Designing a stable and robust flight control system for an Unmanned Aerial Vehicle(UAV)is an arduous task.This paper addresses the trajectory tracking control problem of a Ducted Fan UAV(DFUAV)using offset-free Model ...Designing a stable and robust flight control system for an Unmanned Aerial Vehicle(UAV)is an arduous task.This paper addresses the trajectory tracking control problem of a Ducted Fan UAV(DFUAV)using offset-free Model Predictive Control(MPC)technique in the presence of various uncertainties and external disturbances.The designed strategy aims to ensure adequate flight robustness and stability while overcoming the effects of time delays,parametric uncertainties,and disturbances.The six degrees of freedom DFUAV model is divided into three flight modes based on its airspeed,namely the hover,transition,and cruise mode.The Dryden wind turbulence is applied to the DFUAV in the linear and angular velocity component.Moreover,different uncertainties such as parametric,time delays in state and input,are introduced in translational and rotational components.From the previous work,the Linear Quadratic Tracker with Integrator(LQTI)is used for comparison to corroborate the performance of the designed controller.Simulations are computed to investigate the control performance for the aforementioned modes and different flight phases including the autonomous flight to validate the performance of the designed strategy.Finally,discussions are provided to demonstrate the effectiveness of the given methodology.展开更多
A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass measurements at the next-ge...A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China.Characterized by low energy loss and good performances of timing and position measurements,it would be located at focal planes in fragment separator HFRS for position monitoring,beam turning,Bq measurement,and trajectory reconstruction.Moreover,it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(BqDETOF)method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis.Most importantly,the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci,and position measurements at a dispersive focus of HFRS,thus making it possible to use two complementary mass measurement methods[isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(BqTOF)at the beam-line HFRS]in one single experimental run.展开更多
无人机的自主飞行是无人机相关研究的重点方向,如何在复杂环境中快速分析环境,并规划一条安全可行的路径,是该方向的研究目标。针对传统路径搜索算法存在的路径不平滑问题,采用三阶B样条曲线进行预规划航迹。在欧式有符号距离函数(Eucli...无人机的自主飞行是无人机相关研究的重点方向,如何在复杂环境中快速分析环境,并规划一条安全可行的路径,是该方向的研究目标。针对传统路径搜索算法存在的路径不平滑问题,采用三阶B样条曲线进行预规划航迹。在欧式有符号距离函数(Euclidean Signed Distance Functions, ESDF)地图提供的梯度信息的基础上,分别在平滑、碰撞和可行性上设计约束方程,实现轨迹动态重规划。针对路径动态更新中,时间间隔变化产生的控制点不再符合约束的问题,采用各向异性曲线拟合方法,实现时间再分配,保障在动态更新路径的过程中,新产生的路径与原路径相似且具有同样的可行性。实验证明,该算法实现了无人机的自主路径规划与优化,能够进行动态避障,面对复杂环境具有鲁棒性。展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.61225015,61105092,61422102,and 61703040)the Beijing Natural Science Foundation,China(No.4161001)the China Postdoctoral Science Foundation(No.2017M620640)。
文摘Designing a stable and robust flight control system for an Unmanned Aerial Vehicle(UAV)is an arduous task.This paper addresses the trajectory tracking control problem of a Ducted Fan UAV(DFUAV)using offset-free Model Predictive Control(MPC)technique in the presence of various uncertainties and external disturbances.The designed strategy aims to ensure adequate flight robustness and stability while overcoming the effects of time delays,parametric uncertainties,and disturbances.The six degrees of freedom DFUAV model is divided into three flight modes based on its airspeed,namely the hover,transition,and cruise mode.The Dryden wind turbulence is applied to the DFUAV in the linear and angular velocity component.Moreover,different uncertainties such as parametric,time delays in state and input,are introduced in translational and rotational components.From the previous work,the Linear Quadratic Tracker with Integrator(LQTI)is used for comparison to corroborate the performance of the designed controller.Simulations are computed to investigate the control performance for the aforementioned modes and different flight phases including the autonomous flight to validate the performance of the designed strategy.Finally,discussions are provided to demonstrate the effectiveness of the given methodology.
基金supported by the National Natural Science Foundation of China(Nos.11605248,11605249,11605267,and 11805032.)
文摘A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China.Characterized by low energy loss and good performances of timing and position measurements,it would be located at focal planes in fragment separator HFRS for position monitoring,beam turning,Bq measurement,and trajectory reconstruction.Moreover,it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(BqDETOF)method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis.Most importantly,the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci,and position measurements at a dispersive focus of HFRS,thus making it possible to use two complementary mass measurement methods[isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(BqTOF)at the beam-line HFRS]in one single experimental run.
文摘无人机的自主飞行是无人机相关研究的重点方向,如何在复杂环境中快速分析环境,并规划一条安全可行的路径,是该方向的研究目标。针对传统路径搜索算法存在的路径不平滑问题,采用三阶B样条曲线进行预规划航迹。在欧式有符号距离函数(Euclidean Signed Distance Functions, ESDF)地图提供的梯度信息的基础上,分别在平滑、碰撞和可行性上设计约束方程,实现轨迹动态重规划。针对路径动态更新中,时间间隔变化产生的控制点不再符合约束的问题,采用各向异性曲线拟合方法,实现时间再分配,保障在动态更新路径的过程中,新产生的路径与原路径相似且具有同样的可行性。实验证明,该算法实现了无人机的自主路径规划与优化,能够进行动态避障,面对复杂环境具有鲁棒性。
