Double Iterative Compensation Learning Control for Active Training of Upper Limb Rehabilitation Robot

Xuefeng Zhu,Jian-Hui Wang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.3

In this paper, the problem of non parametric uncertainty in the active training stage of stroke patients is discussed. On the basis of the nonlinear iterative learning theory, a double iterative compensation learning control is proposed. This method adopts the strategy of double loop iteration which can adjust controller parameters in real time to satisfy the patients’ condition. First, a class of saturated nonlinear functions is introduced to satisfy the requirement of position constraints. Then, reference trajectory self-modified strategy is designed for the initial positioning error. Meanwhile, the iterative compensation controller is designed according to the active torque of the patient, which can provide appropriate power compensation to the affected limb and update the parameters of the iterative learning controller continuously. At last, the convergence condition and its proof are given. The simulation results show the effectiveness and practicability of the proposed double iterative compensation optimal control strategy.

Parallel Shunt for the Treatment of Transjugular Intrahepatic Portosystemic Shunt Dysfunction

Xuefeng Luo,Ling Nie,Jiaywei Tsauo,Zhu Wang,Chengwei Tang,Xiao Li 대한영상의학회 2013 Korean Journal of Radiology Vol.14 No.3

Objective: To investigate the safety, efficacy and long-term patency of parallel shunts (PS) in the management of the transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Materials and Methods: Between March 2007 and October 2010, 18 patients (13 men and 5 women) who underwent TIPS revision with the creation of PS were evaluated retrospectively. In the first 10 patients, a 10-mm-diameter Wallgraft endoprosthesis was deployed; in the latter 8 patients, an 8-mm-diameter Fluency endoprosthesis was deployed. Results: The creation of PS was technically successful in all patients. The mean ± standard deviation portosystemic pressure gradient before and after the procedure was 25.5 ± 7.3 mm Hg (range, 16-37 mm Hg) and 10.9 ± 2.3 mm Hg (range, 7-16 mm Hg), respectively. The duration of follow-up was 16.7 ± 10.8 months (range, 6-42 months). The primary shunt patency rates at 12 months after the creation of PS was 70% with Wallgraft endoprostheses and 87.5% with Fluency endoprostheses. Conclusion: TIPS revision with the creation of PS is a safe, effective and durable method for treating shunt dysfunction.

Isogeometric method based in-plane and out-of-plane free vibration analysis for Timoshenko curved beams

Hongliang Liu,Xuefeng Zhu,Dixiong Yang 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.3

In-plane and out-of-plane free vibration analysis of Timoshenko curved beams is addressed based on the isogeometric method, and an effective scheme to avoid numerical locking in both of the two patterns is proposed in this paper. The isogeometric computational model takes into account the effects of shear deformation, rotary inertia and axis extensibility of curved beams, and is applicable for uniform circular beams, and more complicated variable curvature and cross-section beams as illustrated by numerical examples. Meanwhile, it is shown that, the Cp–1-continuous NURBS elements remarkably have higher accuracy than the finite elements with the same number of degrees of freedom. Nevertheless, for in-plane or out-of-plane vibration analysis of Timoshenko curved beams, the NURBS-based isogeometric method also exhibits locking effect to some extent. To eliminate numerical locking, the selective reduced one-point integration and B projection element based on stiffness ratio is devised to achieve locking free analysis for in-plane and out-of-plane models, respectively. The suggested integral schemes for moderately slender models obtain accurate results in both dominated and non-dominated regions of locking effect. Moreover, this strategy is effective for beam structures with different slenderness. Finally, the influence factors of structural parameters of curved beams on their natural frequency are scrutinized.

Sparse reconstruction of guided wavefield from limited measurements using compressed sensing

Baijie Qiao,Zhu Mao,Hao Sun,Songmao Chen,Xuefeng Chen 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.3

A wavefield sparse reconstruction technique based on compressed sensing is developed in this work to dramatically reduce the number of measurements. Firstly, a severely underdetermined representation of guided wavefield at a snapshot is established in the spatial domain. Secondly, an optimal compressed sensing model of guided wavefield sparse reconstruction is established based on l1-norm penalty, where a suite of discrete cosine functions is selected as the dictionary to promote the sparsity. The regular, random and jittered undersampling schemes are compared and selected as the undersampling matrix of compressed sensing. Thirdly, a gradient projection method is employed to solve the compressed sensing model of wavefield sparse reconstruction from highly incomplete measurements. Finally, experiments with different excitation frequencies are conducted on an aluminum plate to verify the effectiveness of the proposed sparse reconstruction method, where a scanning laser Doppler vibrometer as the true benchmark is used to measure the original wavefield in a given inspection region. Experiments demonstrate that the missing wavefield data can be accurately reconstructed from less than 12% of the original measurements; The reconstruction accuracy of the jittered undersampling scheme is slightly higher than that of the random undersampling scheme in high probability, but the regular undersampling scheme fails to reconstruct the wavefield image; A quantified mapping relationship between the sparsity ratio and the recovery error over a special interval is established with respect to statistical modeling and analysis.

The Role of Monoxide Hemoglobin in Color Improvement of Chicken Sausage

Peng Xu,Xuefeng Zhu,Shengjiang Tan,Hao Qin,Cunliu Zhou 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.2

The role of monoxide hemoglobin (COHb) in improvement of chicken sausage color was investigated. COHb and NaNO2 synergistically increased a* values. Addition of 0.1% COHb decreased the residual nitrite content in the presence of 0.001% NaNO2. Compared with controls, the combined treatment resulted in significantly higher nitroso pigment contents while the single treatment resulted in slightly higher nitroso pigment contents. Visible spectrometry indicated that both nitrosohemochrome (NH) and hematin were the main ingredients of pigments extracted from chicken sausage treated with a combination of 0.006% NaNO2 and 0.6% COHb. Formation of NH and hematin caused an increase in a* values and a decrease in L* values, respectively. COHb showed potential for use in meat product formulations.

