Model-Free Adaptive Integral Backstepping Control for PMSM Drive Systems

Li, Hongmei,Li, Xinyu,Chen, Zhiwei,Mao, Jingkui,Huang, Jiandong The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

A SMPMSM drive system is a typical nonlinear system with time-varying parameters and unmodeled dynamics. The speed outer loop and current inner loop control structures are coupled and coexist with various disturbances, which makes the speed control of SMPMSM drive systems challenging. First, an ultra-local model of a PMSM driving system is established online based on the algebraic estimation method of model-free control. Second, based on the backstepping control framework, model-free adaptive integral backstepping (MF-AIB) control is proposed. This scheme is applied to the permanent magnet synchronous motor (PMSM) drive system of an electric vehicle for the first time. The validity of the proposed control scheme is verified by system simulations and experimental results obtained from a SMPMSM drive system bench test.

Smart Anti-jamming Mobile Communication for Cloud and Edge-Aided UAV Network

( Zhiwei Li ),( Yu Lu ),( Zengguang Wang ),( Wenxin Qiao ),( Donghao Zhao ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.12

The Unmanned Aerial Vehicles (UAV) networks consisting of low-cost UAVs are very vulnerable to smart jammers that can choose their jamming policies based on the ongoing communication policies accordingly. In this article, we propose a novel cloud and edge-aided mobile communication scheme for low-cost UAV network against smart jamming. The challenge of this problem is to design a communication scheme that not only meets the requirements of defending against smart jamming attack, but also can be deployed on low-cost UAV platforms. In addition, related studies neglect the problem of decision-making algorithm failure caused by intermittent ground-to-air communication. In this scheme, we use the policy network deployed on the cloud and edge servers to generate an emergency policy tables, and regularly update the generated policy table to the UAVs to solve the decision-making problem when communications are interrupted. In the operation of this communication scheme, UAVs need to offload massive computing tasks to the cloud or the edge servers. In order to prevent these computing tasks from being offloaded to a single computing resource, we deployed a lightweight game algorithm to ensure that the three types of computing resources, namely local, edge and cloud, can maximize their effectiveness. The simulation results show that our communication scheme has only a small decrease in the SINR of UAVs network in the case of momentary communication interruption, and the SINR performance of our algorithm is higher than that of the original Q-learning algorithm.

Modeling Method for Predicting the Shelf Life of Spare Parts under Automatic Modeling Process

Zhiwei Li,Qi Gao,Xinliang Jiang,Shenyang Liu,Tielu Gao 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.9

A modeling method which can predict the shelf life of various types of spare parts in a relatively short time is put forward in this article. At present, it is difficult to solve the problem of mass modeling because the shelf life prediction models for different kinds of spare parts are of great diversification. In this paper, the best fitting nonlinear variables are selected by Gram-Schmidt regression method, and the detailed steps of automatic modeling process are given, which have advantages of strong robustness and are easy in programming. Especially, it can eliminate the influence of multicollinearity among alternative models effectively. By using natural rubber heating elongation data, an example is taken to demonstrate the process of automatic modeling. The nonlinear regression models selected by automatic modeling process are consistent in Dakin equation, and the predict values of natural rubber shelf life are included in the storage period given by manufacturing plant.

Maternal betaine supplementation ameliorates fatty liver disease in offspring mice by inhibiting hepatic NLRP3 inflammasome activation

Li Lun,Sun Liuqiao,Liang Xiaoping,Ou Qian,Tan Xuying,Li Fangyuan,Lai Zhiwei,Ding Chenghe,Chen Hangjun,Yu Xinxue,Wu Qiongmei,Wei Jun,Wu Feng,Wang Lijun 한국영양학회 2023 Nutrition Research and Practice Vol.17 No.6

