To facilitate ground station monitoring and command uploading, unmanned aerial vehicles (UAVs) need to frequently exchange individual state data between units. However, this results in a significant usage of communica...
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ISBN:
(纸本)9798350321050
To facilitate ground station monitoring and command uploading, unmanned aerial vehicles (UAVs) need to frequently exchange individual state data between units. However, this results in a significant usage of communication bandwidth. To address this issue, on the basis of an event-triggered strategy, this paper proposes an Extended Kalman Filter (EKF). aimed at reducing the communication burden of UAVs while maintaining high accuracy. Specifically, a state measurement triggered by an event is selected for filtering only if it contains innovation, thereby reducing the amount of data that needs to be communicated. Since UAV systems are nonlinear, EKF is adopted to fully utilize the information obtained from event-triggered strategies, thereby enhancing the estimation performance. In this paper, a physical UAV was used to verify the proposed algorithm, and it proved to have robust dynamic performance and to effectively reduce the communication rate.
data-driven approach is promising for predicting impedance profile of grid-connected voltage source converters (VSCs) under a wide range of operating points (OPs). However, the conventional approaches rely on a one-to...
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data-driven approach is promising for predicting impedance profile of grid-connected voltage source converters (VSCs) under a wide range of operating points (OPs). However, the conventional approaches rely on a one-to-one mapping between operating points and impedance profiles, which, as pointed out in this article, can be invalid for multiconverter systems. To tackle this challenge, this article proposes a stacked-autoencoder-based machine learning framework for the impedance profile predication of grid-connected VSCs, together with its detailed design guidelines. The proposed method uses features, instead of OPs, to characterize impedance profiles, and hence, it is scalable for multiconverter systems. Another benefit of the proposed method is the capability of predicting VSC impedance profiles at unstable OPs of the grid-VSC system. Such prediction can be realized solely based on data collected during stable operation, showcasing its potential for rapid online state estimation. Experiments on both single-VSC and multi-VSC systems validate the effectiveness of the proposed method.
Fault classification is a common problem in industrial fault diagnosis. Usually, classifiers are built assuming an equal amount of data across different classes. However, the amount of normal data and fault data colle...
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ISBN:
(纸本)9798350321050
Fault classification is a common problem in industrial fault diagnosis. Usually, classifiers are built assuming an equal amount of data across different classes. However, the amount of normal data and fault data collected from industrial processes is often imbalanced. Intrinsically, the fault classification is also an imbalanced data classification problem. To address this issue, data augmentation methods can be used to effectively generate more data and achieve data balance. While the performance of classification is greatly influenced by the generated data. The quality of the generated data can greatly impact the classification performance. To ensure the stability of the generated data, this paper extends the generation of single data to the generation of time series data using a time variational autoencoder. Using the generated time series data, a new classifier called the Time Series data Augmentation Classifier (TSDAC) is proposed to solve the imbalanced fault classification problem. After that, the TSDAC is applied to Tennessee Eastman (TE) benchmark process. The results show that the TSDAC is recommended for imbalanced fault classification.
This paper investigates the control problem of robotic manipulator subjected to uncertain dynamics and output constraints. The robotic manipulator system is described as a Lagrangian system with parameterized uncertai...
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As learning-based methods make their way from perception systems to planning/control stacks, robot controlsystems have started to enjoy the benefits that data-driven methods provide. Because controlsystems directly ...
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As learning-based methods make their way from perception systems to planning/control stacks, robot controlsystems have started to enjoy the benefits that data-driven methods provide. Because controlsystems directly affect the motion of the robot, data-driven methods, especially black box approaches, need to be used with caution considering aspects such as stability and interpretability. In this letter, we describe a differentiable and hierarchical control architecture. The proposed representation, called multi-abstractive neural controller, uses the input image to control the transitions within a novel discrete behavior planner (referred to as the visual automaton generative network, or vAGN). The output of a vAGN controls the parameters of a set of dynamic movement primitives which provides the system controls. We train this neural controller with real-world driving data via behavior cloning and show improved explainability, sample efficiency, and similarity to human driving.
This paper studies the distributed data-driven event-triggered model free adaptive iterative learningcontrol (ETMFAILC) of multiple high-speed trains (MHSTs) under iteration-varying topologies, which breaks away from...
