A dynamically positioned vessel, by the International Maritime Organization （IMO） and the certifying class societies （DNV, ABS, LR, etc.）, is defined as a vessel that maintains its position and heading （fixed loc...A dynamically positioned vessel, by the International Maritime Organization （IMO） and the certifying class societies （DNV, ABS, LR, etc.）, is defined as a vessel that maintains its position and heading （fixed location or pre-determined track） exclu- sively by means of active thrusters. The development of control technology promotes the upgrading of dynamic positioning （DP） systems. Today there are two different DP systems solutions available on the market： DP system based on PID regulator and that based on model-based control. Both systems have limited disturbance rejection capability due to their design principle. In this paper, a new DP system solution is proposed based on Active Dis^n＇bance Rejection Control （ADRC） technology. This technology is com- posed of Tracking-Differentiator （TD）, Extended State Observer （ESO） and Nonlinear Feedback Combination. On one hand, both TD and ESO can act as filters and can be used in place of conventional filters; on the other hand, the total disturbance of the system can be estimated and compensated by ESO, which therefore enhances the system＇s disturbance rejection capability. This technology＇s advantages over other methods lie in two aspects： 1） This method itself can not only achieve control objectives but also filter noisy measurements without other specialized filters; 2） This method offers a new useful approach to suppress the ocean disturbance. The simulation results demonstrate the effectiveness of the proposed method.展开更多
To make the detecting robot move on the surface of the finned tubes, a novel combined moving mechanism is developed. The combined moving mechanism is composed of sprocket wheel and drum-like small wheel installed on t...To make the detecting robot move on the surface of the finned tubes, a novel combined moving mechanism is developed. The combined moving mechanism is composed of sprocket wheel and drum-like small wheel installed on the chain. It can make the robot move independently in the direction parallel to the tubes and in the direction perpendicular to the tubes. This paper made a detailed discussion on the composition of the combined moving mechanism, the design method of the conjugate outline curve and the circular-arc outline curve of the drum-like small wheel that meshes with the tubes. The error of the circular-arc outline curve is also analyzed.展开更多
Train control systems ensure the safety of railways. This paper begins with a summary of the typical train control systems in Japan and Europe. Based on this summary, the author then raises the following question rega...Train control systems ensure the safety of railways. This paper begins with a summary of the typical train control systems in Japan and Europe. Based on this summary, the author then raises the following question regarding current train control systems： What approach should be adopted in order to enhance the functionality, safety, and reliability of train control systems and assist in commercial operations on railways？ Next, the author provides a desirable architecture that is likely to assist with the development of new train control systems based on current information and communication technologies. A new unified train control system （UTCS） is proposed that is effective in enhancing the robustness and com- petitiveness of a train control system. The ultimate architecture of the UTCS will be only composed of essential elements such as point machines and level crossing control devices in the field. Finally, a pro- cessing method of the UTCS is discussed.展开更多
基金The support of the National Nature Science Foundation of China(Nos.61074053 and 61374114)the Applied Basic Research Program of Ministry of Transport of China(No.2011-329-225-390)are gratefully acknowledged
文摘A dynamically positioned vessel, by the International Maritime Organization （IMO） and the certifying class societies （DNV, ABS, LR, etc.）, is defined as a vessel that maintains its position and heading （fixed location or pre-determined track） exclu- sively by means of active thrusters. The development of control technology promotes the upgrading of dynamic positioning （DP） systems. Today there are two different DP systems solutions available on the market： DP system based on PID regulator and that based on model-based control. Both systems have limited disturbance rejection capability due to their design principle. In this paper, a new DP system solution is proposed based on Active Dis^n＇bance Rejection Control （ADRC） technology. This technology is com- posed of Tracking-Differentiator （TD）, Extended State Observer （ESO） and Nonlinear Feedback Combination. On one hand, both TD and ESO can act as filters and can be used in place of conventional filters; on the other hand, the total disturbance of the system can be estimated and compensated by ESO, which therefore enhances the system＇s disturbance rejection capability. This technology＇s advantages over other methods lie in two aspects： 1） This method itself can not only achieve control objectives but also filter noisy measurements without other specialized filters; 2） This method offers a new useful approach to suppress the ocean disturbance. The simulation results demonstrate the effectiveness of the proposed method.
文摘To make the detecting robot move on the surface of the finned tubes, a novel combined moving mechanism is developed. The combined moving mechanism is composed of sprocket wheel and drum-like small wheel installed on the chain. It can make the robot move independently in the direction parallel to the tubes and in the direction perpendicular to the tubes. This paper made a detailed discussion on the composition of the combined moving mechanism, the design method of the conjugate outline curve and the circular-arc outline curve of the drum-like small wheel that meshes with the tubes. The error of the circular-arc outline curve is also analyzed.
文摘Train control systems ensure the safety of railways. This paper begins with a summary of the typical train control systems in Japan and Europe. Based on this summary, the author then raises the following question regarding current train control systems： What approach should be adopted in order to enhance the functionality, safety, and reliability of train control systems and assist in commercial operations on railways？ Next, the author provides a desirable architecture that is likely to assist with the development of new train control systems based on current information and communication technologies. A new unified train control system （UTCS） is proposed that is effective in enhancing the robustness and com- petitiveness of a train control system. The ultimate architecture of the UTCS will be only composed of essential elements such as point machines and level crossing control devices in the field. Finally, a pro- cessing method of the UTCS is discussed.
