This study aims to investigate the problem of attitude control for a spacecraft with inertial uncertainties, external disturbances, and communication restrictions. An event-triggered active disturbance rejection contr...
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This study aims to investigate the problem of attitude control for a spacecraft with inertial uncertainties, external disturbances, and communication restrictions. An event-triggered active disturbance rejection control approach is proposed for attitude tracking of the spacecraft. An event-triggered mechanism is introduced together with an extended state observer to jointly monitor the systemstates and total disturbances. The observation error is proved to be uniformly bounded. Based on the proposed control scheme,the integrated tracking system is shown to be asymptotically stable, implying successful attitude tracking of the spacecraft for the desired motion. Numerical results illustrate the effectiveness of the control strategy in achieving satisfactory tracking performance with a reduced data-transmission cost.
In this work,an event-triggered adaptive robust controller(ET-ARC) design is considered for a continuous-time nonlinear system combined with structural uncertainties and parameter *** the event-trigger scheme,the co...
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ISBN:
(纸本)9781538629185
In this work,an event-triggered adaptive robust controller(ET-ARC) design is considered for a continuous-time nonlinear system combined with structural uncertainties and parameter *** the event-trigger scheme,the controller only can obtain the sampled date of the output measurement at some certain instants determined by the designed triggering condition and therefore the performance of the ET-ARC depends on the triggering condition ***,in this work,for the adaptive robust control scheme,an event-triggered transmission strategy is proposed,which relies on the output measurement of the nonlinear ***,based on this strategy,the design idea of the adaptive robust controller is presented such that the tracking performance is ***,based on a more general assumption,we provide a possible formation of control signal which satisfies the requirement proposed.
Template matching is one of the most important techniques in computer vision,where the algorithm should find the location of template image in scene *** commonly used method of template matching is Normalized Cross Co...
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ISBN:
(纸本)9781509046584
Template matching is one of the most important techniques in computer vision,where the algorithm should find the location of template image in scene *** commonly used method of template matching is Normalized Cross Correlation which has a high matching accuracy while consuming a large amount of computational *** this paper,a novel,fast and robust template matching approach is *** new algorithm randomly visits the pixels and locates local maxima by gradually moving to the regions with larger NCC *** further improve the speed and accuracy of the algorithm,several additional rules are *** analysis and experimental results show that the proposed algorithm maintain a high matching accuracy while providing a significant speedup.
The computation of stereo depth is a very important field of computer vision. Aiming at solving the problem of low accuracy of traditional Census-based stereo matching algorithm, a variable support-weight approach for...
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ISBN:
(纸本)9781467321969
The computation of stereo depth is a very important field of computer vision. Aiming at solving the problem of low accuracy of traditional Census-based stereo matching algorithm, a variable support-weight approach for visual correspondence search based on modified Census transform is proposed in this paper. On the basis of analyzing defects of the traditional Census transform, a modified Census transform algorithm using average value of minimum evenness sub-area as a reference instead of the center pixel intensity as a reference is raised which enhances robustness of the algorithm. The matching accuracy is improved by weighting the average value and the standard deviation of Hamming distances in a block. The experiment results indicate that the proposed approach works better than traditional ones. Accurate disparities can be obtained even in the depth discontinuities regions.
A robust recursive least-squares(RLS) adaptive filter against impulsive noise is proposed for the situation of an unknown desired *** minimizing a saturable nonlinear constrained unsupervised cost function instead of ...
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A robust recursive least-squares(RLS) adaptive filter against impulsive noise is proposed for the situation of an unknown desired *** minimizing a saturable nonlinear constrained unsupervised cost function instead of the conventional least-squares function,a possible impulse-corrupted signal is prevented from entering the filter’s weight updating ***,a multi-step adaptive filter is devised to reconstruct the observed "impulse-free" noisy sequence,and whenever impulsive noise is detected,the impulse contaminated samples are replaced by predictive *** on simulation and experimental results,the proposed unsupervised robust recursive least-square adaptive filter performs as well as conventional RLS filters in "impulse-free" circumstances,and is effective in restricting large disturbances such as impulsive noise when the RLS and the more recent unsupervised adaptive filter fails.
Odometry is a very popular research direction in recent decades and plays a very critical role in the autonomous navigation ***02,as a relatively robust and mature visual odometry algorithm,becomes unreliable when dis...
