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
Taking advantage of company survey data,this paper examines the responsiveness of enterprises in manufacturing sectors to the recent labor market changes characterized by surging wages and shrinking unskilled workers....Taking advantage of company survey data,this paper examines the responsiveness of enterprises in manufacturing sectors to the recent labor market changes characterized by surging wages and shrinking unskilled workers.The result shows that the labor demand elasticity with regard to output is substantial.In other words,growing manufacturing will keep creating jobs and intensify labor scarcity in China.The wage elasticity is-0.40 for unskilled workers and-0.53 for skilled workers,which indicates that Chinese companies are quite responsive to the recent labor market changes.There exists a kind of substitution effect between skilled and unskilled workers,however,the magnitude of elasticity remains small.To promote economic upgrading in China's labor market,institutional and industrial policies should encourage companies to be responsive to the warning signals from the market of production factor.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.
基金supported by National Science Foundation of China grant 71173234the Asian Development Bankthe Chinese Academy of Social Sciences
文摘Taking advantage of company survey data,this paper examines the responsiveness of enterprises in manufacturing sectors to the recent labor market changes characterized by surging wages and shrinking unskilled workers.The result shows that the labor demand elasticity with regard to output is substantial.In other words,growing manufacturing will keep creating jobs and intensify labor scarcity in China.The wage elasticity is-0.40 for unskilled workers and-0.53 for skilled workers,which indicates that Chinese companies are quite responsive to the recent labor market changes.There exists a kind of substitution effect between skilled and unskilled workers,however,the magnitude of elasticity remains small.To promote economic upgrading in China's labor market,institutional and industrial policies should encourage companies to be responsive to the warning signals from the market of production factor.
