简介:通过数学分析建立了EPS数学模型,应用线性PID控制建立了EPS控制模型.采用MATLAB/sim—ulink仿真软件建立了整个EPS的仿真模型.分别选取不同车速对EPS直线型助力特性进行了仿真实验,结果表明:当车速为0km/h时,EPS向汽车转向盘提供的最大助力转矩为20N·M,当车速为40km/h时,助力转矩减小为9N·M,当车速为80km/h时,助力转矩减为最小5N·M.为此,EPS直线型助力特性能贴近驾驶员对不同车速下的转向轻便性与高速行驶下良好路感性的需求.
简介:平板硫化机系统温度控制系统存在控制精度低,难以达到国家硫化标准等问题,提出了一种基于模糊自适应PID控制的平板硫化机温度控制系统,该系统以模糊自适应PID控制为理论基础,以PLC为控制平台,配以高性能的模块化外设,详细介绍了平板硫化机温度控制系统的硬件选型及软件设计。
简介:Long-periodpulsesinnear-fieldearthquakesleadtolargedisplacementsinthebaseofisolatedstructures.Todissipateenergyinisolatedstructuresusingsemi-activecontrol,piezoelectricfrictiondampers(PFD)canbeemployed.TheperformanceofaPFDishighlydependentonthestrategyappliedtoadjustitscontactforce.Inthispaper,theseismiccontrolofabenchmarkisolatedbuildingequippedwithPFDusingPD/PIDcontrollersisdeveloped.Usinggeneticalgorithms,thesecontrollersareoptimizedtocreateabalancebetweentheperformanceandrobustnessoftheclosed-loopstructuralsystem.Oneadvantageofthistechniqueisthatthecontrollerforcescaneasilybeestimated.Inaddition,thestructureisequippedwithonlyasinglesensoratthebasefloortomeasurethebasedisplacement.Consideringsevenpairsofearthquakesandnineperformanceindices,theperformanceoftheclosed-loopsystemisevaluated.Then,theresultsarecomparedwiththosegivenbytwowell-knownmethods:themaximumpossiveoperationofpiezoelectricfrictiondampersandLQGcontrollers.Thesimulationresultsshowthattheproposedcontrollersperformbetterthantheothersintermsofsimultaneousreductionofflooraccelerationandmaximumdisplacementoftheisolator.Moreover,theyareabletoreducethedisplacementoftheisolatorsystemsfordifferentearthquakeswithoutlosingtheadvantagesofisolation.
简介:Asymmetricstereoscopicvideocodingcantakeadvantageofbinocularsuppressioninhumanvisionbyrepresentingoneofthetwoviewsinlowerquality.Thispaperproposesabitallocationstrategyforasymmetricstereoscopicvideocoding.Inordertoimprovetheaccuracyofbitallocationandratecontrolintheleftview,aproportionalintegral-derivativecontrollerisadopted.Meanwhile,tocontrolthequalityfluctuationbetweenconsecutiveframesoftheleftview,aqualitycontrollerisadopted.Besides,afuzzycontrollerisproposedtocontrolthevariationinqualitybetweentheleftandrightviewsbycomparingthePSNRdisparityoftwoviewswithafixedthreshold,whichisusedtoquantizethebinocularpsycho-visualredundancyandadjustthequantizationparameter(QP)oftherightviewcorrespondingly.TheproposedalgorithmhasbeenimplementedinH.264/AVCvideocodec,andtheexperimentalresultsshowitseffectivenessinratecontrolwhilekeepingagoodqualityfortheleftview,andfewerbitsareallocatedfortherightviewsothattheoverallbitrateissavedby7.2%atmostwithoutthelossofsubjectivevisualqualityforstereoscopicvideo.