Flight and Hover Control System Design for a Mini-quadrotor Based on Multi-sensors

Zhongli Ma,Huixin Li,Yanming Gu,Zuoyong Li,Qianqian Li 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.2

Mini-quadrotor is difficult to control in the air due to its small size and light weight. This paper presentsthe flight and hover control system for a mini-quadrotor, including design and simulation of calculations and controllers. Firstly, the attitude and position of the mini-quadrotor are obtained by distributed multi-sensors. Since attitudecalculation of aircraft needs a number of combined rotations and vectors transformed by rotation, quaternionsare applied to express the attitude model. About error compensation of gyroscope and accelerometer, IMU_Updataalgorithm of Mahony filter are applied and improved to realize data fusion [1]. In order to realize accurate hoveringat certain position, UWB (UltraWideband) are applied to gain positional information of mini-quadrotor and correctthe antenna delay caused sensor error by base station positioning. The discrete Kalman filter of original data is usedto achieve the optimized estimation of the airborne position. Px4flow optical flow sensor is able to gets velocityinformation and avoid the noise problem, which is caused by differential of position data. Then, the mathematicalmodel of a mini-quadrotor’s flight and hover control system can be established. Herein, integral items are solved bythe integral separation and integral limiting to mitigate the serious overshoot and oscillation of the system caused bythe cascade PID. Finally, the simulation of the attitude controller and position controller are applied with the MATLABSimulink library. The simulation result shows that the designed attitude controller and position controller canenable the mini-quadrotor to fly smoothly, move in all directions and hover.

Multi-objective optimization model of high-temperature ceramic filter

Longfei Liu,Zhongli Ji,Xin Luan 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.5

Ceramic filters have been widely used in industrial engineering, such as the Shell coal gasification process (SCGP) and Integrated gasification combined cycle (IGCC), where the performance of the ceramic filter is achieved by the pulse jet. Residual pressure drop and gas consumption are directly related to reverse-flow pulse (RFP) pressure. However, in the process of operation, the RFP pressure is too large and gas consumption is too high. In this study, the effects of RFP pressures on filter’s cleaning efficiency, residual pressure drop, and gas consumption were investigated on a ceramic filter. Within a certain range, the cleaning efficiency gradually increased with increased RFP pressure. When the RFP pressure reached a certain value, the cleaning efficiency did not increase with increased pressure, showing a quadratic relationship between cleaning efficiency and RFP pressure. The residual pressure drop and RFP pressure were also in a quadratic relationship. Besides, the gas consumption increased linearly as increased RFP pressure according to the theoretical model. Based on the research results, a multi-objective optimization model of a ceramic filter was established with the cleaning efficiency as a constraint condition, gas consumption and residual pressure drop as the optimization objectives. A fuzzy decision-making method was used to solve the optimization model and calculate the residual pressure drop and gas consumption, from which the optimal RFP pressure was obtained.

Thermo-sensitive Amphiphilic Block Copolymer Poly (styrene-b-Nisopropylacrylamide) with Switchable Catalytic Activity Immobilizing Pectinase

Qin Jiang,Zhongli Lei 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.6

Pectinase was immobilized onto thermo-sensitive amphiphilic block copolymers poly(styrene-b-Nisopropylacrylamide)PS-b-poly(N-isopropylacrylamide)(PNIPAM) by covalent attachment. Biochemical studies have found that the stability of the PS-b-PNIPAM support is not impeded by the bound proteins despite that up to 242.5 mg of enzyme is immobilized per gram of carrier particles. The immobilized enzyme retained nearly 65% of its initial activity over 30 days, and the optimum temperature and pH also increased to the range of 60 ~ 70°C and 4.0 ~ 6.0, respectively. The immobilized enzyme also exhibited great operational stability, and more than 60%residual activity was observed in the immobilized enzyme after 10 batch reactions. Moreover, the lower critical solution temperature of the PS-b-PNIPAM support could be switched on or off by a small change in solution temperature. Thus, the immobilized pectinase could be recovered and showed durable activity during the recycle process.

Existence and uniqueness of positive solutions for second-order Sturm-Liouville and multi-point problems on time scales

Yanbin Sang,Zhongli Wei,Wei Dong 대한수학회 2011 대한수학회보 Vol.48 No.5

In this paper, a class of second-order boundary value problems with Sturm-Liouville boundary conditions or multi-point conditions is considered. Some existence and uniqueness theorems of positive solutions of the problem are obtained by using monotone iterative technique, the iterative sequences yielding approximate solutions are also given. The results are illustrated with an example.