BACKGROUND/OBJECTIVES: Previous research has shown maternal betaine supplementation alleviates fetal-derived hepatic steatosis. Therefore, this study examined the anti-inflammatory effect of maternal betaine intake in offspring mice and its mechanism. MATERIALS/METHODS: Female C57BL/6J mice and their offspring were randomly divided into 3 groups according to the treatment received during gestation and lactation: control diet (CD), fatty liver disease (FLD), and fatty liver disease + 1% betaine (FLD-BET). The FLD group was given a high-fat diet and streptozotocin (HFD + STZ), and the FLD-BET group was treated with HFD + STZ + 1% betaine. After weaning, the offspring mice were given a normal diet for 5 weeks and then dissected to measure the relevant indexes. RESULTS: Compared to the CD group, the offspring mice in the FLD group revealed obvious hepatic steatosis and increased serum levels of alanine aminotransferase, interleukin (IL)-6, and tumor necrosis factor (TNF)-α; maternal betaine supplementation reversed these changes. The hepatic mRNA expression levels of IL-6, IL-18, and Caspase-1 were significantly higher in the FLD group than in the CD group. Maternal betaine supplementation reduced the expression of IL-1β, IL-6, IL-18, and apoptosis-associated speck-like protein containing C-terminal caspase recruitment domain (ASC). Maternal betaine supplementation also reversed the increasing protein expressions of nitric oxide dioxygenase-like receptor family pyrin domain containing 3 (NLRP3), ASC, Caspase-1, IL-1β, and IL-18 in offspring mice exposed to HFD + STZ. Maternal betaine supplementation decreased the homocysteine (Hcy) and s-adenosine homocysteine (SAH) levels significantly in the livers. Furthermore, the hepatic Hcy concentrations showed significant inverse relationships with the mRNA expression of TNF-α, NLRP3, ASC, and IL-18. The hepatic SAH concentration was inversely associated with the IL-1β mRNA expression. CONCLUSIONS: The lipotropic and anti-inflammatory effect of maternal betaine supplementation may be associated with the inhibition of NLRP3 inflammasome in the livers of the offspring mice.

Static and Seismic Experimental Study of Novel Prefabricated Beam-Column Joints with Elongated-Hole Brackets

Zhang Zhiwei,Li Dong,Wang Huajie,Li Songling,Qian Hongliang,Bi Yanhua,Wang Guoxing,Jin Xiaofei,Fan Feng 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.1

To enhance the structural connectivity of prefabricated steel frame systems and augment their construction effi ciency, this study introduces an innovative prefabricated joint design tailored for square steel columns and H-beams characterized by varying beam heights. This study includes both static loading tests and seismic tests performed on full-scale joints featuring two diff erent beam heights. This investigation involved a comprehensive analysis of the static and seismic performance of the joints, employing various performance metrics such as ultimate load capacities, ultimate rotation angles, hysteresis curves, skeleton curves, stiff ness degradation curves, and ductility coeffi cients, in alignment with established structural codes and standards. The results indicate that the plasticity of the H-beam is fully developed, exhibiting a relative slip phenomenon. Additionally, the joints demonstrate commendable rotational capacity, with hysteresis curves consistently manifesting an inverse S-shape and exhibiting noteworthy stiff ness degradation. Furthermore, the comparison with the unimproved joint shows that the novel joint, in addition to being easy to construct, has better ductility and energy dissipation capacity. The results of the study will provide a technical reference for further optimization and application of prefabricated beam-column joints.

Model-Free Adaptive Integral Backstepping Control for PMSM Drive Systems

Hongmei Li,Xinyu Li,Zhiwei Chen,Jingkui Mao,Jiandong Huang 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

A SMPMSM drive system is a typical nonlinear system with time-varying parameters and unmodeled dynamics. The speed outer loop and current inner loop control structures are coupled and coexist with various disturbances, which makes the speed control of SMPMSM drive systems challenging. First, an ultra-local model of a PMSM driving system is established online based on the algebraic estimation method of model-free control. Second, based on the backstepping control framework, modelfree adaptive integral backstepping (MF-AIB) control is proposed. This scheme is applied to the permanent magnet synchronous motor (PMSM) drive system of an electric vehicle for the first time. The validity of the proposed control scheme is verified by system simulations and experimental results obtained from a SMPMSM drive system bench test.

Comparative Study on Anti-interference of Nondestructive Testing System with Annular Array Probes

Ru Bai,Zhiwei Li,Tengda Yang,Boyan Li,Aiyu Dou,Jiakun Tu,Jiaqi Li,Chuanjia Kou,Zhenghong Qian 한국자기학회 2024 Journal of Magnetics Vol.29 No.1

A pulsed eddy current nondestructive testing (PECT) system with annular array probes is designed for inner defect detection of metal pipelines. Tunneling magnetoresistance (TMR) array probes are applied to detect the magnetic signal generated by the inner surface defect of the metal pipelines. Compared to single probe structure, the annular array probes have advantages of high sensitivity, large scanning area and internal realtime detection. However, since many probes are densely arranged in the array, signal interference may occur between adjacent probes. Therefore, two methods of anti-interference, magnetic shielding and time-sharing excitation, are proposed in this work. By modeling and simulation, the working principles of the two antiinterference modes are analyzed and compared respectively. The experimental results show that both methods can reduce the interference between adjacent TMR probes. Compared with the time-sharing excitation method, the magnetic shielding method exhibits better performance with stronger differential signal peak and smaller error, and proves to be a more effective method for the defect detection of the metal pipelines.

