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In this article, we pay attention to develop an event-triggered adaptive neural network (ANN) control strategy for stochastic nonlinear systems with state constraints and time-varying delays. The state constraints are disposed by relying on the barrier Lyapunov function. The neural networks are exploited to identify the unknown dynamics. In addition, the Lyapunov-Krasovskii functional is employed to counteract the adverse effect originating from time-varying delays. The backstepping technique is employed to design controller by combining event-triggered mechanism (ETM), which can alleviate data transmission and save communication resource. The constructed ANN control scheme can guarantee the stability of the considered systems, and the predefined constraints are not violated. Simulation results and comparison are given to validate the feasibility of the presented scheme.
Yongchao Liu; Qidan Zhu. Event-Triggered Adaptive Neural Network Control for Stochastic Nonlinear Systems With State Constraints and Time-Varying Delays. IEEE Transactions on Neural Networks and Learning Systems 2021, PP, 1 -13.
AMA StyleYongchao Liu, Qidan Zhu. Event-Triggered Adaptive Neural Network Control for Stochastic Nonlinear Systems With State Constraints and Time-Varying Delays. IEEE Transactions on Neural Networks and Learning Systems. 2021; PP (99):1-13.
Chicago/Turabian StyleYongchao Liu; Qidan Zhu. 2021. "Event-Triggered Adaptive Neural Network Control for Stochastic Nonlinear Systems With State Constraints and Time-Varying Delays." IEEE Transactions on Neural Networks and Learning Systems PP, no. 99: 1-13.
This article presents an adaptive fuzzy finite-time control (AFFTC) method for nonstrict-feedback nonlinear systems (NFNSs) with unknown dynamics. With the aid of the backstepping technique, by establishing the smooth switch function (SSF), a novel C¹ AFFTC strategy is recursively constructed, which counteracts the effect of nonstrict-feedback structure and unknown dynamics. Different from the reporting finite-time control achievements, the singularity hindrance derived from the differentiating virtual control law is availably surmounted. Moreover, the developed AFFTC strategy can drive the tracking error to converge into a small neighborhood of the origin in a finite time. Simulation results are conducted to substantiate the efficacy of theoretical findings.
Yongchao Liu; Qidan Zhu. Adaptive Fuzzy Finite-Time Control for Nonstrict-Feedback Nonlinear Systems. IEEE Transactions on Cybernetics 2021, PP, 1 -10.
AMA StyleYongchao Liu, Qidan Zhu. Adaptive Fuzzy Finite-Time Control for Nonstrict-Feedback Nonlinear Systems. IEEE Transactions on Cybernetics. 2021; PP (99):1-10.
Chicago/Turabian StyleYongchao Liu; Qidan Zhu. 2021. "Adaptive Fuzzy Finite-Time Control for Nonstrict-Feedback Nonlinear Systems." IEEE Transactions on Cybernetics PP, no. 99: 1-10.
The launch bar is a unique device of carrier-based aircraft, which is connected to the nose gear and shuttle. In order to avoid the launch bar striking the flight deck after the launch bar pops out of the shuttle, it is very important to research the dynamics performance of the launch bar. This paper establishes a staged mathematical model of catapult launch including the launch bar, a steam-powered catapult, a holdback bar, and a carrier-based aircraft. This article studied the effect of the mass of the launch bar, restoring moment of the launch bar, and center of gravity position of the launch bar on the dynamics performance of the launch bar. The results showed the following: (1) we could reduce the risk collision of the launch bar and deck by reducing the mass of the launch bar, increasing the restoring moment, and shifting the center of gravity position of the launch bar; (2) under the working condition of this article, we changed the center of gravity position of the launch bar to control the sink of the launch bar end, having the most obvious effect, and we reduced the mass of the launch bar, having the least effect on controlling the sink of the launch bar end; however, reducing the mass of the launch bar could also greatly reduce the risk collision of the launch bar and deck; (3) in order to avoid the launch bar striking the flight deck, the restoring moment of the launch bar must overcome the sum of other moments. The study results can give a theoretical reference for designing and testing the launch bars of carrier-based aircraft. It can also give a theoretical reference for designing and testing the launch bar’s driving mechanisms.
