Filter-based Immersion and Invariance Adaptive Control of Nonlinear Systems

Wei Chen,Jian Hu,Jianyong Yao,Weirong Nie,Haibo Zhou 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.1

This paper proposes a novel filter-based immersion and invariance (I&I) adaptive method for nonlinear systems with additive disturbances and parameter uncertainties. The key innovation of the proposed method is a filter construction that involves the dynamics of the system, based on which the I&I parameter estimator with a sigma modification term is designed. Comparing existing I&I methods, the expression for the novel filter-based I&I estimator is given in terms of total derivatives rather than partial derivatives, which is no longer subject to the integrability condition. In combining the sigma modification term, the proposed parameter estimator also guarantee the uniformly ultimately bounded stability of the parameter estimation error when the system is disturbed, which cannot be achieved by the original I&I method. Furthermore, Lyapunov theory demonstrates that the proposed method can guarantee the stability of the nonlinear systems discussed in this paper. Simulation and experimental results confirm the effectiveness of the proposed method.

Stretchable Wire-Shaped Asymmetric Supercapacitors Based on Pristine and MnO₂ Coated Carbon Nanotube Fibers

Xu, Ping,Wei, Bingqing,Cao, Zeyuan,Zheng, Jie,Gong, Ke,Li, Faxue,Yu, Jianyong,Li, Qingwen,Lu, Weibang,Byun, Joon-Hyung,Kim, Byung-Sun,Yan, Yushan,Chou, Tsu-Wei American Chemical Society 2015 ACS NANO Vol.9 No.6

<P>While the emerging wire-shaped supercapacitors (WSS) have been demonstrated as promising energy storage devices to be implemented in smart textiles, challenges in achieving the combination of both high mechanical stretchability and excellent electrochemical performance still exist. Here, an asymmetric configuration is applied to the WSS, extending the potential window from 0.8 to 1.5 V, achieving tripled energy density and doubled power density compared to its asymmetric counterpart while accomplishing stretchability of up to 100% through the prestrainning-then-buckling approach. The stretchable asymmetric WSS constituted of MnO<SUB>2</SUB>/CNT hybrid fiber positive electrode, aerogel CNT fiber negative electrode and KOH-PVA electrolyte possesses a high specific capacitance of around 157.53 μF cm<SUP>–1</SUP> at 50 mV s<SUP>–1</SUP> and a high energy density varying from 17.26 to 46.59 nWh cm<SUP>–1</SUP> with the corresponding power density changing from 7.63 to 61.55 μW cm<SUP>–1</SUP>. Remarkably, a cyclic tensile strain of up to 100% exerts negligible effects on the electrochemical performance of the stretchable asymmetric WSS. Moreover, after 10 000 galvanostatic charge–discharge cycles, the specific capacitance retains over 99%, demonstrating a long cyclic stability.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-6/acsnano.5b01244/production/images/medium/nn-2015-012442_0007.gif'></P>

A Three-Dimensional Deep Convolutional Neural Network for Automatic Segmentation and Diameter Measurement of Type B Aortic Dissection

Yu Yitong,Gao Yang,Wei Jianyong,Liao Fangzhou,Xiao Qianjiang,Zhang Jie,Yin Weihua,Lu Bin 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.2

Objective: To provide an automatic method for segmentation and diameter measurement of type B aortic dissection (TBAD). Materials and Methods: Aortic computed tomography angiographic images from 139 patients with TBAD were consecutively collected. We implemented a deep learning method based on a three-dimensional (3D) deep convolutional neural (CNN) network, which realizes automatic segmentation and measurement of the entire aorta (EA), true lumen (TL), and false lumen (FL). The accuracy, stability, and measurement time were compared between deep learning and manual methods. The intra- and inter-observer reproducibility of the manual method was also evaluated. Results: The mean dice coefficient scores were 0.958, 0.961, and 0.932 for EA, TL, and FL, respectively. There was a linear relationship between the reference standard and measurement by the manual and deep learning method (r = 0.964 and 0.991, respectively). The average measurement error of the deep learning method was less than that of the manual method (EA, 1.64% vs. 4.13%; TL, 2.46% vs. 11.67%; FL, 2.50% vs. 8.02%). Bland-Altman plots revealed that the deviations of the diameters between the deep learning method and the reference standard were -0.042 mm (-3.412 to 3.330 mm), -0.376 mm (-3.328 to 2.577 mm), and 0.026 mm (-3.040 to 3.092 mm) for EA, TL, and FL, respectively. For the manual method, the corresponding deviations were -0.166 mm (-1.419 to 1.086 mm), -0.050 mm (-0.970 to 1.070 mm), and -0.085 mm (-1.010 to 0.084 mm). Intra- and inter-observer differences were found in measurements with the manual method, but not with the deep learning method. The measurement time with the deep learning method was markedly shorter than with the manual method (21.7 ± 1.1 vs. 82.5 ± 16.1 minutes, p < 0.001). Conclusion: The performance of efficient segmentation and diameter measurement of TBADs based on the 3D deep CNN was both accurate and stable. This method is promising for evaluating aortic morphology automatically and alleviating the workload of radiologists in the near future.