Numerical Design and Performance Prediction of Low Specific Speed Centrifugal Pump Impeller

Yongxue, Zhang,Xin, Zhou,Zhongli, Ji,Cuiwei, Jiang Korean Society for Fluid machinery 2011 International journal of fluid machinery and syste Vol.4 No.1

In this paper, Based on Two-dimensional Flow Theory, adopting quasi-orthogonal method and point-by-point integration method to design the impeller of the low specific speed centrifugal pump by code, and using RANS (Reynolds Averaged N-S) Equation with a standard k-${\varepsilon}$ two-equation turbulence model and log-law wall function to solve 3D turbulent flow field in the impeller of the low specific speed pump. An analysis of the influences of the blade profile on velocity distributions, pressure distributions and pump performance and the investigation of the flow regulation pattern in the impeller of the centrifugal pump are presented. And the result shows that this method can be used as a new way in low speed centrifugal pump impeller design.

Characteristics of Pulse Gas Flow during the Pulse-jet Cleaning of a Ceramic Filter Candle

Xian-Yi Zhao,최주홍,Zhongli Ji 한국에너지학회 2013 에너지공학 Vol.22 No.4

The existence of the under-pressure accompanied by the oscillation of the pulse gas around the pulse nozzleis an interesting point as it improves the jet pulse effect by the entrainment of environmental clean gas whileits prolong forms a dead zone near just input position into the filter element. This phenomenon has been studiedby a few workers. Moreover, its mechanism or the origin has not been clearly unveiled so far. In order toapproach the real system to investigate the dynamic pulse flow gas, the experimental investigation of the transientpressure distribution of pulse gas around the pulse nozzle was carried out using commercial filter candle inthis study. Differential pressure around the pulse nozzle was carefully measured during the injection of the pulsegas and the peak of the differential pressure was traced to visualize the pulse gas flow. The formation of negativepressure during the pulse gas injection was observed around the pulse nozzle. And the pulse propagation ofthe oscillation wave was observed during the expansion of the pulse gas after leaving the pulse nozzle andits phenomena observed in the experimental results showing qualitatively good agreement with the simulationresults.

Experimental study of cured dust layer structure parameters based on semantic segmentation

Li Bin,Ji Zhongli,Mu Junfeng,Ren Yulin,Liu Zhen 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

The structural properties of the dust layer, including its thickness, porosity, and particle size distribution, play a critical role in ensuring the high precision and long-term stability of filter elements. However, observing these properties is challenging due to the weak adherence and cohesiveness of the layer. To address this issue, atomization thermosetting glue was used to achieve pre-curing, and the entire dust layer was cured with epoxy resin. After the sample was frozen and fractured using liquid nitrogen, the boundaries of the dust particles became plainly visible. Traditional binarization techniques were insufficient in identifying the edges of the dust particles since the grayscale values of particles and their environment partially overlap. As a result, a deep learning model based on the DeeplabV3+ network architecture was used to identify particles in the dust layer and achieved an accuracy of 90.99%. The research reveals that pulse-jet cleaning can double the thickness of the local dust layer on adjacent filter elements. Additionally, the surface morphology of the filter element significantly impacts the shape and thickness of the dust layer, causing it to change dramatically. Uneven thickness of the dust layer can result in a higher number of dust particles passing through the filter element membrane.

EXISTENCE AND UNIQUENESS OF POSITIVE SOLUTIONS FOR SECOND-ORDER STURM-LIOUVILLE AND MULTI-POINT PROBLEMS ON TIME SCALES

Sang, Yan-Bin,Wei, Zhongli,Dong, Wei Korean Mathematical Society 2011 대한수학회보 Vol.48 No.5

In this paper, a class of second-order boundary value problems with Sturm-Liouville boundary conditions or multi-point conditions is considered. Some existence and uniqueness theorems of positive solutions of the problem are obtained by using monotone iterative technique, the iterative sequences yielding approximate solutions are also given. The results are illustrated with an example.

