A large area multi-finger configuration power SiGe HBT device （with an emitter area of about 880μm^2） was fabricated with 2μm double-mesa technology. The maximum DC current gain β is 214. The BVCEO is up to 10V,a...A large area multi-finger configuration power SiGe HBT device （with an emitter area of about 880μm^2） was fabricated with 2μm double-mesa technology. The maximum DC current gain β is 214. The BVCEO is up to 10V,and the BVCBO is up to 16V with a collector doping concentration of 1 × 10^17cm^-3 and collector thickness of 400nm. The device exhibits a maximum oscillation frequency fmax of 19. 3GHz and a cut-off frequency fT of 18.0GHz at a DC bias point of Ic = 30mA and VCE = 3V.MSG （maximum stable gain） is 24.5dB,and U （Mason unilateral gain） is 26.6dB at 1GHz. Due to the novel distribution layout, no notable current gain fall-off or thermal effects are observed in the I-V characteristics at high collector current.展开更多
The self-heating effect severely limits device performance and reliability.Although some studies have revealed the heat distribution ofβ-Ga_(2)O_(3) MOSFETs under biases,those devices all have small areas and have di...The self-heating effect severely limits device performance and reliability.Although some studies have revealed the heat distribution ofβ-Ga_(2)O_(3) MOSFETs under biases,those devices all have small areas and have difficulty reflecting practical con-ditions.This work demonstrated a multi-fingerβ-Ga_(2)O_(3) MOSFET with a maximum drain current of 0.5 A.Electrical characteris-tics were measured,and the heat dissipation of the device was investigated through infrared images.The relationship between device temperature and time/bias is analyzed.展开更多
We present a mathematical method for acceleration workspace analysis of cooperating multi-finger robot systems using a model of point-contact with friction. A new unified formulation from dynamic equations of cooperat...We present a mathematical method for acceleration workspace analysis of cooperating multi-finger robot systems using a model of point-contact with friction. A new unified formulation from dynamic equations of cooperating multi-finger robots is derived considering the force and acceleration relationships between the fingers and the object to be handled. From the dynamic equation, maximum translational and rotational acceleration bounds of an object are calculated under given constraints of contact conditions, configurations of fingers, and bounds on the torques of joint actuators for each finger. Here, the rotational acceleration bounds can be applied as an important manipulability index when the multi-finger robot grasps an object. To verify the proposed method, we used a set of case studies with a simple multi-finger mechanism system. The achievable acceleration boundary in task space can be obtained successfully with the proposed method and the acceleration boundary depends on the configurations of fingers.展开更多
The classical gradient flow optimization algorithm requires a valid initial point before starting the recursive algorithm,and the existing methods can’t guarantee that the initial values fully satisfy the friction co...The classical gradient flow optimization algorithm requires a valid initial point before starting the recursive algorithm,and the existing methods can’t guarantee that the initial values fully satisfy the friction cone constraints of contact point in the optimization process of gradient flow algorithm.In order to improve safety margin and prevent the finger from slipping at contact point,we present an iterative method of safe initial values with safety margin detection and develop a gradient flow optimization algorithm based on the safe initial values.Firstly,the safety margin is defined which more intuitively reflects the margin of the grasping forces at contact point.The resulting safe initial values can be achieved by the detection of desired safety margin at each iteration.Secondly,the safe initial values are usually not optimal,even with the valid initial values,and it can’t always ensure that the finger contact force always satisfies the friction cone constraints during the optimization.It is an effective way to eliminate the unreliable initial values in the optimization and obtain a safer initial values by increasing the safety margin.By transforming the safe initial values into an initial point of the gradient flow algorithm,the final optimized values of grasping forces can be generated efficiently by gradient flow iteration.Grasp examples of the soft multi-fingered hand indicate the effectiveness of the general solution of the force optimization algorithm based on safety margin detection.The method eliminates the shortcomings of the gradient flow optimization process caused by the initial value problem and provides a more accurate and reliable force optimization result for multi-fingered dexterous manipulation.展开更多
