This paper investigates the fractional-order active disturbance rejection control for the synchronization of two different fractional-order chaotic systems. By the fractional-order extended state observers, the nonlin...
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This paper investigates the fractional-order active disturbance rejection control for the synchronization of two different fractional-order chaotic systems. By the fractional-order extended state observers, the nonlinear dynamics in the synchronization error equations for each subsystems are estimated in real time. Compensating the nonlinear estimations into controllers, the active disturbance rejection controllers are designed to achieve the synchronization. Finally, two examples of synchronization issues on different fractional-order chaotic systems are provided to verify that the fractional-order ADRC is irrelevant with the nonlinear dynamics in the fractional-order chaotic systems. The proposed controllers can achieve the synchronization and estimate the nonlinear dynamics effectively for different fractional-order chaotic systems.
In this paper,an effective approach to vehicle license plate recognition based on Extremal Regions(ERs) and Self-adaptive Evolutionary Extreme Learning Machine(Sa EELM) is *** the license plate detection step,some com...
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In this paper,an effective approach to vehicle license plate recognition based on Extremal Regions(ERs) and Self-adaptive Evolutionary Extreme Learning Machine(Sa EELM) is *** the license plate detection step,some computations including morphological operations,various filters,different contours and validations are sequentially performed to extract some image regions as candidate license ***,accurate character segmentation is achieved through a proper selection of *** the character recognition step,the HOG(histogram of oriented gradients) feature vector in each character region is extracted,and then the characters are recognized using an offline trained pattern classifier of Sa *** results show that our approach works quite well in complex traffic environments.
This paper proposes an approach to moving vehicle tracking in surveillance videos based on conditional random fields(CRF).The key idea is to integrate a variety of relevant knowledge about vehicle tracking into a unif...
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This paper proposes an approach to moving vehicle tracking in surveillance videos based on conditional random fields(CRF).The key idea is to integrate a variety of relevant knowledge about vehicle tracking into a uniform probabilistic framework by using the CRF *** this work,the CRF model integrates spatial and temporal contextual information of vehicle motion,and the appearance information of the *** approximate inference algorithm,loopy belief propagation,is used to recursively estimate the vehicle region from the history of observed ***,the background model is updated adaptively to cope with non-stationary background *** results show that the proposed approach is able to accurately track moving vehicles in monocular image ***,region-level tracking realizes precise localization of vehicles.
Both disturbance rejection and human-like motions, like toe-off and heel-strike, are important for a biped robot to enhance its performance. However, the required motions for them may influence each other, which is wh...
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ISBN:
(纸本)9781479971756
Both disturbance rejection and human-like motions, like toe-off and heel-strike, are important for a biped robot to enhance its performance. However, the required motions for them may influence each other, which is why few studies consider them simultaneously. This paper presents a method to realize stable walking with toe-off and heel-strike even when the robot experiences disturbances. We propose a walking controller which can constrain the desired ground reaction force. On the one hand, the controller can adjust the torso acceleration to make the supporting leg compliant with the external disturbances on the torso. On the other hand, it can rotate the supporting foot by adjusting the ZMP to an appropriate location. The linear inverted pendulum is utilized to generate the CoM trajectory and the foot placement. Meanwhile, its ZMP can be predefined as required so that the toe-off and heel-strike can be achieved by the controller. The effectiveness of the proposed method is demonstrated by simulations.
Stable walking of bipedal humanoid is an crucial and challenge issue of research in bipedal robots. And the structure of shoe sole plays a significant role in preventing someone from slipping in human life. The humano...
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ISBN:
(纸本)9781479973989
Stable walking of bipedal humanoid is an crucial and challenge issue of research in bipedal robots. And the structure of shoe sole plays a significant role in preventing someone from slipping in human life. The humanoid robot foot often skid while the robot is walking fast, and it may cause serious harmfulness. This study presents some foot pads for humanoid robot to improve its stability and reliability. First, anti-skid foot for a humanoid robot is proposed in this paper. Second, the material and pattern of foot pads are selected. Finally, the better foot pads are chosen by several experiments and the effectiveness of the new foot pads is confirmed by comparison experiments.
Electro-hydraulic servo systems(EHSSs) have been widely used in industrial and military applications for their high power-to-size ratio and the ability to supply huge ***,precise control of EHSSs cannot be easily obta...
