Backstepping Sliding Mode Control Based on Extended State Observer for Robotic Manipulators with LuGre Friction

Zhenghong Xu,Xiaohui Yang,Wenjie Zhang,Wei Zhang,Liufang Zhang,Peter Xiaoping Liu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.6

In this paper, we propose a backstepping integral nonsingular fast terminal sliding mode control approach based on an extended state observer to the trajectory tracking control of robotic manipulators with LuGre friction. In order to improve convergence speed and tracking precision, an integral fast terminal sliding surface is introduced. An appropriate saturation function is designed in the control input to avoid singularity. An extended state observer is employed to estimate the uncertainties and disturbances, and they are compensated by the control laws, for which the chattering can be effectively eliminated. The backstepping method is used to design the control input of the system to ensure the globally asymptotic stability based on the Lyapunov criterion. In comparison with other control methods, simulation results show effectiveness and superiority of this proposed control scheme.

Extended State Observer Based Adaptive Backstepping Nonsingular Fast Terminal Sliding-mode Control for Robotic Manipulators with Uncertainties

Zhenghong Xu,Xiaohui Yang,Wenjie Zhang,Wei Zhang,Shuang Yang,Siyi Zhou,Peter Xiaoping Liu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.9

This paper proposes a novel robust finite-time tracking control scheme for robotic manipulators with uncertainties and external disturbances. In order to reduce the chattering phenomenon and enhance the robustness of the system, we design a novel extended state observer with filter function for estimating the lumped term of system uncertainties and external disturbances. We adopt the backstepping mechanism to design an adaptive backstepping nonsingular fast terminal sliding mode controller, achieve finite time convergence of the tracking errors while avoiding the singularity problem. An adaptive update law is designed for the switching gain, which further weakens the chattering problem. The finite-time convergence of tracking errors and the stability of the closed-loop system are ensured by the Lyapunov criterion. In comparison with other control methods, numerical simulation on a two-link rigid robot manipulator demonstrates the effectiveness and superiority of the proposed method.

Synchronization for IR-UWB System Using a Switching Phase Detector-Based Impulse Phase-Locked Loop

Lin Zheng,Zhenghong Liu,Mei Wang 한국전자통신연구원 2012 ETRI Journal Vol.34 No.2

Conventional synchronization algorithms for impulse radio require high-speed sampling and a precise local clock. Here, a phase-locked loop (PLL) scheme is introduced to acquire and track periodical impulses. The proposed impulse PLL (iPLL) is analyzed under an ideal Gaussian noise channel and multipath environment. The timing synchronization can be recovered directly from the locked frequency and phase. To make full use of the high harmonics of the received impulses efficiently in synchronization, the switching phase detector is applied in iPLL. It is capable of obtaining higher loop gain without a rise in timing errors. In different environments, simulations verify our analysis and show about one-tenth of the root mean square errors of conventional impulse synchronizations. The developed iPLL prototype applied in a high-speed ultra-wideband transceiver shows its feasibility, low complexity, and high precision.

MiR-338-3p Enhances Ovarian Cancer Cell Sensitivity to Cisplatin by Downregulating WNT2B

Qin Niu,Zhenghong Liu,Jia Gao,Qiao Wang 연세대학교의과대학 2019 Yonsei medical journal Vol.60 No.12

Purpose: Chemoresistance is a concern in ovarian cancer patients, in whom survival remains. MicroRNA, a novel class of smallRNAs, have frequently been found to be dysregulated in human malignancies and to act as negative regulators of gene expression. This study aimed to explore the function of miR-338-3p in cisplatin resistance in ovarian cancer and potential molecular mechanismsthereof. Materials and Methods: The expression levels of miR-338-3p and WNT2B in ovarian cancer tissues and cells were estimated byreal-time quantitative polymerase chain reaction (RT-qPCR). In addition, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT), transwell, and flow cytometry assays were used to assess biological role of miR-338-3p in vitro. Western blotassay was conducted to measure protein expression of WNT2B, epithelial-mesenchymal transition (EMT)-related proteins, andapoptosis-related proteins. The relationship between miR-338-3p and WNT2B was confirmed by dual-luciferase reporter. Finally, axenograft tumor model was developed to explore the effects of overexpression of miR-338-3p on tumor growth in ovarian cancerin vivo. Results: MiR-338-3p was downregulated in cisplatin resistant ovarian cancer tissues and cells. Mechanistically, high expression ofmiR-338-3p enhanced cell sensitivity to cisplatin by inhibiting proliferation, motility, and EMT and by promoting apoptosis via targetingWNT2B expression in vitro. Furthermore, overexpression of miR-338-3p increased cisplatin sensitivity among ovarian cancerin an in vivo xenograft tumor model. Conclusion: MiR-338-3p enhances the sensitivity of ovarian cancer cells to cisplatin by downregulating WNT2B.