Qidan Zhu; Peng Lu; Zhibo Yang; Xun Ji; Yu Han; Lipeng Wang; Zhu; Lu; Yang; Ji; Han; Wang. Launch Bar Dynamics Character Analysis of Carrier-Based Aircraft Catapult Launch. Applied Sciences 2019, 9, 3079 .
AMA StyleQidan Zhu, Peng Lu, Zhibo Yang, Xun Ji, Yu Han, Lipeng Wang, Zhu, Lu, Yang, Ji, Han, Wang. Launch Bar Dynamics Character Analysis of Carrier-Based Aircraft Catapult Launch. Applied Sciences. 2019; 9 (15):3079.
Chicago/Turabian StyleQidan Zhu; Peng Lu; Zhibo Yang; Xun Ji; Yu Han; Lipeng Wang; Zhu; Lu; Yang; Ji; Han; Wang. 2019. "Launch Bar Dynamics Character Analysis of Carrier-Based Aircraft Catapult Launch." Applied Sciences 9, no. 15: 3079.
This paper presents an improved active disturbances rejecter control (ADRC) for path following control of autonomous underwater vehicles under significant fast-varying disturbances caused by waves and sea currents. Two significant and efficient improvements are introduced to the traditional ADRC in order to accomplish this task. First, a generalized ESO (GESO) and Harmonic ESO (HESO) were designed to achieve a high disturbances estimation quality. Secondly, two AUV path following controllers based on ADRC-GESO and ADRC-HESO were designed to ensure a high performance tracking in presence of periodic-type disturbances. Finally, numerical simulations were performed and the obtained results showed very significant enhancements of robustness and tracking accuracy by the proposed methods compared to conventional ADRC.
Habib Choukri Lamraoui; Zhu Qidan. Path following control of fully-actuated autonomous underwater vehicle in presence of fast-varying disturbances. Applied Ocean Research 2019, 86, 40 -46.
AMA StyleHabib Choukri Lamraoui, Zhu Qidan. Path following control of fully-actuated autonomous underwater vehicle in presence of fast-varying disturbances. Applied Ocean Research. 2019; 86 ():40-46.
Chicago/Turabian StyleHabib Choukri Lamraoui; Zhu Qidan. 2019. "Path following control of fully-actuated autonomous underwater vehicle in presence of fast-varying disturbances." Applied Ocean Research 86, no. : 40-46.
Selecting the optimal parameters for wet steam accumulator of steam-powered catapult is an important task, due to launching safety. There is no literature on the topic of the parameters optimization for wet steam accumulator of steam-powered catapult. The genetic algorithm (GA) was used to determine the optimal wet steam accumulator in this article. The sink-off-the-bow (SOB), angle of attack and rate of climb were used to create the objective function. The multi-objective optimization can be converted to single-objective optimization, which is subject to angle of attack and rate of climb. Moreover, the simulation model of the steam catapult system was built by creating a thermodynamics model of steam-powered catapult, a mathematical model of traction release device, a statics model of tensioning, a statics model of full takeoff power, a mathematical model of catapult force build-up with holdback, a model of release, a dynamics model of power stroke, a dynamics model of free deck run and a dynamics model of fly away. Finally, the optimal combination of the wet steam accumulator was obtained via numerical simulation. The GA method can effectively find the optimal parameters of wet steam accumulator, and its optimized parameters can increase the safety of catapult launch process.
Qidan Zhu; Peng Lu; Zhibo Yang; Xun Ji; Yu Han. Multi-Parameter Optimization for the Wet Steam Accumulator of a Steam-Powered Catapult. Energies 2019, 12, 234 .
AMA StyleQidan Zhu, Peng Lu, Zhibo Yang, Xun Ji, Yu Han. Multi-Parameter Optimization for the Wet Steam Accumulator of a Steam-Powered Catapult. Energies. 2019; 12 (2):234.
Chicago/Turabian StyleQidan Zhu; Peng Lu; Zhibo Yang; Xun Ji; Yu Han. 2019. "Multi-Parameter Optimization for the Wet Steam Accumulator of a Steam-Powered Catapult." Energies 12, no. 2: 234.
