With the development of mobile technologies,mobile learning has become a trend and a necessary means in the e-learning environment.E-learners' autonomous learning processes can also be facilitated through the adop...With the development of mobile technologies,mobile learning has become a trend and a necessary means in the e-learning environment.E-learners' autonomous learning processes can also be facilitated through the adoption of various mobile learning tools.Mobile learning tools can be classified into different types according to their different features and functions.Mobile learning devices,mobile learning software,mobile learning resources,and mobile learning services are the four types of learning tools suggested in the paper.Different mobile learning tools are proven to be able to fulfill different needs of autonomous learning.展开更多
In order to solve the existing problems of current metal cutting equipment,combined with the development situation of metal cutting industry in China,on this basis,a design can realize multi-shaped metal cutting machi...In order to solve the existing problems of current metal cutting equipment,combined with the development situation of metal cutting industry in China,on this basis,a design can realize multi-shaped metal cutting machine tool. Introduces the working principle of the machine tool,the structure and parameters of the main component,and the establishment of the model by using the 3D modeling software Pro / Engineer( Pro / E);through listing the advantages of the mobile machine,shown that the metal machine tool has the structural characteristics of mobile,semi automated,can improve the cutting precision,increase cutting efficiency,and the utility market has certain value. It has guiding significance for the further study and the potential applications of the mobile cutting machine tool.展开更多
The manufacture and maintenance of large parts in ships,trains,aircrafts,and so on create an increasing demand for mobile machine tools to perform in-situ operations.However,few mobile robots can accommodate the compl...The manufacture and maintenance of large parts in ships,trains,aircrafts,and so on create an increasing demand for mobile machine tools to perform in-situ operations.However,few mobile robots can accommodate the complex environment of industrial plants while performing machining tasks.This study proposes a novel six-legged walking machine tool consisting of a legged mobile robot and a portable parallel kinematic machine tool.The kinematic model of the entire system is presented,and the workspace of different components,including a leg,the body,and the head,is analyzed.A hierarchical motion planning scheme is proposed to take advantage of the large workspace of the legged mobile platform and the high precision of the parallel machine tool.The repeatability of the head motion,body motion,and walking distance is evaluated through experiments,which is 0.11,1.0,and 3.4 mm,respectively.Finally,an application scenario is shown in which the walking machine tool steps successfully over a 250 mmhigh obstacle and drills a hole in an aluminum plate.The experiments prove the rationality of the hierarchical motion planning scheme and demonstrate the extensive potential of the walking machine tool for in-situ operations on large parts.展开更多
基金Beijing Higher Education Young Elite Teacher Project,China(No.YETP0471)
文摘With the development of mobile technologies,mobile learning has become a trend and a necessary means in the e-learning environment.E-learners' autonomous learning processes can also be facilitated through the adoption of various mobile learning tools.Mobile learning tools can be classified into different types according to their different features and functions.Mobile learning devices,mobile learning software,mobile learning resources,and mobile learning services are the four types of learning tools suggested in the paper.Different mobile learning tools are proven to be able to fulfill different needs of autonomous learning.
文摘In order to solve the existing problems of current metal cutting equipment,combined with the development situation of metal cutting industry in China,on this basis,a design can realize multi-shaped metal cutting machine tool. Introduces the working principle of the machine tool,the structure and parameters of the main component,and the establishment of the model by using the 3D modeling software Pro / Engineer( Pro / E);through listing the advantages of the mobile machine,shown that the metal machine tool has the structural characteristics of mobile,semi automated,can improve the cutting precision,increase cutting efficiency,and the utility market has certain value. It has guiding significance for the further study and the potential applications of the mobile cutting machine tool.
基金Funded by the National Natural Science Foundation of China(Grant No.U1613208)the National Key Research and Development Plan of China(Grant No.2017YFE0112200)the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement No.734575.
文摘The manufacture and maintenance of large parts in ships,trains,aircrafts,and so on create an increasing demand for mobile machine tools to perform in-situ operations.However,few mobile robots can accommodate the complex environment of industrial plants while performing machining tasks.This study proposes a novel six-legged walking machine tool consisting of a legged mobile robot and a portable parallel kinematic machine tool.The kinematic model of the entire system is presented,and the workspace of different components,including a leg,the body,and the head,is analyzed.A hierarchical motion planning scheme is proposed to take advantage of the large workspace of the legged mobile platform and the high precision of the parallel machine tool.The repeatability of the head motion,body motion,and walking distance is evaluated through experiments,which is 0.11,1.0,and 3.4 mm,respectively.Finally,an application scenario is shown in which the walking machine tool steps successfully over a 250 mmhigh obstacle and drills a hole in an aluminum plate.The experiments prove the rationality of the hierarchical motion planning scheme and demonstrate the extensive potential of the walking machine tool for in-situ operations on large parts.