针对已有的算法在基于到达时间差(time difference of arrival,TDOA)测量方案中存在的搜索能力不均衡,导致三维定位区域局部存在定位精度低甚至求解失败的问题,提出了一种基于改进探路者优化算法(pathfinder algorithm,PFA)的TDOA定位算...针对已有的算法在基于到达时间差(time difference of arrival,TDOA)测量方案中存在的搜索能力不均衡,导致三维定位区域局部存在定位精度低甚至求解失败的问题,提出了一种基于改进探路者优化算法(pathfinder algorithm,PFA)的TDOA定位算法,通过将自适应Levy飞行和改进后的PFA算法进行融合,增强了个体对定位区域复杂环境的适应性,解决算法早熟、易陷入局部最优等问题,提升了算法综合性能.通过仿真和实验,结果表明:与Taylor算法、LM算法相比,本文提出的算法(Levy-pathfinder algorithm,LPFA)可以提高定位精度;与PSO算法、PFA算法相比,LPFA算法可以在提高运算速度的同时得到更准确的定位结果.展开更多
雷达寻的导弹在末端寻的工作方式中,其导引头接收到的目标视线与真实目标视线有一误差,此误差的大小与天线罩折射斜率 R 有关,R 的引入增加了弹体角运动之间的耦合,恶化了系统的动态性能,必须予以补偿。本文从另一个侧面将天线罩折射斜...雷达寻的导弹在末端寻的工作方式中,其导引头接收到的目标视线与真实目标视线有一误差,此误差的大小与天线罩折射斜率 R 有关,R 的引入增加了弹体角运动之间的耦合,恶化了系统的动态性能,必须予以补偿。本文从另一个侧面将天线罩折射斜率误差对导弹系统的影响,归结为对一参数时变、不确定性系统的控制问题,利用带遗忘因子的最小二乘辩识法,快速辩识系统参数,采用自适应控制策略,重新构造新的控制律。仿真结果表明对天线罩折射误差有较好的抑制作用。展开更多
The formation maintenance of multiple unmanned aerial vehicles(UAVs)based on proximity behavior is explored in this study.Individual decision-making is conducted according to the expected UAV formation structure and t...The formation maintenance of multiple unmanned aerial vehicles(UAVs)based on proximity behavior is explored in this study.Individual decision-making is conducted according to the expected UAV formation structure and the position,velocity,and attitude information of other UAVs in the azimuth area.This resolves problems wherein nodes are necessarily strongly connected and communication is strictly consistent under the traditional distributed formation control method.An adaptive distributed formation flight strategy is established for multiple UAVs by exploiting proximity behavior observations,which remedies the poor flexibility in distributed formation.This technique ensures consistent position and attitude among UAVs.In the proposed method,the azimuth area relative to the UAV itself is established to capture the state information of proximal UAVs.The dependency degree factor is introduced to state update equation based on proximity behavior.Finally,the formation position,speed,and attitude errors are used to form an adaptive dynamic adjustment strategy.Simulations are conducted to demonstrate the effectiveness and robustness of the theoretical results,thus validating the effectiveness of the proposed method.展开更多
A new general robust fuzzy approach was presented to control the position and the attitude of unmanned flying vehicles(UFVs). Control of these vehicles was challenging due to their nonlinear underactuated behaviors. T...A new general robust fuzzy approach was presented to control the position and the attitude of unmanned flying vehicles(UFVs). Control of these vehicles was challenging due to their nonlinear underactuated behaviors. The proposed control system combined great advantages of generalized indirect adaptive sliding mode control(IASMC) and fuzzy control for the UFVs. An on-line adaptive tuning algorithm based on Lyapunov function and Barbalat lemma was designed, thus the stability of the system can be guaranteed. The chattering phenomenon in the sliding mode control was reduced and the steady error was also alleviated. The numerical results, for an underactuated quadcopter and a high speed underwater vehicle as case studies, indicate that the presented adaptive design of fuzzy sliding mode controller performs robustly in the presence of sensor noise and external disturbances. In addition, online unknown parameter estimation of the UFVs, such as ground effect and planing force especially in the cases with the Gaussian sensor noise with zero mean and standard deviation of 0.5 m and 0.1 rad and external disturbances with amplitude of 0.1 m/s2 and frequency of 0.2 Hz, is one of the advantages of this method. These estimated parameters are then used in the controller to improve the trajectory tracking performance.展开更多
The design of an L_1 adaptive controller for hypersonic formation flight is presented. The traditional leader/wingman formation control problem is considered, with focused attention on dealing with the input disturban...The design of an L_1 adaptive controller for hypersonic formation flight is presented. The traditional leader/wingman formation control problem is considered, with focused attention on dealing with the input disturbance and parametric variations, both of which are intrinsic properties of the system that result in undesired control performance. A proportional-derivative control scheme based on nonlinear dynamic inversion is implemented as the baseline controller, and an L_1 adaptive controller is augmented to the baseline controller to attenuate the effects of input disturbance and parametric variations. Simulation results illustrate the effectiveness of the proposed control scheme.展开更多
The entry-glide guidance strategy for hypersonic vehicles that can satisfy both terminal and path constraints is investigated in this paper.We propose a quasi-equilibrium glide adaptive guidance methodology based on t...The entry-glide guidance strategy for hypersonic vehicles that can satisfy both terminal and path constraints is investigated in this paper.We propose a quasi-equilibrium glide adaptive guidance methodology based on the quasi-equilibrium glide condition(QEGC),which innovatively utilizes the quasi-equilibrium glide phenomenon in lifting entry.With the aid of QEGC,both range and terminal velocity can be predicted analytically with high precision.The path constraints are converted into angle of attack constraints,which has been difficult to realize by using traditional predictive guidance methods.The algorithm is independent of the standard trajectory.All the guidance commands,including the bank angle and the angle of attack,are calculated analytically in real time,which endows the algorithm with sufficient adapbility.The results of a CAV-H vehicle guidance test show that the algorithm leads the vehicle along a quasi-equilibrium glide trajectory satisfying both the terminal and path constraints and has sufficient flexibility for occasional mission changes.Furthermore,the robustness of the guidance algorithm under disturbances is validated through a Monte Carlo simulation.展开更多
