS suspensions. It is concluded that the vorticity alignment of CB, MWNT and graphene agglomerates under shear results in the negative ΔN. However, no obvious structural change is observed in HCS suspension under weak shear, and accordingly, the ΔN is almost zero.展开更多
In this paper, we try to use the coating of effective electrode surface and change the direction of polarization to design the mode shape piezoelectric motors of the first three modes. We also com-pare the gain of the...In this paper, we try to use the coating of effective electrode surface and change the direction of polarization to design the mode shape piezoelectric motors of the first three modes. We also com-pare the gain of the mode shape piezoelectric motors with respect to the normal shape piezoelectric motor, including rotational speed, loading ability, torque, phase angle conversion and efficiency. According to the results of theoretical and simulation analysis, we have found that the gain of the mode shape piezoelectric stators are larger than the normal shape piezoelectric stator on average. According to the results of experiments, we found that the gain of the rotational speed, loading ability, torque, driving phase angle conversion and efficiency of the mode shape (MS1 - 3) piezoelectric motors are higher than the normal shape piezoelectric motor (NS) under driving condition of the second vibration mode. Also, the gain of the rotational speed and loading ability of the mode shape 2 (MS2) piezoelectric motor are higher than other shapes piezoelectric motors (NS, MS1 and MS3) under driving condition of the second vibration mode. The used maximum rotational speed of the mode shape 2 (MS2) piezoelectric motor is up to 946 rpm under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency, 0o driving phase angle and 13.0 gw net weight. The maximum loading ability and torque of the mode shape 2 (MS2) piezoelectric motor is respectively 451 gw and 0.91 mkgw-m under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency, 0o driving phase angle and 173 rpm rotational speed. And the gain of efficiency (output power) and maximum loading ability (torque) of the mode shape 2 (MS2) piezoelectric motor are respectively 2.28 and 1.54 with respect to the normal shape piezoelectric motor under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency and 0o driving phase angle. According to the results of the experiments, we have finally found that the piezoelectric motors (NS and MS1 - 3) can be driven only by the second vibration mode because the stator can produce elliptical motion and allows the rotor to generate orientation rotation. However, the first vibration mode can allow the rotor to be rotated very fast but it can’t make the rotation of the rotor orientation. Furthermore, we also found that the rotor can’t rotate by the third vibration mode because its vibration energy is absorbed by the structure itself, so causing the rotor stagnation.展开更多
In this paper, we want to make a new type linear piezoelectric motor by mode shape coating or effective electrode surface coating. The mode shape is derived from the mechanical boundary conditions of the linear piezoe...In this paper, we want to make a new type linear piezoelectric motor by mode shape coating or effective electrode surface coating. The mode shape is derived from the mechanical boundary conditions of the linear piezoelectric motor. We only have access to the first three modes of formas, the effective electrode surface coating basis, as well as with the linear piezoelectric motor of normal shape do comparison. Next, we will inspect their gain or axial velocity through theoretical analysis, simulation and experiment. According to the results of the theoretical analysis, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much larger than the linear piezoelectric motors of normal shape. However, according to the results of simulation and experiments, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much greater than the linear piezoelectric motors of normal shape, which is about 1.2 to 1.4 times. The linear piezoelectric motor of mode shape 3 has the fastest axial velocity, which is about -48 mm/s and 48 mm/s under conditions of 180 Vp-p driving voltage, 21.2 kHz driving frequency (the third vibration modal), 25 gw loading and the position of loading or mass at x = 5 mm & 45 mm respectively. And its axial velocity is about 1.4 times the linear piezoelectric motor of normal shape under the same conditions. Overall, the mode shape coating helps to enhance the gain or axial velocity of the linear piezoelectric motor.展开更多