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This paper studies the distributed data-driven event-triggered model free adaptive iterative learningcontrol (ETMFAILC) of multiple high-speed trains (MHSTs) under iteration-varying topologies, which breaks away from the dependence on the train dynamics. Firstly, the nonlinear MHSTs with unknown dynamics are converted into a linear model. Then, combining the proposed event-based triggering condition and the linear model, the ETMFAILC scheme under the fixed topology is designed. Next, theoretical analysis proves the bounded input bounded output (BIBO) stability of MHSTs. Finally, the study is extended to the switching topologies and the validity of the ETMFAILC is verified by a numerical example.
This paper discusses the leader-follower consistency problem in multi-quadruped robot systems. Initially, the dynamics of quadruped robots are modeled as a first-order integral model. Then, a PD-type distributed proto...
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In this paper, a direct method of adaptive input shaping algorithm for a harvesting mechanical arm clamps the tomato bunches is proposed to achieved zero residual vibration. The traditional input shaping would lose it...
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ISBN:
(纸本)9798350321050
In this paper, a direct method of adaptive input shaping algorithm for a harvesting mechanical arm clamps the tomato bunches is proposed to achieved zero residual vibration. The traditional input shaping would lose its vibration suppressing function when the system parameter changed during mechanical arm's load varied. The adaptive input shaping algorithm based on recursive least square method (RLS) requires no system identification. The residual vibration of output signal is used as the input of the algorithm to calculate the impulse time and amplitude of shaper. An adaptive forgetting factor updating algorithm is proposed to improve the control performance in variable load condition. The experimental results show that the adaptive forgetting factor input shaper greatly reduces the residual vibration.
Rolling bearing is a key component of rotating machinery, which affects the reliability of the equipment. In order to make the equipment intelligent, facilitate the maintenance of the equipment, and improve the operat...
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ISBN:
(纸本)9798350321050
Rolling bearing is a key component of rotating machinery, which affects the reliability of the equipment. In order to make the equipment intelligent, facilitate the maintenance of the equipment, and improve the operation efficiency of the equipment, a data-driven residual life prediction method of rolling bearing is proposed, which is used to intelligently predict the remaining service life of the equipment, providing great convenience for the maintenance of the equipment. First, wavelet packet de-noising method is used to remove the noise in the original signal, and then extract the time-domain and frequency-domain features of the de-noised signal, after that PCA is used to reduce the dimension of the feature information and fuse it into the comprehensive life characteristics of the bearing. Last, with the input of the subsequent life prediction features, the residual life prediction model based on PCA-SVR is finally constructed. The experimental results show that the residual life prediction model based on PCA-SVR has low error rate and high accuracy which can accurately predict the residual life of rolling bearings.
This article presents the guided Bayesian optimization (BO) algorithm as an efficient data-driven method for iteratively tuning closed-loop controller parameters using a digital twin of the system. The digital twin is...
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This article presents the guided Bayesian optimization (BO) algorithm as an efficient data-driven method for iteratively tuning closed-loop controller parameters using a digital twin of the system. The digital twin is built using closed-loop data acquired during standard BO iterations, and activated when the uncertainty in the Gaussian Process model of the optimization objective on the real system is high. We define a controller tuning framework independent of the controller or the plant structure. Our proposed methodology is model-free, making it suitable for nonlinear and unmodelled plants with measurement noise. The objective function consists of performance metrics modeled by Gaussian processes. We utilize the available information in the closed-loop system to progressively maintain a digital twin that guides the optimizer, improving the data efficiency of our method. Switching the digital twin on and off is triggered by our data-driven criteria related to the digital twin's uncertainty estimations in the BO tuning framework. Effectively, it replaces much of the exploration of the real system with exploration performed on the digital twin. We analyze the properties of our method in simulation and demonstrate its performance on two real closed-loop systems with different plant and controller structures. The experimental results show that our method requires fewer experiments on the physical plant than Bayesian optimization to find the optimal controller parameters. Note to Practitioners-Industrial applications typically are difficult to model due to disturbances. Bayesian optimization is a data-efficient iterative tuning method for a black box system in which the performance can only be measured given the control parameters. Iterative measurements involve operational costs. We propose a guided Bayesian optimization method that uses all information flow in a system to define a simplified digital twin of the system using out-of-the-box methods. It is continuously u
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