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Jianyong Yao,Zongxia Jiao,Bin Yao 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4
High performance robust force control of hydraulic load simulator with constant but unknown hydraulic parameters is considered. Incontrast to the linear control based on hydraulic linearization equations, hydraulic inherent nonlinear properties and uncertainties makethe conventional feedback proportional-integral-derivative (PID) control not yield to high performance requirements. Furthermore, thehydraulic system may be subjected to non-smooth and discontinuous nonlinearities due to the directional change of valve opening. In thispaper, based on a nonlinear system model of hydraulic load simulator, a discontinuous projection-based nonlinear adaptive robust backsteppingcontroller is developed with servo valve dynamics. The proposed controller constructs a novel stable adaptive controller andadaptation laws with additional pressure dynamic related unknown parameters, which can compensate for the system nonlinearities anduncertain parameters, meanwhile a well-designed robust controller is also synthesized to dominate the model uncertainties coming fromboth parametric uncertainties and uncertain nonlinearities including unmodeled and ignored system dynamics. The controller theoreticallyguarantee a prescribed transient performance and final tracking accuracy in presence of both parametric uncertainties and uncertainnonlinearities; while achieving asymptotic output tracking in the absence of unstructured uncertainties. The implementation issues arealso discussed for controller simplification. Some comparative results are obtained to verify the high-performance nature of the proposedcontroller.
Jiahui Liu,Jianyong Yao,Wenxiang Deng 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.4
Electro-hydrostatic actuators (EHAs) have gradually been applied in the flight control systems of multielectric/all-electric aircraft due to the high power-to-volume ratio and the absence of throttling loss as well as overflow loss. However, the existence of high-order dynamics, system nonlinearities, and uncertainties significantly limits the tracking performance of EHAs. This article developed a robust adaptive controller with continuous friction compensation to improve the precise control performance of an EHA with a variable load, nonlinear friction, parametric uncertainties, and unmodeled disturbances. A nonlinear robust control law is used to attenuate various disturbances, and an adaptive law is adopted to cope with parametric uncertainties. Additionally, a continuous friction model is used to describe the friction behavior of an EHA to achieve effective friction compensation and further enhance the motion performance. Moreover, the upper bounds of the matched and mismatched uncertainties can be updated in real-time via adaptive laws, which can reduce design conservatism to some degree. The Lyapunov stability analysis reveals that asymptotic performance can be guaranteed despite the presence of unmodeled disturbances and parametric uncertainties. Furthermore, the applicability of the designed control algorithm with continuous friction compensation is demonstrated with experimental results.
Filter-based Immersion and Invariance Adaptive Control of Nonlinear Systems
Wei Chen,Jian Hu,Jianyong Yao,Weirong Nie,Haibo Zhou 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.1
This paper proposes a novel filter-based immersion and invariance (I&I) adaptive method for nonlinear systems with additive disturbances and parameter uncertainties. The key innovation of the proposed method is a filter construction that involves the dynamics of the system, based on which the I&I parameter estimator with a sigma modification term is designed. Comparing existing I&I methods, the expression for the novel filter-based I&I estimator is given in terms of total derivatives rather than partial derivatives, which is no longer subject to the integrability condition. In combining the sigma modification term, the proposed parameter estimator also guarantee the uniformly ultimately bounded stability of the parameter estimation error when the system is disturbed, which cannot be achieved by the original I&I method. Furthermore, Lyapunov theory demonstrates that the proposed method can guarantee the stability of the nonlinear systems discussed in this paper. Simulation and experimental results confirm the effectiveness of the proposed method.
Zuan Lin,Rongfang Xie,Chenhui Zhong,Jianyong Huang,Peiying Shi,Hong Yao 고려인삼학회 2022 Journal of Ginseng Research Vol.46 No.1
Ginsenoside Rb1 (Rb1), one of the most important ingredients in Panax ginseng Meyer, has been confirmed to have favorable activities, including reducing antioxidative stress, inhibiting inflammation, regulating cell autophagy and apoptosis, affecting sugar and lipid metabolism, and regulating various cytokines. This study reviewed the recent progress on the pharmacological effects and mechanisms of Rb1 against cardiovascular and nervous system diseases, diabetes, and their complications, especially those related to neurodegenerative diseases, myocardial ischemia, hypoxia injury, and traumatic brain injury. This review retrieved articles from PubMed and Web of Science that were published from 2015 to 2020. The molecular targets or pathways of the effects of Rb1 on these diseases are referring to HMGB1, GLUT4, 11b-HSD1, ERK, Akt, Notch, NF-kB, MAPK, PPAR-g, TGF-b1/Smad pathway, PI3K/mTOR pathway, Nrf2/HO-1 pathway, Nrf2/ARE pathway, and MAPK/NF-kB pathway. The potential effects of Rb1 and its possible mechanisms against diseases were further predicted via Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and disease ontology semantic and enrichment (DOSE) analyses with the reported targets. This study provides insights into the therapeutic effects of Rb1 and its mechanisms against diseases, which is expected to help in promoting the drug development of Rb1 and its clinical applications.