Design of Adaptive RBFNN and Computed-torque Control for Manipulator Joint Considering Friction Modeling

Xiaobin Shen,Kun Zhou,Rui Yu,Binrui Wang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.7

In this paper, we aim to improve the tracking performance of the manipulator joint system by establishing accurate friction model based on the Stribeck model and the cubic polynomial method. Meanwhile, in view of the established system model, an adaptive Radial Basis Function Neural Network (RBFNN) compensation computedtorque controller is designed for the manipulator joint system. Firstly, we consider the friction modeling process at low- and high- velocity regions to advance the model accuracy, and identify the parameters in the friction model equation offline via the particle swarm optimization (PSO) algorithm. Secondly, an adaptive RBFNN algorithm is developed to analyze the unmodeled dynamics online and introduce it to the computed-torque controller design. After that, we further conduct the stability analysis for the proposed controller based on the Lyapunov stability criterion. Finally, the self-developed manipulator joint platform introduction, the simulation experiment and the contradistinctive experiments are given to illustrate the effectiveness of designed controller.

Metabolite profiles of ginsenosides Rk1 and Rg5 in zebrafish using ultraperformance liquid chromatography/quadrupole-time-of-flight MS

Shen, Wenwen,Wei, Yingjie,Tang, Daoquan,Jia, Xiaobin,Chen, Bin The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.1

Background: In the present study, metabolite profiles of ginsenosides Rk1 and Rg5 from red ginseng or red notoginseng in zebrafish were qualitatively analyzed with ultraperformance liquid chromatography/quadrupole-time-of-flight MS, and the possible metabolic were pathways proposed. Methods: After exposing to zebrafish for 24 h, we determined the metabolites of ginsenosides Rk1 and Rg5. The chromatography was accomplished on UPLC BEH C18 column using a binary gradient elution of 0.1% formic acetonitrile-0.1% formic acid water. The quasimolecular ions of compounds were analyzed in the negative mode. With reference to quasimolecular ions and MS2 spectra, by comparing with reference standards and matching the empirical molecular formula with that of known published compounds, and then the potential structures of metabolites of ginsenosides Rk1 and Rg5 were acquired. Results: Four and seven metabolites of ginsenoside Rk1 and ginsenoside Rg5, respectively, were identified in zebrafish. The mechanisms involved were further deduced to be desugarization, glucuronidation, sulfation, and dehydroxymethylation pathways. Dehydroxylation and loss of C-17 residue were also metabolic pathways of ginsenoside Rg5 in zebrafish. Conclusion: Loss of glucose at position C-3 and glucuronidation at position C-12 in zebrafish were regarded as the primary physiological processes of ginsenosides Rk1 and Rg5.

Computational fluid dynamic analysis of mass transfer and hydrodynamics in a planetary centrifugal bioreactor

Baojun Shen,Xiaobin Zhan,Yu He,Zhibin Sun,Jiecai Long,Yili Yang,Xiwen Li 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.7

Planetary centrifugal bioreactors are promising candidates for cell culture platforms since there is no pollution caused by stirring blades. In this work, the fluid structure in a planetary centrifugal bioreactor was investigated using the computational fluid dynamics (CFD) method. The effects of operating conditions on the oxygen transfer rate (OTR), mixing efficiency and shear environment of the bioreactor were studied with the revolution speed (N) ranging from 60 to 160 rpm and the rotation-to-revolution speed ratio (i) from 2 to 1. The results show that the volumetric mass transfer coefficient (kLa), turbulence intensity, volumetric power consumption, and shear stress increase along with the increase of the revolution and rotation speeds. Furthermore, the rotation in the opposite direction to the revolution is beneficial to the performance of the bioreactor. The planetary centrifugal bioreactor has a higher kLa of 50- 200/h and a lower average shear stress of 0.01-0.05 Pa in comparison with conventional stirred tank bioreactors, which makes it suitable for biological culture of oxygen-consuming cells and shear-sensitive cells.

An Embedded Software Power Consumption Model based on Software Architecture and Support Vector Machine Regression

Xiong Wei,Xiaobin Liu,Bing Guo,Shen Yan,Wenli Zhang 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.3

As embedded devices prevail in daily life, high energy consumption caused by embedded software caught academic attentions. Multifarious testing and predicting methods are developed accordingly. This paper proposes a model about energy consumption of embedded device based on analysis of embedded software structure and support vector machine regression. The nonlinear relationship between energy consumption and software structure is revealed. The research finds software structure is determined by features like number of components, complexity of component interface, component coupling, and path length. These features are qualified and modeled by using support vector machine regression and energy consumption is predicted based on this model. The experiments results confirm the proposed model.

