In recent years,an innovative underactuated robot was developed,named as underactuated cable-driven trusslike manipulator(UCTM),to be suitable in aerospace applications.However,there has been strong consensus that the...In recent years,an innovative underactuated robot was developed,named as underactuated cable-driven trusslike manipulator(UCTM),to be suitable in aerospace applications.However,there has been strong consensus that the stabilization of planar underactuated manipulators without gravity is a great challenge since the system includes a second order nonholonomic constraint and most classical control methods are not suitable for this kind of system.Furthermore,the complexity of the truss-like structure results in tremendous difficulty of computational complicacy and high nonlinearity during dynamic modelling in addition to controller design.It is paramount to solve these difficulties for UCTM's future applications.To solve the above difficulties,this paper presents a dynamic modelling method for UCTM and a trajectory tracking control method based on partial feedback linearization(PFL)that fulfills the control goal of moving UCTM from its original position to a desired position by tracking a given trajectory of the joint angles.To achieve this,a model equivalent method is proposed to make UCTM equivalent with a three-link manipulator in the sense of dynamic behavior.Then the Lagrangian equation combined with complex vector method is proposed in the dynamic modelling process of UCTM,which simplifies the derivation procedure.Based on the established dynamic model,a coordinate transformation method is proposed to transform the control force matrix into the conventional form of an underactuated system,so that the control force can be separated from the unactuated term.The PFL method in combination with the LQR control method is then proposed to realize the targets that the joint angles can track given desired trajectory.Simulation experiments are conducted to verify the correctness and effectiveness of the proposed methods.展开更多
An adaptive backstepping-based non-singular termi- nal sliding mode （NTSM） control method is proposed for a class of uncertain nonlinear systems in the parameteric-strict feedback form. The adaptive control law is c...An adaptive backstepping-based non-singular termi- nal sliding mode （NTSM） control method is proposed for a class of uncertain nonlinear systems in the parameteric-strict feedback form. The adaptive control law is combined with the first n - 1 steps of the backstepping method to estimate the unknown pa- rameters of the system. In the nth step, an NTSM control strategy is utilized to drive the last state of the system to converge in a finite time. Furthermore, the derivate estimator is used to obtain the derivates of the states of the error system; the higher-order non-singular terminal sliding mode control （HONTSMC） law is de- signed to eliminate the chattering and make the system robust to both matched and unmatched uncertainties. Compared to the adaptive backstepping-based linear sliding mode control method （LSMC）, the proposed method improves the convergence rate and the steady-state tracking accuracy of the system, and makes the control signal smoother. Finally, the compared simulation results are presented to validate the method.展开更多