This paper presents an active disturbances rejecter controller (ADRC) for position and path following control of a fully actuated autonomous underwater vehicle (AUV). The unmodeled, undesirable dynamics and disturbances reduce the performances of classical controllers and complicate the design of appropriate and efficient controllers. In the proposed approach, the different modeling complexities; such as uncertain parameters, non-linearities, and external disturbances are considered all as a part of disturbance which is estimated in real-time by the extended state observer ESO, and effectively compensated from the control law. The ESO is also able to estimate the position and velocity of the system in real-time, in case where the full state measurement of the AUV is not possible during experiments. Computer simulations demonstrate the high ability of the AUV tracking control based on ADRC, to follow the desired trajectory in the horizontal plane and space with high precision, and showed high robustness and efficiency in rejecting the external and internal disturbances caused by significant changes in parameters of the system, and the added position disturbances.
Habib Choukri Lamraoui; Lamraoui Zhu Qidan. Path Following Control of Fully Actuated Autonomous Underwater Vehicle Based on LADRC. Polish Maritime Research 2018, 25, 39 -48.
AMA StyleHabib Choukri Lamraoui, Lamraoui Zhu Qidan. Path Following Control of Fully Actuated Autonomous Underwater Vehicle Based on LADRC. Polish Maritime Research. 2018; 25 (4):39-48.
Chicago/Turabian StyleHabib Choukri Lamraoui; Lamraoui Zhu Qidan. 2018. "Path Following Control of Fully Actuated Autonomous Underwater Vehicle Based on LADRC." Polish Maritime Research 25, no. 4: 39-48.
We present a liquid-level measurement system based on second-confirm recognition algorithm. Compared with the traditional methods of the liquid-level measurement system, which has low accuracy, slow measurement speed, and limited range of measurements, this system can accurately and quickly measure the liquid level. Moreover, it can automatically complete the measurement of the liquid-level line position. The main component of the system includes a vision detection system and a tracking control system. The vision detection system mainly includes image preprocessing, numeral recognition, and liquid-level line recognition. Among the vision detection system, numeral recognition is the key task. Therefore, we propose a numeral recognition algorithm that employs a second-confirm algorithm to recognize numerals. The algorithm first utilizes template matching to find one numeral from the image. Afterward, we can divide the numeral image out of the rule image. This can greatly optimize the issues of time-consumption. The numerals can be segmented from the numeral image when the numeral image is obtained. After the numerals are captured, the numerals and template image difference is computed to complete numeral recognition. In addition, tracking control system tracks the liquid line in real time through the level value feedback by the vision system, which calculates the position of the liquid level in the image and feeds back the level value to the tracking control system. After experimental verification, the system can meet the expected requirements of liquid-level measurement.
Chengtao Cai; Haiyang Meng; Renjie Qiao; Qidan Zhu. Liquid-level measurement system based on second-confirm recognition algorithm. Journal of Electronic Imaging 2018, 27, 063009 .
AMA StyleChengtao Cai, Haiyang Meng, Renjie Qiao, Qidan Zhu. Liquid-level measurement system based on second-confirm recognition algorithm. Journal of Electronic Imaging. 2018; 27 (6):063009.
Chicago/Turabian StyleChengtao Cai; Haiyang Meng; Renjie Qiao; Qidan Zhu. 2018. "Liquid-level measurement system based on second-confirm recognition algorithm." Journal of Electronic Imaging 27, no. 6: 063009.
Infrared images acquired by forward-looking infrared camera have a limited field of view that is insufficient to monitor the entire scene with a single frame. To generate images containing the entire scene, infrared images can be assembled using image stitching. However, direct application of traditional image stitching methods has the disadvantage of long delays, large amounts of computation, and high memory storage. We present a real-time stitching method for infrared images. First, modified normalized cross correlation is introduced to find the overlapping area. Therefore, feature detection only needs to operate in overlapping areas. Also, scale-invariant feature transform is modified according to the properties of the infrared image. In addition, we implement the proposed method on an embedded system that is low cost, portable, and highly real-time. Our experimental results show the proposed method has almost the same quality of panorama compared with state-of-the-art methods, but the computation time is reduced significantly.
Chengtao Cai; Bing Fan; Qidan Zhu. Real-time stitching method for infrared image. Optical Engineering 2018, 57, 113103 .