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ISBN:
(纸本)9781538629185
Odometry is a very popular research direction in recent decades and plays a very critical role in the autonomous navigation ***02,as a relatively robust and mature visual odometry algorithm,becomes unreliable when distinct visual features are insufficiently or when the texture of the environment is *** if not in such a challenging environment,the drift is still a big problem for the practical ***,a lidar odometry algorithm,has been leading the way for the performance on KITTI data *** fact,it also has limitations in shape features not prominent environment,like a highway with few buildings *** that the current mobile unmanned platforms(e.g.,unmanned vehicles) are almost equipped with both lidar and cameras,this paper proposes a loose coupling visual-lidar odometry by combining VIS02 and LOAM to achieve the advantages of both camera and lidar and reduce the number of restricted *** algorithm proposed in this paper is tested on the raw data set of *** average translation error is about 1.37% on 10 sequences,and the accuracy is improved with respect to LOAM with the same *** the help of VIS02,the algorithm also performs well in shape features not prominent environment(e.g.,highway),and from the experiment results,we confirmed the efficient strategy to combine VIS02 and LOAM to adapt to challenging environment and to keep the accuracy of the algorithm.
Obstacle information detection is a prerequisite for safety and stability driving of unmanned platforms in the unknown *** detection of the obstacle using the 3D laser radar(3D LADAR) and camera is proposed in this **...
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ISBN:
(纸本)9781538629185
Obstacle information detection is a prerequisite for safety and stability driving of unmanned platforms in the unknown *** detection of the obstacle using the 3D laser radar(3D LADAR) and camera is proposed in this ***,joint calibration between 3D LADAR and camera based on the planar feature method is ***,laser point cloud is clustered to identify the number of obstacles,and then detected image is divided into the corresponding small regions according to the number of ***,we use the image processing technology to detect the obstacle *** experiments in the real world are implemented to show that the proposed approach can effectively detect the size of the obstacles.
作者:
ZENG JieDOU LihuaXIN BinSchool of Automation
State Key Laboratory of Intelligent Control and Decision of Complex SystemsBeijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Technology
This paper proposes a solution for the problem of cooperative salvo attack of multiple cruise missiles against targets in a group. Synchronization of the arrival time of missiles to hit their common target, minimizing...
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This paper proposes a solution for the problem of cooperative salvo attack of multiple cruise missiles against targets in a group. Synchronization of the arrival time of missiles to hit their common target, minimizing the time consumption of attack and maximizing the expected damage to group targets are taken into consideration simultaneously. These operational objectives result in a hierarchical mixed-variable optimization problem which includes two types of subproblems, namely the multi-objective missile-target assignment(MOMTA) problem at the upper level and the time-optimal coordinated path planning(TOCPP) problems at the lower level. In order to solve the challenging problem, a recently proposed coordinated path planning method is employed to solve the TOCPP problems to achieve the soonest salvo attack against each target. With the aim of finding a more competent solver for MOMTA, three state-of-the-art multi-objective optimization methods(MOMs),namely NSGA-II, MOEA/D and DMOEA-εC, are adopted. Finally, a typical example is used to demonstrate the advantage of the proposed method. A simple rule-based method is also employed for comparison. Comparative results show that DMOEA-εC is the best choice among the three MOMs for solving the MOMTA problem. The combination of DMOEA-εC for MOMTA and the coordinated path planning method for TOCPP can generate obviously better salvo attack schemes than the rule-based method.
This paper addresses the position tracking control problem of electric linear actuator in the presence of nonlinearities due to its transmission process.A torque decoupling approach for electric linear actuator is pro...
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ISBN:
(纸本)9789881563835
This paper addresses the position tracking control problem of electric linear actuator in the presence of nonlinearities due to its transmission process.A torque decoupling approach for electric linear actuator is proposed to achieve respective *** improve the speed of time varying parameters estimating,a load-based adaption law is proposed by designing a new projection mapping which has both variable bounds and good robust *** adaptive robust controller is designed such that it combines decoupled torque and dead-zone compensation to preserve robustness to both parametric and nonparametric *** modified LuGre model is used for friction compensation making a continuous transition from static model. A Lyapunov stability analysis demonstrates that all signals including tracking errors have guaranteed convergent and bounded *** co-simulation results show the effectiveness and the achievable control performance of the proposed control strategy with sinusoidal and point-to-point tracking experiments.
A new method based on adaptive Hessian matrix threshold of finding key SRUF ( speeded up robust features) features is proposed and is applied to an unmanned vehicle for its dynamic object recognition and guided navi...
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A new method based on adaptive Hessian matrix threshold of finding key SRUF ( speeded up robust features) features is proposed and is applied to an unmanned vehicle for its dynamic object recognition and guided navigation. First, the object recognition algorithm based on SURF feature matching for unmanned vehicle guided navigation is introduced. Then, the standard local invariant feature extraction algorithm SRUF is analyzed, the Hessian Metrix is especially discussed, and a method of adaptive Hessian threshold is proposed which is based on correct matching point pairs threshold feedback under a close loop frame. At last, different dynamic object recognition experi- ments under different weather light conditions are discussed. The experimental result shows that the key SURF feature abstract algorithm and the dynamic object recognition method can be used for un- manned vehicle systems.
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