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19th IFAC World Congress on International Federation of Automatic control, IFAC 2014

作者： Cong, B.L. Chen, Z. Liu, X.D. Beijing Institute of Technology Beijing100081 China Key Laboratory for Intelligent Control and Decision of Complex Systems Beijing Institute of Technology Beijing100081 China

ISBN: (纸本)9783902823625

This paper aims to present a robust attitude control strategy with guaranteed transient performance. Firstly, a Lyapunov-based control law is designed to achieve highperformance attitude control in the absence of disturbance and parameter variation. The proposed control law uses small feedback gains to suppress the control torque at large attitude error, and increases those gains with the convergence of attitude error to accelerate the system response. The overshooting phenomenon is also avoided by imposing a restriction on the parameter selection. Then, the integral sliding mode control technique is employed to improve the robustness, where the Lyapunov-based control law is used as the equivalent control part. Theoretical analysis and simulation results verify the effectiveness of the proposed strategy. © IFAC.

关键词： control theory

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Modeling of hysteresis in piezoelectric actuator using linear play operator adaptive filter

Modeling of hysteresis in piezoelectric actuator using linea...

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16th Annual Conference and 5th International Conference on Chinese Society of Micro-Nano Technology, CSMNT 2014

作者： Xiong, Rui Liu, Xiangdong Shan, Fengmin Key Laboratory for Intelligent Control and Decision of Complex Systems Beijing China Automation College Beijing Institute of Technology Beijing China

ISBN: (纸本)9783038354628

Piezoelectric actuator(PEA) is widely applied in micro/nano positioning system. However, its inherent hysteresis limits its application. Modeling of hysteresis plays an important role in solving this problem. Linear play operators (LPO) adaptive hysteresis model is introduced in this paper. LPO operators are used to replace delay operators of adaptive transversal filter to compose a new serial structure of adaptive transversal filter model, and LMS (Least Mean Square) algorithm is used to adjust the weight values. As hysteresis loop of piezoelectric actuator is asymmetric and LPO operator is symmetric, a modified LPO (MLPO) adaptive filter is proposed for asymmetric hysteresis effect. At last, the two LPO filters are applied to model hysteresis characteristic of Piezoelectric actuator, and the modeling effect is verified via a micro-positioning system experiment platform based on Piezoelectric actuator. Experimental results show that the modified LPO filters can achieve better accurate hysteresis modeling. © (2015) Trans Tech Publications, Switzerland.

关键词： Hysteresis

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Parameter-dependent H2state estimation for nonlinearl systems 34

Parameter-dependent H2state estimation for nonlinearl system...

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34th Chinese control Conference, CCC 2015

作者： Yu, Yin Li, Zhen Liu, Xiangdong Liu, Bing School of Automation Beijing Institute of Technology Beijing China Key Laboratory for Intelligent Control and Decision on Complex Systems Beijing Institute of Technology Beijing China

ISBN: (纸本)9789881563897

The state estimation of general nonlinear systems is investigated through a parameter-dependent approach. This paper adopts the polytopic approximation for the nonlinear systems, which facilitates the application of analytical approaches for resultant convex-bounded linear systems into the given nonlinear systems. The design of a high performance H2state estimator is firstly determined by solving a convex optimization problem constrained by relaxed linear matrix inequalities (LMIs). The tensor product (TP) model transformation is then adopted to obtain the polytopic linearization. Specifically, A new process is presented to correct the result of the TP model transformation such that a necessary condition to solve the state estimation problem is assured. Finally, a numerical simulation is performed to illustrate the design process and verify the performance. © 2015 Technical Committee on control Theory, Chinese Association of Automation.

