Disturbance Observer-based Neural Network Integral Sliding Mode Control for a Constrained Flexible Joint Robotic Manipulator

Quanwei Wen,Xiaohui Yang,Chao Huang,Junping Zeng,Zhixin Yuan,Peter Xiaoping Liu 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.4

In this paper, the tracking control problem of flexible joint robotic manipulator (FJRM) system subjected to system uncertainties and time-varying external disturbances (TVED) is addressed. A new disturbance observerbased neural network integral sliding mode controller with output constraints (DNISMCOC) that comprises the merits of neural networks, disturbance observer and integral sliding mode is proposed. Considering that the radial basis function neural network (RBFNN) has a fast learning convergence speed and great approximation ability, two matrices of RBFNN are utilized to estimate the parameter matrices of the dynamic model of FJRM. In view of the estimation errors of RBFNNs and TVED in the system, a disturbance observer is introduced to estimate the lump uncertainties which consist of them. Integral sliding mode is introduced for eliminating steady errors further. For ensuring security in some high-accuracy using occasions, a barrier lyapunov functions (BLF) is adopted to achieve output constraints of FJRM. To validate the effectiveness of the proposed control scheme, numerical simulations on 2-link FJRM are conducted. According to the comparisons among DNISMCOC and other state-ofthe-art controllers, the superiorities of DNISMCOC in several aspects are proved.

Simplified topology optimization of damping layer in plate structures for vibration and acoustic response

Le Qi,Quanwei Cui,Cheng Wang,Xueyan Sun,Janxing Zhou,Pengcheng Jin,Guochun Liu,Lirui Song 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

In this paper, a simplified acoustic optimization method is proposed to replace the sound power with the maximum normal velocity of the surface as a direct target, a topological optimization model of the variable density method is established to reduce the acoustic radiation of the structure, and the relationship between the form of damping distribution and the acoustic radiation is investigated. The complex modulus model is used to describe the viscoelastic material intrinsic relationship of the damping layer. The effects of different excitation frequencies on the topology optimization results are discussed. The radiated noise is simulated using the finite element method and the boundary element method. Five plates are fabricated according to the damping layer layout for different single-frequency excitations. Modal and acoustic experiments are carried out to validate the proposed method. The numerical and experimental results show that there is a significant reduction in the sound pressure level (SPL).

Differential effects of type 1 diabetes mellitus and subsequent osteoblastic βcatenin activation on trabecular and cortical bone in a mouse model

Sixu Chen,Daocheng Liu,Sihao He,Lei Yang,Quanwei Bao,Hao Qin,Huayu Liu,Yufeng Zhao,Zhaowen Zong 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Type 1 diabetes mellitus (T1DM) is a pathological condition associated with osteopenia. WNT/β-catenin signaling is implicated in this process. Trabecular and cortical bone respond differently to WNT/β-catenin signaling in healthy mice. We investigated whether this signaling has different effects on trabecular and cortical bone in T1DM. We first established a streptozotocin-induced T1DM mouse model and then constitutively activated β-catenin in osteoblasts in the setting of T1DM (T1-CA). The extent of bone loss was greater in trabecular bone than that in cortical bone in T1DM mice, and this difference was consistent with the reduction in the expression of β-catenin signaling in the two bone compartments. Further experiments demonstrated that in T1DM mice, trabecular bone showed lower levels of insulin-like growth factor-1 receptor (IGF-1R) than the levels in cortical bone, leading to lower WNT/β-catenin signaling activity through the inhibition of the IGF-1R/Akt/glycogen synthase kinase 3β (GSK3β) pathway. After β-catenin was activated in T1-CA mice, the bone mass and bone strength increased to substantially greater extents in trabecular bone than those in cortical bone. In addition, the cortical bone of the T1-CA mice displayed an unexpected increase in bone porosity, with increased bone resorption. The downregulated expression of WNT16 might be responsible for these cortical bone changes. In conclusion, we found that although the activation of WNT/ β-catenin signaling increased the trabecular bone mass and bone strength in T1DM mice, it also increased the cortical bone porosity, impairing the bone strength. These findings should be considered in the future treatment of T1DM-related osteopenia.

