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- 저자 : Jiqing Chen (검색결과 5 건)
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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.
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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.
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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.
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Wenqiang Sun,Deqiang Zhang,Xiang Chen,Keyan Wang,Jiqing Zhang,Yunjie Jia 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2
Cold work dies (of Cr12MoV) surface of the WC/Ni composite coating prepared by laser cladding can be used to quickly repair worn areas of dies. The composition, hardness, fracture morphology, microstructure, and shear strength of the coating were characterized by microhardness tester, universal tensile testing machine, XRD, EDS, and SEM. The results show that the main phase of the coating is composed are M 23 C 6 , FeNi 3 , Cr 7 C 3 , WC, W 2 C, Cr 2 B, Fe 2 B, and W 2 B. The change of scanning speed only changes the diffraction peak, but has little effect on the internal structure and strengthening mechanism of the coating. With the decrease of scanning speed, the powder deposition density per unit time increases, and a large number of pores and unmelted particles are mixed in the coating, which weakens the bonding strength between the coating and the substrate, and the fracture mechanism of the coating changes from quasi-cleavage fracture to brittle fracture.
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Luminescence Emission Mediated by Surface Plasmon in the Semiconductor Quantum Dots
HUIBING MAO,Ling Du,Ye Chen,Bo Li,Rong Huang,JIQING WANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.1
The luminescence of the hybrid CdSe/ZnS QDs–Ag nanocrystals has a weak blue shift in comparison with the luminescence of the pure quantum dots (QDs). The luminescence of the CdSe/ZnS QDs only has a single exponential decay process, and the decay rates are almost same for different emission wavelengths. The luminescence of the hybrid CdSe/ZnS QDs–Ag nanocrystals structure has two decay processes: The first is a fast decay process, and then there is a slow decay process with nearly the same decay rate of the pure QDs. The fast decay process is due to the surface plasmon coupling and the coupling rate depends on the energy difference between the confined exciton in the QDs and the resonance energy of the Ag plasmon.
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