AMA StyleChengtao Cai, Bing Fan, Qidan Zhu. Real-time stitching method for infrared image. Optical Engineering. 2018; 57 (11):113103.
Chicago/Turabian StyleChengtao Cai; Bing Fan; Qidan Zhu. 2018. "Real-time stitching method for infrared image." Optical Engineering 57, no. 11: 113103.
This paper denotes to obtain an accuracy blur kernel and a shape image. An efficient method that blind deconvolution for image deblurring based on edge enhancement and noise suppression is proposed. First, we exploited an edge detection method to extract the strong edge portion of blurred image. Then, the blurred image was divided into weak edge portion and strong edge portion. At this time, we apply a trilateral filter method to suppress the noise in the weak edge portion. Through mathematical operations for weak edge portion and strong edge portion, we can obtain the new blurred image which as the input of blur kernel estimation. At the phase of the kernel estimation, the problem can be solved via alternate between $x$ and $k$ updating. In addition, we utilize improved fast iterative shrinkage thresholding algorithm method to solve the optimization problem. Finally, non-blind deconvolution was employed at the phase of image recovery. A comprehensive evaluation shows that our approach achieves state-of-the-art results for uniformly blurred images.
Chengtao Cai; Haiyang Meng; Qidan Zhu. Blind Deconvolution for Image Deblurring Based on Edge Enhancement and Noise Suppression. IEEE Access 2018, 6, 58710 -58718.
AMA StyleChengtao Cai, Haiyang Meng, Qidan Zhu. Blind Deconvolution for Image Deblurring Based on Edge Enhancement and Noise Suppression. IEEE Access. 2018; 6 ():58710-58718.
Chicago/Turabian StyleChengtao Cai; Haiyang Meng; Qidan Zhu. 2018. "Blind Deconvolution for Image Deblurring Based on Edge Enhancement and Noise Suppression." IEEE Access 6, no. : 58710-58718.
By combining the advantages of 360-degree field of view cameras and the high resolution of conventional cameras, the hybrid stereo vision system could be widely used in surveillance. As the relative position of the two cameras is not constant over time, its automatic rectification is highly desirable when adopting a hybrid stereo vision system for practical use. In this work, we provide a method for rectifying the dynamic hybrid stereo vision system automatically. A perspective projection model is proposed to reduce the computation complexity of the hybrid stereoscopic 3D reconstruction. The rectification transformation is calculated by solving a nonlinear constrained optimization problem for a given set of corresponding point pairs. The experimental results demonstrate the accuracy and effectiveness of the proposed method.
Chengtao Cai; Bing Fan; Xin Liang; Qidan Zhu. Automatic Rectification of the Hybrid Stereo Vision System. Sensors 2018, 18, 3355 .
AMA StyleChengtao Cai, Bing Fan, Xin Liang, Qidan Zhu. Automatic Rectification of the Hybrid Stereo Vision System. Sensors. 2018; 18 (10):3355.
Chicago/Turabian StyleChengtao Cai; Bing Fan; Xin Liang; Qidan Zhu. 2018. "Automatic Rectification of the Hybrid Stereo Vision System." Sensors 18, no. 10: 3355.
In this paper, we present an optimized landmark distribution method for mobile robot visual homing technology. To satisfy the equal distance assumption for feature-based homing algorithms, the proposed method eliminates the low-quality features according to the image pixel distance difference and the scale information. Finally, a near-ideal distribution of the landmarks can be obtained. We take the feature-based average landmark vector (ALV) algorithm as the example, and prove the effectiveness of the proposed method by the experiments.
Xun Ji; Qidan Zhu. Optimized Landmark Distribution for Mobile Robot Visual Homing. IOP Conference Series: Materials Science and Engineering 2018, 428, 012056 .
AMA StyleXun Ji, Qidan Zhu. Optimized Landmark Distribution for Mobile Robot Visual Homing. IOP Conference Series: Materials Science and Engineering. 2018; 428 (1):012056.
Chicago/Turabian StyleXun Ji; Qidan Zhu. 2018. "Optimized Landmark Distribution for Mobile Robot Visual Homing." IOP Conference Series: Materials Science and Engineering 428, no. 1: 012056.
