This paper presents a novel method to improve the performance of high-DOF image base visual servoing （IBVS） with an uncalibrated camera. Firstly, analysis and comparison between point-based and moment-based features...This paper presents a novel method to improve the performance of high-DOF image base visual servoing （IBVS） with an uncalibrated camera. Firstly, analysis and comparison between point-based and moment-based features are carried out with respect to a 4-DOF positioning task. Then, an extended interaction matrix （IM） related to the digital image, and a Kalman filter （KF）-based estimation algorithm of the extended IM without calibration and IM model are proposed. Finally, the KF-based algorithm is extended to realize an approximation to decoupled control scheme. Experimental results conducted on an industrial robot show that our proposed methods can provide accurate estimation of IM, and achieve similar performance compared with traditional calibration-based method. Therefore, the proposed methods can be applied to any robot control system in variational environments, and can realize instant operation to planar object with complex and unknown shape at large displacement.展开更多
Hair transplantation surgery is an effective solution for hair loss problems,among which follicle unit extraction(FUE)surgery is more widely used and favored.At present,most hair transplantation surgeries still rely h...Hair transplantation surgery is an effective solution for hair loss problems,among which follicle unit extraction(FUE)surgery is more widely used and favored.At present,most hair transplantation surgeries still rely heavily on manual operation by doctors and very few hair transplantation robots with complex structures have been introduced.This paper proposes a pneumatic hair transplantation mechanism for FUE surgery,equipped with a camera,capable of automatically performing both hair implantation and extraction with airflow.This pneumatic method eliminates the complex needle structure,has the function of temporarily storing the follicles inside the needle,thus facilitating the automation of transferring follicles from extraction to implantation.Then a visual feedback system is proposed to accurately position the follicles during the transplantation.The experimental results show that average distance deviation between the actual and target positions is 0.6128 mm and the average deviation of hair implantation depth is 1.7176 mm,which verify the feasibility of the proposed system.展开更多
This paper addresses a coordinated control problem for Spacecraft Formation Flying(SFF). The distributed followers are required to track and synchronize with the leader spacecraft.By using the feature points in the tw...This paper addresses a coordinated control problem for Spacecraft Formation Flying(SFF). The distributed followers are required to track and synchronize with the leader spacecraft.By using the feature points in the two-dimensional image space, an integrated 6-degree-of-freedom dynamic model is formulated for spacecraft relative motion. Without sophisticated threedimensional reconstruction, image features are directly utilized for the controller design. The proposed image-based controller can drive the follower spacecraft in the desired configuration with respect to the leader when the real-time captured images match their reference counterparts. To improve the precision of the formation configuration, the proposed controller employs a coordinated term to reduce the relative distance errors between followers. The uncertainties in the system dynamics are handled by integrating the adaptive technique into the controller, which increases the robustness of the SFF system. The closed-loop system stability is analyzed using the Lyapunov method and algebraic graph theory. A numerical simulation for a given SFF scenario is performed to evaluate the performance of the controller.展开更多
基金supported by the National Natural Science Foundation of China (No. 60675048)
文摘This paper presents a novel method to improve the performance of high-DOF image base visual servoing （IBVS） with an uncalibrated camera. Firstly, analysis and comparison between point-based and moment-based features are carried out with respect to a 4-DOF positioning task. Then, an extended interaction matrix （IM） related to the digital image, and a Kalman filter （KF）-based estimation algorithm of the extended IM without calibration and IM model are proposed. Finally, the KF-based algorithm is extended to realize an approximation to decoupled control scheme. Experimental results conducted on an industrial robot show that our proposed methods can provide accurate estimation of IM, and achieve similar performance compared with traditional calibration-based method. Therefore, the proposed methods can be applied to any robot control system in variational environments, and can realize instant operation to planar object with complex and unknown shape at large displacement.
基金supported by Special Funds for the Cultivation of Guangdong College Students’Scientific and Technological Innovation(Pdjh2022b0568).
文摘Hair transplantation surgery is an effective solution for hair loss problems,among which follicle unit extraction(FUE)surgery is more widely used and favored.At present,most hair transplantation surgeries still rely heavily on manual operation by doctors and very few hair transplantation robots with complex structures have been introduced.This paper proposes a pneumatic hair transplantation mechanism for FUE surgery,equipped with a camera,capable of automatically performing both hair implantation and extraction with airflow.This pneumatic method eliminates the complex needle structure,has the function of temporarily storing the follicles inside the needle,thus facilitating the automation of transferring follicles from extraction to implantation.Then a visual feedback system is proposed to accurately position the follicles during the transplantation.The experimental results show that average distance deviation between the actual and target positions is 0.6128 mm and the average deviation of hair implantation depth is 1.7176 mm,which verify the feasibility of the proposed system.
文摘This paper addresses a coordinated control problem for Spacecraft Formation Flying(SFF). The distributed followers are required to track and synchronize with the leader spacecraft.By using the feature points in the two-dimensional image space, an integrated 6-degree-of-freedom dynamic model is formulated for spacecraft relative motion. Without sophisticated threedimensional reconstruction, image features are directly utilized for the controller design. The proposed image-based controller can drive the follower spacecraft in the desired configuration with respect to the leader when the real-time captured images match their reference counterparts. To improve the precision of the formation configuration, the proposed controller employs a coordinated term to reduce the relative distance errors between followers. The uncertainties in the system dynamics are handled by integrating the adaptive technique into the controller, which increases the robustness of the SFF system. The closed-loop system stability is analyzed using the Lyapunov method and algebraic graph theory. A numerical simulation for a given SFF scenario is performed to evaluate the performance of the controller.
