ROBUST COMBINED LANE KEEPING AND DIRECT YAW MOMENT CONTROL FOR INTELLIGENT ELECTRIC VEHICLES WITH TIME DELAY

Jinghua Guo,Yugong Luo,Chuan Hu,Chen Tao,Keqiang Li 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.2

In order to enhance the tracking performance and improve the stability of intelligent electric vehicles, combined Lane keeping and direct yaw moment control is a good choice. In this paper, an uncertain model of intelligent electric vehicles for combing the lane keeping and direct yaw moment control is deduced, in which time delay and data dropouts are involved. Since the intelligent electric vehicles have the features of time delay and strong uncertainties, a novel robust guaranteed cost combined lane keeping and direct yaw moment control system is constructed to manage the lateral motion of intelligent electric vehicles. The asymptotic stability of combined lane keeping and direct moment control system is verified based on the Lyapunov stability theory. Simulation tests are carried out to demonstrate the feasibility of the proposed control approach, and the results indicate that the presented robust combined control approach can accurately achieve the lane tracking capability, stability and maneuverability of intelligent electric vehicles.

ROBUST H∞ FAULT-TOLERANT LATERAL CONTROL OF FOUR-WHEEL-STEERING AUTONOMOUS VEHICLES

Jinghua Guo,Yugong Luo,Keqiang Li 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.4

This paper presents a robust H∞ fault-tolerant lateral controller of four wheel steering autonomous vehicles to enhance the autonomous driving performance and to track the desired road when a steering wheel fault happens. First, the lateral dynamic model of four wheel steering autonomous vehicles is constructed, which contains the features of parameter uncertainties and actuator faults of vehicles. Then, since the faulty steering wheel may fail to offer the desired torque and harm the lateral motion control system of autonomous vehicles, a novel robust H∞ fault tolerant state feedback lateral control law of four steering autonomous vehicles is designed to deal with actuator faults and parameter uncertainties. Finally, simulation tests are implemented in the Adams-Simulink joint platform with a high-fidelity and full-car model, and results verify the validity of this proposed control scheme.

MODEL PREDICTIVE ADAPTIVE CRUISE CONTROL OF INTELLIGENT ELECTRIC VEHICLES BASED ON DEEP REINFORCEMENT LEARNING ALGORITHM FWOR DRIVER CHARACTERISTICS

Guo Jinghua,Li WenChang,Luo Yugong,Li Keqiang 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.4

This paper presents a novel model predictive adaptive cruise control strategy of intelligent electric vehicles based on deep reinforcement learning algorithm for driver characteristics. Firstly, the influence mechanism of factors such as inter-vehicle distance, relative speed and time headway (THW) on the driver’s behavior in the process of car following is analyzed by the correlation coefficient method. Then, the driver behavior in the process of car following is learned from the natural driving data, the car following model is established by the deep deterministic policy gradient (DDPG) algorithm, and the output acceleration of the DDPG model is used as the reference trajectory of the ego vehicle’s acceleration. Next, in order to reflect the driver behavior and achieve multi performance objective optimization of adaptive cruise control of intelligent electric vehicles, the model predictive controller (MPC) is designed and used for tracking the desired acceleration produced by the car following DDPG model. Finally, the performance of the proposed adaptive cruise control strategy is evaluated by the experimental tests, and the results demonstrate the effectiveness of proposed control strategy.

Multi-orientation optimization of complex parts based on model segmentation in additive manufacturing

Hongshuai Guo,Jinghua Xu,Shuyou Zhang,Yiming Zhang,Jianrong Tan 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

Build orientation has a significant impact on the surface quality, support structure, and final cost of the fabricated model. In this study, we focus our attention on the surface quality and printing cost of complex parts when fabricated under multiple build orientations. A novel method using model segmentation is proposed to search for an optimal build orientation for each sub-model decomposed by Reeb graph. The sub-model is divided into separate regions that are treated differently based on modified curvature shift strategy. Every flat facet of the regions is given a different weight factor to build the volume error function. The optimal build orientation for each sub-model is the one leading to the minimal error of the volume error function. The case study demonstrates that the proposed method obtains a smaller error without any support structure. The model surface in higher weighted regions obtains a higher surface quality and is more cost saving when printed, especially for complex models.

