Seven-degree-of-freedom redundant manipulators with link offset have many advantages,including obvious geometric significance and suitability for configuration control.Their configuration is similar to that of the exp...Seven-degree-of-freedom redundant manipulators with link offset have many advantages,including obvious geometric significance and suitability for configuration control.Their configuration is similar to that of the experimental module manipulator(EMM)in the Chinese Space Station Remote Manipulator System.However,finding the analytical solution of an EMM on the basis of arm angle parameterization is difficult.This study proposes a high-precision,semi-analytical inverse method for EMMs.Firstly,the analytical inverse kinematic solution is established based on joint angle parameterization.Secondly,the analytical inverse kinematic solution for a non-offset spherical-roll-spherical(SRS)redundant manipulator is derived based on arm angle parameterization.The approximate solution of the EMM is calculated in accordance with the relationship between the joint angles of the EMM and the SRS manipulator.Thirdly,the error is corrected using a numerical method through the analytical inverse solution based on joint angle parameterization.After selecting the stride and termination condition,the precise inverse solution is computed for the EMM based on arm angle parameterization.Lastly,case solutions confirm that this method has high precision,and the arm angle parameterization method is superior to the joint angle parameterization method in terms of parameter selection.展开更多
An analytic inverse kinematic solution is presented for a 7-DOF(degree of freedom)redundant space manipulator.The proposed method can obtain all the feasible solutions in the global joint space,which are denoted by a ...An analytic inverse kinematic solution is presented for a 7-DOF(degree of freedom)redundant space manipulator.The proposed method can obtain all the feasible solutions in the global joint space,which are denoted by a joint angle parameter.Meanwhile,both the singularity problem and the joint limits are considered in detail.Besides,an optimization approach is provided to get one near optimal inverse kinematic solution from all the feasible solutions.The proposed method can reduce effectively the computational complexity,so that it can be applied online.Finally,the method’s validity is shown by kinematic simulations.展开更多
DOF(DNA binding with one finger)转录因子是植物特有的转录因子家族,含有一个独特的富含Cys残基的单锌指DNA结合区域,在植物生长发育中参与多种生物学过程。本研究根据拟南芥AtDof1.7基因(GenBank登录号为AT1G51700)序列设计含有不同...DOF(DNA binding with one finger)转录因子是植物特有的转录因子家族,含有一个独特的富含Cys残基的单锌指DNA结合区域,在植物生长发育中参与多种生物学过程。本研究根据拟南芥AtDof1.7基因(GenBank登录号为AT1G51700)序列设计含有不同酶切位点的特异性扩增引物,以拟南芥总DNA为模板,扩增AtDof1.7基因片段,将AtDof1.7基因正向反向分别插入表达载体的相应位置,构建成AtDof1.7基因的RNA干扰载体pADOF1。利用改良的floral-dip方法将干扰载体pADOF1成功转入野生型拟南芥,经草甘膦抗性筛选和PCR检测获得5株阳性转基因植株。利用RT-PCR技术和气相色谱法分别分析了AtDof1.7基因的表达和种子脂肪酸组成,结果表明,5株转基因植株中AtDof1.7基因的表达量不同程度低于野生型植株,种子油酸含量明显上升,亚麻酸含量明显下降,说明AtDof1.7转录因子与拟南芥种子脂肪酸代谢途径有一定的关系,为进一步研究其在脂肪酸代谢过程中的调控作用以及在油菜中研究该类转录因子的功能奠定了基础。展开更多
基金This work was supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.51521003)the Major Research Plan of National Natural Science Foundation of China(Grant No.91848202).
文摘Seven-degree-of-freedom redundant manipulators with link offset have many advantages,including obvious geometric significance and suitability for configuration control.Their configuration is similar to that of the experimental module manipulator(EMM)in the Chinese Space Station Remote Manipulator System.However,finding the analytical solution of an EMM on the basis of arm angle parameterization is difficult.This study proposes a high-precision,semi-analytical inverse method for EMMs.Firstly,the analytical inverse kinematic solution is established based on joint angle parameterization.Secondly,the analytical inverse kinematic solution for a non-offset spherical-roll-spherical(SRS)redundant manipulator is derived based on arm angle parameterization.The approximate solution of the EMM is calculated in accordance with the relationship between the joint angles of the EMM and the SRS manipulator.Thirdly,the error is corrected using a numerical method through the analytical inverse solution based on joint angle parameterization.After selecting the stride and termination condition,the precise inverse solution is computed for the EMM based on arm angle parameterization.Lastly,case solutions confirm that this method has high precision,and the arm angle parameterization method is superior to the joint angle parameterization method in terms of parameter selection.
基金the National 863 Program of China(2012AA041403)the National Natural Science Foundation of China(61305107)
文摘An analytic inverse kinematic solution is presented for a 7-DOF(degree of freedom)redundant space manipulator.The proposed method can obtain all the feasible solutions in the global joint space,which are denoted by a joint angle parameter.Meanwhile,both the singularity problem and the joint limits are considered in detail.Besides,an optimization approach is provided to get one near optimal inverse kinematic solution from all the feasible solutions.The proposed method can reduce effectively the computational complexity,so that it can be applied online.Finally,the method’s validity is shown by kinematic simulations.
文摘DOF(DNA binding with one finger)转录因子是植物特有的转录因子家族,含有一个独特的富含Cys残基的单锌指DNA结合区域,在植物生长发育中参与多种生物学过程。本研究根据拟南芥AtDof1.7基因(GenBank登录号为AT1G51700)序列设计含有不同酶切位点的特异性扩增引物,以拟南芥总DNA为模板,扩增AtDof1.7基因片段,将AtDof1.7基因正向反向分别插入表达载体的相应位置,构建成AtDof1.7基因的RNA干扰载体pADOF1。利用改良的floral-dip方法将干扰载体pADOF1成功转入野生型拟南芥,经草甘膦抗性筛选和PCR检测获得5株阳性转基因植株。利用RT-PCR技术和气相色谱法分别分析了AtDof1.7基因的表达和种子脂肪酸组成,结果表明,5株转基因植株中AtDof1.7基因的表达量不同程度低于野生型植株,种子油酸含量明显上升,亚麻酸含量明显下降,说明AtDof1.7转录因子与拟南芥种子脂肪酸代谢途径有一定的关系,为进一步研究其在脂肪酸代谢过程中的调控作用以及在油菜中研究该类转录因子的功能奠定了基础。