以无花果为主要原料,搭配多种果蔬杂粮,采用DPPH自由基清除能力、ABTS自由基清除能力、铁离子还原能力(FRAP法)以及感官评价为检测指标,用总评归一法计算综合得分,并通过Plackett-Burman实验和响应面实验优化主辅料配方制成高抗氧化能...以无花果为主要原料,搭配多种果蔬杂粮,采用DPPH自由基清除能力、ABTS自由基清除能力、铁离子还原能力(FRAP法)以及感官评价为检测指标,用总评归一法计算综合得分,并通过Plackett-Burman实验和响应面实验优化主辅料配方制成高抗氧化能力的无花果代餐粉。结果表明:最优主料配方为无花果、桑葚、山药质量比为7.10∶5.00∶3.00(以15.00 g代餐粉主料计)。高抗氧化能力无花果代餐粉最优配方为主料、南瓜、黑芝麻、赤小豆、糙米质量比为15.00∶9.10∶1.40∶3.00∶1.40(以30.00 g代餐粉计),此时代餐粉清除DPPH自由基的能力为705.73μg Trolox/mL、总抗氧化能力(ABTS法)为9.89 mM TEAC、总抗氧化能力(FRAP法)为12.54 mM FeSO 4。总评归一法进行综合抗氧化能力得分达到94.83,感官评分为78.25,综合得分为85.04。展开更多
目的探讨在阈下和阈上刺激条件下,癌症复发恐惧的乳腺癌患者对癌症相关刺激的注意偏向特点。方法2022年09月至2023年03月在陆军军医大学第一附属医院招募94名女性乳腺癌患者完成癌症复发恐惧量表简版(fear of cancer recurrence invento...目的探讨在阈下和阈上刺激条件下,癌症复发恐惧的乳腺癌患者对癌症相关刺激的注意偏向特点。方法2022年09月至2023年03月在陆军军医大学第一附属医院招募94名女性乳腺癌患者完成癌症复发恐惧量表简版(fear of cancer recurrence inventory-short form,FCRI-SF)及点探测任务。以FCRI-SF划界分(13分)将乳腺癌患者分为临床和非临床癌症复发恐惧组,每组招募患者47人。采用单样本t检验及重复测量方差分析对两组被试在注意偏向分数、注意定向分数及注意脱离困难分数上进行统计分析。结果临床癌症复发恐惧的乳腺癌患者对癌症相关负性词语有显著注意偏向(P<0.05)。在阈下刺激条件下,其主要成分为对癌症相关负性词语注意定向(P<0.05)。在阈上刺激条件下,其主要成分为对癌症相关负性词语所匹配的中性词语注意定向,且对癌症相关负性词语注意脱离困难以及对癌症相关正性词语注意回避(P<0.05)。结论临床癌症复发恐惧的乳腺癌患者存在对癌症相关负性刺激的注意偏向。减少对癌症相关负性刺激的关注可能是降低乳腺癌患者癌症复发恐惧的有效方法。展开更多
[目的]为实现CO_(2)和NO3-通过C—N偶联绿色合成尿素,制备一种新型的碳纸基铜镍合金(Cux-Niy/CP)催化剂.[方法]使用CO_(2)热活化工艺制备缺陷碳纸,再通过快速碳热冲击法合成一系列具有不同Cu/Ni投料比(物质的量之比)的催化剂,通过扫描电...[目的]为实现CO_(2)和NO3-通过C—N偶联绿色合成尿素,制备一种新型的碳纸基铜镍合金(Cux-Niy/CP)催化剂.[方法]使用CO_(2)热活化工艺制备缺陷碳纸,再通过快速碳热冲击法合成一系列具有不同Cu/Ni投料比(物质的量之比)的催化剂,通过扫描电镜(SEM)、透射电镜(TEM)、X射线能谱元素成像(EDS mapping)、X射线粉末衍射(XRD)、拉曼光谱(Raman)、X射线光电子能谱(XPS)对催化剂的形貌与结构进行分析.对催化剂电催化C—N偶联合成尿素的性能进行测试,通过表征催化剂的电化学阻抗与电化学活性面积来分析催化机理.[结果]形貌表征结果显示催化剂呈现大小不一的类球形纳米颗粒形状,且Cu元素与Ni元素分布均匀.结构表征结果证明了催化剂的合金构型,并揭示金属以氧化态的形式存在于催化剂表面,在测试的负电位下被还原为金属态,提升催化活性.电催化测试结果表明Cu_(7)-Ni_(3)/CP催化剂在-0.57 V vs可逆氢电极(RHE)的测试电位下尿素产率达到98.9μg/(h·cm^(2)),尿素法拉第效率为34.1%.[结论]本研究通过构筑合金的策略解决单一金属催化剂导致的选择性或产率较低的问题,制备的Cu_(7)-Ni_(3)/CP催化剂具有相对优异的电催化C—N偶联合成尿素综合性能,为尿素的绿色合成提供了应用前景.展开更多
基金Projects(51275107,52005124)supported by the National Natural Science Foundation of China。
文摘In recent years,an innovative underactuated robot was developed,named as underactuated cable-driven trusslike manipulator(UCTM),to be suitable in aerospace applications.However,there has been strong consensus that the stabilization of planar underactuated manipulators without gravity is a great challenge since the system includes a second order nonholonomic constraint and most classical control methods are not suitable for this kind of system.Furthermore,the complexity of the truss-like structure results in tremendous difficulty of computational complicacy and high nonlinearity during dynamic modelling in addition to controller design.It is paramount to solve these difficulties for UCTM's future applications.To solve the above difficulties,this paper presents a dynamic modelling method for UCTM and a trajectory tracking control method based on partial feedback linearization(PFL)that fulfills the control goal of moving UCTM from its original position to a desired position by tracking a given trajectory of the joint angles.To achieve this,a model equivalent method is proposed to make UCTM equivalent with a three-link manipulator in the sense of dynamic behavior.Then the Lagrangian equation combined with complex vector method is proposed in the dynamic modelling process of UCTM,which simplifies the derivation procedure.Based on the established dynamic model,a coordinate transformation method is proposed to transform the control force matrix into the conventional form of an underactuated system,so that the control force can be separated from the unactuated term.The PFL method in combination with the LQR control method is then proposed to realize the targets that the joint angles can track given desired trajectory.Simulation experiments are conducted to verify the correctness and effectiveness of the proposed methods.
