A fault tolerant control methodology based adaptive sliding mode(ASM) backstepping is proposed for near space vehicle(NSV) attitude control system under engine faults. The proposed scheme combined adaptive backsteppin...A fault tolerant control methodology based adaptive sliding mode(ASM) backstepping is proposed for near space vehicle(NSV) attitude control system under engine faults. The proposed scheme combined adaptive backstepping with the sliding mode control strategy could guarantee the system’s stability and track desired signals under external disturbances and engine faults. Firstly, attitude mode description and the engine faulty model are given. Secondly, a nominal control law is designed.Thirdly, a sliding mode observer is given later in order to estimate both the information of engine faults and external disturbances. An adaptive sliding mode technology based on the previous nominal control law is developed via updating faulty parameters. Finally,analyze the system’s fault-tolerant performance and reliability through experiment simulation, which verifies the proposed design of fault-tolerant control can tolerate engine faults, as well as the strong robustness for external disturbance.展开更多
A switching disturbance rejection attitude control law is proposed for a near space vehicle(NSV) with variable structure.The multiple flight modes, system uncertainties and disturbances of the NSV are taken into accou...A switching disturbance rejection attitude control law is proposed for a near space vehicle(NSV) with variable structure.The multiple flight modes, system uncertainties and disturbances of the NSV are taken into account based on switched nonlinear systems. Compared with traditional backstepping design methods,the proposed method utilizes the added integrals of attitude angle and angular rate tracking errors to further decrease the tracking errors. Moreover, to reduce the computation complexity, a rapid convergent differentiator is employed to obtain the derivative of the virtual control command. Finally, for disturbance rejection, based on the idea from the extended state observer(ESO), two disturbance observers are designed by using non-smooth functions to estimate the disturbances in the switched nonlinear systems. All signals of the closed-loop system are proven to be uniformly ultimately bounded under the Lyapunov function framework. Simulation results demonstrate the effectiveness of the proposed control scheme.展开更多
The control law design for a near-space hypersonic vehicle(NHV) is highly challenging due to its inherent nonlinearity,plant uncertainties and sensitivity to disturbances.This paper presents a novel functional link ...The control law design for a near-space hypersonic vehicle(NHV) is highly challenging due to its inherent nonlinearity,plant uncertainties and sensitivity to disturbances.This paper presents a novel functional link network(FLN) control method for an NHV with dynamical thrust and parameter uncertainties.The approach devises a new partially-feedback-functional-link-network(PFFLN) adaptive law and combines it with the nonlinear generalized predictive control(NGPC) algorithm.The PFFLN is employed for approximating uncertainties in flight.Its weights are online tuned based on Lyapunov stability theorem for the first time.The learning process does not need any offline training phase.Additionally,a robust controller with an adaptive gain is designed to offset the approximation error.Finally,simulation results show a satisfactory performance for the NHV attitude tracking,and also illustrate the controller's robustness.展开更多
The research status on the development of RBCC engines and corresponding aerospace vehicles around the world was overviewed,and the technical and application characteristics of RBCC technology were summarized.New deve...The research status on the development of RBCC engines and corresponding aerospace vehicles around the world was overviewed,and the technical and application characteristics of RBCC technology were summarized.New development trends of combined cycle engines as well as space transportation were analyzed,and lastly,some suggestions on the development of RBCC and the relative aerospace vehicles were proposed.展开更多
Lane change prediction is critical for crash avoidance but challenging as it requires the understanding of the instantaneous driving environment.With cutting-edge artificial intelligence and sensing technologies,auton...Lane change prediction is critical for crash avoidance but challenging as it requires the understanding of the instantaneous driving environment.With cutting-edge artificial intelligence and sensing technologies,autonomous vehicles(AVs)are expected to have exceptional perception systems to capture instantaneously their driving environments for predicting lane changes.By exploring the Waymo open motion dataset,this study proposes a framework to explore autonomous driving data and investigate lane change behaviors.In the framework,this study develops a Long Short-Term Memory(LSTM)model to predict lane changing behaviors.The concept of Vehicle Operating Space(VOS)is introduced to quantify a vehicle's instantaneous driving environment as an important indicator used to predict vehicle lane changes.To examine the robustness of the model,a series of sensitivity analysis are conducted by varying the feature selection,prediction horizon,and training data balancing ratios.The test results show that including VOS into modeling can speed up the loss decay in the training process and lead to higher accuracy and recall for predicting lane-change behaviors.This study offers an example along with a methodological framework for transportation researchers to use emerging autonomous driving data to investigate driving behaviors and traffic environments.展开更多
针对智能网联车辆(intelligent and connected vehicle,ICV)跟驰建模中基于恒定车头时距的问题,文中在考虑可变车头时距下对期望车头间距做出了新的描述,优化ICV跟驰模型的车头间距模型结构.拟定了车辆跟驰行驶中期望车头时距的一般函...针对智能网联车辆(intelligent and connected vehicle,ICV)跟驰建模中基于恒定车头时距的问题,文中在考虑可变车头时距下对期望车头间距做出了新的描述,优化ICV跟驰模型的车头间距模型结构.拟定了车辆跟驰行驶中期望车头时距的一般函数形式及适用范围,论证了基于所提模型的参数物理含义,理论推导了稳定态与动态两种交通流下的稳定性条件.在以前车为干扰条件下通过MATLAB数值仿真实验对比模型改进前后稳定性.结果表明:新的ICV模型具备比原ICV模型更良好的稳定性,且在0~33.3 m/s速度范围内均保持稳定,同时可以比原ICV模型更有效地抑制不稳定流的传播,更好地描述期望车头间距与车速的非线性关系,更加真实地反映实际交通流跟驰特征.展开更多
基金supported by the National Natural Science Foundation of China(6140321061601228+3 种基金61603191)the Natural Science Foundation of Jiangsu(BK20161021)the Nanjing University of Posts and Telecommunications Science Foundation(NY214173)the Open Program of Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing(3DL201607)
文摘A fault tolerant control methodology based adaptive sliding mode(ASM) backstepping is proposed for near space vehicle(NSV) attitude control system under engine faults. The proposed scheme combined adaptive backstepping with the sliding mode control strategy could guarantee the system’s stability and track desired signals under external disturbances and engine faults. Firstly, attitude mode description and the engine faulty model are given. Secondly, a nominal control law is designed.Thirdly, a sliding mode observer is given later in order to estimate both the information of engine faults and external disturbances. An adaptive sliding mode technology based on the previous nominal control law is developed via updating faulty parameters. Finally,analyze the system’s fault-tolerant performance and reliability through experiment simulation, which verifies the proposed design of fault-tolerant control can tolerate engine faults, as well as the strong robustness for external disturbance.