Visual homing is an attractive autonomous mobile robot navigation technique, which only uses vision sensors to guide the robot to the specified target location. Landmark is the only input form of the visual homing approaches, which is usually represented by scale-invariant features. However, the landmark distribution has a great impact on the homing performance of the robot, as irregularly distributed landmarks will significantly reduce the navigation precision. In this paper, we propose three strategies to solve this problem. We use scale-invariant feature transform (SIFT) features as natural landmarks, and the proposed strategies can optimize the landmark distribution without over-eliminating landmarks or increasing calculation amount. Experiments on both panoramic image databases and a real mobile robot have verified the effectiveness and feasibility of the proposed strategies.
Xun Ji; Qidan Zhu; Junda Ma; Peng Lu; Tianhao Yan. Three Landmark Optimization Strategies for Mobile Robot Visual Homing. Sensors 2018, 18, 3180 .
AMA StyleXun Ji, Qidan Zhu, Junda Ma, Peng Lu, Tianhao Yan. Three Landmark Optimization Strategies for Mobile Robot Visual Homing. Sensors. 2018; 18 (10):3180.
Chicago/Turabian StyleXun Ji; Qidan Zhu; Junda Ma; Peng Lu; Tianhao Yan. 2018. "Three Landmark Optimization Strategies for Mobile Robot Visual Homing." Sensors 18, no. 10: 3180.
This paper presents a novel navigation strategy of robot to achieve reaching target and obstacle avoidance in unknown dynamic environment. Considering possible generation of uncertainty, disturbances brought to system are separated into two parts, i.e., bounded part and unbounded part. A dual-layer closed-loop control system is then designed to deal with two kinds of disturbances, respectively. In order to realize global optimization of navigation, recurrent fuzzy neural network is used to predict optimal motion of robot for its ability of processing nonlinearity and learning. Extended Kalman filter method is used to train RFNN online. Moving horizon technique is used for RFNN motion planner to guarantee optimization in dynamic environment. Then, model predictive control is designed against bounded disturbances to drive robot to track predicted trajectories and limit robot’s position in a tube with good robustness. A novel iterative online learning method is also proposed to estimate intrinsic error of system using online data that makes system adaptive. Feasibility and stability of proposed method are analyzed. By examining our navigation method on mobile robot, effectiveness is proved in both simulation and hardware experiments. Robustness and optimization of proposed navigation method can be guaranteed in dynamic environment.
Qidan Zhu; Yu Han; Chengtao Cai; Yao Xiao. Robust Optimal Navigation Using Nonlinear Model Predictive Control Method Combined with Recurrent Fuzzy Neural Network. Mathematical Problems in Engineering 2018, 2018, 1 -19.
AMA StyleQidan Zhu, Yu Han, Chengtao Cai, Yao Xiao. Robust Optimal Navigation Using Nonlinear Model Predictive Control Method Combined with Recurrent Fuzzy Neural Network. Mathematical Problems in Engineering. 2018; 2018 ():1-19.
Chicago/Turabian StyleQidan Zhu; Yu Han; Chengtao Cai; Yao Xiao. 2018. "Robust Optimal Navigation Using Nonlinear Model Predictive Control Method Combined with Recurrent Fuzzy Neural Network." Mathematical Problems in Engineering 2018, no. : 1-19.
Learning variable impedance control is a powerful method to improve the performance of force control. However, current methods typically require too many interactions to achieve good performance. Data-inefficiency has limited these methods to learn force-sensitive tasks in real systems. In order to improve the sampling efficiency and decrease the required interactions during the learning process, this paper develops a data-efficient learning variable impedance control method that enables the industrial robots automatically learn to control the contact force in the unstructured environment. To this end, a Gaussian process model is learned as a faithful proxy of the system, which is then used to predict long-term state evolution for internal simulation, allowing for efficient strategy updates. The effects of model bias are reduced effectively by incorporating model uncertainty into long-term planning. Then the impedance profiles are regulated online according to the learned humanlike impedance strategy. In this way, the flexibility and adaptivity of the system could be enhanced. Both simulated and experimental tests have been performed on an industrial manipulator to verify the performance of the proposed method.
Chao Li; Zhi Zhang; Guihua Xia; Xinru Xie; Qidan Zhu. Efficient Force Control Learning System for Industrial Robots Based on Variable Impedance Control. Sensors 2018, 18, 2539 .
