A zero-speed fin stabilizer system was developed for rolling control of a marine robot.As a robot steering device near the sea surface with low speed,it will have rolling motion due to disturbance from waves.Based on ...A zero-speed fin stabilizer system was developed for rolling control of a marine robot.As a robot steering device near the sea surface with low speed,it will have rolling motion due to disturbance from waves.Based on the working principle of a zero-speed fin stabilizer and a marine robot’s dynamic properties,a roll damping controller was designed with a master-slave structure.It was composed of a sliding mode controller and an output tracking controller that calculates the desired righting moment and drives the zero-speed fin stabilizer.The methods of input-output linearization and model reference were used to realize the tracking control.Simulations were presented to demonstrate the validity of the control law proposed.展开更多
A novel seedling transplanting mechanism with planetary five-bar was developed in order to solve some problems when transplanting seedlings on mulch film,such as a large cave diameter,a low proportion of upright seedl...A novel seedling transplanting mechanism with planetary five-bar was developed in order to solve some problems when transplanting seedlings on mulch film,such as a large cave diameter,a low proportion of upright seedlings,and inconsistent planting depths,which seriously restrict the development of transplanting equipment used in dryland agriculture.The planetary five-bar structure of transplanting mechanism was designed based on analysis of the seedling transplanter on mulch film.The kinematics model of the transplanting mechanism was established and the optimal parameters of the transplanting mechanism were obtained by satisfying the motion trajectory conditions.Subsequently,the virtual prototype of transplanting mechanism was developed,and the simulation of motion trajectory was illustrated.Finally,the physical prototype of the transplanting mechanism was assembled and tested with the high-speed photography.The simulation results indicated that the desired“spindle”trajectory for the duckbill can be obtained,of which the height was 350 mm,and the diameter of the planting cave was 32 mm.The experimental results showed that the diameter of the planting cave was less than 70 mm,the seedling perpendicularity qualification rate reached 96%,the film injury rate was less than 0.5%,and the hanging membrane phenomenon was avoided.Therefore,the proposed transplanting mechanism can meet the requirements for a mulch-film transplanting machine.展开更多
为解决高速铁路旅客服务系统(简称:旅服系统)业务终端设备数量多且统一安全接入管理权限复杂、零信任访问控制手段不足,以及传统软件定义边界(SDP,Software Defined Perimeter)零信任架构在实际应用中存在单点故障等问题,设计一种DSDP(D...为解决高速铁路旅客服务系统(简称:旅服系统)业务终端设备数量多且统一安全接入管理权限复杂、零信任访问控制手段不足,以及传统软件定义边界(SDP,Software Defined Perimeter)零信任架构在实际应用中存在单点故障等问题,设计一种DSDP(Dual-identity SDP)零信任架构,用以改造旅服系统主数据中心(简称:主数据中心)和铁路局集团公司服务器集群架构,保障其代管的车站业务终端设备接入的安全性;提出基于同态加密技术的双重认证流程算法,用以实现DSDP零信任架构下,主数据中心和铁路局集团公司SDP控制模块双向互认功能。实验结果表明:DSDP零信任架构可有效对抗劫持风险;在多用户的情况下,可保障旅服系统响应时间在合理范围内;具有可用性,可为旅服系统终端设备的统一接入与不同权限要求的零信任身份认证提供技术手段。展开更多
基金Supported by the National Natural Science Foundation under Grant No50879012
文摘A zero-speed fin stabilizer system was developed for rolling control of a marine robot.As a robot steering device near the sea surface with low speed,it will have rolling motion due to disturbance from waves.Based on the working principle of a zero-speed fin stabilizer and a marine robot’s dynamic properties,a roll damping controller was designed with a master-slave structure.It was composed of a sliding mode controller and an output tracking controller that calculates the desired righting moment and drives the zero-speed fin stabilizer.The methods of input-output linearization and model reference were used to realize the tracking control.Simulations were presented to demonstrate the validity of the control law proposed.
基金the Open Fund of the State Key Laboratory of Mechanical Transmissions(Grant No.SKLMT-KFKT-201516)the National Natural Science Foundation of China(Grant No.51565048)the Chinese Technology Aid Project in Xinjiang(Grant No.2013AB013)。
文摘A novel seedling transplanting mechanism with planetary five-bar was developed in order to solve some problems when transplanting seedlings on mulch film,such as a large cave diameter,a low proportion of upright seedlings,and inconsistent planting depths,which seriously restrict the development of transplanting equipment used in dryland agriculture.The planetary five-bar structure of transplanting mechanism was designed based on analysis of the seedling transplanter on mulch film.The kinematics model of the transplanting mechanism was established and the optimal parameters of the transplanting mechanism were obtained by satisfying the motion trajectory conditions.Subsequently,the virtual prototype of transplanting mechanism was developed,and the simulation of motion trajectory was illustrated.Finally,the physical prototype of the transplanting mechanism was assembled and tested with the high-speed photography.The simulation results indicated that the desired“spindle”trajectory for the duckbill can be obtained,of which the height was 350 mm,and the diameter of the planting cave was 32 mm.The experimental results showed that the diameter of the planting cave was less than 70 mm,the seedling perpendicularity qualification rate reached 96%,the film injury rate was less than 0.5%,and the hanging membrane phenomenon was avoided.Therefore,the proposed transplanting mechanism can meet the requirements for a mulch-film transplanting machine.
文摘为解决高速铁路旅客服务系统(简称:旅服系统)业务终端设备数量多且统一安全接入管理权限复杂、零信任访问控制手段不足,以及传统软件定义边界(SDP,Software Defined Perimeter)零信任架构在实际应用中存在单点故障等问题,设计一种DSDP(Dual-identity SDP)零信任架构,用以改造旅服系统主数据中心(简称:主数据中心)和铁路局集团公司服务器集群架构,保障其代管的车站业务终端设备接入的安全性;提出基于同态加密技术的双重认证流程算法,用以实现DSDP零信任架构下,主数据中心和铁路局集团公司SDP控制模块双向互认功能。实验结果表明:DSDP零信任架构可有效对抗劫持风险;在多用户的情况下,可保障旅服系统响应时间在合理范围内;具有可用性,可为旅服系统终端设备的统一接入与不同权限要求的零信任身份认证提供技术手段。
