Low Chattering Trajectory Tracking Control of Non-singular Fast Terminal Sliding Mode Based on Disturbance Observer

Jiqing Chen,Chaoyang Zhao,Qingsong Tang,Xu Liu,Zhikui Wang,Chengzhi Tan,Jiahua Wu,Teng Long 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.2

The improvement of the performance of the multi-joint manipulator control system is of great significance to improve the level of industrial automation. The existing sliding mode control methods are difficult to ensure the high-precision and fast-tracking of joints of a manipulator to the desired trajectory under low chattering control input. Therefore, a non-singular fast terminal sliding mode control method based on a nonlinear disturbance observer is proposed. In addition, a new non-singular fast terminal sliding mode surface is designed. The performance comparison method of the sliding mode surface proves its better control quality. Aiming at the problem of serious chattering, the nonlinear disturbance observer technology, and saturation function method are introduced to effectively weaken the chattering. Finally, taking the 3-DOF manipulator as the research object, a comparative simulation experiment is carried out in the MATLAB / Simulink environment. The results show that under the uncertainty of modeling error, external disturbance, and joint friction, the designed control method not only solves the problems of singular control input and serious chattering but also realizes the high-precision and fast-tracking of each joint to the desired trajectory. Thus, the effectiveness and feasibility of the design method are verified. The improvement of the performance of the multi-joint manipulator control system is of great significance to improve the level of industrial automation. The existing sliding mode control methods are difficult to ensure the high-precision and fast-tracking of joints of a manipulator to the desired trajectory under low chattering control input. Therefore, a non-singular fast terminal sliding mode control method based on a nonlinear disturbance observer is proposed. In addition, a new non-singular fast terminal sliding mode surface is designed. The performance comparison method of the sliding mode surface proves its better control quality. Aiming at the problem of serious chattering, the nonlinear disturbance observer technology, and saturation function method are introduced to effectively weaken the chattering. Finally, taking the 3-DOF manipulator as the research object, a comparative simulation experiment is carried out in the MATLAB / Simulink environment. The results show that under the uncertainty of modeling error, external disturbance, and joint friction, the designed control method not only solves the problems of singular control input and serious chattering but also realizes the high-precision and fast-tracking of each joint to the desired trajectory. Thus, the effectiveness and feasibility of the design method are verified.

Terminal-based Dynamic Clustering Algorithm in Multi-Cell Cellular System

( Jiqing Ni ),( Zesong Fei ),( Chengwen Xing ),( Di Zhao ),( Jingming Kuang ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.9

A terminal-based dynamic clustering algorithm is proposed in a multi-cell scenario, where the user could select the cooperative BSs from the predetermined static base stations (BSs) set based on dynamic channel condition. First, the user transmission rate is derived based on linear precoding and per-cell feedback scheme. Then, the dynamic clustering algorithm can be implemented based on two criteria: (a) the transmission rate should meet the user requirement for quality of service (QoS); (b) the rate increment exceeds the predetermined constant threshold. By adopting random vector quantization (RVQ), the optimized number of cooperative BSs and the corresponding channel conditions are presented respectively. Numerical results are given and show that the performance of the proposed method can improve the system resources utilization effectively.

Motion Control of Autonomous Vehicles with Guaranteed Prescribed Performance

Hongyang Xia,Jiqing Chen,Fengchong Lan,Zhaolin Liu 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.6

In this paper, a novel motion control scheme with guaranteed prescribed performance is proposed for autonomous vehicles with consideration of couplings between lateral and longitudinal motions. Firstly, a prescribed performance transformation function is constructed to equivalently release the output error constraints. Then, a coordinated controller is designed to complete lateral and longitudinal motion control tasks simultaneously based on sliding-mode control. The designed coordinated controller can guarantee predefined trajectory tracking performance (e.g., minimum speed of convergence, maximum steady state error and overshoot), in presence of strongcoupled characteristics, model uncertainties and external disturbance. Finally, simulation results under different boundary constraints further validate the feasibility and good robustness of the controller.

NUMERICAL PROJECTION ON OCCUPANT THERMAL COMFORT VIA DYNAMIC RESPONSES TO HUMAN THERMOREGULATION

Weijian Li,Jiqing Chen,Fengchong Lan,Xijiao Zheng,Wenbo Zeng 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.1

With the different physiological properties and thermal conditions, different body parts of passengers have inconsistent thermal sensations and thermal requirements in a highly non-uniform and transient vehicle cabin thermal environment. Determining the thermal comfort requirements for different body parts of a passenger is essential for effectively supplying warm air to the right human part especially for electric vehicles with energy-saving attributes. In this paper, a comprehensive numerical model that integrates human thermal regulation mechanism and dynamic environmental characteristics is established to calculate the thermal comfort for passengers via thermal responses to a dynamic environment. The numerical computation sets up such a model structure, firstly considering human thermal regulation functions into the thermal response to the in-cabin dynamic thermal distributions, then combining Berkeley thermal comfort model to identify the thermal comfort level at different body parts, that would implement total numerical simulations to get thermal comfort evaluation, independent of human subjective feedbacks. The model is validated by experiments with an acceptable error and implemented for a cabin heating case study. The models can effectively predict the thermal comfort and thermal requirements of various body parts in a dynamic environment with human thermoregulation, as an important tool for designing a non-uniform environment.