Carbon Nanotube Fiber Based Stretchable Wire-Shaped Supercapacitors

Xu, Ping,Gu, Taoli,Cao, Zeyuan,Wei, Bingqing,Yu, Jianyong,Li, Faxue,Byun, Joon-Hyung,Lu, Weibang,Li, Qingwen,Chou, Tsu-Wei Wiley Blackwell (John Wiley Sons) 2014 ADVANCED ENERGY MATERIALS Vol.4 No.3

Printing direction dependence of mechanical behavior of additively manufactured 3D preforms and composites

Quan, Zhenzhen,Suhr, Jonghwan,Yu, Jianyong,Qin, Xiaohong,Cotton, Chase,Mirotznik, Mark,Chou, Tsu-Wei Elsevier 2018 Composite structures Vol.184 No.-

<P><B>Abstract</B></P> <P>Among the processing parameters of additive manufacturing, printing direction is of critical importance. While studies on effects of printing direction have so far mainly focused on mechanical properties of solid specimens, the present research is intended to demonstrate printing direction dependence of mechanical behavior of additively manufactured 3D preforms and their composites. Compressive behavior of additively manufactured 3D braid preforms and composites was investigated for three distinct printing directions (0°, 45° and Z-direction). Fused filament fabrication (FFF) of acrylonitrile-butadiene-styrene (ABS) filament and short carbon fiber/ABS (CF/ABS) filament was adopted. First, solid cube specimens were fabricated; the parts printed along 0° and 45° directions showed more fabrication-induced pores. Then, 3D braid preforms were fabricated and infused with silicone matrix. For preforms printed along 45° direction, inter-yarn adhesion was observed, which enhanced specimen initial modulus. On the other hand, Z-direction specimens showed higher structural ductility, due to inter-yarn slippage.</P>

Spatial strain variation of graphene films for stretchable electrodes

Xu, Ping,Kang, Junmo,Suhr, Jonghwan,Smith, Joseph P.,Booksh, Karl S.,Wei, Bingqing,Yu, Jianyong,Li, Faxue,Byun, Joon-Hyung,Oh, Youngseok,Chou, Tsu-Wei Elsevier 2015 Carbon Vol.93 No.-

<P><B>Abstract</B></P> <P>Graphene films fabricated by chemical vapor deposition are promising electrode materials for stretchable energy storage devices. The buckled four-layer graphene on a polydimethylsiloxane film substrate subject to various applied tensile strains has been characterized by atomic force microscopy and micro-Raman mapping. The small redshift of 2D band and the indiscernible D band demonstrated that the tensile strains of up to 40% only induced a strain variation of less than 0.2% and did not cause any observable damage in the graphene film. This study has confirmed that the graphene film in the buckled state is suitable for its application as a stretchable electrode.</P>

Laminated Ultrathin Chemical Vapor Deposition Graphene Films Based Stretchable and Transparent High-Rate Supercapacitor

Xu, Ping,Kang, Junmo,Choi, Jae-Boong,Suhr, Jonghwan,Yu, Jianyong,Li, Faxue,Byun, Joon-Hyung,Kim, Byung-Sun,Chou, Tsu-Wei American Chemical Society 2014 ACS NANO Vol.8 No.9

<P>Due to their exceptional flexibility and transparency, CVD graphene films have been regarded as an ideal replacement of indium tin oxide for transparent electrodes, especially in applications where electronic devices may be subjected to large tensile strain. However, the search for a desirable combination of stretchability and electrochemical performance of such devices remains a huge challenge. Here, we demonstrate the implementation of a laminated ultrathin CVD graphene film as a stretchable and transparent electrode for supercapacitors. Transferred and buckled on PDMS substrates by a prestraininig-then-buckling strategy, the four-layer graphene film maintained its outstanding quality, as evidenced by Raman spectra. Optical transmittance of up to 72.9% at a wavelength of 550 nm and stretchability of 40% were achieved. As the tensile strain increased up to 40%, the specific capacitance showed no degradation and even increased slightly. Furthermore, the supercapacitor demonstrated excellent frequency capability with small time constants under stretching.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2014/ancac3.2014.8.issue-9/nn503570j/production/images/medium/nn-2014-03570j_0008.gif'></P>