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non-smooth environment modeling and global path planning for mobile robots

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Journal of Central South University of Technology 2003年第3期10卷 248-254页

作者：邹小兵蔡自兴孙国荣 College of Information Science and Engineering Central South University Changsha 410083 China

An Approximate Voronoi Boundary Network is constructed as the environmental model by way of enlar-ging the obstacle raster. The connectivity of the path network under complex environment is ensured through build-ing the second order Approximate Voronoi Boundary Network after adding virtual obstacles at joint-close grids. Thismethod embodies the network structure of the free area of environment with less nodes, so the complexity of pathplanning problem is reduced largely. An optimized path for mobile robot under complex environment is obtainedthrough the Genetic Algorithm based on the elitist rule and re-optimized by using the path-tightening method. Sincethe elitist one has the only authority of crossover, the management of one group becomes simple, which makes forobtaining the optimized path quickly. The Approximate Voronoi Boundary Network has a good tolerance to the im-precise a priori information and the noises of sensors under complex environment. Especially it is robust in dealingwith the local or partial changes, so a small quantity of dynamic obstacles is difficult to alter the overall character ofits connectivity, which means that it can also be adopted in dynamic environment by fusing the local path planning.

关键词： non-smooth modeling Voronoi diagram path planning genetic algorithm

Research on semi-active control method of a building structure based on non-smooth control

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 425-432页

作者： Wang Qing Wang Jianhui Ma Kemao School of Mechanical and Electric Engineering Guangzhou University School of Astronautics Harbin Institute of Technology

This study investigates the effectiveness of the non-smooth semi-active control algorithm on suppressing the vibration performance of a building structure subjected to seismic waves. According to the Lyapunov stability theory, it has bene proven that the non-smooth semi-active control algorithm can achieve a finite-time stability of the vibration relative to the isolation layer of a building structure. Through numerical simulation of two buildings with different parameters subjected to the input of a seismic wave, the vibration conditions of passive control, LQR semi-active control and non-smooth semiactive control are compared and analyzed. The simulation results show that the non-smooth semi-active control algorithm has a better robustness and effectiveness in restraining the impact of earthquakes on the structure.

关键词： building structure isolation layer semi-active control non-smooth control vibration

Friction and Wear Study on Friction Pairs with a Biomimetic non-smooth Surface of 316L Relative to CF/PEEK under a Seawater Lubricated Condition

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Chinese Journal of Mechanical Engineering 2019年第4期32卷 47-60页

作者： Yingna Liang Dianrong Gao Bo Chen Jianhua Zhao School of Mechanical Engineering Yanshan University Qinhuangdao 066004China Liren College Yanshan University Qinhuangdao 066004 China Heibei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao 066004 China

Current studies of a seawater axial piston pump mainly solve the problems of corrosion and wear in a slipper pair by selecting materials with corrosion resistance, self-lubrication, and wear resistance. In addition, an appropriate biomimetic non-smooth surface design for the slipper pair can further improve the tribological behavior. In this paper, 316 L stainless steel and CF/PEEK were selected to process the upper and bottom specimens, and the biomimetic non-smooth surface was introduced into the interface between the friction pair. The friction and wear tests were performed on a MMD-5 A tester at a rotation speed of 1000 r/min and load of 200 N under seawater lubricated condition. The results indicate that the main friction form of the smooth surface friction pair corresponds to abrasive wear and adhesive wear and that it exhibits a friction coe cient of 0.05–0.07, a specimen temperature of 56 ℃, a high wear rate, and surface roughness. Pits on the non-smooth surface friction pairs produced hydrodynamic lubrication and reduced abrasive wear, and thus the plowing e ect is their main friction form. The non-smooth surface friction pairs exhibit a friction coe cient of 0.03–0.04, a specimen temperature of 48 ℃, a low wear rate, and surface roughness. The study has important theoretical significance for enriching the lubrication, friction, and wear theory of a seawater axial piston pump, and economic significance and military significance for promoting the marine development and the national defense military.

关键词： Biomimetic non-smooth surface 316L CF/PEEK Seawater lubrication Friction and wear

Weighted estimates for bilinear square functions with non-smooth kernels and commutators

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Frontiers of Mathematics in China 2020年第1期15卷 1-20页

作者： Rui BU Zunwei FU Yandan ZHANG Department of Mathematics Qingdao University of Science and TechnologyQingdao 266061China School of Mathematics and Statistics Linyi UniversityLinyi 276005China School of Mathematical Sciences Qufu Normal UniversityQufu 273100China

Under weaker conditions on the kernel functions,we discuss the boundedness of bilinear square functions associated with non-smooth kernels on the product of weighted Lebesgue ***,we investigate the weighted boundedness of the commutators of bilinear square functions(with symbols which are BMO functions and their weighted version,respectively)on the product of Lebesgue *** an application,we deduce the corresponding boundedness of bilinear Marcinkiewicz integrals and bilinear Littlewood-Paley^-functions.

