This paper presents a coordinated target localization method for clustered space robot.According to the different measuring capabilities of cluster members,the master-slave coordinated relative navigation strategy for...This paper presents a coordinated target localization method for clustered space robot.According to the different measuring capabilities of cluster members,the master-slave coordinated relative navigation strategy for target localization with respect to slavery space robots is proposed;then the basic mathematical models,including coordinated relative measurement model and cluster centralized dynamics,are established respectively.By employing the linear Kalman flter theorem,the centralized estimator based on truth measurements is developed and analyzed frstly,and with an intention to inhabit the initial uncertainties related to target localization,the globally stabilized estimator is designed through introduction of pseudo measurements.Furthermore,the observability and controllability of stochastic system are also analyzed to qualitatively evaluate the convergence performance of pseudo measurement estimator.Finally,on-orbit target approaching scenario is simulated by using semi-physical simulation system,which is used to verify the convergence performance of proposed estimator.During the simulation,both the known and unknown maneuvering acceleration cases are considered to demonstrate the robustness of coordinated localization strategy.展开更多
Integrated circuit chips are produced on silicon wafers.Robotic cluster tools are widely used since they provide a reconfigurable and efficient environment for most wafer fabrication processes.Recent advances in new s...Integrated circuit chips are produced on silicon wafers.Robotic cluster tools are widely used since they provide a reconfigurable and efficient environment for most wafer fabrication processes.Recent advances in new semiconductor materials bring about new functionality for integrated circuits.After a wafer is processed in a processing chamber,the wafer should be removed from there as fast as possible to guarantee its high-quality integrated circuits.Meanwhile,maximization of the throughput of robotic cluster tools is desired.This work aims to perform post-processing time-aware scheduling for such tools subject to wafer residencytime constraints.To do so,closed-form expression algorithms are derived to compute robot waiting time accurately upon the analysis of particular events of robot waiting for singlearm cluster tools.Examples are given to show the application and effectiveness of the proposed algorithms.展开更多
In the robotic welding process with thick steel plates,laser vision sensors are widely used to profile the weld seam to implement automatic seam tracking.The weld seam profile extraction(WSPE)result is a crucial step ...In the robotic welding process with thick steel plates,laser vision sensors are widely used to profile the weld seam to implement automatic seam tracking.The weld seam profile extraction(WSPE)result is a crucial step for identifying the feature points of the extracted profile to guide the welding torch in real time.The visual information processing system may collapse when interference data points in the image survive during the phase of feature point identification,which results in low tracking accuracy and poor welding quality.This paper presents a visual attention featurebased method to extract the weld seam profile(WSP)from the strong arc background using clustering results.First,a binary image is obtained through the preprocessing stage.Second,all data points with a gray value 255 are clustered with the nearest neighborhood clustering algorithm.Third,a strategy is developed to discern one cluster belonging to the WSP from the appointed candidate clusters in each loop,and a scheme is proposed to extract the entire WSP using visual continuity.Compared with the previous methods the proposed method in this paper can extract more useful details of the WSP and has better stability in terms of removing the interference data.Considerable WSPE tests with butt joints and T-joints show the anti-interference ability of the proposed method,which contributes to smoothing the welding process and shows its practical value in robotic automated welding with thick steel plates.展开更多
基金supported by the National Natural Science Foundation of China (No.11102018)
文摘This paper presents a coordinated target localization method for clustered space robot.According to the different measuring capabilities of cluster members,the master-slave coordinated relative navigation strategy for target localization with respect to slavery space robots is proposed;then the basic mathematical models,including coordinated relative measurement model and cluster centralized dynamics,are established respectively.By employing the linear Kalman flter theorem,the centralized estimator based on truth measurements is developed and analyzed frstly,and with an intention to inhabit the initial uncertainties related to target localization,the globally stabilized estimator is designed through introduction of pseudo measurements.Furthermore,the observability and controllability of stochastic system are also analyzed to qualitatively evaluate the convergence performance of pseudo measurement estimator.Finally,on-orbit target approaching scenario is simulated by using semi-physical simulation system,which is used to verify the convergence performance of proposed estimator.During the simulation,both the known and unknown maneuvering acceleration cases are considered to demonstrate the robustness of coordinated localization strategy.
基金supported in part by the National Natural Science Foundation of China(61673123,61803397,61603100)Science and Technology Development Fund(FDCT)Macao SAR of China(0017/2019/A1,005/2018/A1,011/2017/A)
文摘Integrated circuit chips are produced on silicon wafers.Robotic cluster tools are widely used since they provide a reconfigurable and efficient environment for most wafer fabrication processes.Recent advances in new semiconductor materials bring about new functionality for integrated circuits.After a wafer is processed in a processing chamber,the wafer should be removed from there as fast as possible to guarantee its high-quality integrated circuits.Meanwhile,maximization of the throughput of robotic cluster tools is desired.This work aims to perform post-processing time-aware scheduling for such tools subject to wafer residencytime constraints.To do so,closed-form expression algorithms are derived to compute robot waiting time accurately upon the analysis of particular events of robot waiting for singlearm cluster tools.Examples are given to show the application and effectiveness of the proposed algorithms.
基金Supported by National Natural Science Foundation of China(Grant Nos.51575349,51665037,51575348)State Key Laboratory of Smart Manufacturing for Special Vehicles and Transmission System(Grant No.GZ2016KF002).
文摘In the robotic welding process with thick steel plates,laser vision sensors are widely used to profile the weld seam to implement automatic seam tracking.The weld seam profile extraction(WSPE)result is a crucial step for identifying the feature points of the extracted profile to guide the welding torch in real time.The visual information processing system may collapse when interference data points in the image survive during the phase of feature point identification,which results in low tracking accuracy and poor welding quality.This paper presents a visual attention featurebased method to extract the weld seam profile(WSP)from the strong arc background using clustering results.First,a binary image is obtained through the preprocessing stage.Second,all data points with a gray value 255 are clustered with the nearest neighborhood clustering algorithm.Third,a strategy is developed to discern one cluster belonging to the WSP from the appointed candidate clusters in each loop,and a scheme is proposed to extract the entire WSP using visual continuity.Compared with the previous methods the proposed method in this paper can extract more useful details of the WSP and has better stability in terms of removing the interference data.Considerable WSPE tests with butt joints and T-joints show the anti-interference ability of the proposed method,which contributes to smoothing the welding process and shows its practical value in robotic automated welding with thick steel plates.