文摘雷达寻的导弹在末端寻的工作方式中,其导引头接收到的目标视线与真实目标视线有一误差,此误差的大小与天线罩折射斜率 R 有关,R 的引入增加了弹体角运动之间的耦合,恶化了系统的动态性能,必须予以补偿。本文从另一个侧面将天线罩折射斜率误差对导弹系统的影响,归结为对一参数时变、不确定性系统的控制问题,利用带遗忘因子的最小二乘辩识法,快速辩识系统参数,采用自适应控制策略,重新构造新的控制律。仿真结果表明对天线罩折射误差有较好的抑制作用。
文摘The formation maintenance of multiple unmanned aerial vehicles(UAVs)based on proximity behavior is explored in this study.Individual decision-making is conducted according to the expected UAV formation structure and the position,velocity,and attitude information of other UAVs in the azimuth area.This resolves problems wherein nodes are necessarily strongly connected and communication is strictly consistent under the traditional distributed formation control method.An adaptive distributed formation flight strategy is established for multiple UAVs by exploiting proximity behavior observations,which remedies the poor flexibility in distributed formation.This technique ensures consistent position and attitude among UAVs.In the proposed method,the azimuth area relative to the UAV itself is established to capture the state information of proximal UAVs.The dependency degree factor is introduced to state update equation based on proximity behavior.Finally,the formation position,speed,and attitude errors are used to form an adaptive dynamic adjustment strategy.Simulations are conducted to demonstrate the effectiveness and robustness of the theoretical results,thus validating the effectiveness of the proposed method.
文摘A new general robust fuzzy approach was presented to control the position and the attitude of unmanned flying vehicles(UFVs). Control of these vehicles was challenging due to their nonlinear underactuated behaviors. The proposed control system combined great advantages of generalized indirect adaptive sliding mode control(IASMC) and fuzzy control for the UFVs. An on-line adaptive tuning algorithm based on Lyapunov function and Barbalat lemma was designed, thus the stability of the system can be guaranteed. The chattering phenomenon in the sliding mode control was reduced and the steady error was also alleviated. The numerical results, for an underactuated quadcopter and a high speed underwater vehicle as case studies, indicate that the presented adaptive design of fuzzy sliding mode controller performs robustly in the presence of sensor noise and external disturbances. In addition, online unknown parameter estimation of the UFVs, such as ground effect and planing force especially in the cases with the Gaussian sensor noise with zero mean and standard deviation of 0.5 m and 0.1 rad and external disturbances with amplitude of 0.1 m/s2 and frequency of 0.2 Hz, is one of the advantages of this method. These estimated parameters are then used in the controller to improve the trajectory tracking performance.
文摘The design of an L_1 adaptive controller for hypersonic formation flight is presented. The traditional leader/wingman formation control problem is considered, with focused attention on dealing with the input disturbance and parametric variations, both of which are intrinsic properties of the system that result in undesired control performance. A proportional-derivative control scheme based on nonlinear dynamic inversion is implemented as the baseline controller, and an L_1 adaptive controller is augmented to the baseline controller to attenuate the effects of input disturbance and parametric variations. Simulation results illustrate the effectiveness of the proposed control scheme.
基金supported by the National Natural Science Foundation of China (Grant No. 61104200)
文摘The entry-glide guidance strategy for hypersonic vehicles that can satisfy both terminal and path constraints is investigated in this paper.We propose a quasi-equilibrium glide adaptive guidance methodology based on the quasi-equilibrium glide condition(QEGC),which innovatively utilizes the quasi-equilibrium glide phenomenon in lifting entry.With the aid of QEGC,both range and terminal velocity can be predicted analytically with high precision.The path constraints are converted into angle of attack constraints,which has been difficult to realize by using traditional predictive guidance methods.The algorithm is independent of the standard trajectory.All the guidance commands,including the bank angle and the angle of attack,are calculated analytically in real time,which endows the algorithm with sufficient adapbility.The results of a CAV-H vehicle guidance test show that the algorithm leads the vehicle along a quasi-equilibrium glide trajectory satisfying both the terminal and path constraints and has sufficient flexibility for occasional mission changes.Furthermore,the robustness of the guidance algorithm under disturbances is validated through a Monte Carlo simulation.