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ISBN:
(纸本)9781479900305
Electro-hydraulic servo systems(EHSSs) have been widely used in industrial and military applications for their high power-to-size ratio and the ability to supply huge ***,precise control of EHSSs cannot be easily obtained due to their inner nonlinearity and parameter *** load is another factor to decrease the tracking performance of *** adaptive robust control(IARC) was proposed to improve the tracking performance of EHSS,but due to the poor parameter adapting speed,IARC can be further improved to have better *** projection type parameter estimation algorithm is redesigned to increase the adapting speed when parameter is changed.A fast adaptive robust control (FARC) is then proposed to speed up the parameter adapting speed,so that a better tracking performance of FARC is maintained. Simulation results show that the proposed FARC gives an improved tracking performance and a faster parameter adaptation.
This paper considers the distributed attitude synchronization problem for multiple spacecraft with external disturbances. Distributed discontinuous adaptive controller is designed based on the relative attitudes and a...
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ISBN:
(纸本)9781467355322
This paper considers the distributed attitude synchronization problem for multiple spacecraft with external disturbances. Distributed discontinuous adaptive controller is designed based on the relative attitudes and angular velocities of neighboring spacecraft and attitude synchronization can be reached for any communication graph containing a directed spanning tree. To tackle the chattering effect caused by the discontinuous controller, a continuous controller is further proposed, under which both the synchronization errors and the adaptive gains are ultimately bounded. Extensions to the case with a leader-follower communication graph with the leader as the spanning tree's root are further studied.
This paper considers the distributed attitude tracking problem of multiple spacecraft with disturbances and unknown inertia matrices. Based on the relative attitudes and angular velocities of neighboring spacecraft, w...
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ISBN:
(纸本)9781479900305
This paper considers the distributed attitude tracking problem of multiple spacecraft with disturbances and unknown inertia matrices. Based on the relative attitudes and angular velocities of neighboring spacecraft, we design a distributed robust controller to each follower to guarantee that the attitude errors between the followers and the leader converge to zero for any communication graph containing a directed spanning tree with the leader as the root. To deal with the problem of parameters uncertainties, we further propose a distributed adaptive sliding mode controller, under which the system is globally robust with respect to external disturbances and inertia matrices uncertainties.
To enhance the safety of a humanoid robot when it is operating a complex environment, a number of methods that combine visual and force information have been presented. These methods are generally divided into two app...
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To enhance the safety of a humanoid robot when it is operating a complex environment, a number of methods that combine visual and force information have been presented. These methods are generally divided into two approaches. The first approach is to coordinate the visual controller and force controller in a parallel way, and the second approach is to coordinate them in series. However, these two approaches do not consider the interaction between the visual controller and force controller. Specifically, the first approach does not consider the interaction between the controllers. The second approach only considers the effect of the output of the visual controller on the force controller, while the effect of the force controller on the visual controller is not considered. This study presents a design for a new flexible controller for a humanoid robot that considers the interaction of visual and force information. The advantages of the proposed method are that it simultaneously incorporates the functions of a visual servo controller and a flexible controller as well as its ability to consider the interaction of visual and force information when a humanoid robot is operating.
To resemble the appearance of human beings, humanoid robots should be designed with many DOFs, however, it increases the complexity of the mechanical design and the real-time control, which will make a high cost and h...
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ISBN:
(纸本)9781479973989
To resemble the appearance of human beings, humanoid robots should be designed with many DOFs, however, it increases the complexity of the mechanical design and the real-time control, which will make a high cost and have a poor reliability and will not fit for the application in museums or human's daily lives. In this paper, to enable the low cost and high reliability robot to interact with humans naturally and sever humans more friendly, we imported advanced technology of the Waseda's flute robot and retained the most important mechanical parts, such as the lip, lungs and the fingers for the flute playing, on this basis, some other mechanical structures were redesigned; particularly, the robot's appearance was carefully designed; in addition, we also redesigned the hardware structure using our own joint controllers and software system based on CAN bus communication for the cost saving and high reliability. The redesigned robot had just 16 DOFs. Preliminary performance test results showed that this new redesigned robot achieved in producing high quality of flute sound and high sound conversion efficiency, and the period of communication was about 4ms.
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