AR model-based crosstalk cancellation method for operational transfer path analysis

Wei Cheng,Yan Zhu,Xuefeng Chen,Chao Song,Le Zhang,Lin Gao,Yilong Liu,Zelin Nie,Hongrui Cao,Yang Yang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3

To reduce the crosstalk effects between the signals at reference points in operational transfer path analysis (OTPA) and improve the reliability of solutions, a novel OTPA method based on auto-regressive (AR) model is proposed in this paper. The key to this method is to obtain the power spectrum by AR model for estimating the prior transmissibility function matrix. Firstly, in view of the lack of noise reduction process in conventional crosstalk cancellation method, singular value decomposition (SVD) is applied to reduce the noise of original signals. Secondly, Burg algorithm is used to calculate AR model parameters. Thirdly, auto-power spectrum and cross-power spectrum are obtained by AR model and the periodogram method respectively. Fourthly, the transmissibility function matrix is obtained by Landweber iterative method based on corrected signals at reference points. Finally, the proposed method can significantly reduce the crosstalk effects, resulting in more accurate evaluation of transfer path contributions. Generally, this study can provide accurate and reliable evidences for vibration & noise monitoring and reduction for mechanical systems, and thus benefit for the active control of vibration & noise.

Core–shell structure g-MnO2-PANI carbon fiber paper-based flexible electrode material for high-performance supercapacitors

Xuxia Ling,Guoliang Zhang,Zhu Long,Xuefeng Lu,Zhibin He,Jie Li,Yuheng Wang,Dan Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-

Good conductivity is the key to ensuring high electrochemical performance, and the uniformity of theactive material directly affects the electrical conductivity. This paper proposes a novel modified stepwisein situ polymerization method to prepare composite materials, and then uses the K/S value method tocharacterize the uniformity of polyaniline distribution. Specifically, the study presents a papermakingwet-lay technique to prepare a carbonfiber paper substrate (CP) that is light-weight,flexible, andfoldable while also having low internal resistance and high porosity. The g-MnO2 is wrapped with PANI toform a core–shell structure, and a modified stepwise in situ polymerization method is adopted to depositthe core–shell structure uniformly on the CP substrate by physical adsorption. This process yields aflexible electrode material for supercapacitors, called g-MnO2-PANI-CP electrode. Results show thatthe g-MnO2-PANI-CP electrode has a high specific capacitance of 642.5 F g 1 at a current density of 1A g 1, and also has a high energy density of 114.2 Wh kg 1 at a power density of 798.6 W kg 1. In addition,the electrode retains 81.3% of the initial capacitance after 5000 cycles, demonstrating high cyclingperformance.

Optimization of Processing Conditions of Chinese Smoke-cured Bacon (Larou) with a New Natural Coating Solution during Storage Period

Na Liu,Qiujin Zhu,Xuefeng Zeng,Bowen Yang,Meilian Liang,Li Deng,Laping He,Cai Liang,Ruping Zhang,Juan Zhou 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.3

The study aims to determine the optimum sterilization rate and water activity of Chinese traditional smoke-cured bacon product (Larou) in the preservation with natural coating solution. With the response surface methodology (RSM), we analyzed 3 factors of processing conditions (the concentration of lysozyme, concentration of sodium alginate, and concentration of chitosan) and 2 response factors (sterilization rate and water activity). Sterilization rate and water activity of Larou were largely affected by the concentration of lysozyme, concentration of sodium alginate, and concentration of chitosan. The final optimum concentrations of lysozyme, sodium alginate, and chitosan were 0.09, 1.40, and 1.60% and realized the high sterilization rate. Water activity of sliced Larou was significantly correlated with the sterilization rate. Low-field nuclear magnetic resonance analysis verified the optimum processing conditions. The coating resulted in 99.69% rate of reducing bacteria after 30-day storage. The data of the total number of colony, peroxidation value, moisture content, pH, and sensory evaluation provided the theoretical basis for extending the shelf life of Chinese traditional smoke-cured bacon product (Larou) with natural coating solution.

The Centralized Containment Strategy and Mathematical Modeling Analysis

Liu Yang,Wang Bailing,Yuan Xinling,Bai Xuefeng,Zhu Qiang 보안공학연구지원센터 2013 International Journal of Smart Home Vol.7 No.3

Development of a novel self-validating soft sensor

Yiqi Liu,Daoping Huang,Yan Li,Xuefeng Zhu 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.9

A self-validating soft sensor is proposed that not only can perform self-diagnostics and self-reconstruction,but also generate a variety of output data types, including the prediction values, input sensors status of soft sensor and the uncertainty values which represent the credibility of soft sensor’s output. The input sensors are validated before performing a prediction by principal components analysis (PCA) model. These validated data are then employed for subsequent recursive partial least square (RPLS) prediction. Other than input sensor validation and modeling for prediction,a t-statistic confidence interval is created and the status of input sensors is offered. By using this self-validating soft sensor, we can determine the work condition of the soft sensor and take proper actions in real time. The usefulness of the proposed method is demonstrated through a case study of a wastewater treatment process.