基金supported by the National Natural Science Foundation of China(61374012)the Aeronautical Science Foundation of China(2016ZA51011)
文摘A switching disturbance rejection attitude control law is proposed for a near space vehicle(NSV) with variable structure.The multiple flight modes, system uncertainties and disturbances of the NSV are taken into account based on switched nonlinear systems. Compared with traditional backstepping design methods,the proposed method utilizes the added integrals of attitude angle and angular rate tracking errors to further decrease the tracking errors. Moreover, to reduce the computation complexity, a rapid convergent differentiator is employed to obtain the derivative of the virtual control command. Finally, for disturbance rejection, based on the idea from the extended state observer(ESO), two disturbance observers are designed by using non-smooth functions to estimate the disturbances in the switched nonlinear systems. All signals of the closed-loop system are proven to be uniformly ultimately bounded under the Lyapunov function framework. Simulation results demonstrate the effectiveness of the proposed control scheme.
基金supported by the National Natural Science Foundation of China (9071602860974106)
文摘The control law design for a near-space hypersonic vehicle(NHV) is highly challenging due to its inherent nonlinearity,plant uncertainties and sensitivity to disturbances.This paper presents a novel functional link network(FLN) control method for an NHV with dynamical thrust and parameter uncertainties.The approach devises a new partially-feedback-functional-link-network(PFFLN) adaptive law and combines it with the nonlinear generalized predictive control(NGPC) algorithm.The PFFLN is employed for approximating uncertainties in flight.Its weights are online tuned based on Lyapunov stability theorem for the first time.The learning process does not need any offline training phase.Additionally,a robust controller with an adaptive gain is designed to offset the approximation error.Finally,simulation results show a satisfactory performance for the NHV attitude tracking,and also illustrate the controller's robustness.
文摘The research status on the development of RBCC engines and corresponding aerospace vehicles around the world was overviewed,and the technical and application characteristics of RBCC technology were summarized.New development trends of combined cycle engines as well as space transportation were analyzed,and lastly,some suggestions on the development of RBCC and the relative aerospace vehicles were proposed.
文摘Lane change prediction is critical for crash avoidance but challenging as it requires the understanding of the instantaneous driving environment.With cutting-edge artificial intelligence and sensing technologies,autonomous vehicles(AVs)are expected to have exceptional perception systems to capture instantaneously their driving environments for predicting lane changes.By exploring the Waymo open motion dataset,this study proposes a framework to explore autonomous driving data and investigate lane change behaviors.In the framework,this study develops a Long Short-Term Memory(LSTM)model to predict lane changing behaviors.The concept of Vehicle Operating Space(VOS)is introduced to quantify a vehicle's instantaneous driving environment as an important indicator used to predict vehicle lane changes.To examine the robustness of the model,a series of sensitivity analysis are conducted by varying the feature selection,prediction horizon,and training data balancing ratios.The test results show that including VOS into modeling can speed up the loss decay in the training process and lead to higher accuracy and recall for predicting lane-change behaviors.This study offers an example along with a methodological framework for transportation researchers to use emerging autonomous driving data to investigate driving behaviors and traffic environments.
文摘针对智能网联车辆(intelligent and connected vehicle,ICV)跟驰建模中基于恒定车头时距的问题,文中在考虑可变车头时距下对期望车头间距做出了新的描述,优化ICV跟驰模型的车头间距模型结构.拟定了车辆跟驰行驶中期望车头时距的一般函数形式及适用范围,论证了基于所提模型的参数物理含义,理论推导了稳定态与动态两种交通流下的稳定性条件.在以前车为干扰条件下通过MATLAB数值仿真实验对比模型改进前后稳定性.结果表明:新的ICV模型具备比原ICV模型更良好的稳定性,且在0~33.3 m/s速度范围内均保持稳定,同时可以比原ICV模型更有效地抑制不稳定流的传播,更好地描述期望车头间距与车速的非线性关系,更加真实地反映实际交通流跟驰特征.