In this paper, we give some characteristic properties of star-shaped sets which include a subset of a convex metric space. Using the characteristic properties, we discuss the existence problems of fixed points of none...In this paper, we give some characteristic properties of star-shaped sets which include a subset of a convex metric space. Using the characteristic properties, we discuss the existence problems of fixed points of nonexpansive type mappings on star-shaped subsets of convex metric spaces, which generalize the recent results obtained by Ding Xie-ping, Beg and Azam. Finally, we give an example which shows that our generalizations are essential.展开更多
A formula is developed to estimate the total mass loss of projectile, based on the assump- tions that the peeling of molten surface layer in projectile nose is the primary cause of mass loss, and the frictional heat i...A formula is developed to estimate the total mass loss of projectile, based on the assump- tions that the peeling of molten surface layer in projectile nose is the primary cause of mass loss, and the frictional heat is totally absorbed by the projectile. Extrapolating this formula to predict the mass loss of local area of projectile, the receding displacement on projectile surface is obtained, which is vertical to the symmetry axis of projectile. Thereby, a finite difference method model is constructed to simulate the variation of projectile shape. The shape of residual projectile, depth of penetration of projectile and its mass loss obtained by calculation are found in good consistency with respective experimental data.展开更多
目的工业机器人视觉领域经常需要对一些由拼装、冲压或贴合等工艺造成的形变工件进行精准定位,工件的大部分特征表现出一定程度的非刚性,其他具备良好一致性的部分通常特征简单,导致一些常用的目标检测算法精度不足或鲁棒性不强,难以满...目的工业机器人视觉领域经常需要对一些由拼装、冲压或贴合等工艺造成的形变工件进行精准定位,工件的大部分特征表现出一定程度的非刚性,其他具备良好一致性的部分通常特征简单,导致一些常用的目标检测算法精度不足或鲁棒性不强,难以满足实际需求。针对这一问题,提出融合边缘与灰度特征的形变工件精准定位方法。方法第1阶段提出多归一化互相关的模板匹配MNCC(multi normalized cross correlation)方法检测形变目标,利用余弦距离下的灰度聚类获得均值模板,通过滑动窗口的方式,结合金字塔跟踪,自顶向下地优先搜索类均值模板,得到类匹配候选,然后进行类内细搜索获得最佳位置匹配。第2阶段提出一种改进的形状匹配方法T-SBM(truncated shape-based matching),通过改变原始SBM(shape-based matching)的梯度方向内积的计算方式,对负梯度极性方向截断,削弱目标背景不稳定导致局部梯度方向反转时对整体评分的负贡献,改善边缘稀疏或特征简单导致检测鲁棒性低的问题。最后提出二维高斯条件密度评价,将灰度特征、形状特征和形变量进行综合加权,获得理想目标评价,实现序贯检测。结果实验部分分别与SBM、归一化互相关匹配算法(normalized cross correlation,NCC)、LINE2D(linearizing the memory 2D)算法和YOLOv5s(you only look once version 5 small)算法在5种类型工件的472幅真实工业图像上进行了对比测试,在检出分值大于0.8(实际常用的阈值区间)时,提出算法的召回率优于其他几种测试算法;在IoU(intersection over union)阈值0.9时的平均检测准确率为81.7%,F1-Score为95%,两组指标相比其他测试算法分别至少提升了10.8%和8.3%。在平均定位精度方面,提出算法的定位偏差在IoU阈值0.9时达到了2.44像素,在5种测试算法中的表现也为最佳。结论提出了一种两阶段的定位方法,该方法适用于检测工业场景中由拼装、冲压和贴合等工艺制成的形变工件并能够进行精准定位,尤其适用于工业机器人视觉引导定位应用场景,并在实际项目中得到了应用。展开更多
文摘In this paper, we will try to find a universal theoretical model and approximate solutions which can be applied to both mode shape and normal shape actuators and sensors, and which can be predicted the gain of the first three modes of the mode shape and normal shape actuators and sensors, finally through computer simulation analysis to validate. In order to prove the feasibility of the theory and as well as convenient to use on the electro-mechanical engineering, we will try to simplify the three-dimension structure problem into an one-dimension structure problem. Furthermore we will design one kind of bimorph type piezoelectric cantilever beam, so that it can be used as with the actuator and sensor simultaneously, but also conducive to the theory and simulation analysis. As for the simulation analysis, we will use the ANSYS code.