基金supported by the Natural Science Foundation of Heilongjiang Province(E201426)
文摘An adaptive backstepping-based non-singular termi- nal sliding mode （NTSM） control method is proposed for a class of uncertain nonlinear systems in the parameteric-strict feedback form. The adaptive control law is combined with the first n - 1 steps of the backstepping method to estimate the unknown pa- rameters of the system. In the nth step, an NTSM control strategy is utilized to drive the last state of the system to converge in a finite time. Furthermore, the derivate estimator is used to obtain the derivates of the states of the error system; the higher-order non-singular terminal sliding mode control （HONTSMC） law is de- signed to eliminate the chattering and make the system robust to both matched and unmatched uncertainties. Compared to the adaptive backstepping-based linear sliding mode control method （LSMC）, the proposed method improves the convergence rate and the steady-state tracking accuracy of the system, and makes the control signal smoother. Finally, the compared simulation results are presented to validate the method.
文摘以无花果为主要原料,搭配多种果蔬杂粮,采用DPPH自由基清除能力、ABTS自由基清除能力、铁离子还原能力(FRAP法)以及感官评价为检测指标,用总评归一法计算综合得分,并通过Plackett-Burman实验和响应面实验优化主辅料配方制成高抗氧化能力的无花果代餐粉。结果表明:最优主料配方为无花果、桑葚、山药质量比为7.10∶5.00∶3.00(以15.00 g代餐粉主料计)。高抗氧化能力无花果代餐粉最优配方为主料、南瓜、黑芝麻、赤小豆、糙米质量比为15.00∶9.10∶1.40∶3.00∶1.40(以30.00 g代餐粉计),此时代餐粉清除DPPH自由基的能力为705.73μg Trolox/mL、总抗氧化能力(ABTS法)为9.89 mM TEAC、总抗氧化能力(FRAP法)为12.54 mM FeSO 4。总评归一法进行综合抗氧化能力得分达到94.83,感官评分为78.25,综合得分为85.04。
文摘目的探讨在阈下和阈上刺激条件下,癌症复发恐惧的乳腺癌患者对癌症相关刺激的注意偏向特点。方法2022年09月至2023年03月在陆军军医大学第一附属医院招募94名女性乳腺癌患者完成癌症复发恐惧量表简版(fear of cancer recurrence inventory-short form,FCRI-SF)及点探测任务。以FCRI-SF划界分(13分)将乳腺癌患者分为临床和非临床癌症复发恐惧组,每组招募患者47人。采用单样本t检验及重复测量方差分析对两组被试在注意偏向分数、注意定向分数及注意脱离困难分数上进行统计分析。结果临床癌症复发恐惧的乳腺癌患者对癌症相关负性词语有显著注意偏向(P<0.05)。在阈下刺激条件下,其主要成分为对癌症相关负性词语注意定向(P<0.05)。在阈上刺激条件下,其主要成分为对癌症相关负性词语所匹配的中性词语注意定向,且对癌症相关负性词语注意脱离困难以及对癌症相关正性词语注意回避(P<0.05)。结论临床癌症复发恐惧的乳腺癌患者存在对癌症相关负性刺激的注意偏向。减少对癌症相关负性刺激的关注可能是降低乳腺癌患者癌症复发恐惧的有效方法。
文摘[目的]为实现CO_(2)和NO3-通过C—N偶联绿色合成尿素,制备一种新型的碳纸基铜镍合金(Cux-Niy/CP)催化剂.[方法]使用CO_(2)热活化工艺制备缺陷碳纸,再通过快速碳热冲击法合成一系列具有不同Cu/Ni投料比(物质的量之比)的催化剂,通过扫描电镜(SEM)、透射电镜(TEM)、X射线能谱元素成像(EDS mapping)、X射线粉末衍射(XRD)、拉曼光谱(Raman)、X射线光电子能谱(XPS)对催化剂的形貌与结构进行分析.对催化剂电催化C—N偶联合成尿素的性能进行测试,通过表征催化剂的电化学阻抗与电化学活性面积来分析催化机理.[结果]形貌表征结果显示催化剂呈现大小不一的类球形纳米颗粒形状,且Cu元素与Ni元素分布均匀.结构表征结果证明了催化剂的合金构型,并揭示金属以氧化态的形式存在于催化剂表面,在测试的负电位下被还原为金属态,提升催化活性.电催化测试结果表明Cu_(7)-Ni_(3)/CP催化剂在-0.57 V vs可逆氢电极(RHE)的测试电位下尿素产率达到98.9μg/(h·cm^(2)),尿素法拉第效率为34.1%.[结论]本研究通过构筑合金的策略解决单一金属催化剂导致的选择性或产率较低的问题,制备的Cu_(7)-Ni_(3)/CP催化剂具有相对优异的电催化C—N偶联合成尿素综合性能,为尿素的绿色合成提供了应用前景.