Elaborately assembled core-shell structured metal sulfides as a bifunctional catalyst for highly efficient electrochemical overall water splitting

Guo, Yanna,Tang, Jing,Wang, Zhongli,Kang, Yong-Mook,Bando, Yoshio,Yamauchi, Yusuke Elsevier 2018 Nano energy Vol.47 No.-

<P><B>Abstract</B></P> <P>Low efficiency, short lifetimes, and limited kinds of catalysts are still three fundamental shortcomings that have plagued electrochemical water splitting. Herein, we rationally synthesized a cost-effective Co<SUB>3</SUB>S<SUB>4</SUB>@MoS<SUB>2</SUB> hetero-structured catalyst that has proven to be a highly active and stable bifunctional catalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline environment. The heterostructure was obtained <I>via</I> a first hydrothermal approach to obtain hollow Co<SUB>3</SUB>S<SUB>4</SUB> nanoboxes based on the ionic exchange reaction between Fe(CN)<SUB>6</SUB> <SUP>3−</SUP> of Co-Fe Prussian blue analogue (PBA) and S<SUP>2−</SUP> at 120 °C, and the subsequent <I>in situ</I> growth of MoS<SUB>2</SUB> nanosheets on the surface of Co<SUB>3</SUB>S<SUB>4</SUB> nanoboxes at an elevated temperature of 200 °C. The synergistic effects between the active and stable HER catalyst of MoS<SUB>2</SUB> and the efficient OER catalyst of Co<SUB>3</SUB>S<SUB>4</SUB>, as well as the morphological superiority of hollow and core-shell structures, endow Co<SUB>3</SUB>S<SUB>4</SUB>@MoS<SUB>2</SUB> with remarkable electrocatalytic performance and robust durability toward overall water splitting. As a result, the designed non-noble electrocatalyst of Co<SUB>3</SUB>S<SUB>4</SUB>@MoS<SUB>2</SUB> exhibits a low overpotential of 280 mV for OER and 136 mV for HER at a current density of 10 mA cm<SUP>−2</SUP> in an alkaline solution. Meanwhile, a low cell voltage of 1.58 V is achieved by using the heterostructure as both anode and cathode catalysts. This work paves the way to the design and construction of other prominent electrocatalysts for overall water splitting.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Co<SUB>3</SUB>S<SUB>4</SUB>@MoS<SUB>2</SUB> is prepared by using a two-step temperature-raising hydrothermal reaction process. </LI> <LI> Co<SUB>3</SUB>S<SUB>4</SUB>@MoS<SUB>2</SUB> is a core-shell, hollow cubic heterostructure with strong interfacial coupling. </LI> <LI> Co<SUB>3</SUB>S<SUB>4</SUB>@MoS<SUB>2</SUB> shows outstanding electrocatalytic activity and stability for overall water splitting. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Herein, we rationally synthesized a cost-effective Co<SUB>3</SUB>S<SUB>4</SUB>@MoS<SUB>2</SUB> hetero-structured catalyst that has proven to be a highly active and stable bifunctional catalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline environment.</P> <P>[DISPLAY OMISSION]</P>

An Improved Method for Extracting Bacteria from Soil for High Molecular Weight DNA Recovery and BAC Library Construction

Juan Liu,Jingquan Li,Li Feng,Hui Cao,Zhongli Cui 한국미생물학회 2010 The journal of microbiology Vol.48 No.6

Separation of bacterial cells from soil is a key step in the construction of metagenomic BAC libraries with large DNA inserts. Our results showed that when combined with sodium pyro-phosphate and homogenization for soil dispersion, sucrose density gradient centrifugation (SDGC) was more effective at separating bacteria from soil than was low speed centrifugation (LSC). More than 70% of the cells, along with some soil colloids,were recovered with one round of centrifugation. A solution of 0.8% NaCl was used to resuspend these cell and soil pellets for purification with nycodenz density gradient centrifugation (NDGC). After purification,more than 30% of the bacterial cells in the primary soil were extracted. This procedure effectively removed soil contamination and yielded sufficient cells for high molecular weight (HMW) DNA isolation. Ribosomal intergenic spacer analysis (RISA) showed that the microbial community structure of the extracted cells was similar to that of the primary soil, suggesting that this extraction procedure did not significantly change the the soil bacteria community structure. HMW DNA was isolated from bacterial cells extracted from red soil for metagenomic BAC library construction. This library contained DNA inserts of more than 200 Mb with an average size of 75 kb.