Mechanical Properties of Desert-Sand-Based Steel-PVA Hybrid Fiber Reinforced Engineered Cementitious Composites (H-DSECC)

Jialing Che,Ziwei Guo,Quanwei Li,Haifeng Liu 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.12

At present, the exploitation of river sand is forbidden because of the harm to the environment. The production processes of microsilica sand are complicated and the cost is high. The excellent availability of desert sand provides a practical solution for using it as the aggregate, this research used high-volume fly ash, steel fiber, PVA fiber and some or all of the Mu Us desert sand to replace the river sand to prepare the Desert-Sand-based steel-PVA hybrid Fiber Reinforced ECC (H-DSECC) that meets the performance requirements. Through the single factor test, the steel fiber replacement rate and the desert sand replacement rate were taken as the main factors, and the mechanical properties of H-DSECC were initially explored. The results show that the high steel fiber replacement rate or high desert sand replacement rate is not conducive to the realization of strain-hardening. An H-DSECC mixture containing 40% desert sand with W/B ratio of 0.29 has delivered the best properties with the tensile strain capacity of 1.467%, the tensile strength is 7.5 MPa and the cylinder compressive strength is 41.03 MPa at 28 days. Based on the measured stress-strain curves, the uniaxial tension/compression stress-strain curve equations are proposed.

Genome-wide single-nucleotide polymorphism data and mitochondrial hypervariable region 1 nucleotide sequence reveal the origin of the Akhal-Teke horse

Zhoucairang Kang,Jinping Shi,Ting Liu,Yong Zhang,Quanwei Zhang,Zhe Liu,Jianfu Wang,Shuru Cheng Asian Australasian Association of Animal Productio 2023 Animal Bioscience Vol.36 No.10

Objective: The study investigated the origin of the Akhal-Teke horse using genome-wide single-nucleotide polymorphism (SNP) data and mitochondrial hypervariable region 1 (HVR-1) nucleotide sequences Methods: Genome-wide SNP data from 22 breeds (481 horses) and mitochondrial HVR-1 sequences from 24 breeds (544 sequences) worldwide to examine the origin of the Akhal-Teke horse. The data were analyzed using principal component analysis, linkage disequilibrium analysis, neighbor-joining dendrograms, and ancestry inference to determine the population relationships, ancestral source, genetic structure, and relationships with other varieties. Results: A close genetic relationship between the Akhal-Teke horse and horses from the Middle East was found. Analysis of mitochondrial HVR-1 sequences showed that there were no shared haplotypes between the Akhal-Teke and Tarpan horses, and the mitochondrial data indicated that the Akhal-Teke horse has not historically expanded its group. Ancestral inference suggested that Arabian and Caspian horses were the likely ancestors of the Akhal-Teke horse. Conclusion: The Akhal-Teke horse originated in the Middle East.

Experimental and Numerical Analysis of the Construction Process for the Oblique Cantilevered Steel Reinforced Concrete Structure

Qinglin Tao,Wanyun Yin,Rencai Jin,Feng Yu,Beng Niu,Yi Hu,Zhitao Li,Quanwei Liu,Yuandi Qian,Dongyun Jia 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.5

The oblique cantilevered steel reinforced concrete structure (OCSRCS) which includes members of oblique beam, upright column, and the oblique column is manly applied in Olympic Sports Center Stadium and has the characteristics of large section, long span, and large inclination angle. For the safe and economical construction of the OCSRCS, a new construction method named Self-balancing and Self-supporting Method is proposed to take place of traditional construction method of Full-space Support. In this method, cables are utilized to transfer the lateral pressure and gravity load of concrete in pouring to the embedded steel in the OCSRCS and the platform. For ensure the safety of this method, the fi nite element method is proposed to predict the mechanical behavior of the OCSRCS in construction, and the strain variation of the embedded steel in the OCSRCS during the construction process has also observed by the in-situ experiment. The stress distribution of steel and cables in the OCSRCS is investigated and validated in this paper. The results show that the Self-balancing and Self-supporting Method for the OCSRCS can eff ectively ensures the safety of the construction, and it provides references for the construction of large-scale OCSRCS in engineering.