Embedding Cobalt Into ZIF-67 to Obtain Cobalt-Nanoporous Carbon Composites as Electrode Materials for Lithium ion Battery

Zheng, Guoxu,Yin, Jinghua,Guo, Ziqiang,Tian, Shiyi,Yang, Xu The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.4

Lithium ion batteries (LIBs) is a kind of rechargeable secondary battery, developed from lithium battery, lithium ions move between the positive and negative electrodes to realize the charging and discharging of external circuits. Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials in which organic imidazole esters are cross-linked to transition metals to form a framework structure. In this article, ZIF-67 is used as a sacrificial template to prepare nano porous carbon (NPC) coated cobalt nanoparticles. The final product Co/NPC composites with complete structure, regular morphology and uniform size were obtained by this method. The conductive network of cobalt and nitrogen doped carbon can shorten the lithium ion transport path and present high conductivity. In addition, amorphous carbon has more pores that can be fully in contact with the electrolyte during charging and discharging. At the same time, it also reduces the volume expansion during the cycle and slows down the rate of capacity attenuation caused by structure collapse. Co/NPC composites first discharge specific capacity up to 3115 mA h/g, under the current density of 200 mA/g, circular 200 reversible capacity as high as 751.1 mA h/g, and the excellent rate and resistance performance. The experimental results show that the Co/NPC composite material improves the electrical conductivity and electrochemical properties of the electrode. The cobalt based ZIF-67 as the precursor has opened the way for the design of highly performance electrodes for energy storage and electrochemical catalysis.

<i>Pseudomonas aeruginosa</i> injects NDK into host cells through a type III secretion system

Neeld, Dennis,Jin, Yongxin,Bichsel, Candace,Jia, Jinghua,Guo, Jianhui,Bai, Fang,Wu, Weihui,Ha, Un-Hwan,Terada, Naohiro,Jin, Shouguang Society for General Microbiology 2014 Microbiology Vol.160 No.7

<P><I>Pseudomonas aeruginosa</I> is a Gram-negative opportunistic human pathogen possessing a type III secretion system (T3SS) which injects toxic effector proteins into mammalian host cells. In previous studies, <I>P. aeruginosa</I> strains lacking all of the known type III effectors were shown to cause cytotoxicity upon prolonged infection time. In this study, we report the identification of a new cytotoxin, nucleoside diphosphate kinase (NDK), which is injected into eukaryotic cells in a T3SS-dependent manner. Injection of NDK is inhibited by the presence of previously known effectors of the T3SS, with an effectorless strain injecting the highest amount, suggesting active competition with the known T3SS effectors. NDK is shown to cause a cytotoxic response when expressed in eukaryotic cells, and <I>P. aeruginosa</I> strains harbouring NDK also show a greater toxicity than strains lacking it. Interestingly, the cytotoxic effect of intracellular NDK is independent of its kinase activity. In previous studies, NDK was shown to be secreted into culture supernatants via a type I secretion system and cause cytotoxicity in a kinase-dependent manner. Therefore, the current study highlights an alternative route of NDK secretion as well as two different cytotoxic mechanisms of NDK, depending on the extra- or intra-cellular location of the protein.</P>

A Chaperone Function of NO CATALASE ACTIVITY1 Is Required to Maintain Catalase Activity and for Multiple Stress Responses in Arabidopsis

Li, Jing,Liu, Juntao,Wang, Guoqiang,Cha, Joon-Yung,Li, Guannan,Chen, She,Li, Zhen,Guo, Jinghua,Zhang, Caiguo,Yang, Yongqing,Kim, Woe-Yeon,Yun, Dae-Jin,Schumaker, Karen S.,Chen, Zhongzhou,Guo, Yan American Society of Plant Biologists 2015 The Plant cell Vol.27 No.3

<P>Arabidopsis protein NCA1 interacts with catalases in the cytosol and increases catalase activity through maintaining catalase folding state, which is required for stress responses.</P><P>Catalases are key regulators of reactive oxygen species homeostasis in plant cells. However, the regulation of catalase activity is not well understood. In this study, we isolated an <I>Arabidopsis thaliana</I> mutant, <I>no catalase activity1-3</I> (<I>nca1-3</I>) that is hypersensitive to many abiotic stress treatments. The mutated gene was identified by map-based cloning as NCA1, which encodes a protein containing an N-terminal RING-finger domain and a C-terminal tetratricopeptide repeat-like helical domain. NCA1 interacts with and increases catalase activity maximally in a 240-kD complex in planta. In vitro, NCA1 interacts with CATALASE2 (CAT2) in a 1:1 molar ratio, and the NCA1 C terminus is essential for this interaction. CAT2 activity increased 10-fold in the presence of NCA1, and zinc ion binding of the NCA1 N terminus is required for this increase. NCA1 has chaperone protein activity that may maintain the folding of catalase in a functional state. NCA1 is a cytosol-located protein. Expression of <I>NCA1</I> in the mitochondrion of the <I>nca1-3</I> mutant does not rescue the abiotic stress phenotypes of the mutant, while expression in the cytosol or peroxisome does. Our results suggest that NCA1 is essential for catalase activity.</P>