基金financially supported by the National Natural Science Foundation of China(Nos.21474111,21222407 and 21274152)subsidized by the National Basic Research Program of China(973 Program,2012CB821500)
文摘The structure and rheological properties of carbon-based particle suspensions, i.e., carbon black（CB）, multi-wall carbon nanotube（MWNT）, graphene and hollow carbon sphere（HCS） suspended in polydimethylsiloxane（PDMS）, are investigated. In order to study the effect of particle shape on the structure and rheological properties of suspensions, the content of surface oxygen-containing functional groups of carbon-based particles is controlled to be similar. Original spherical-like CB（fractal filler）, rod-like MWNT and sheet-like graphene form large agglomerates in PDMS, while spherical HCS particles disperse relatively well in PDMS. The dispersion state of carbon-based particles affects the critical concentration of forming a rheological percolation network. Under weak shear, negative normal stress differences（ΔN） are observed in CB, MWNT and graphene suspensions, while ΔN is nearly zero for HCS suspensions. It is concluded that the vorticity alignment of CB, MWNT and graphene agglomerates under shear results in the negative ΔN. However, no obvious structural change is observed in HCS suspension under weak shear, and accordingly, the ΔN is almost zero.
文摘In this paper, we try to use the coating of effective electrode surface and change the direction of polarization to design the mode shape piezoelectric motors of the first three modes. We also com-pare the gain of the mode shape piezoelectric motors with respect to the normal shape piezoelectric motor, including rotational speed, loading ability, torque, phase angle conversion and efficiency. According to the results of theoretical and simulation analysis, we have found that the gain of the mode shape piezoelectric stators are larger than the normal shape piezoelectric stator on average. According to the results of experiments, we found that the gain of the rotational speed, loading ability, torque, driving phase angle conversion and efficiency of the mode shape (MS1 - 3) piezoelectric motors are higher than the normal shape piezoelectric motor (NS) under driving condition of the second vibration mode. Also, the gain of the rotational speed and loading ability of the mode shape 2 (MS2) piezoelectric motor are higher than other shapes piezoelectric motors (NS, MS1 and MS3) under driving condition of the second vibration mode. The used maximum rotational speed of the mode shape 2 (MS2) piezoelectric motor is up to 946 rpm under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency, 0o driving phase angle and 13.0 gw net weight. The maximum loading ability and torque of the mode shape 2 (MS2) piezoelectric motor is respectively 451 gw and 0.91 mkgw-m under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency, 0o driving phase angle and 173 rpm rotational speed. And the gain of efficiency (output power) and maximum loading ability (torque) of the mode shape 2 (MS2) piezoelectric motor are respectively 2.28 and 1.54 with respect to the normal shape piezoelectric motor under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency and 0o driving phase angle. According to the results of the experiments, we have finally found that the piezoelectric motors (NS and MS1 - 3) can be driven only by the second vibration mode because the stator can produce elliptical motion and allows the rotor to generate orientation rotation. However, the first vibration mode can allow the rotor to be rotated very fast but it can’t make the rotation of the rotor orientation. Furthermore, we also found that the rotor can’t rotate by the third vibration mode because its vibration energy is absorbed by the structure itself, so causing the rotor stagnation.