The dynamics properties of a kind of multi-fingered robot hand is analyzed. It is pointed out that the dynamics property of this kind of multifingered robot hand in the approaching process is quite different from that...The dynamics properties of a kind of multi-fingered robot hand is analyzed. It is pointed out that the dynamics property of this kind of multifingered robot hand in the approaching process is quite different from that in the grasping process and,different control algorithm should be taken in the two process. A position-force hybrid control algorithm is proposed which is applied to the control system of the University of Science and Technology Beijing double-thumb robot hand successfully.展开更多
Gives an overview of the present status of researches on grasp stability of multi fingered dexterous robot hands,presents the imaginary displacement method for evaluating the grasp stability, which is easy to realize...Gives an overview of the present status of researches on grasp stability of multi fingered dexterous robot hands,presents the imaginary displacement method for evaluating the grasp stability, which is easy to realize on computer,and has no limit on contact points for each finger. Analyses for grasping stability with single contact point of typical objects with different curvature proved the effectiveness of the method proposed and optimal grasp examples are given as well.展开更多
With the impact of the non-uniform turn-on phenomenon,the ESD robustness of high-voltage multifinger devices is limited.This paper describes the operational mechanism of a GG-nLDMOS device under ESD stress conditions ...With the impact of the non-uniform turn-on phenomenon,the ESD robustness of high-voltage multifinger devices is limited.This paper describes the operational mechanism of a GG-nLDMOS device under ESD stress conditions and analyzes the reason that causes the non-uniform turn-on characteristics of a multi-finger GGnLDMOS device.By means of increasing substrate resistance,an optimized device structure is proposed to improve the turn-on uniformity of a high-voltage multi-finger GG-nLDMOS.This approach has been successfully verified in a 0.35 m 40 V BCD process.The TLP test results reveal that increasing the substrate resistance can effectively enhance the turn-on uniformity of the 40 V multi-finger GG-nLDMOS device and improve its ESD robustness.展开更多
This paper deals with the problem of force-closure analysis for soft multi-fingered grasps. The first step is the study of the relationship between the external wrench space and the manipulation force space at any con...This paper deals with the problem of force-closure analysis for soft multi-fingered grasps. The first step is the study of the relationship between the external wrench space and the manipulation force space at any contact. Constraint force set, strictly constraint force set and normal force set are defined in the contact force space, followed by an investigation of their relationships. Based on the convexity of the friction constraints for soft finger contact, the necessary and sufficient conditions for force-closure grasps are derived. Accordingly an efficient algorithm for testing force-closure is presented. Some illustrative examples are given.展开更多
针对近红外光下采集的指静脉图像存在局部像素相似性强、单一方向识别效果差的问题,提出模板投票和多方向融合的指静脉识别方法。首先,提出基于模板投票的局部三值模式(template voting local three pattern,TVTP),充分利用局部多邻域...针对近红外光下采集的指静脉图像存在局部像素相似性强、单一方向识别效果差的问题,提出模板投票和多方向融合的指静脉识别方法。首先,提出基于模板投票的局部三值模式(template voting local three pattern,TVTP),充分利用局部多邻域点的信息,减少局部像素相似性;其次,指静脉图像中含有丰富的方向特征信息,提出多方向编码(multi-directional coding,MDC),获取图像中具有辨别力的方向特征,加强不同方向特征之间的鲁棒性,解决单一方向识别率差的问题;最后,利用分块直方图统计特征,并使用协同表示(collaborative representation,CR)进行分类,提高识别效率。实验结果证明,所提方法在SDUMLA数据集、USM数据集和THU-FVFDT2数据集上的识别率分别达到99.32%、99.73%和99.75%,与其他经典和新颖算法相比,不仅取得了更好的识别效果,还能同时满足实时性要求,具有应用价值。展开更多
文摘A large area multi-finger configuration power SiGe HBT device （with an emitter area of about 880μm^2） was fabricated with 2μm double-mesa technology. The maximum DC current gain β is 214. The BVCEO is up to 10V,and the BVCBO is up to 16V with a collector doping concentration of 1 × 10^17cm^-3 and collector thickness of 400nm. The device exhibits a maximum oscillation frequency fmax of 19. 3GHz and a cut-off frequency fT of 18.0GHz at a DC bias point of Ic = 30mA and VCE = 3V.MSG （maximum stable gain） is 24.5dB,and U （Mason unilateral gain） is 26.6dB at 1GHz. Due to the novel distribution layout, no notable current gain fall-off or thermal effects are observed in the I-V characteristics at high collector current.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.61925110,62004184 and 62234007the Key-Area Research and Development Program of Guangdong Province under Grant No.2020B010174002.
文摘The self-heating effect severely limits device performance and reliability.Although some studies have revealed the heat distribution ofβ-Ga_(2)O_(3) MOSFETs under biases,those devices all have small areas and have difficulty reflecting practical con-ditions.This work demonstrated a multi-fingerβ-Ga_(2)O_(3) MOSFET with a maximum drain current of 0.5 A.Electrical characteris-tics were measured,and the heat dissipation of the device was investigated through infrared images.The relationship between device temperature and time/bias is analyzed.
