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1

Path following control of the underactuated USV based on the improved line-of-sight guidance algorithm

Liu T., Dong Z., Du H., Song L., Mao Y.

Polish Maritime Research

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2017

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nr 1

3--11

EN

The path following control problem of the underactuated unmanned surface vessel (USV) is studied in this paper. An improved line-of-sight (LOS) guidance algorithm is proposed which can adjust adaptively based on the path following error. The global asymptotically stable path following controller is designed based on the nonlinear backstepping method and the Lyapunov stability theory. Firstly, the USV path following error model is established in the Serret-Frenet (SF) coordinate frame. The path following error in the inertial coordinate frame is transformed into the SF coordinate frame, which is used to define the path following control problem. Secondly, inspired by the traditional LOS guidance algorithm, the longitudinal path following error in the SF coordinate frame is introduced into the improved LOS guidance algorithm. This allows the algorithm to adjust adaptively to the desired path. Thirdly, in order to solve the underactuated problem of the USV path following control system, the tangential velocity of the desired path is designed as a virtual input. The underactuated problem is converted to a virtual fully actuated problem by designing the virtual control law for the tangential velocity. Finally, by combining backstepping design principles and the Lyapunov stability theory, the longitudinal thrust control law and the yaw torque control law are designed for the underactuated USV. Meanwhile, the global asymptotic stability of the path following error is proved. Simulation experiments demonstrate the effectiveness and reliability of the improved LOS guidance algorithm and the path following controller.

2

Potato waste treatment by microbial fuel cell. Evaluation based on electricity generation, organic matter removal and microbial structure

Du H., Li F., Huang K., Li W., Feng C.

Environment Protection Engineering

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2017

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Vol. 43, nr 1

5--18

EN

The performance of microbial fuel cell (MFC) in treating potato waste was evaluated using a two-chamber MFC supplied with potato liquid after mastication of market available fresh potato. Evaluation was conducted based on electricity generation, organic matter removal (CODCr, DOC and volatile fatty acids (VFAs)), and microbial structure on the anode and in the anodic solution of the reactor. Current density exhibited a trend that followed the concentration changes of organic matter in the solution, with its highest value being observed as 208 mA/m2. Effective removal of organic matter was also observed. By the end of the experiment, the removal for total COD reached about 84%. Bacterial structure analysis based on PCR, DGGE and sequencing indicated that more species were developed in the anodic solution than on the anode, with Proteobacteria, Firmicutes and Bacteroides being dominant. Geobacter, a well reported exoelectrogenic species, was found more predominant on the anode than in the anodic solution. The results thus indicated that simultaneous stabilization and electricity generation could be achieved when potato waste is treated in MFC.

3

Reaction kinetics and thiourea removal by ozone oxidation

Xie Q., Dong X., Huang W., Xu H., Du H.

Environment Protection Engineering

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2012

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Vol. 38, nr 4

87--98

EN

Thiourea is a toxicant which will bring some adverse effects to the public health. In the study, thiourea was degraded via ozonation process. The results show that the ozonation is an effective method to remove thiourea from wastewaters. When the ozone flow rate was 600 cm3*min-1, pH was 7.3, the temperature was 20 °C, 93.97% of thiourea (200 cm3 solution of 3 g dm-3) could be degraded after 9 min of reaction. The reaction order of ozonation of thiourea n was 0.11, and the reaction rate constant k = 0.4898 g0.89 (dm3)-0.89*min -1.

4

Takagi-Sugeno fuzzy control scheme for electrohydraulic active suspensions

Du H., Zhang N.

Control and Cybernetics

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2010

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Vol. 39, no 4

1095-1115

EN

The paper presents a new control strategy for active vehicle suspensions using electrohydraulic actuators based on Takagi-Sugeno (T-S) fuzzy modelling technique. As the electrohydraulic actuator dynamics is highly nonlinear, the T-S fuzzy modelling technique using the idea of "sector nonlinearity" is applied to exactly represent the nonlinear dynamics of electrohydraulic actuator in a denned region at first. Then, by means of parallel distributed compensation (PDC) scheme and Lyapunov method, a fuzzy HOO controller is designed for the T-S fuzzy model to optimise the suspension ride comfort performance, considering actuator input voltage saturation problem. The sufficient conditions for the existence of such a controller are derived in terms of linear matrix inequalities (LMIs). The advantage of this new control strategy for electro-hydraulic active suspensions is that it directly aims at optimising suspension performance with guaranteeing the closed-loop system stability. Thus, two-loop control strategy, where the inner loop is used to make the electrohydraulic actuator tracking a desired force (pressure, or displacement, etc.), is not necessary. In addition, the controller is simple in structure compared to the adaptive control algorithms. A numerical example is used to validate the effectiveness of the proposed approach. It is confirmed by the simulations that the designed controller can achieve better performance than the active suspension with optimal skyhook damper.

5

Study on an improved grey dynamic programming model

Shi H., Liu S., Fang Z., Du H.

Systems Science

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2009

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Vol. 35, no 1

75-79

EN

The purpose of our study is to present an improved grey dynamic programming model. Considering the uncertainty of information, the conception of grey dynamic programming is proposed in this paper. It also studies the programming model when the profit values are interval numbers and figure out the optimal solution by defining the superiority, inferiority and equipollence position degree. A case study is stated in the end to prove the applicability of the model. Our approach consists in treating profit value as positive interval grey number and we get the optimal strategy solution by means of defining standard interval grey number. As a result, an improved grey dynamic programming model is put forward. The algorithms of interval grey numbers and grey algebraic system of interval grey number should be improved further. The model is useful to realize optimal control in the process of uncertain manufacture such as production plan, storage, source distribution, investment and sorting problems. An algorithm based on position degree for the grey dynamic programming model is put forward.

6

Several extended analogues of Hilbert's inequalities

Du H., Miao Y.

Demonstratio Mathematica

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2009

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Vol. 42, nr 2

297-302

EN

By introducing the function [...] with real numbers alpha, beta, gamma we get several extended analogues of Hilbert's inequalities.

7

Monitoring of optical transmission loss through optical fiber embedded in SiC fiber reinforced aluminum composite during tensile test

Asanuma H., Du H.

Applied Mechanics and Engineering

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2000

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Vol. 5, no 1

7-18

EN

This paper describes a trial of monitoring fracture processes of SiC fiber reinforced aluminum composites with embedded optical fiber. It was embedded in composites reinforced with SiC fiber of different volume fractions by the interphase forming/bonding method using copper insert. These composites were tensile tested with measuring optical transmission loss. The results show that breakage of optical fiber starts at smaller strain than that of SiC fiber. The embedded optical fiber works as an optical path even after severe multiple fractures. Optical transmission loss is dependent on the number of optical fiber breakages. As fracture of SiC fiber enhances that of optical fiber and is reflected on optical transmission loss, fractures of SiC fibers can be detected by monitoring of optical transmission loss. It can also reflect the type of fracture process of the composite, that is, cumulative or non-cumulative.