文摘In this paper, we want to make a new type linear piezoelectric motor by mode shape coating or effective electrode surface coating. The mode shape is derived from the mechanical boundary conditions of the linear piezoelectric motor. We only have access to the first three modes of formas, the effective electrode surface coating basis, as well as with the linear piezoelectric motor of normal shape do comparison. Next, we will inspect their gain or axial velocity through theoretical analysis, simulation and experiment. According to the results of the theoretical analysis, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much larger than the linear piezoelectric motors of normal shape. However, according to the results of simulation and experiments, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much greater than the linear piezoelectric motors of normal shape, which is about 1.2 to 1.4 times. The linear piezoelectric motor of mode shape 3 has the fastest axial velocity, which is about -48 mm/s and 48 mm/s under conditions of 180 Vp-p driving voltage, 21.2 kHz driving frequency (the third vibration modal), 25 gw loading and the position of loading or mass at x = 5 mm & 45 mm respectively. And its axial velocity is about 1.4 times the linear piezoelectric motor of normal shape under the same conditions. Overall, the mode shape coating helps to enhance the gain or axial velocity of the linear piezoelectric motor.
文摘In this paper, we give some characteristic properties of star-shaped sets which include a subset of a convex metric space. Using the characteristic properties, we discuss the existence problems of fixed points of nonexpansive type mappings on star-shaped subsets of convex metric spaces, which generalize the recent results obtained by Ding Xie-ping, Beg and Azam. Finally, we give an example which shows that our generalizations are essential.
基金supported by the National Natural Science Foundation of China (11172282)the Science Foundation of China Academy of Engineering Physics(2009A0201009)
文摘A formula is developed to estimate the total mass loss of projectile, based on the assump- tions that the peeling of molten surface layer in projectile nose is the primary cause of mass loss, and the frictional heat is totally absorbed by the projectile. Extrapolating this formula to predict the mass loss of local area of projectile, the receding displacement on projectile surface is obtained, which is vertical to the symmetry axis of projectile. Thereby, a finite difference method model is constructed to simulate the variation of projectile shape. The shape of residual projectile, depth of penetration of projectile and its mass loss obtained by calculation are found in good consistency with respective experimental data.
文摘目的工业机器人视觉领域经常需要对一些由拼装、冲压或贴合等工艺造成的形变工件进行精准定位,工件的大部分特征表现出一定程度的非刚性,其他具备良好一致性的部分通常特征简单,导致一些常用的目标检测算法精度不足或鲁棒性不强,难以满足实际需求。针对这一问题,提出融合边缘与灰度特征的形变工件精准定位方法。方法第1阶段提出多归一化互相关的模板匹配MNCC(multi normalized cross correlation)方法检测形变目标,利用余弦距离下的灰度聚类获得均值模板,通过滑动窗口的方式,结合金字塔跟踪,自顶向下地优先搜索类均值模板,得到类匹配候选,然后进行类内细搜索获得最佳位置匹配。第2阶段提出一种改进的形状匹配方法T-SBM(truncated shape-based matching),通过改变原始SBM(shape-based matching)的梯度方向内积的计算方式,对负梯度极性方向截断,削弱目标背景不稳定导致局部梯度方向反转时对整体评分的负贡献,改善边缘稀疏或特征简单导致检测鲁棒性低的问题。最后提出二维高斯条件密度评价,将灰度特征、形状特征和形变量进行综合加权,获得理想目标评价,实现序贯检测。结果实验部分分别与SBM、归一化互相关匹配算法(normalized cross correlation,NCC)、LINE2D(linearizing the memory 2D)算法和YOLOv5s(you only look once version 5 small)算法在5种类型工件的472幅真实工业图像上进行了对比测试,在检出分值大于0.8(实际常用的阈值区间)时,提出算法的召回率优于其他几种测试算法;在IoU(intersection over union)阈值0.9时的平均检测准确率为81.7%,F1-Score为95%,两组指标相比其他测试算法分别至少提升了10.8%和8.3%。在平均定位精度方面,提出算法的定位偏差在IoU阈值0.9时达到了2.44像素,在5种测试算法中的表现也为最佳。结论提出了一种两阶段的定位方法,该方法适用于检测工业场景中由拼装、冲压和贴合等工艺制成的形变工件并能够进行精准定位,尤其适用于工业机器人视觉引导定位应用场景,并在实际项目中得到了应用。