AMA StyleChao Li, Zhi Zhang, Guihua Xia, Xinru Xie, Qidan Zhu. Efficient Force Control Learning System for Industrial Robots Based on Variable Impedance Control. Sensors. 2018; 18 (8):2539.
Chicago/Turabian StyleChao Li; Zhi Zhang; Guihua Xia; Xinru Xie; Qidan Zhu. 2018. "Efficient Force Control Learning System for Industrial Robots Based on Variable Impedance Control." Sensors 18, no. 8: 2539.
Qidan Zhu; Peng Lu; Zhibo Yang; Yujia Cui. Model Research of Steam Catapult Launch Process for Carrier-based Aircraft. 2018 37th Chinese Control Conference (CCC) 2018, 1 .
AMA StyleQidan Zhu, Peng Lu, Zhibo Yang, Yujia Cui. Model Research of Steam Catapult Launch Process for Carrier-based Aircraft. 2018 37th Chinese Control Conference (CCC). 2018; ():1.
Chicago/Turabian StyleQidan Zhu; Peng Lu; Zhibo Yang; Yujia Cui. 2018. "Model Research of Steam Catapult Launch Process for Carrier-based Aircraft." 2018 37th Chinese Control Conference (CCC) , no. : 1.
This study presents a solution to the problem of containment control of multiple fully actuated autonomous surface vehicles subject to environmental disturbances. Using finite-time stability theory, a nonlinear disturbance observer is constructed to provide an estimation of unknown disturbances online. By employing nonlinear disturbance observer to compensate disturbances, a robust containment controller is constructed by combining backstepping technique and dynamic surface control technique. It is proved that the proposed containment control scheme can force all the followers to move into the convex hull spanned by the leaders and guarantee that all the signals in the closed-loop system are globally uniformly ultimately bounded. Finally, four simulation examples are provided to demonstrate the effectiveness of the containment controller and its robustness to external disturbances.
Qidan Zhu; Junda Ma; Zhilin Liu; Ke Liu. Containment control of autonomous surface vehicles: A nonlinear disturbance observer–based dynamic surface control design. Advances in Mechanical Engineering 2017, 9, 1 .
AMA StyleQidan Zhu, Junda Ma, Zhilin Liu, Ke Liu. Containment control of autonomous surface vehicles: A nonlinear disturbance observer–based dynamic surface control design. Advances in Mechanical Engineering. 2017; 9 (10):1.
Chicago/Turabian StyleQidan Zhu; Junda Ma; Zhilin Liu; Ke Liu. 2017. "Containment control of autonomous surface vehicles: A nonlinear disturbance observer–based dynamic surface control design." Advances in Mechanical Engineering 9, no. 10: 1.
. Omnidirectional vision with the advantage of a large field-of-view overcomes the problem that a target is easily lost due to the narrow sight of perspective vision. We improve a target-tracking algorithm based on discriminative tracking features in several aspects and propose a target-tracking algorithm for an omnidirectional vision system. (1) An elliptical target window expression model is presented to represent the target’s outline, which can adapt to the deformation of an object and reduce background interference. (2) The background-weighted linear RGB histogram target feature is introduced, which decreases the weight of the background feature. (3) The Bhattacharyya coefficients-based feature identification method is employed, which reduces the computation time of the tracking algorithm. (4) An adaptive target scale and orientation measurement method is applied to adapt to severe deformations of the target’s outline. (5) A model update strategy is put forward, which is based on similarity measurements to achieve an effective and accurate model update. The experimental results show the proposed algorithm can achieve better performance than the state-of-the-art algorithms when using omnidirectional vision to perform long-term target-tracking tasks.
Chengtao Cai; Xiangyu Weng; Bing Fan; Qidan Zhu. Target-tracking algorithm for omnidirectional vision. Journal of Electronic Imaging 2017, 26, 33014 .
AMA StyleChengtao Cai, Xiangyu Weng, Bing Fan, Qidan Zhu. Target-tracking algorithm for omnidirectional vision. Journal of Electronic Imaging. 2017; 26 (3):33014.
Chicago/Turabian StyleChengtao Cai; Xiangyu Weng; Bing Fan; Qidan Zhu. 2017. "Target-tracking algorithm for omnidirectional vision." Journal of Electronic Imaging 26, no. 3: 33014.