关键词： Bilinear square function non-smooth kernel weight commutator BMO function

Effects of bionic non-smooth surface on reducing soil resistance to disc ploughing

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Science China(Technological Sciences) 2010年第11期53卷 2960-2965页

作者： CHIRENDE Benard SIMALENGA Timothy Emmanuel Key Laboratory for Bionic Engineering of Ministry of Education of China Jilin University Agricultural Research Council Institute for Agricultural Engineering(South Africa)

Past researches have shown that the non-smooth body surfaces of soil burrowing animals help to reduce soil resistance. In this research, this concept of bionic non-smooth surface was applied to disc ploughs and an experiment was conducted in an indoor soil bin to find out the effects of different bionic units on reducing soil resistance to disc ploughing. Horizontal force acting on the disc plough during soil deformation was measured using a 5 kN sensor. Convex and concave bionic units were used and the material used for making convex ones is ultra high molecular weight polyethylene (UHMWPE) which is hydrophobic. From the experiment results, higher or deeper bionic units always resulted in less soil resistance. Convex bionic units gave the highest resistance reduction reaching a maximum of 19% reduction (from 1715.36 N to 1383.65 N) compared to concave bi-onic units. Also, samples with a bionic unit density of 30% gave the highest resistance reduction compared to the other two, which were either plain or had 10% density. In conclusion, the concept of bionic non-smooth units can be applied to disc ploughs in order to reduce soil resistance.

关键词： bionics disc plough soil resistance convex units concave units non-smooth surface

Homogenization of Elliptic Problems with Neumann Boundary Conditions in non-smooth Domains

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Acta Mathematica Sinica,English Series 2018年第4期34卷 612-628页

作者： Jun GENG School of Mathematics and Statistics Lanzhou University

We consider a family of second-order elliptic operators {LE } in divergence form with rapidly oscillating and periodic coefficients in Lipschitz and convex domains in Rn. We are able to show that the uniform WI＇p estimate of second order elliptic systems holds for 2n/n＋1-δ〈p〈2n/n-1＋δ where δ 〉 0 is independent of ~ and the ranges are sharp for n = 2, 3. And for elliptic equations in Lipschitz domains,the W1,p estimate is true for 3/2 -δ 〈 p〈 3 ＋ δ ifn ≥ 4, similar estimate was extended to domains, the WI＇p estimate is true for nconvex domains for 1 〈 p 〈 ∞.

关键词： Homogenization elliptic non-smooth

Influence of Bionic non-smooth Surface on Water Flow in Antiskid Tire Tread Pattern

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Journal of Donghua University(English Edition) 2013年第4期30卷 336-342页

作者：王国林周海超杨建梁晨金梁 School of Automotive and Traffic Engineering Jiangsu University

Inspired by the idea that bionic non-smooth surfaces(BNSS)can reduce water flow resistance,the application of BNSS resistance reduction method in grooves surface of antiskid tire tread pattern has been investigated for increasing hydroplaning velocity of tire by using computational fluid dynamics(CFD)*** kinds of BNSS(riblet,convex dome,and dimple concave)are arranged in tire tread grooves to study the water flow resistance effects in grooves with non-smooth characteristics.A tire-water coupled model is established and CFD technique is applied to simulating *** simulation results show that BNSS grooves can reduce water flow resistance and increase mean flow rate by disturbing the eddy movement in boundary *** drag forces of riblet and dimple surface are lower and drainage capacity is higher than those of smooth surface under the same void space on tread pattern,but it is not in *** is a good way to promote antiskid performance without increasing additional groove space;extra tire-road noise production is therefore avoided due to groove space enlargement.

关键词： bionic non-smooth drag reduction tire hydroplaningCLC number:U463.341 O35Document code:AArticle ID:1672-5220(2013)04-0336-07

non-smooth Bifurcation of a Simply-Supported Rectangular Plate with an All-over Part-through Breathing Crack

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Non-smooth Bifurcation of a Simply-Supported Rectangular Pla...

Bifurcations and Sequences of Elements in non-smooth Systems Cycles

第九届全国动力学与控制学术会议

作者： Zhi-jie Zhang Li-hua Chen Wei Zhang College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology

Breathing crack of the plate is an important fault observed in the big machinery, which can lead to catastrophic *** paper addresses the influence of the breathing crack on the non-smooth nonlinear dynamics characteristics of *** the aim of comparison,the nonlinear dynamics characteristics of open-crack model, no-crack model and breathing-crack model are investigated at the same *** all-over breathing crack on the plate surface having arbitrary depth and location is assumed to be non-propagating and parallel to one side of the plate.A line spring

关键词： plate breathing crack non-smooth bifurcation

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American Journal of Computational Mathematics 2013年第3期3卷 222-230页

作者： Ivan Arango Fabio Pineda Oscar Ruiz Laboratorio de CAD/CAM/CAE Universidad EAFIT Medellin Colombia Mechatronics and Machine Design Group Universidad EAFIT Medellin Colombia

This article describes the implementation of a novel method for detection and continuation of bifurcations in non-smooth complex dynamic systems. The method is an alternative to existing ones for the follow-up of associated phenomena, precisely in the circumstances in which the traditional ones have limitations (simultaneous impact, Filippov and first derivative discontinuities and multiple discontinuous boundaries). The topology of cycles in non-smooth systems is determined by a group of ordered segments and points of different regions and their boundaries. In this article, we compare the limit cycles of non-smooth systems against the sequences of elements, in order to find patterns. To achieve this goal, a method was used, which characterizes and records the elements comprising the cycles in the order that they appear during the integration process. The characterization discriminates: a) types of points and segments;b) direction of sliding segments;and c) regions or discontinuity boundaries to which each element belongs. When a change takes place in the value of a parameter of a system, our comparison method is an alternative to determine topological changes and hence bifurcations and associated phenomena. This comparison has been tested in systems with discontinuities of three types: 1) impact;2) Filippov and 3) first derivative discontinuities. By coding well-known cycles as sequences of elements, an initial comparison database was built. Our comparison method offers a convenient approach for large systems with more than two regions and more than two sliding segments.

关键词： Bifurcation Sequences non-smooth Systems Limit Cycles Dynamic Systems