关键词： linear matrix inequalities (LMIs) Nonlinear state estimation parameter-dependent H2 filter tensor product (TP) model transformation

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Event-based Cubature Kalman Filter for Smart Grid Subject to Communication Constraint

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IFAC-PapersOnLine 2017年第1期50卷 49-54页

作者： Li S. Li Z. Li J. Wang Q. Song Z. Chen Z. Sheng Y. Liu X. Liu Y. School of Automation and Key Laboratory for Intelligent Control Decision on Complex Systems Beijing Institute of Technology Beijing 100081 China Department of control science and engineering Harbin Institute of Technology Harbin 150001 China

Accurate real-time estimation plays an important role in smart grids. Although various filtering algorithms, such as unscented Kalman filter (UKF), have been proposed for phasor measurement unit (PMU), they occupy huge communication bandwidth without specific concern, which puts heavy burden on the communication network especially when wireless communications are applied. In order to relief this burden, the event-based cubature Kalman filter (EBCKF) is proposed based on event-based schemes in this paper. The event-based strategy guarantees that only the observations containing innovational information are transmitted, and cubature Kalman filter (CKF), which is based on the spherical cubature integration, provides more accurate estimation than UKF. Besides, the design-oriented communication rate is provided corresponding to the event-based strategy design. The proposed filter can effectively reduce the communication rate while ensuring the accuracy of filtering. Finally, the standard IEEE 39-bus system is utilized to verify the feasibility and performance of the proposed method. © 2017

关键词： communication rate dynamic state estimation Event-based cubature Kalman filter (EBCKF) IEEE 39-bus phasor measurement unit (PMU)

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Two Degree of Freedom Active Disturbance Rejection control Strategy for Time Delay systems 42

Two Degree of Freedom Active Disturbance Rejection Control S...

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42nd Chinese control Conference, CCC 2023

作者： Shan, Xiyuan Cai, Tao School of Automation Beijing Institute of Technology Beijing100081 China State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing100081 China

ISBN: (纸本)9789887581543

This paper is concerned with the controller design and the theoretical analysis for time-delay systems, a two degree of freedom (feedforward and feedback) control method is proposed, which combines advantages of the Smith predictor and the active disturbance rejection control (ADRC). The feedforward part of controller is used to track the set point, the feedback part of controller (ADRC) is used to suppress interferences and the Smith predictor is used to correct time delay. The proposed control design is easy to tune parameters and has been proved to effectively control systems with large time delay. The bounded input bounded output (BIBO) stability of closed-loop system is verified. Finally, numerical simulations show the effectiveness and practicality of the proposed design. © 2023 Technical Committee on control Theory, Chinese Association of Automation.

关键词： Time delay

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Adaptive robust dynamic surface control of DC torque motors with true parameter estimates

Adaptive robust dynamic surface control of DC torque motors ...

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作者： Li, Zhiping Chen, Jie Gan, Minggang Fang, Hao Zhang, Guozhu Beijing Institute of Technology and Education Ministry Key Laboratory of Complex Systems Intelligent Control and Decision School of Automation Beijing China

ISBN: (纸本)9781424474264

This paper presents an adaptive robust dynamic surface control (ARDSC) algorithm for the position control of DC torque motors which are modeled as third-order nonlinear systems with parametric and nonlinear uncertainties. Based on the dynamic surface control (DSC) approach, the "explosion of terms" problem in the normal adaptive robust control (ARC) is avoided, which enhances the practicability of the controller. Furthermore, besides theoretically proving that the tracking error is uniformly ultimate bounded or asymptotically converge to zero in presence of parametric uncertainties only, the true estimates of the unknown parameters are achieved by designing a novel adaptation law, which improves the system performance and can be used in system monitor and diagnosis on-line as byproducts. Finally, the comparative simulation results illustrate that the proposed algorithm is very effective. © 2010 AACC.

关键词： Position control

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Coordinated Motion control for a Six-wheel-drive Skid-steering Mobile Robot

Coordinated Motion Control for a Six-wheel-drive Skid-steeri...

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2021 China Automation Congress, CAC 2021

作者： Xu, Yongkang Wang, Shoukun Zhao, Hongqiang Chen, Zhihua State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing Institute of Technology Beijing China State Key Laboratory of High Performance and Complex Manufacturing Central South University Changsha China

ISBN: (纸本)9781665426473

A speed consensus control strategy for a six-wheel-drive skid-steering mobile robot was proposed based on a hierarchical controller in a complex environment with unknown disturbances. The effective method of reliable speed consensus control strategy should consider some disturbances, such as the internal-robot assembly error, which including instability of motor control system and external physical interference in robot dynamic system. In this paper, a driving anti-slip control system with PID and the stability control system with sliding mode by variable structure is designed and integrated to elevate the stability of the robot. And, a G-vector control algorithm based on sliding mode control is proposed to reduce the yaw angle as much as possible during the process of differential steering of robots. The effectiveness of the proposed control strategy is verified by an example of a *** results show that the method has good control performance in control accuracy and stability. © 2021 IEEE

