The collision-free straight-line following of an unmanned surface vehicle(USV)moving in a constrained water region subject to stationary and moving obstacles is addressed in this paper.USV systems are normally subject...The collision-free straight-line following of an unmanned surface vehicle(USV)moving in a constrained water region subject to stationary and moving obstacles is addressed in this paper.USV systems are normally subjected to surge velocity constraints,yaw rate constraints,and unknown ocean currents.Herein,a safety-certificated line-of-sight(LOS)guidance method is proposed to achieve a constrained straight-line following task.First,an antidisturbance LOS guidance law is designed based on the LOS guidance scheme and an extended state observer.Furthermore,collision avoidance with waterway boundaries and stationary/moving obstacles is encoded in control barrier functions,utilizing which the safety constraints are transformed into input constraints.Finally,safety-certificated guidance signals are obtained by solving a quadratic programming problem subject to input constraints.Using the proposed safety-certified LOS guidance method,the USV can accomplish a straight-line following task with guaranteed input-to-state safety.Simulation results substantiate the efficacy of the proposed safety-certificated LOS guidance method for the straight-line following of USVs moving in a constrained water region subject to unknown ocean currents.展开更多
随着电力系统的高速发展,其结构日益复杂且运行环境更加多变,而电力电子技术的发展推动了静止同步串联补偿器(static synchronous series compensator,SSSC)的应用以提高电网特性。该文结合SSSC拓扑结构特性,分析了H-SSSC的稳态输出模型...随着电力系统的高速发展,其结构日益复杂且运行环境更加多变,而电力电子技术的发展推动了静止同步串联补偿器(static synchronous series compensator,SSSC)的应用以提高电网特性。该文结合SSSC拓扑结构特性,分析了H-SSSC的稳态输出模型;通过对H-SSSC的运行约束分析推导了相关公式,系统地提出了针对H-SSSC主参数的设计原则,其主要包括滤波器、直流电压、电容和换流器的设计方案;通过对解耦控制方式的分析,提出了基于电容电压不均衡控制策略的3类稳态运行控制方法;通过分析和仿真验证了第3种综合控制策略的优势,为SSSC的工程应用提供参数设计及控制方案理论;最后,通过EMTDC/PSCAD仿真验证了参数选取的合理性和控制策略的准确性。展开更多
以尾叶桉、细叶桉、粗皮桉为材料,采用L16(45)正交设计对SSR-PCR反应体系中的引物浓度、DNA浓度、Mg2+浓度、d NTP浓度和Taq酶含量5种因素的4个水平进行优化实验,确立了适合细叶桉、粗皮桉、尾叶桉SSR-PCR最佳反应体系,最终优化的SSR-PC...以尾叶桉、细叶桉、粗皮桉为材料,采用L16(45)正交设计对SSR-PCR反应体系中的引物浓度、DNA浓度、Mg2+浓度、d NTP浓度和Taq酶含量5种因素的4个水平进行优化实验,确立了适合细叶桉、粗皮桉、尾叶桉SSR-PCR最佳反应体系,最终优化的SSR-PCR反应体系为:0.25μmol/L引物、5 ng模板DNA、3.75 mmol/L Mg2+、0.4 mmol/L d NTP、1.5 U Taq酶、1 m L 10×PCR Buffer,双蒸水补齐10μL;并利用优化的体系从74对SSR引物中筛选出12对多态性较高的引物,12对引物在3种桉树中均能扩增出条带,在尾叶桉、细叶桉、粗皮桉中的多态率分别为100%、92.86%、64.29%,为尾叶桉、细叶桉、粗皮桉的遗传多样性分析、品种鉴定、亲缘关系分析等提供了分子技术基础。展开更多
基金Supported by the National Key R&D Program of China under Grant No.2022ZD0119902the National Natural Science Foundation of China under Grant No.51979020+5 种基金the Top-notch Young Talents Program of China under Grant No.36261402the Dalian High-level Talents Innovation Support Program under Grant No.2022RQ010the Liaoning Revitalization Talents Program under Grant No.XLYC2007188the Natural Science Foundation of Fujian Province under Grant No.2022J01131710the Postdoctoral Research Foundation of China under Grant No.2022M720619in part by the Fundamental Research Funds for the Central Universities 3132023107.
文摘The collision-free straight-line following of an unmanned surface vehicle(USV)moving in a constrained water region subject to stationary and moving obstacles is addressed in this paper.USV systems are normally subjected to surge velocity constraints,yaw rate constraints,and unknown ocean currents.Herein,a safety-certificated line-of-sight(LOS)guidance method is proposed to achieve a constrained straight-line following task.First,an antidisturbance LOS guidance law is designed based on the LOS guidance scheme and an extended state observer.Furthermore,collision avoidance with waterway boundaries and stationary/moving obstacles is encoded in control barrier functions,utilizing which the safety constraints are transformed into input constraints.Finally,safety-certificated guidance signals are obtained by solving a quadratic programming problem subject to input constraints.Using the proposed safety-certified LOS guidance method,the USV can accomplish a straight-line following task with guaranteed input-to-state safety.Simulation results substantiate the efficacy of the proposed safety-certificated LOS guidance method for the straight-line following of USVs moving in a constrained water region subject to unknown ocean currents.
文摘随着电力系统的高速发展,其结构日益复杂且运行环境更加多变,而电力电子技术的发展推动了静止同步串联补偿器(static synchronous series compensator,SSSC)的应用以提高电网特性。该文结合SSSC拓扑结构特性,分析了H-SSSC的稳态输出模型;通过对H-SSSC的运行约束分析推导了相关公式,系统地提出了针对H-SSSC主参数的设计原则,其主要包括滤波器、直流电压、电容和换流器的设计方案;通过对解耦控制方式的分析,提出了基于电容电压不均衡控制策略的3类稳态运行控制方法;通过分析和仿真验证了第3种综合控制策略的优势,为SSSC的工程应用提供参数设计及控制方案理论;最后,通过EMTDC/PSCAD仿真验证了参数选取的合理性和控制策略的准确性。
文摘以尾叶桉、细叶桉、粗皮桉为材料,采用L16(45)正交设计对SSR-PCR反应体系中的引物浓度、DNA浓度、Mg2+浓度、d NTP浓度和Taq酶含量5种因素的4个水平进行优化实验,确立了适合细叶桉、粗皮桉、尾叶桉SSR-PCR最佳反应体系,最终优化的SSR-PCR反应体系为:0.25μmol/L引物、5 ng模板DNA、3.75 mmol/L Mg2+、0.4 mmol/L d NTP、1.5 U Taq酶、1 m L 10×PCR Buffer,双蒸水补齐10μL;并利用优化的体系从74对SSR引物中筛选出12对多态性较高的引物,12对引物在3种桉树中均能扩增出条带,在尾叶桉、细叶桉、粗皮桉中的多态率分别为100%、92.86%、64.29%,为尾叶桉、细叶桉、粗皮桉的遗传多样性分析、品种鉴定、亲缘关系分析等提供了分子技术基础。