A New BISON-like Construction Block Cipher: DBISON

Haixia Zhao,Yongzhuang Wei,Zhenghong Liu 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.5

At EUROCRYPT 2019, a new block cipher algorithm called BISON was proposed by Canteaut et al. which uses a novel structure named as Whitened Swap−Or−Not (WSN). Unlike the traditional wide trail strategy, the differential and linear properties of this algorithm can be easily determined. However, the encryption speed of the BISON algorithm is quite low due to a large number of iterative rounds needed to ensure certain security margins. Commonly, denoting by n is the data block length, this design requires 3n encryption rounds. Moreover, the block size n of BISON is always odd, which is not convenient for operations performed on a byte level. In order to overcome these issues, we propose a new block cipher, named DBISON, which more efficiently employs the ideas of double layers typical to the BISON-like construction. More precisely, DBISON divides the input into two parts of size n/2 bits and performs the round computations in parallel, which leads to an increased encryption speed. In particular, the data block length n of DBISON can be even, which gives certain additional implementation benefits over BISON. Furthermore, the resistance of DBISON against differential and linear attacks is also investigated. It is shown the maximal differential probability (MDP) is 1/2n-1 for n encryption rounds and that the maximal linear probability (MLP) is strictly less than 1/2n-1 when (n/2+3) iterative encryption rounds are used. These estimates are very close to the ideal values when n is close to 256.

An Adaptive Fault-tolerant Control Method for Robot Manipulators

Wenjie Zhang,Xiaohui Yang,Zhenghong Xu,Wei Zhang,Li Yang,Xiaoping Liu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.12

This paper presents a new method for adaptive continuous nonsingular fast terminal sliding mode control (ACNFTSMC) based on a novel structure-improved extended state observer (SIESO) for fault-tolerant control (FTC). In response to the initial peaking phenomenon in traditional ESO (TESO), which can severely degrade the accuracy and stability of the control system, The SIESO is designed to replace TESO to estimate the lump disturbances/faults. Besides, to address the problem of the unknown estimation error of ESO, an adaptive technique is applied to compensate for the observation error in real-time. To guarantee fast convergence and chattering-free, the CNFTSMC method is employed. Afterward, the stability and rapid convergence of the control system is demonstrated using Lyapunov theory. Finally, the simulation results verify the superiority of the proposed control strategy compared to the other existing advanced control techniques.

Provenance and tectonic setting of the Yimianpo Group in the southeastern Songnen–Zhangguangcai Range Block: constraints on the closure of the Mudanjiang Ocean

Mishan Zhong,Jin Liu,Zhenghong Liu,Jundian Chen,Hongchao Yu,Haipeng Wang,Junshi Lu,Zijie Wu,Mingchen Pan,Liaoning Geological Exploration Institute Co., Ltd.,Yilong Wang 한국지질과학협의회 2023 Geosciences Journal Vol.27 No.4

The timing of the collision between the Songnen–Zhangguangcai Range Block (SNZRB) and the Jiamusi Block (JMSB) is poorly constrained; however, detrital zircons may provide crucial information on the history of this collision. This study focuses on the Yangmugang and Tumenling formations of the Yimianpo Group in the southeastern SNZRB, which were previously thought to have been deposited during the closure of the Mudanjiang Ocean. Detrital zircon U-Pb dating was carried out to constrain the age, provenance, and tectonic setting of the Yangmugang and Tumenling formations, and ultimately the timing of the final closure of the Mudanjiang Ocean. The detrital zircon grains in the two formations yield similar age spectra, with two major age peaks at 275 Ma and 280 Ma, 512 Ma and 525 Ma, respectively. Given the age of the youngest group and that of a granite intrusion, the Yangmugang and Tumenling formations were probably deposited during the middle Permian. The detrital zircon ages also suggest that the Paleozoic igneous rocks distributed across the eastern SNZRB were the major source of the zircons in the formations. Combined with evidence for synchronous arc magmatism, this shows that the Yangmugang and Tumenling formations were likely deposited at a convergent margin and that the collision between the SNZRB and JMSB occurred after the late Permian.

Improved Mutual MRAS Speed Identification Based on Back-EMF

Zheng, Hong,Zhao, Jiancheng,Liu, Liangzhong The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

In the design of sensorless control system for induction motor, high-precision speed estimation is one of the most difficult problems. To solve this problem, the common method is model reference adaptive method (MRAS). MRAS requires accurate motor parameters to estimate rotor speed precisely. However, when motor is running, the variety of temperature and magnetic saturation will lead to the change of motor parameters such as stator resistance and rotor resistance, which will lower the accuracy of the speed estimation. To improve the accuracy and rapidity of speed estimation, this paper analyses the mutual MRAS speed identification based on rotor flux linkage, and proposes an improved mutual MRAS speed identification based on back-EMF. The improved method is verified by Simulink simulation and motor experimental platform based on DSP2812. The results of simulation and experiment indicate that the method proposed by this paper can significantly improve the accuracy of speed identification, and speed up the response of identification.