Advanced glycation end products promote meniscal calcification by activating the mTOR-ATF4 positive feedback loop

Yang Sheng,Xie JiaJun,Pan ZhiJie,Guan HongMei,Tu YueSheng,Ye YuanJian,Huang ShouBin,Fu ShiQiang,Li KangXian,Huang ZhiWei,Li XiaoQi,Shi ZhanJun,Li Le,Zhang Yang 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

The meniscus is vital for maintaining knee homeostasis and function. Meniscal calcification is one of the earliest radiological indicators of knee osteoarthritis (KOA), and meniscal calcification is associated with alterations in biomechanical properties. Meniscal calcification originates from a biochemical process similar to vascular calcification. Advanced glycation end products (AGEs) and their receptors (RAGEs) reportedly play critical roles in vascular calcification. Herein, we investigated whether targeting AGE-RAGE is a potential treatment for meniscal calcification. In our study, we demonstrated that AGE-RAGE promotes the osteogenesis of meniscal cells and exacerbates meniscal calcification. Mechanistically, AGE-RAGE activates mTOR and simultaneously promotes ATF4 accumulation, thereby facilitating the ATF4-mTOR positive feedback loop that enhances the osteogenic capacity of meniscal cells. In this regard, mTOR inhibits ATF4 degradation by reducing its ubiquitination, while ATF4 activates mTOR by increasing arginine uptake. Our findings substantiate the unique role of AGE-RAGE in the meniscus and reveal the role of the ATF4-mTOR positive feedback loop during the osteogenesis of meniscal cells; these results provide potential therapeutic targets for KOA.

Stability and non-stationary vibration analysis of beams subjected to periodic axial forces using discrete singular convolution

Zhiwei Song,Wei Li,Guirong Liu 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.4

Dynamic instability of beams subjected to periodic axial forces is studied using the discrete singular convolution (DSC) method with the regularized Shannon’s delta kernel. The principal regions of dynamic instability under different boundary conditions are examined in detail, and the non-stationary vibrations near the stability-instability critical regions have been investigated. It is found that the results obtained by using the DSC method are consistent with the analytical solutions, which shows that the DSC algorithm is suitable for the problems considered in this study. It was found that there is a narrow region of beat vibration existed in the vicinity of one side (θ/Ω > 1) of the boundaries of the instable region for each condition.

Photosynthetic carbon fixation by tropical coral reef phytoplankton assemblages: a UVR perspective

Li, Gang,Che, Zhiwei,Gao, Kunshan The Korean Society of Phycology 2013 ALGAE Vol.28 No.3

Photosynthetic carbon fixation regulates air-sea $CO_2$ fluxes in the waters of coral reefs. However, little has been documented on the effects of solar UV radiation (UVR, 280-400 nm) upon photosynthetic behaviors of phytoplankton dwelling in these ecosystems. In order to evaluate the aforesaid, surface dwelling tropical coral reef phytoplankton assemblages collected from the South China Sea were exposed to solar radiation (i.e., photosynthetically active radiation [PAR] + UV radiation A [UVA] + UV radiation B [UVB], 280-700 nm; PAR + UVA, 320-700 nm; and PAR, 400-700 nm) under static or simulated-mixing conditions. Under the static condition, UVA and UVB significantly reduced the carbon fixation with the maximum of 22.4 and 15.3%, respectively; while lower UVR-related photosynthetic inhibition was observed in case of phytoplankton samples being subjected to mixing. At a moderate level of mixing (i.e., circulation time 80 min), the UVA and UVB caused inhibition were lowered by 52.1 and 79.6%, respectively. Based on this it could be stated that vertical mixing induced by winds and/or tides in the natural environments could reduce the inhibitory effect of solar UVR on phytoplankton productivity in the coral reefs water.