SURFACE PLASMON COUPLING EFFECTS ON THE FUNDAMENTAL MODES IN THE NANOWIRE

HUIBING MAO,JIQING WANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.4

The degeneracy of the two fundamental modes HE 11 of the nanowire (NW) is removed due to thecoupling of surface plasmon (SP). For the coupled mode 1 of HE 11 the electric ¯eld is con-centrated between the metal sphere and the NW because of the coupling of the metal sphere. Thecoupling intensity depends on the relative position of the metal sphere. There is no ¯eld con-centration phenomenon for the coupled mode 2 of HE 11 , and the coupling only a®ects the dis-tribution of the local ¯eld in the NW. For the coupled mode 2 of HE 11 , both the mode volume andthe Purcell factor do not have obvious change. However, for the coupled mode 1 of HE 11 both themode volume and the Purcell factor have a fundamental change. The mode volume increases withthe increase of the metal sphere distance from the point of maximum ¯eld intensity of the Fabry –Perot standing wave. The Purcell factor decreases with the increase of the metal sphere distancefrom the point of maximum ¯eld intensity of the Fabry – Perot standing wave.

Quality evaluation and optimization of confusion network for LVCSR

Huanliang Wang,Jiqing Han,Tieran Zheng 한국어정보학회 2005 국제학술대회 Vol.2005 No.08

A Robust Audio Retrieval Method

Guibin Zheng,Jiqing Han 한국어정보학회 2006 한국어정보학 Vol.8 No.1

This paper presents a robust audio retrieval method. In the method, the retrieval target is divided into short segments, each segment is searched respectively, and a retrieval window is used to maintain a list of segments that can be searched simultaneously. The method can quickly detect and locate known sound in real‐time audio stream, multimedia archives or the Internet. It can maintain high performance even if large part of target is absent in the input stream. Its retrieval speed can be adjusted by the length of retrieval window and is independent on target length. The recall rate and precision rate of the method are 100% and 99.7% respectively.

Speaker Recognition via Block Sparse Bayesian Learning

Wei Wang,Jiqing Han,Tieran Zheng,Guibin Zheng,Mingguang Shao 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.7

In order to demonstrate the effectiveness of sparse representation techniques for speaker recognition, a dictionary of feature vectors belonging to all speakers is constructed by total variability i-vectors. Each feature vector from unknown utterance is expressed as linear weighted sum of a dictionary. The weights are calculated using Block Sparse Bayesian Learning (BSBL) where the sparsest solution can be obtained. By exploiting the speech signal’s block structure and intra-block correlation, the system performance is improved. The experimental results validate that our method outperforms the baseline systems and the system using Orthogonal Matching Pursuit (OMP) algorithm on the typical corpus and realizes the identity validation function.

Quality Evaluation and Optimization of Confusion Network for LVCSR

Huanliang Wang,Jiqing Han,Tieran Zheng 한국어정보학회 2006 한국어정보학 Vol.8 No.1

Confusion network (CN) is an aligned and compact representation form of word lattice that stores median results of decoding procedure and connects the acoustic decoding and succeeding process steps. The quality of confusion network is very important for multi‐pass decoding based recognition method. Three new quality evaluation measures are proposed for confusion network in this paper. The first is called confusion network word error rate (CWER), which gives a lower bound of recognition word error rate. The second is used to measure the size of confusion set, called confusion word density (CWD). The third is word confusion probability (WCP), which can measure average distinguishability between words in a confusion set. Based on the proposed measures, we present a new method of quality optimization for confusion network, called as confusion probability based pruning algorithm. The experiments, carried out on a large vocabulary Chinese continuous speech recognition system, demonstrate that the new method leads to a significant reduction in CWD and WCP without an increase of CWER.

A Novel Approach to Digital Audio Watermarking Based on Pre-attack

Tao Feng,Jiqing Han 한국어정보학회 2006 한국어정보학 Vol.8 No.1

In this paper, a novel algorithm of audio watermarking is presented on the base of preattacking by predicting possible attacks for the special purpose of watermarking. Dividing frequency band in discrete wavelet transform (DWT) domain, and calculating the defined distortion measure, the appropriate band can be located to embed watermarking with hopping frequency technique. The imperceptible of audio host maintains by using psychoacoustics model to constrain the embedding strength. Experimental results show the proposed method obtains higher robustness to common watermarking attacks, especially for the forecasted attacks.