关键词： Motion control

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Detection and Positioning of Workpiece Grinding Area in Dark Scenes with Large Exposure 1

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16th International Conference on intelligent Robotics and Applications, ICIRA 2023

作者： Guo, Zhentao Zhao, Guiyu Bian, Jinyue Ma, Hongbin School of Automation Beijing Institute of Technology Beijing100081 China State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing100081 China

ISBN: (数字)9789819964987

ISBN: (纸本)9789819964970

Workpiece grinding is a crucial process in the smart manufacturing chain. In order to meet the requirements of industrial precision and relieve heavy work, researchers have developed a vision-based grinding robot. However, the problem of workpiece grinding area detection and positioning is difficult to be solved in dark scenes with large exposure. This paper proposes a method that fuses technologies such as processing of the image, coordinate and point cloud, which can accurately detect and locate the workpiece grinding area. Firstly, A method based on YOLOv7 and improved image preprocessing is used to detect labels of the grinding area. Secondly, A model for the prediction of the coordinates based on multiple linear regression was used to predict the coordinates of missing labels for the same grinding area. Finally, Data processing of the point cloud and transformation of the system of coordinates are used to achieve the acquisition of the coordinates of positioning vertices in the grinding area and conversion from the camera coordinate system to the world coordinate system. We used several sets of data for evaluation in our experiments, and the experimental results show that our proposed method can effectively detect the workpiece grinding area. At the same time, our method can also predict the coordinates of missing labels, which provides a more stable and reliable guarantee for industrial production. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.

关键词： Multiple linear regression

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Robust human-computer interaction for unstable camera systems

Robust human-computer interaction for unstable camera system...

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作者： Zhu, Hao You, Qing Chen, Wenjie School of Automation Beijing Institute of Technology Beijing100081 China State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing100081 China

A lot of vision systems have been embedded in devices around us, like mobile phones, vehicles and UAVs. Many of them still need interactive operations of human users. However, specifying accurate object information could be a challenging task due to video jitters caused by camera shakes and target motions. In this paper, we first collect practical hand drawn bounding boxes on real-life videos which are captured by hand-held cameras and UAV-based cameras. We give a deep look into human-computer interactive operations on unstable images. The collected data shows that human input suffers heavy deviations which are harmful to interaction accuracy. To achieve robust interactions on unstable platforms, we propose a target-focused video stabilization method which utilizes a proposal-based object detector and a tracking-based motion estimation component. This method starts with a single manual click and outputs stabilized video stream in which the specified target stays almost stationary. Our method removes not only camera jitters but also target motions simultaneously, therefore offering an comfortable environment for users to do further interactive operations. The experiments demonstrate that the proposed method effectively eliminates image vibrations and significantly increases human input accuracy. © Copyright 2018 The Institute of Electronics Information and Communication Engineers.

关键词： Cameras

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CFSeRec: A Contrastive Framework for Sequential Recommendation 42

CFSeRec: A Contrastive Framework for Sequential Recommendati...

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42nd Chinese control Conference, CCC 2023

作者： Wang, Tong Dai, Yaping Shao, Shuai School of Automation Beijing Institute of Technology Beijing100081 China State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing100081 China

ISBN: (纸本)9789887581543

In sequential recommender systems, the main problems are the long-tailed distribution of data and noise interference. A Contrastive Framework for Sequential Recommendation (CFSeRec) is proposed to solve these two problems respectively. Token shuffling and adversarial attack data augmentation methods are used in the framework to improve the quality and quantity of training data, so that the long-tailed problem is mitigated. Through the application of projection head method, the sequence representation becomes more general and robust, rather than just adapted to the task of contrastive learning. Therefore, the impact of noise on sequence recommender systems is effectively alleviated. Experiments on four public datasets show that CFSeRec achieves state-of-the-art performance in the metrics of hit ratio and normalized discounted cumulative gain, when comparing to the seven previous frameworks. © 2023 Technical Committee on control Theory, Chinese Association of Automation.

关键词： Recommender systems

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