An implementable robust containment control algorithm is proposed for a group of underactuated ships in the presence of hydrodynamic parameter uncertainties and external disturbances. The control objective is to drive all the followers into the convex hull spanned by the virtual leaders, whose state information is available only to a subset of the followers. For this purpose, the ship model is primarily transformed to a strict-feedback form. In the kinematic design, a virtual containment controller, requiring the state information from its neighbors, is presented based on the results obtained from graph theory. In the dynamic design, a robust containment controller is developed through utilizing upper-to-up sliding mode control. In addition, in order to simplify the implementations of the control law, the command filtered backstepping (CFBP) method is introduced to prevent the analytic differentiations of the virtual law from each design step of the backstepping (BP) method. Subsequently, it is well proven that all the tracking errors could converge to and remain small neighborhoods of the equilibrium point. Finally, several simulation experiments are conducted to demonstrate the performance of the proposed control algorithm.
Qidan Zhu; Junda Ma; Zhilin Liu; Ke Liu. Containment Control of Underactuated Ships with Environment Disturbances and Parameter Uncertainties. Mathematical Problems in Engineering 2017, 2017, 1 -19.
AMA StyleQidan Zhu, Junda Ma, Zhilin Liu, Ke Liu. Containment Control of Underactuated Ships with Environment Disturbances and Parameter Uncertainties. Mathematical Problems in Engineering. 2017; 2017 ():1-19.
Chicago/Turabian StyleQidan Zhu; Junda Ma; Zhilin Liu; Ke Liu. 2017. "Containment Control of Underactuated Ships with Environment Disturbances and Parameter Uncertainties." Mathematical Problems in Engineering 2017, no. : 1-19.
This paper is concerned with consensus problem of a class of second-order multi-agent systems subjecting to external disturbance generated from some unknown exosystems. In comparison with the case where the disturbance is generated from some known exosystems, we need to combine adaptive control and internal model design to deal with the external disturbance generated from the unknown exosystems. With the help of the internal model, an adaptive protocol is proposed for the consensus problem of the multi-agent systems. Finally, one numerical example is provided to demonstrate the effectiveness of the control design.
Xuxi Zhang; Qidan Zhu; Xianping Liu. Consensus of Second Order Multi-Agent Systems with Exogenous Disturbance Generated by Unknown Exosystems. Entropy 2016, 18, 423 .
AMA StyleXuxi Zhang, Qidan Zhu, Xianping Liu. Consensus of Second Order Multi-Agent Systems with Exogenous Disturbance Generated by Unknown Exosystems. Entropy. 2016; 18 (12):423.
Chicago/Turabian StyleXuxi Zhang; Qidan Zhu; Xianping Liu. 2016. "Consensus of Second Order Multi-Agent Systems with Exogenous Disturbance Generated by Unknown Exosystems." Entropy 18, no. 12: 423.
Warping is an effective visual homing method for robot local navigation. However, the performance of the warping method can be greatly influenced by the changes of the environment in a real scene, thus resulting in lower accuracy. In order to solve the above problem and to get higher homing precision, a novel robot visual homing algorithm is proposed by combining SIFT (scale-invariant feature transform) features with the warping method. The algorithm is novel in using SIFT features as landmarks instead of the pixels in the horizon region of the panoramic image. In addition, to further improve the matching accuracy of landmarks in the homing algorithm, a novel mismatching elimination algorithm, based on the distribution characteristics of landmarks in the catadioptric panoramic image, is proposed. Experiments on image databases and on a real scene confirm the effectiveness of the proposed method.
Qidan Zhu; Chuanjia Liu; Chengtao Cai. A Novel Robot Visual Homing Method Based on SIFT Features. Sensors 2015, 15, 26063 -26084.
AMA StyleQidan Zhu, Chuanjia Liu, Chengtao Cai. A Novel Robot Visual Homing Method Based on SIFT Features. Sensors. 2015; 15 (10):26063-26084.
Chicago/Turabian StyleQidan Zhu; Chuanjia Liu; Chengtao Cai. 2015. "A Novel Robot Visual Homing Method Based on SIFT Features." Sensors 15, no. 10: 26063-26084.