Analysis of the extrusion pressure of a cylindrical extruder for extruding highly viscous fluids

Zhibin Sun,Baojun Shen,Yu He,Jiecai Long,Xiaobin Zhan,Yujin Li,Xiwen Li 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10

Extrusion pressure is crucial for the security and performance of a cylindrical extruder during the extrusion process. In this study, a validated CFD model was adopted to evaluate the relationship between the extrusion velocity, fluid viscosity, and the extrusion pressure of a cylindrical extruder while extruding highly viscous fluids. The simulated and experimental results of the extrusion pressure and velocity profiles show good agreement. This study reveals that extrusion pressure evolution can be divided into two stages during the extrusion process. At stage I, the distance between the ram and the bottom of the vessel (liquid height) is greater than the critical height and the extrusion pressure remains almost constant. At stage II, the distance is less than the critical height and the extrusion pressure increases exponentially. The results indicate that an increase in extrusion velocity and fluid viscosity leads to a linear increase in the extrusion pressure at stage I. Furthermore, by introducing a pressure number, Np, and a pressurerelated Reynolds number, Rep, a novel correlation of the extrusion pressure with the extrusion velocity, viscosity of highly viscous fluids and liquid height has been developed.

Numerical investigation of the mixing process in a Twin Cam Mixer: Influence of triangular cam height-base ratio and eccentricity

Yu He,Xiwen Li,Jiecai Long,Baojun Shen,Zhibin Sun,Yili Yang,Xiaobin Zhan 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.3

The twin cam mixer (TCM), as a general-purpose mixer, shares many attributes in common with 3D industrial mixers, like the internal mixer. We investigated the mixing process in a 2D TCM with two identical isosceles triangular cams rotating at 0.5 rpm. A 2D numerical model coupled with the species transport model was employed to study the influence of cam height-base ratio and eccentricity qualitatively and quantitatively, and both were found to have a significant effect on the mixing behavior of the mixer. Furthermore, a dimensionless parameter, named the modified pressurization coefficient, is put forward to quantify the geometry of the mixer. The logarithmic relationship between the modified pressurization coefficient and the mixing quality was discovered and expected to provide new ideas for establishing the relationship between the geometric parameters of a mixer and its mixing performance.

3D Numerical Simulation of Ice Accretion on a Rotating Surface

Zuodong Mu,Guiping Lin,Lizhan Bai,Xiaobin Shen,Xueqin Bu 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.2

A novel 3D mathematical model for water film runback and icing on a rotating surface is established in this work, where both inertial forces caused by the rotation and shear forces due to the air flow are taken into account. The mathematical model of the water film runback and energy conservation of phase transition process is established, with a cyclical average method applied to simulate the unsteady parameters variation at angles of attack. Ice accretion on a conical spinner surface is simulated and the results are compared with the experimental data to validate the presented model. Then Ice accretion on a cowling surface is numerically investigated. Results show that a higher temperature would correspond to a larger runback ice area and thinner ice layer for glaze ice. Rotation would enhance the icing process, while it would not significantly affect the droplet collection efficiency for an axi-symmetric surface. In the case at angle of attack, the effect of rotation on ice shape is appreciable, ice would present a symmetric shape, while in a stationary case the shape is asymmetric.

3D Numerical Simulation of Ice Accretion on a Rotating Surface

Mu, Zuodong,Lin, Guiping,Bai, Lizhan,Shen, Xiaobin,Bu, Xueqin The Korean Society for Aeronautical and Space Scie 2017 International Journal of Aeronautical and Space Sc Vol.18 No.2

A novel 3D mathematical model for water film runback and icing on a rotating surface is established in this work, where both inertial forces caused by the rotation and shear forces due to the air flow are taken into account. The mathematical model of the water film runback and energy conservation of phase transition process is established, with a cyclical average method applied to simulate the unsteady parameters variation at angles of attack. Ice accretion on a conical spinner surface is simulated and the results are compared with the experimental data to validate the presented model. Then Ice accretion on a cowling surface is numerically investigated. Results show that a higher temperature would correspond to a larger runback ice area and thinner ice layer for glaze ice. Rotation would enhance the icing process, while it would not significantly affect the droplet collection efficiency for an axi-symmetric surface. In the case at angle of attack, the effect of rotation on ice shape is appreciable, ice would present a symmetric shape, while in a stationary case the shape is asymmetric.