文摘We present a mathematical method for acceleration workspace analysis of cooperating multi-finger robot systems using a model of point-contact with friction. A new unified formulation from dynamic equations of cooperating multi-finger robots is derived considering the force and acceleration relationships between the fingers and the object to be handled. From the dynamic equation, maximum translational and rotational acceleration bounds of an object are calculated under given constraints of contact conditions, configurations of fingers, and bounds on the torques of joint actuators for each finger. Here, the rotational acceleration bounds can be applied as an important manipulability index when the multi-finger robot grasps an object. To verify the proposed method, we used a set of case studies with a simple multi-finger mechanism system. The achievable acceleration boundary in task space can be obtained successfully with the proposed method and the acceleration boundary depends on the configurations of fingers.
基金National Natural Science Foundation of China(51305180)International Science&Technology Cooperation Program of China(2014DFR10620)Shandong Provincial Natural Science Foundation(ZR2013FM026,ZR2014YL009)
文摘The classical gradient flow optimization algorithm requires a valid initial point before starting the recursive algorithm,and the existing methods can’t guarantee that the initial values fully satisfy the friction cone constraints of contact point in the optimization process of gradient flow algorithm.In order to improve safety margin and prevent the finger from slipping at contact point,we present an iterative method of safe initial values with safety margin detection and develop a gradient flow optimization algorithm based on the safe initial values.Firstly,the safety margin is defined which more intuitively reflects the margin of the grasping forces at contact point.The resulting safe initial values can be achieved by the detection of desired safety margin at each iteration.Secondly,the safe initial values are usually not optimal,even with the valid initial values,and it can’t always ensure that the finger contact force always satisfies the friction cone constraints during the optimization.It is an effective way to eliminate the unreliable initial values in the optimization and obtain a safer initial values by increasing the safety margin.By transforming the safe initial values into an initial point of the gradient flow algorithm,the final optimized values of grasping forces can be generated efficiently by gradient flow iteration.Grasp examples of the soft multi-fingered hand indicate the effectiveness of the general solution of the force optimization algorithm based on safety margin detection.The method eliminates the shortcomings of the gradient flow optimization process caused by the initial value problem and provides a more accurate and reliable force optimization result for multi-fingered dexterous manipulation.
文摘The dynamics properties of a kind of multi-fingered robot hand is analyzed. It is pointed out that the dynamics property of this kind of multifingered robot hand in the approaching process is quite different from that in the grasping process and,different control algorithm should be taken in the two process. A position-force hybrid control algorithm is proposed which is applied to the control system of the University of Science and Technology Beijing double-thumb robot hand successfully.
文摘Gives an overview of the present status of researches on grasp stability of multi fingered dexterous robot hands,presents the imaginary displacement method for evaluating the grasp stability, which is easy to realize on computer,and has no limit on contact points for each finger. Analyses for grasping stability with single contact point of typical objects with different curvature proved the effectiveness of the method proposed and optimal grasp examples are given as well.
文摘With the impact of the non-uniform turn-on phenomenon,the ESD robustness of high-voltage multifinger devices is limited.This paper describes the operational mechanism of a GG-nLDMOS device under ESD stress conditions and analyzes the reason that causes the non-uniform turn-on characteristics of a multi-finger GGnLDMOS device.By means of increasing substrate resistance,an optimized device structure is proposed to improve the turn-on uniformity of a high-voltage multi-finger GG-nLDMOS.This approach has been successfully verified in a 0.35 m 40 V BCD process.The TLP test results reveal that increasing the substrate resistance can effectively enhance the turn-on uniformity of the 40 V multi-finger GG-nLDMOS device and improve its ESD robustness.
文摘This paper deals with the problem of force-closure analysis for soft multi-fingered grasps. The first step is the study of the relationship between the external wrench space and the manipulation force space at any contact. Constraint force set, strictly constraint force set and normal force set are defined in the contact force space, followed by an investigation of their relationships. Based on the convexity of the friction constraints for soft finger contact, the necessary and sufficient conditions for force-closure grasps are derived. Accordingly an efficient algorithm for testing force-closure is presented. Some illustrative examples are given.
文摘针对近红外光下采集的指静脉图像存在局部像素相似性强、单一方向识别效果差的问题,提出模板投票和多方向融合的指静脉识别方法。首先,提出基于模板投票的局部三值模式(template voting local three pattern,TVTP),充分利用局部多邻域点的信息,减少局部像素相似性;其次,指静脉图像中含有丰富的方向特征信息,提出多方向编码(multi-directional coding,MDC),获取图像中具有辨别力的方向特征,加强不同方向特征之间的鲁棒性,解决单一方向识别率差的问题;最后,利用分块直方图统计特征,并使用协同表示(collaborative representation,CR)进行分类,提高识别效率。实验结果证明,所提方法在SDUMLA数据集、USM数据集和THU-FVFDT2数据集上的识别率分别达到99.32%、99.73%和99.75%,与其他经典和新颖算法相比,不仅取得了更好的识别效果,还能同时满足实时性要求,具有应用价值。
