The paper is devoted to the elastostatic calibration of industrial robots, which is used for precise machining of large-dimensional parts made of composite materials. In this technological process, the interaction bet...The paper is devoted to the elastostatic calibration of industrial robots, which is used for precise machining of large-dimensional parts made of composite materials. In this technological process, the interaction between the robot and the workpiece causes essential elastic deflections of the manipulator components that should be compensated by the robot controller using relevant elastostatic model of this mechanism. To estimate parameters of this model, an advanced calibration technique is applied that is based on the non-linear experiment design theory, which is adopted for this particular application. In contrast to previous works, it is proposed a concept of the user-defined test-pose, which is used to evaluate the calibration experiments quality. In the frame of this concept, the related optimization problem is defined and numerical routines are developed, which allow generating optimal set of manipulator configurations and corresponding forces/torques for a given number of the calibration experiments. Some specific kinematic constraints are also taken into account, which insure feasibility of calibration experiments for the obtained configurations and allow avoiding collision between the robotic manipulator and the measurement equipment. The efficiency of the developed technique is illustrated by an application example that deals with elastostatic calibration of the serial manipulator used for robot-based machining.展开更多
Since the late 1990s, the study on cooperative learning has been an educational fad in linguistic circle. The previous studies have shown that cooperative learning is a good method of learning. However, very few Chine...Since the late 1990s, the study on cooperative learning has been an educational fad in linguistic circle. The previous studies have shown that cooperative learning is a good method of learning. However, very few Chinese English teachers have really or commonly tried to apply the theory of cooperative learning in English reading class. On the basis of reading some related literatures, the author combine his teaching experience and the reality of the teaching subjects to put forward the following questions：l） Whether cooperative learning helps improve students＇ reading achievements？ 2） Whether cooperative learning can inspire students＇ motivation in learning English？ 3） Whether cooperative learning can improve students＇ English reading ability？ The results of the study show that cooperative learning used in the English reading class can not only stimulate students＇ learning interests, boost the students＇ motivation, but also raise their English language proficiency and reading ability.展开更多
文摘The paper is devoted to the elastostatic calibration of industrial robots, which is used for precise machining of large-dimensional parts made of composite materials. In this technological process, the interaction between the robot and the workpiece causes essential elastic deflections of the manipulator components that should be compensated by the robot controller using relevant elastostatic model of this mechanism. To estimate parameters of this model, an advanced calibration technique is applied that is based on the non-linear experiment design theory, which is adopted for this particular application. In contrast to previous works, it is proposed a concept of the user-defined test-pose, which is used to evaluate the calibration experiments quality. In the frame of this concept, the related optimization problem is defined and numerical routines are developed, which allow generating optimal set of manipulator configurations and corresponding forces/torques for a given number of the calibration experiments. Some specific kinematic constraints are also taken into account, which insure feasibility of calibration experiments for the obtained configurations and allow avoiding collision between the robotic manipulator and the measurement equipment. The efficiency of the developed technique is illustrated by an application example that deals with elastostatic calibration of the serial manipulator used for robot-based machining.
文摘Since the late 1990s, the study on cooperative learning has been an educational fad in linguistic circle. The previous studies have shown that cooperative learning is a good method of learning. However, very few Chinese English teachers have really or commonly tried to apply the theory of cooperative learning in English reading class. On the basis of reading some related literatures, the author combine his teaching experience and the reality of the teaching subjects to put forward the following questions：l） Whether cooperative learning helps improve students＇ reading achievements？ 2） Whether cooperative learning can inspire students＇ motivation in learning English？ 3） Whether cooperative learning can improve students＇ English reading ability？ The results of the study show that cooperative learning used in the English reading class can not only stimulate students＇ learning interests, boost the students＇ motivation, but also raise their English language proficiency and reading ability.
